OVERVIEW
Subpart I of this section discusses the characteristics and treatment of severe dysarthria, apraxia, and aphasia, the medical conditions most closely associated with the need for AAC interventions. Subpart II discusses the clinical decision making process by which the need for specific AAC devices is determined. It delineates the process that SLPs undertake in ascertaining the need for AAC treatment, i.e., whether an AAC device is required and, if so, which device will enable the individual to meet the treatment goals specified in his or her treatment plan. In addition, this section describes the nine key clinical indicators used to determine the specific category of AAC devices and the specific AAC device and accessories that are appropriate for an individual. The decision making process is outlined in outlined in Figure 1. These clinical indicators and relationship with device categories are identified in Table 4. The narrative report is then sent to the beneficiary’s treating physician. The physician is responsible for prescribing AAC treatment and completing the certificate of medical necessity.
AAC devices generally are recognized as appropriate treatment for, and have become standard practice in, the treatment of individuals with severe dysarthria, apraxia, and aphasia. These speech (dysarthria, apraxia) and language (aphasia) impairments are associated with a variety of neurologic conditions, the most common including amyotrophic lateral sclerosis (also known as ALS or Lou Gehrig’s Disease), cerebral palsy, locked-in-syndrome, multiple sclerosis, Parkinson disease, brain-stem stroke, cortical stroke, progressive aphasia, and traumatic brain injury. Each of these conditions can adversely affect the ability of individuals to communicate during the course of daily activities. When these conditions are severe, the preferred treatment in speech-language pathology is utilizing an AAC device. One important approach to AAC treatment is the use of speech output communication devices, which can enable an individual who is unable to produce intelligible speech to ‘speak’ using machine-generated synthetic speech. Thus, for some individuals with these conditions, AAC devices provide the primary means to overcome severe speech and language impairments and thereby to communicate effectively.
Dysarthria, apraxia and aphasia are speech and language impairments that each adversely affects the speech production process. The ‘communication chain’ model describes speech production as a sequential process involving five distinct physical structures and functions that are inter-connected like links of a chain (Crystal and Valley, 1999). Dysarthria, apraxia and aphasia each ‘breaks’ a different link of the communication chain, adversely affecting the ability to communicate by using speech.
The communication chain begins with an idea or thought, which occurs within the memory storage structures of the brain. The formulation of an idea or thought is called the ‘pre-linguistic link.’ It suggests that thoughts and ideas exist independently of language (Pinker, 1994).
A second, separate link gives the idea a linguistic shape. ‘Language’ or ‘linguistic’ encoding is the second link in the communication chain. These involve pragmatic (communicative intent), semantic (meaning), syntactic (word order), and phonological (sound) processing, transforming an idea into the substantive message to be communicated. When the linguistic encoding process is completed, the message is fully specified in terms of its communicative intent, its meaning, its word order, and its sound.
The third link is motor programming, which converts the linguistically encoded message into a form that can be conveyed to some external receiver, such as the ear of a communication partner. Motor programming takes the linguistic message and converts it to a set of instructions used to command the muscles used in speech. Motor programming can be compared to a software program which contains the operating instructions for the hardware ( the vocal organs and associated nerves) required for speech production.
Once the message is programmed for speech production, the fourth link of the chain, the motor execution system, is activated to implement the program. The motor system is comprised of the motor areas of the brain and nerves which run from the brain to the muscles of the speech mechanism. The system also includes a network of nerves that provides feedback to the brain to ensure the motor instructions are being executed correctly, and as needed, to modify the instructions.
Finally, the fifth link in the chain is speech production, which is the result of the integrated functioning of three sub-systems: respiration, phonation, and articulation. The respiratory system provides the power source for speech. The movements of the muscles inside the chest cavity force air either into or out of the lungs. The phonatory component of speech involves the action (vibration) of the vocal folds within the larynx. The vibration or non-vibration of the vocal folds, as well as their length affect pitch, loudness, tone of voice, as well as the ability to produce particular sounds. The articulatory component of speech production involves various structures within the mouth, including the tongue, lips, palate, and teeth. The airstream, set in motion by the action of the lungs and chest muscles, and which may or may not have vibration super-imposed on it by the action of the larynx, is shaped by the various articulatory structures to produce the different sounds of speech. To produce intelligible speech, each link of the communication chain must be working properly, in a finely controlled sequence, and in a very short span of time.
Dysarthria, apraxia, and aphasia, the conditions that give rise to AAC intervention needs, ‘break’ different links of the communication chain. Aphasia is a disorder affecting the first two links: those involved in the formulation of meaningful expressions. Apraxia is a disorder of the third link: the retrieval and implementation of an articulatory program (motor programming). Dysarthria is an impairment to the fourth and fifth links: the subsequent action of the speech production system to give linguistic units phonetic reality (motor execution and speech production). In some individuals, only one link of the chain is disrupted. In many others, however, more than one link is affected by the individual’s primary disease or condition. The characteristics of each of the conditions requiring AAC interventions are discussed more fully below.
The dysarthrias refer to a widely varying group of motor speech disorders associated with many neurologic conditions ( ALS, multiple sclerosis, Parkinson disease). The perceptual and physiologic characteristics of the dysarthrias are well described, and a variety of treatments that increase the intelligibility and naturalness of speech are now part of standard practice in speech-language pathology. For some individuals with severe dysarthria, regaining use of natural speech to meet communication needs in daily living is not a realistic goal of intervention. For this small number of individuals, AAC intervention is the most efficacious treatment focus.
Dysarthria is a collective term used to describe a group of speech disorders caused by disturbances in muscular control resulting from damage to the central and/or peripheral nervous system (Darley, Aronson, & Brown, 1975; Duffy, 1995; McNeil, 1997; Yorkston, Beukelman, Strand, & Bell, 1999). Depending on the location of the central and/or peripheral nerve damage, an individual may manifest a variety of motor impairments including weakness, slowness, incoordination, or altered muscle tone, which in turn disrupt the respiration, phonation, articulation, resonance, and prosody required for intelligible speech. By definition, dysarthria does not affect receptive communication abilities (the ability to understand what is spoken or written). The effects of dysarthria on speech production can range from mild speech production problems to a complete inability to speak intelligibly or even to make guttural sounds, a condition known as anarthria. Dysarthria and anarthria occur in both children and adults. The condition can be stable, improving, or degenerative.
The prevalence of dysarthria in the United States must be extrapolated from demographic data detailing the incidence of neuromuscular diseases associated with dysarthria, such as cerebral palsy, Parkinson disease, amyotrophic lateral sclerosis (ALS), traumatic brain injury, brain-stem stroke, and later stages of multiple sclerosis, because dysarthria often is a symptom of these diseases/conditions. Table 1 offers an overview of each, depicting the typical course, age of onset, symptoms and prevalence of dysarthria among people with the disease or condition. It should be noted, however, that dysarthria also may arise from other diseases with neurologic sequelae, including tumor, postoperative complications, inflammatory and metabolic diseases, and other sporadic degenerative neurology conditions (Yorkston et al, 1999).
Table 1: Diseases And Conditions Associated With Severe Dysarthria
.
Condition |
Course |
Age of Onset |
Motor Symptoms |
Prevalence of Dysarthria |
Cerebral palsy |
Stable |
Congenital |
Spasticity, flaccidity, ataxia, and/or dyskinesia |
31% to 88% |
Amyotrophic Lateral Sclerosis |
Rapidly progressive |
Mean age of onset mid-50’s |
Degeneration of motor neurons. Symptoms depend upon the course of disease |
75% of patients are unable to speak at time of death |
Multiple Sclerosis |
Slowly progressive |
Between 18 - 40 years of age |
Variable depending on the size, age, activity, location of CNS lesions |
40% to 44% report speech affected; Less than 20% report severe dysarthria |
Parkinson Disease |
Slowly progressive. |
Mean age 55 years |
Resting tremor, rigidity, paucity of movement, impaired postural reflexes, dysarthria |
22% - moderate dysarthria, 29% - severe dysarthria |
Brain-stem Stroke |
Improving with later stabilization |
Age 45-64: 998 per 100,000 Age 65+: 5,063 per 100,000 |
Variable depending on the site of lesion and amount of damage to the central nervous system |
Severe dysarthria to anarthria for individuals with ‘locked-in syndrome |
Traumatic Brain Injury |
Improving with later stabilization |
Bimodal population. Peaks at ages 15-24 and 65-75 |
Variable depending on nature of injury |
60% in acute rehab setting to approximately 10% long-term post-onset |
.
- AAC Devices As Treatment For Dysarthria
Whether AAC treatment is recommended for someone with dysarthria depends upon the severity of their speech impairment and the projected course of their disease or condition. An SLP determines individual need through a motor speech assessment consisting of five parts including a case history, the examination of the oral mechanism during nonspeech activities, assessment of perceptual speech characteristics, assessment of intelligibility, and acoustic physiologic analyses (Duffy, 1995). Typically, an SLP uses a severity-based classification system as a guide for selecting an appropriate treatment for dysarthria. Staging is a term common in medical practice that creates classifications for the purpose of identifying appropriate and effective interventions for different severity levels of a disorder. Table 2 summarizes five stages of severity for the dysarthrias. Based on several factors, including the natural course of the disease or condition and the severity of the speech disorder, clinicians can determine when (and what type of) AAC treatment is necessary. (Yorkston et al, 1999).
As noted below, Stages I, II, and III require techniques that focus on strengthening the speech musculature and improving articulation, voicing, and overall intelligibility. For individuals with severe dysarthria or (Stages IV or V), AAC intervention is recognized as the most effective course of treatment (National Joint Committee on the Communicative Needs of Persons with Severe Disabilities (1992)). At Stage IV, AAC treatments often include no-tech and low-tech techniques. In addition, AAC devices may be recommended for use in social and community contexts, for telephone use, and with unfamiliar partners. At Stage V, when speech is no longer functional, most individuals with dysarthria require the use of electronic AAC devices and other accessories to enable them to communicate effectively.
Table 2: Stages Of Severity For Dysarthria
Description |
Treatment Approaches |
|
Stage I |
No detectable speech disorder |
Educate the patient, family, and caregivers regarding the course of the disease and future communication needs and options. |
Stage II |
Obvious speech disorder with intelligible speech |
Reduce the impairment through strengthening muscles related to speech production and range of motion exercises. |
Stage III |
Reduction in speech intelligibility |
Same as above. In addition, introduce to the speaker and listeners to strategies that improve intelligibility (slower rate of speech, first-letter cueing). |
Stage IV |
Residual natural speech and AAC |
Supplement natural speech and teach compensatory strategies to individual and their partners. Introduce AAC treatment, such as an AAC device. |
Stage V |
Loss of useful speech |
Provide a multi-purpose AAC device and accessories as well as non-electronic (back up) strategies. |
After determining the need for AAC treatment, the SLP, often in collaboration with other allied health professionals, continues the assessment process in order to identify the specific type of AAC treatment required and type of device and accessories needed. Section II, below, contains additional information about the AAC decision making process, i.e., how the SLP considers these data in making a recommendation for an AAC device.
Individuals with severe dysarthria often employ a variety of AAC techniques to improve or restore their ability to communicate. Treatment may include non-electronic communication aids (e.g., alphabet boards) and electronic devices that provide speech output. The purpose of AAC treatment is to establish effective independent communicative capabilities so that the person with severe dysarthria can meet the communication needs that arise in the course of daily activities (Beukelman et al., 1985; Beukelman & Mirenda, 1998; Kearns & Simmons, 1988; Rosenbek & LaPointe, 1985; Beukelman & Yorkston, 1977). The characteristics of common conditions or diseases that cause dysarthria and the treatment effectiveness of AAC devices are described below.
Efficacy of AAC Devices as Treatment for the DysarthriasAmyotrophic Lateral Sclerosis. Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurological disease involving the motor neurons of the cortex, brainstem, and spinal cord. The classical picture of ALS is one of motor loss with preserved sensation and cognition. AAC treatment, including the use of AAC devices, has long been a part of management of this disease (Adams, 1966; Kazandjian, 1997; Yorkston, Miller & Strand, 1995). At the ALS Standard of Care Consensus Conference, AAC intervention was recognized as the standard of care for treatment of the communication impairments associated with ALS. (R. Sufit, 1997).
A number of studies demonstrate that AAC devices are an effective treatment for the communication problems experienced by individuals with ALS. In a cross sectional study of 110 individuals with ALS seen in an outpatient clinic, Yorkston and her colleagues identified six groups of people with ALS based on speech, upper extremity and lower extremity functioning. Each group presented with a different set of symptoms affecting communication (speech and writing), given the course of the disease process. According to the study, Group 1 (45%) was comprised of individuals who had both adequate speech and upper extremity function; thus, management involved monitoring for potential deterioration. Group 2 (20%) included individuals with adequate speech but poor hand function. This group required assistive technology for written communication. Group 3 (16%) included individuals with severe dysarthria who had adequate hand function and mobility. This group often used handwriting for face-to-face communication but required AAC devices when interacting in groups and to talk on the telephone. In consideration of the progressive nature of the disease process, AAC devices with a range of access options (direct selection, scanning) were recommended for individuals in this group. Individuals in Group 4 (10%) had insufficient speech, adequate hand function, and were non-ambulatory. They used handwriting, direct selection AAC devices (low and high tech), typewriters, and computers. Equipment was mounted on wheelchairs and beds, or placed on tables. Group 5 (2%) included individuals who had severe dysarthria, poor hand function, and good mobility. These individuals required lightweight, portable AAC devices with features that included alternate access modes. Finally, Group 6 (7%) had severe dysarthria, poor hand function, and poor mobility. This group often required AAC devices that enabled them to use switches and scanning techniques for access. Over the course of the disease process, it is typical for individuals to move from Group 1 to other groups. (Yorkston, Strand, Miller, Hillel, & Smith, 1993).
Parkinson Disease. Parkinson disease is a relatively common slowly progressive disease of the central nervous system, especially the basal ganglia. Although speech disorders typically do not occur early in the disease, as the disorder progresses, about two thirds of individuals with Parkinson disease have reported changes in speech, rate, and voice. (Hartelius & Svensson, 1994). Simple, non-electronic AAC systems have a long history of successful use with this population (Beukelman & Mirenda, 1998; Helm, 1979; Lang 1983; Yorkston, Beukelman, Strand & Bell, 1999). Delayed Auditory Feedback stategies are sometimes effective in slowing speaking rates and improving intelligibility while preserving the naturalness of speech. (Adams, 1966). Only a small minority of these individuals require speech output AAC devices.
Multiple Sclerosis. Multiple sclerosis (MS) is a demyelinating disease of the central nervous system most typically diagnosed in young adults, ages 18 to 40 years (Yorkston, Miller & Strand, 1995). The two most common forms of MS are relapsing-remitting (approximately 40% of cases) and chronic progressive (20% - 30% of cases). It has been estimated that there are 250,000 to 500,000 cases of MS in the United States (Scheinberg & Smith, (1987). Approximately 40% of all patients with MS experience dysarthria which typically presents as spastic-ataxic dysarthria along with reductions in voice intensity and disturbances in vocal quality (Merson & Rolnick, 1998). In a survey of 460 patients with Parkinson disease or MS, Hartelius and Svensson (1994) found that 44% of the MS patients had experienced impairment of speech and voice after the onset of their disease. Their speech disorder was considered one of their greatest problems by 16% of the patients with MS, however only 2% of the patients surveyed had received any speech intervention.
Locked-in-Syndrome. The term ‘locked-in syndrome’ is used to describe a condition in which the patient is mute but consciousness may be preserved, and the only volitional motor activity is vertical eye movements and blinking. It is usually of vascular origin with the majority of cases experiencing a brainstem infarct or hemorrhage (Haig, Katz, & Sahgal, 1987; Patterson & Grabois, 1986). Initially, only simple blink systems to indicate yes/no or to generate messages using Morse code were reported (Feldman, 1971; Gallo & Fonanarosa, 1989; Gauger, 1980; Kenny & Luke, 1989). For example, Jean Dominique Bauby, who had been the editor of Elle magazine in France, and who developed locked in syndrome following a stroke, wrote a best selling memoir, The Diving Bell and the Butterfly (1997) that described his condition. The title of this book is itself a metaphor for locked-in-syndrome: the body, trapped in a diving bell, while the mind and the imagination, can still soar like a butterfly. Bauby’s book was written using a non-electronic eye-blink process. ‘Its a simple enough system. You read the alphabet . . . until with a blink of my eye, I stop you at the letter to be noted. The maneuver is repeated for the letters that follow . . . [until] you have a whole word, and then fragments of more or less intelligible sentences.’ Despite its laboriousness, Bauby was clear in his gratitude for having even this crude means of communication. He wrote: ‘The identity badge pinned to Sandrine’s white tunic says ‘Speech Therapist,’ but it should read ‘Guardian Angel.’ She was the one who set up the communication code without which I would be cut off from the world.’ (Bauby, 1997).
In patients with incomplete locked-in syndrome, alphabet boards have been documented as effective in supplementing natural speech (Beukelman & Yorkston, 1977). As more technology is becoming available, personal testimonies of people with locked-in-syndrome utilizing AAC devices are appearing in the mainstream literature. For example, Julia Tavalaro’s book ‘If you want to talk with me, I look up for Yes,’ chronicles her experience of being considered ‘brain-dead’ for six years after a brain stem stroke, during which she was paralyzed without a way to communicate. She says, ‘No one knows how dark the night is until you can’t speak into it.’ (Tavalaro & Tyson, 1997). Thirty years later, Ms. Tavalaro is publishing her poems and communicating with family and friends from her residence on Roosevelt Island, New York. Another example is an engineer who experienced a brainstem stroke in his mid 50s. Even after he had regained some natural speech he commented about his AAC device: ‘I only used one finger to touch any key but it was, and even today, still is at times, a ‘sanity saver’ to me!
. . . I can only too well envisage my world without this little ‘workhorse.’’ (Montgomery, 1991, p.75).Traumatic Brain Injury. Traumatic brain injury (TBI) occurs most frequently as a result of a motor vehicle accident or a fall. Injuries to the head that result in temporary or permanent brain damage are quite common, however, only about one-third of those with TBI ever experience dysarthria, and only a small proportion of those require AAC devices (Sarno, 1986). As in many other populations, simple non-electronic AAC techniques were the first to be reported (Beukelman & Yorkston, 1977; Keenan & Barnhart, 1993).
Issues related to the AAC management of individuals with TBI are complex (DeRuyter & Becker, 1988; DeRuyter & Kennedy, 1991; DeRuyter & LaFountaine, 1987). Cognitive limitations during early phases of recovery make the operation of complex AAC devices difficult for many. Changing cognitive and motor performance may make selection of an appropriate long-term AAC system ill-advised until later in the recovery process. Thus, the focus of intervention has shifted from providing single long-term AAC devices to providing a series of AAC techniques designed to meet current communication needs. These transitions are illustrated in a case report of an adolescent with TBI followed for 3 years, initially to establish a yes/no system, later to use an electronic AAC device, and finally to re-establish natural speech (Light, Beesley & Collier, 1988). Other successful interventions are reported in complex cases wherein cognitive issues are challenging. (DeRuyter & Donoghue, 1989).
Cerebral Palsy. Cerebral palsy refers to a developmental neuromotor disorder that is the result of a non-progressive abnormality of the developing brain. Dysarthria is common. Several types of motor problems may be present depending on the location of the brain lesion. Associated disorders are also common, including cognitive impairment, vision problems, hearing impairments, and seizure activity. (Beukelman & Mirenda, 1998). Although prevalence statistics for adults are difficult to obtain, studies suggest that the majority of the most severely affected individuals survive to adulthood. (Evans, Evans & Alberman, 1990). AAC interventions, including use of electronic devices, have long been recognized as appropriate for individuals with cerebral palsy. Research related to the use of AAC interventions by individuals with cerebral palsy as well as individual case studies are discussed in sub-section b (‘stable (improving) conditions’) below.
Progressive (degenerating) conditions. The most research to date has been done with ALS because it results in the largest proportion of individuals who are unable to speak at some point during the disease process. For example, in a retrospective chart review of treatment data for 126 persons with ALS (61 males; 65 females), Guttman and Gryfe, (1999) found that, 72% of the men and 73% of the women had begun AAC treatment. There were clear patterns of preferences, by gender, with respect to the type and nature of augmentative intervention received. Women preferred speech output systems almost twice as often as did men (49% of women; 26% of men). Women used low tech options ( alphabet boards) almost three times as often as men (20% of women; 6% of men). Men chose high tech AAC devices with extensive language storage capacity that could support written communication and spoken communication almost three times more often than did women (34.9% of men; 12.1% of women). These data suggest gender differences in the use of AAC devices among people with ALS.
Studies of user satisfaction for individuals with ALS also are becoming available (Mathy, Yorkston & Gutmann, in press). Based on interviews using in-depth rating scales, individuals with ALS reported generally high levels of satisfaction (ratings ranging from 5 to 7 on a 1 to 7 scale with 1 being the least satisfied and 7 being the most satisfied) with their AAC devices in meeting their daily communication needs. Individuals expressed the highest level of satisfaction with devices that provided extensive language storage that supported the ability to create, store and retrieve lengthy messages pertaining to needs/wants, and sharing information with their family and care providers. Subjects were less satisfied (average rating 4) with their high tech AAC devices for conversation. Because conversation is a rapid exchange of ideas, opinions, etc. between at least two people, it is likely that subjects’ poorer evaluation of their augmentative communication methods for use in conversation reflects the reduced message construction rate imposed by their severe motor impairments.
Beukelman, Kraft and Freal (1985) surveyed 656 persons with a diagnosis of MS regarding the presence of expressive communication disorders and the frequency of use of AAC devices. They found that 23% of those surveyed reported the presence of speech deficits with 4% of the sample indicating that their speech disability was so severe that strangers could not understand them. Of the group reporting severe speech impairments, 28.8% indicated that they used an augmentative communication device.
Stable (improving) conditions. Reports of individuals with locked-in syndrome followed longitudinally have noted progress from individual communication based on minimal eye movement to successful use of computerized AAC devices (McGann & Paslawki, 1991; Simpson, Till & Goff, 1988). Culp and Ladtkow (1992) followed a series of 16 individuals with locked-in syndrome for at least 1 year to document their AAC needs. At follow-up, half were able to use direct selection to access communication devices and half relied on visual or auditory scanning techniques. Only 20% of cases in this study chose not to pursue electronic communication options.
Longitudinal research tracking the AAC needs of individuals with TBI has been reported. Ladtkow and Culp (1992) followed 132 individuals with TBI over an 18-month period. Approximately 20% were judged to be ‘non-speaking’ at some point in their recovery. Of these individuals, 55 % regained function speech while the remainder did not. Although dysarthria generally resolves during the early and middle stages of recovery, severe motor speech deficit may persist (Dongilli, Hakel, & Beukelman, 1992). The implication of these findings is that for a small number of individuals with TBI, the need for AAC devices may extend over long periods of time. AAC use is critical, because it allows individuals with TBI to participate effectively in their rehabilitation programs as well as meet their ongoing communication needs.
Studies of the AAC needs of individuals with cerebral palsy also are available. In a survey of 66 non-speaking clients with cerebral palsy, the majority used simple augmentative communication systems (57.5%) and accessed them through direct selection in 62% of the cases (LaFontaine & DeRuyter, 1987). Research into the effectiveness of AAC devices has focused on the features of the systems, particularly identifying those features that are most beneficial. For example, Angelo (1992) compared three different scanning modes and found that individuals with different types of cerebral palsy benefited from different scanning modes. Light and Lindsay (1992) studied message-encoding strategies and found that letter-encoding resulted in more accurate learning than iconic techniques. McNaughton and Tawny (1993) studied two different spelling strategies and found that although learning rates were the same, one technique showed a retention advantage.
Treatment studies focusing on learning to use AAC devices have recently received considerable attention. Learning has been documented in groups of individuals (Udwin & Yule, 1990, 1991a & b), single-case research designs (Dattilo & Camerata, 1991; Glennen & Calculator, 1985), and case reports (Ferrier, 1991, Goossens, 1989; Spiegel, Benjamin & Siegel, 1993). Outcomes are documented using a variety of parameters, including conversational participation (Dattilo & Camarata, 1991), increased spontaneously initiated requests (Glennen & Calculator, 1985), and percentage of hours in the day that systems were used (Culp, Ambrosi & Berniger, 1986).
In addition, there are a plethora of case examples of individuals with cerebral palsy and severe dysarthria who use AAC devices effectively in their daily lives. Bob Williams, Rick Creech, Peg Johnson, Gus Estrella, Mick Joyce, Jennifer Lowe, Michael Williams, Gordon Richmond, and Bill Rush are some of the men and women ranging in ages from 20 to 65 who lecture and have written extensively about the impact of AAC devices on their lives. All are productive and highly respected members of their communities. They represent just a small sample of the growing number of individuals with cerebral palsy in the United States who use AAC devices effectively to do things they would otherwise not be able to accomplish.
Summary of Evidence Supporting the Effectiveness of AAC Devices in Severe Dysarthria
In summary, motor speech disorders such as severe dysarthria cause profound adverse effects on the ability to meet the communication needs that arise in the course of daily activities. The limitations associated with severe dysarthria have been described as causing ‘not a loss of life, but a loss of access to life,’ (Beukelman and Garrett, 1988). The inability to speak severely affects an individual’s ability to maintain family roles, participate in family activities, and maintain personal independence. It also leads to significant isolation and precludes the very communication -- about home, family, health, and social matters -- that research recognizes is typical of older adults. (Stuart, Vanderhoof and Beukelman, 1993).
When working with adults with severe dysarthria, clinicians quickly begin to appreciate the fact that no one "wants" to use AAC devices. One woman with severe dysarthria associated with ALS told her clinician, ‘You above all people should know that I’d rather be talking, but I must admit that this thing [the AAC device] is my lifeline to the world." This client’s mixed feelings reflect both the extent of her loss and an appreciation of the importance of communication, albeit via technology. In sum, the evidence presented here supports the fact that carefully selected AAC devices are a reasonable, necessary, and effective treatment for individuals with severe dysarthria.
Apraxia is a deficit in the third link of the communication chain, where planning and programming of the sequence of movements for speech occur. Acquired apraxia of speech is a speech disorder resulting from brain injury that is characterized by changes in articulatory features (e.g.,. multiple speech sound errors that occur inconsistently), movement characteristics (e.g., groping for the correct articulatory posture), and disturbances in prosody (slow rate and unusual stress patterning). The most common cause of apraxia is stroke although it also may occur with brain damage resulting from a tumor or traumatic brain injury. In a recent neuro-imaging study of individuals with stroke with and without apraxia, a specific area of the brain was implicated. Individuals with apraxia had lesions that included a discrete region of the left precentral gyrus of the insula, a cortical area beneath the frontal and temporal lobes (Dronker, 1996). This area was completely spared in all individuals who did not exhibit apraxia. Recent literature also contains reports of individuals with primary progressive aphasia, a disorder of unknown etiology in which there is a history of isolated speech and language deterioration (Didic, Ceccaldi, & Poncet, 1998; Hart, Beach, & Taylor, 1997; Southwood & Chatterjee, 1998). Primary progressive aphasia is associated with apraxia of speech and non-fluent aphasia in approximately 30% of cases (Rogers & Alarcon, 1997). Many of these individuals progress to the point that they are unable to communicate without the assistance of AAC devices.
Evidence confirms that apraxia is a motor rather than linguistic deficit (Duffy, 1995; McNeil, Robin, & Schmidt, 1997; Yorkston, Beukelman, Strand, & Bell, 1999). This distinction is important because of its implication for planning treatment. Because of the specific nature of their deficits, it can be argued that individuals with apraxia should receive different types of treatment than individuals with aphasia (Tonkovich & Peach, 1989). For example, persons with apraxia in the absence of aphasia would be more likely to use spelling based AAC devices because their linguistic processing abilities are not affected. Whereas persons with apraxia and concomitant aphasia, may need devices that provide the ability to combine picture symbols to construct messages due to impairments in linguistic abilities (i.e., spelling, syntax) associated with aphasia. It is important to determine the relative contribution of apraxia and aphasia and design treatment programs that fit the disorder (Yorkston et al., 1999).
Apraxia rarely occurs as an isolated disorder. In other words, it co-occurs with aphasia, dysarthria, or both. In an early report (Wertz, 1985), apraxia was estimated to occur in isolation only approximately ten percent of the time, with aphasia 85 percent of the time and with dysarthria approximately 5 percent of the time. When apraxia is severe, it is nearly always is associated with aphasia. Thus, it is particularly important to note the co-occurrence of apraxia and aphasia because of the consequences for AAC intervention. Exact statistics about the prevalence of apraxia are not available. But because aphasia and apraxia typically co-occur, apraxia can be considered a subset of aphasia occurring in perhaps a quarter of cases with aphasia.
The past 30 years have seen remarkable progress in our understanding and treatment of apraxia/dyspraxia of speech. As a clinical entity, apraxia, has been defined and distinguished from aphasia and dysarthria. Understanding the nature of apraxia has allowed SLPs to develop more effective treatment programs to restore use of natural speech. At the same time, increased attention has been given to the treatment needs of those individuals with severe apraxia, for whom the return of natural speech is not possible. For these individuals, the professional literature confirms the effectiveness of AAC intervention in general and AAC devices in particular.
AAC intervention is recognized as appropriate treatment for individuals with severe apraxia who are unable through traditional speech-language treatment methods to restore natural speech and communication needs arising in their daily activities (Duffy, 1995 ). A speaker with severe apraxia may produce no speech or perhaps a few stereotypical utterances that may or may not be meaningful. Speakers also may exhibit extensive groping in an apparent attempt to achieve articulatory targets. Imitation of even very simple utterances (e.g., ‘me,’ ‘no,’ ‘bye’) probably will be difficult. Individuals with severe apraxia also will exhibit considerable frustration. Some individuals will respond to their frustration by repeated phonation and groping movements accompanied by gesture. Others may give up and not want to initiate any attempts at speech. The diagnosis of apraxia is made by an SLP based on a speech/language evaluation. While there are published tests (Dabul, 1979; Di Simoni, 1989) that measure speech-motor function and assist in the diagnostic process, the most important assessment tools are the eyes and ears of the examiner an audio or audio-video recorder and a systematic series of tasks for observing non-speech (vegetative) and speech programming abilities (Duffy, 1995).
Typically, a recommendation for AAC intervention in apraxia occurs after an unsuccessful period of traditional speech therapies. The beneficial effects of traditional speech treatment are well documented for some individuals with apraxia (Cherney, 1995; Deal & Florance, 1978; Dworkin, Abkarian, & Johns, 1988; Dworkin & Abkarian, 1996; Howard & Valley, 1995; Rosenbek, Lemme, Ahern, Harris, & Wertz, 1973; Wambaugh, Kalinyak, Michelene, West, & Doyle, 1998a; Wambaugh, West, & Doyle, 1998b; Wertz, 1984). Unfortunately, with severe apraxia even extensive drill and practice may not bring about the return of functional, natural speech. For these individuals, AAC intervention is appropriate. The following questions are pertinent: (1) what is the prognosis for the return of natural speech; (2) if AAC intervention is appropriate, should it consist of a gestural system, writing, the use of a communication board (Skelly, Schinsky, Smith, & Fust, 1974; Rosenbek, 1985), and/or an electronic device. If an electronic device is appropriate, the AAC assessment is carried out as outlined in Subpart II of this section. AAC devices are available that offer individuals with apraxia features that enhance their communication effectiveness in their daily lives ( small, portable devices that store vocabulary, options to use symbols/words, speech output with intelligible female/male voices and rate enhancement options). Preliminary studies demonstrate that AAC devices effectively can improve the functional communication of some individuals with severe dyspraxia/apraxia and are a necessary treatment option.
The professional literature related to treatment of apraxia of speech includes a number of reports describing AAC interventions using electronic devices. One early study reported on three individuals who used one of the first voice output communication devices. Although more appropriate technology is available today, these early reports document that AAC devices can have an important impact on the lives of individuals with severe apraxia. For example, one woman who prior to AAC intervention would not leave her home, considered herself ‘communicatively independent’ after she learned to use the AAC device and was able to return to nearly all of the same activities she engaged in premorbidly (Radioux, Forance, & McCauslin, 1980).
AAC devices are reported to enable individuals with apraxia to achieve a variety of functional goals. For example, Yorkston & Waugh (1989) give an account of an individual who had a combination of apraxia of speech, limb apraxia, and aphasia, which made it impossible to respond even to simple yes/no questions using natural speech or gestures. This failure to respond often is attributed to poor auditory comprehension skills but also may be due, at least in part, to the inability to formulate an adequate response. She learned to use an AAC device to indicate ‘yes’ and ‘no’ and appeared to benefit from the additional cueing provided by the visual presence of the symbol on a display and auditory signal of the speech synthesized word.
Another case example is that of a 47 year old interior designer who experienced a left CVA with severe apraxia and moderate aphasia. Yorkston & Waugh (1989) and Beukelman, Yorkston, and Dowden (1985) described a period of traditional speech therapy that included the development of a multi-component, non-electronic AAC system. Three years post stroke, when the client wished to return to his business, an electronic AAC device was programmed with conversational control phrases that allowed the client to initiate, direct, and terminate conversations with his clients. Reportedly, the AAC device enabled the client to return to work.
More recently, Murray (1997), Rogers & Alarcon (1997), Rogers & Alarcon (1998) reported on the use of an AAC device for individuals with apraxia and progressive aphasia. In the Roger’s case, a five-year trajectory of the communication impairment and intervention was described. Speech symptoms began with apraxia of speech and later developed into a decline in appropriate use of grammar, decrease in writing skills, auditory comprehension decline, reading decline, and finally mutism. Treatment strategies paralleled the onset of symptoms beginning with pacing of the speaking rate and progressing to strategies involving the identification of topic and key words, gestural and drawing systems, a communication book, and finally a synthesized speech AAC device with access to symbol-based pre-selected messages. The individual was able to use the AAC system successfully despite severe impairment.
Aphasia is the impairment of the second link in the communication chain involving an individual’s ability to understand and formulate language. It typically occurs as a result of brain damage involving the language-dominant cerebral hemisphere. Depending upon its severity, aphasia significantly can affect an individual’s ability to converse, exchange information, and in some cases, to communicate basic needs. Language and communication can be permanently altered. Individuals who previously communicated with no difficulty suddenly find themselves unable or limited in their ability to participate in the vast range of communicative activities that typify human behavior (Holland, Fromm, DeRuyter, and Stein, 1996).
Severe aphasia profoundly impacts the daily life experiences of individuals because the automaticity and accuracy of their communication is affected. Individuals with aphasia usually have reduced abilities in all language and communication modalities, including speaking, auditory comprehension, reading, writing, and communicating through gestures or pantomime. The degree of impairment in each modality may differ, which creates distinct patterns of communication disability (Broca’s/nonfluent aphasia, Wernicke’s/fluent aphasia, transcortical sensory aphasia, anomic aphasia) (Benson & Ardilla, 1996; Davis, 1993; Goodglass & Kaplan, 1983).
From a medical perspective, aphasia generally is considered a relatively stable condition after the first few months post insult. For example, in persons who have recently sustained a stroke, most motor recovery takes place within 3-6 weeks, although upper extremity functioning may continue to improve over 6 months. With regard to language function, the first six months post insult is considered the period during which most spontaneous recovery will occur (Culton, 1969; Kertesz & McCabe, 1977). However, long-term improvement in communication skills may take place for months and even years (Benson & Ardilla, 1996; Kertesz, 1988; Poeck, Huber, & Willmes, 1989). The mechanisms for this type of long-term recovery are not well understood but explanations point to therapy (Darley, 1975), strategy learning (Penn, 1987), or functional systemic reorganization (Luria, 1963, 1976). One exception to this pattern of immediate recovery followed by long-term improvement is the relatively rare condition of primary progressive aphasia. These individuals demonstrate a gradual speech and language deterioration of unknown etiology (Mesulam, 1982; Tyler, Moss, Patterson, & Hodges, 1997).
Few individuals with aphasia regain sufficient verbal communication skills to participate fully in adult communication activities, i.e., talking with family members, conducting transactions in the community, interacting in the workplace, or sharing life experiences with others. Such limitations have resulted in social isolation and deterioration in life satisfaction for many individuals with aphasia (Kinsella & Duffy, 1979; Parr, 1994). Persons with aphasia report that their activities are restricted, their interpersonal relationships are negatively impacted, and their autonomy is lessened (LeDorze & Brassard, 1995). Approximately 70 percent of those who responded to a National Aphasia Association survey felt that people avoided contact with them because of their difficulty with communication. Despite speech-language therapy, 72 percent of all individuals with aphasia could not return to work (National Aphasia Association, 1987). Individuals with severe and global aphasia often are so profoundly affected that they cannot always communicate adequately to meet their basic needs (Collins, 1986; Garrett & Beukelman, 1992).
Treatment for severe aphasia focuses on improving functional communication skills as well as remediating speech and language impairments. As a result, many individuals with severe aphasia rely on a range of low-tech AAC strategies including picture books, partner-assisted communication strategies, gestures, and word boards. Others benefit from the use of electronic, voice output AAC devices to express basic needs, exchange information, engage in social interaction, and participate more actively and independently in daily activities. Studies demonstrate that AAC devices are effective in treating some of the communication difficulties associated with severe aphasia.
By far the most common cause of aphasia is stroke, although aphasia also may result from brain tumors, head injuries, or other insults to areas of the brain that mediate language processing. Strokes in the language-dominant hemisphere (typically the left hemisphere) result in 80,000 new cases of aphasia annually (National Institute on Neurological Disorders and Stroke, 1990; Broderick, Brott, Kothari, Miller, Khoury, Pancioli, Gebel, Mills, Minneci, & Shukla, 1998). The prevalence of aphasia in the United States is estimated at approximately one million people. Most of these individuals are over the age of 60. The incidence of aphasia is equal for males and females, and persons of all races, educational, and social-economic backgrounds experience aphasia (National Aphasia Association, 1987).
Research shows that recovery following an insult or injury to the brain varies considerably across individuals as a result of biological and neurological factors (Basso, 1992). However, several factors have been found to be predictive of positive outcomes following stroke. Marshall and Phillips (1983) found that verbal communication outcomes in 80 aphasic men could be predicted 86 percent of the time by 6 variables: 1) initial severity of aphasia, 2) number of months after stroke, 3) auditory comprehension ability, 4) age, 5) speech fluency, and 6) general health. In general, younger patients recover better than older patients, individuals with large lesions or mass effects do more poorly than those with focal infarcts, patients with poor auditory comprehension regain fewer language skills than those with good comprehension, and those patients who receive treatment earlier regain more function.
With regard to recovery of speech and communication skills, some individuals with aphasia experience a nearly complete recovery of their language capabilities. Others demonstrate mild or moderate language impairments that reduce the efficiency of their communication. There also is a significant number of persons with aphasia for whom severe communication disorders are permanent. Global aphasia, or aphasia with profound impairment across all language modalities, is in fact, the most common type of aphasia. Alexander and Loverso (1991) reported that of 850 cases of stroke admitted to an urban hospital, 21 percent were aphasic, and 41 percent of these patients were diagnosed with global aphasia. At four to twelve weeks post onset, 33 percent of the patients with global aphasia were dead, 22 percent had progressed to milder forms of aphasia, and 44 percent continued to receive the classification of global aphasia. Persons with severe or global aphasia often benefit from the use of a range of AAC treatments.
Historically, treatment for aphasia reflected an impairment model with treatment focusing on improving speaking, comprehending, reading, and writing, typically by means of various ‘stimulation’ approaches in which the individual practiced communication sub- skills in the targeted modality. This type of traditional speech and language rehabilitation, typically administered by SLPs has been evaluated extensively in large- and small-group investigations, well-controlled single-subject experimental studies, and single case efficacy studies. Positive outcomes of speech and language therapy are documented extensively for individuals across settings and treatment conditions (Aten, Caligiuri, & Holland, 1982; Basso, Capitani, & Vignolo, 1979; Elman, 1999; Homan, 1991; Poeck, Huber and Willmes, 1989; Robey, 1994; Robey, 1998; Wertz, Collins, Weiss, Kurtzke, Friden, Brookshere, Pierce, Holzapple, Hubbard, Porch, West, Davis, Matorich, Morley & Resurrecion, 1981; Wertz, Weiss, Aten, Brookshire, Garcia-Bunuel, Kurtzke, La Pointe, Milianti, Brannegan, Greenbaum, Marshall, Vogel, Cortes, Barnes and Goodman, 1986).
More recently, treatment for aphasia has broadened from a focus at the level of impairment to the level of disability. (Elman, 1999; Homan, 1991; Hopper and Holland, 1998; Kagan, 1998; Lasker, Hux, Garrett, Moncrief and Eischeid, 1997). Thus, the emphasis of treatment even in the early stages of spontaneous recovery, addresses an individual’s need to communicate immediately in the face of severe speech and language impairment. Nicholas and Helm-Estabrooks (1990) noted that the restoration of speech is not realistic for many individuals with severe aphasia. They advocated shifting the goals of treatment from talking to communicating through alternative modalities. Likewise, Wallace and Canter (1985) suggested that language treatment with severely aphasic adults should maximize the individual’s communication in the day-to-day environment. In conjunction with this shift, AAC approaches increasingly have been incorporated into comprehensive management approaches for persons with severe aphasia (Fox & Fried-Oken, 1996; Garrett & Beukelman, 1998; Kraat, 1990).
SLPs use a number of well-known tests, standardized for the evaluation of aphasia. Examples are the Western Aphasia Battery (Kertesz, 1982); the Boston Diagnostic Aphasia Examination (Goodglass & Kaplan, 1983); the Boston Assessment of Severe Aphasia (Helm-Estabrooks, Ramsberger, Morgan, & Nicholas, 1992); Revised Token Test (McNeil & Prescott, 1978); and the Porch Index of Communicative Ability (Porch, 1981). These instruments help to determine the existence and severity of aphasia and differentiate between the various types of speech and language impairments that occur with aphasia. They also enable clinicians to develop a profile of linguistic strengths and weaknesses. More recently developed test instruments, such as the ASHA Functional Assessment of Communication Skills (ASHA-FACS) (Frattalli, Thompson, Holland, Wohl, & Ferketic, 1995) and the Communicative Abilities in Daily Living (CADL) (Holland, Frattali, & Fromm, 1999), document how aphasia affects the individual’s ability to use speech and language functionally in real-life contexts.
To better determine which individuals with aphasia will benefit from AAC treatment approaches and what type of treatment approaches are most efficacious, Garrett and Beukelman (1992) developed the following Classification System for Individuals with Severe Aphasia. This paradigm increasingly guides assessment and treatment planning among SLPs working with individuals with severe aphasia. The paradigm summarized in
Table 3
Table 3: Classification System For Individuals With Severe Aphasia
Type Of Severe Aphasia |
Description |
Treatment Goals |
Basic-Choice Communicator. (Chronic global aphasia with severe neurological impairment).
|
Profound cognitive-linguistic disorder across modalities. With maximal assistance, can make basic choices and develop turn-taking skills in familiar contexts. Note: Shortly after a stroke, many individuals with aphasia function as basic-choice communicators. Those with persistent global aphasia remain basic-choice communicators for an extended period of time. |
Provide simple system for communicating basic messages and prepare for more advanced types of communication strategies when, and if, the individual improves medically. Need for speech output AAC devices is minimal. |
Type Of Severe Aphasia |
Description |
Treatment Goals |
Controlled-Situation Communicator. (Chronic global aphasia, Broca’s aphasia, Wernicke’s aphasia).
|
Often are isolated socially. Can initiate communication with assistance in structured situations. Can indicate needs by spontaneously pointing to objects and items. Many have a limb apraxia, and speech is often stereotypic or nonexistent. Individuals are aware of daily routines and can participate in conversations and communicate specific information, opinions, and feelings when supported. |
Provide AAC treatment to enable person to express basic needs, talk on phone, provide basic social information and communicate medical/ emergency information. Some benefit from digitized speech AAC devices. Teach caregivers to use ‘written-choice communication. |
Comprehensive Communicator. (Chronic Broca’s aphasia and conduction aphasia).
|
Retain a variety of communication skills (drawing, gestures, limited speaking abilities, first-letter of word spelling and pointing to words or symbols). Communication efforts are often fragmented or inconsistent, i.e., they often can provide scraps of information.
|
Use low-tech communication notebook or wallet to supplement impaired speech. Some use digitized AAC devices for transactions in the community and to engage in specific conversations where intelligible speech is mandatory ( talking to doctor, on the phone). Some demonstrate cognitive-linguistic ability, partner support, and extensive vocabulary needs to use synthesized AAC devices. |
Augmented-input Communicator. (Wernicke’s aphasia).
|
Have auditory processing difficulties that interfere with the comprehension of spoken language. During conversations, may nod their heads, but this often signals ‘listening’ rather than a comprehension of the language being spoken. |
Minimize conversational breakdowns by teaching communication partners to write, show photographs, draw, or use symbols and diagrams to represent key words and topics as they speak. Some use digitized AAC devices. |
Specific-need Communicator.
|
Most of the time, manage communication through gestures and their limited speech. Require support in situations that call for specificity, clarity, or efficiency. |
Enable individuals to carry out specific communication tasks using AAC treatment approaches. May require a digitized speech output AAC device over the telephone or for transactions in the community. |
The selection of an appropriate AAC device for an individual with aphasia follows the same data gathering process described in Subpart II of this Section. The assessment process gathers data that relates to the individual’s linguistic skills, functional communication skills, nonverbal communication skills, motor skills, sensory skills, perceptual skills, pragmatic skills, experiential skills, and daily communication needs.
AAC strategies and devices have been shown to be effective for persons with aphasia (Fox & Fried-Oken, 1996; Garrett & Beukelman, 1998; Kraat, 1990; Steele, Weinrich, Wertz, Kleczewska, & Carlson, 1989). Many individuals with severe aphasia are candidates for communication notebooks or wallets, alphabet boards for first-letter spelling, and ‘yes-no’ boards (Beukelman, Yorkston, & Dowden, 1985; Fox, Sohlberg, & Fried-Oken, in press; Yanak & Light, 1991). In addition, AAC devices can enable people with aphasia to become more independent in the community, communicate functional needs more specifically, participate more fully in social exchanges, tell stories, and make telephone calls (Garrett and Beukelman, 1998; Hopper & Holland, 1998).
According to Fox and Fried-Oken (1996), outcome studies in AAC and aphasia fall into four broad classifications: comprehensive case studies, carefully controlled single-case experimental studies, group studies and other types of descriptive or comparative studies. For example, Belliare, Georges and Thompson (1991) used a multiple-baseline design to demonstrate that when individuals with severe aphasia are taught to use communication boards designed to meet their needs in a natural setting, learning occurs and generalization takes place.
In 1985, Beukelman, Yorkston, & Dowden described an aphasic adult who used a variety of communication methods at home and at work. The subject had severe verbal apraxia and a moderate-severe aphasia and used the Handivoice 130 (an AAC device with synthesized speech that is no longer available) to communicate a restricted number of messages. The device enabled the subject to return to work. The authors concluded that the use of an AAC device was an important part of the subject’s more comprehensive communication system, which included (1) a communication notebook (words related to specific needs), (2) a more general conversational photograph album, and (3) gestures, facial expressions, and intonation.
Garrett, Beukelman, and Low (1989) described a case in which an individual with Broca’s aphasia (i.e., limited expressive language skills and good receptive skills) learned to use a multi-component AAC system in various community environments. The AAC device contained individualized messages that the client used successfully to obtain veteran’s benefits and community-based transportation. In addition, during a controlled clinical interaction, the authors documented that when the individual used his AAC system, he experienced a decrease in communication breakdowns (from 50 percent to 17 percent of all communication turns) and an increase in the number of successful communication turns as compared to when he relied solely on speech and gestures.
In 1989, Steele and his colleagues showed that a subject with global aphasia was successful in communicating trained syntactical forms using an AAC device (Weinrich, et. al., 1989). Using an alternative treatment design, Steele, Kleczewska, Carson & Weinrich, 1992 compared a single aphasic person’s ability to comprehend instructions given three different language modalities: (1) a computer-based system that used icons; (2) written commands, and (3) spoken commands. The subject consistently performed better when the commands were given using the AAC device. They concluded that the device was a superior input communication modality for this type of task with this type of patient.
Beck and Fritz (1998) studied a group of 10 people with aphasia, 5 with anterior aphasias and 5 with posterior aphasias, and a group of 10 non-brain-damaged controls to investigate four questions: (1) Can people with aphasia learn iconic encoding? (2) Does the ability to learn iconic encoding vary with different types of aphasia? (3) Does the level of abstraction of the messages affect the ability to learn iconic encoding? (4) Does the length of an icon sequence affect the ability to learn iconic encoding? Results indicated that people with aphasia can learn iconic encoding under specific conditions. The type of aphasia, level of abstraction, and length of icon sequence influenced learning.
Waller, Dennis, Brodie, Cairns, (1998) describe the design and evaluation of a computer-based communication system called ‘TalksBac’ with four nonfluent adults with aphasia. The system is word-based and exploits the ability of some nonfluent aphasics to recognize familiar words and short sentences. At the end of a 9-month training period, each subject’s communication skills were reassessed by use of a battery of tests comparing skills with and without the TalksBac system. The results indicated that two of the subjects improved in their conversational abilities using the system. The researchers concluded that TalksBac has the potential to augment the communication abilities of some nonfluent adults with aphasia. Work continues to improve the efficiency of the software.
Fox, Sohlberg, & Fried-Oken (1999) investigated the outcomes of AAC intervention for adults with severe nonfluent aphasia. Subjects had severely limited spoken language abilities with moderate-to-mild auditory comprehension impairment. Results showed that aphasic subjects used their conversational communication aids increasingly well over time in a clinical environment. In addition, researchers reported that the subjects also used their devices in natural environments. Finally, Kagan (1995) reported that individuals with aphasia can communicate effectively with medical professionals who have been trained to use AAC strategies in ways that support conversations with their patients. Other studies also have documented the importance of appropriate partner training and support for successful AAC use (Garrett & Beukelman, 1995; Lasker, Hux, Garrett, Moncrief, & Eischeid, 1997).
Clinical decisions regarding AAC intervention are made in the context of a comprehensive speech-language assessment. The AAC assessment process is well established in the professional literature as well as in standards of practice for SLPs (ASHA Standards of Practice, Clinical Competencies in AAC, Yorkston (in press); Beukelman and Mirenda (1998). The assessment process begins with data gathering, as described below and in the Flow Chart depicted in Figure 1 that follows this section on page *. It requires a series of clinical decisions that determine the diagnosis and severity of the disabling condition (dysarthria, apraxia, and/or aphasia) and the kind of speech-language pathology treatment that is required to achieve functional communication goals, including AAC treatment where indicated.
The outcome of an AAC assessment is a narrative report, which describes the clinical facts relevant to a beneficiary’s speech-language impairment, the need for AAC treatment, and when recommended, information germane to the selection of an AAC device. The assessment report also includes an AAC treatment plan that states the functional communication goals the beneficiary is expected to achieve with the AAC device. The AAC treatment plan is based on the clinical facts presented and the application of the SLP’s professional judgment regarding the specific AAC treatment.
In the course of the AAC assessment process, the SLP makes six major clinical decisions regarding the need for AAC treatment and the type of AAC treatment required. These decisions are highlighted in red along the left margin of the Flow Chart (Figure 1). The six AAC assessment decisions include: (1) determining current functional communication levels; (2) predicting future levels of communication effectiveness; (3) identifying functional communication goals and treatment approaches; (4) selecting specific AAC treatment approaches; (5) selecting an AAC device and accessories; and (6) procuring, training, and following up.
Assess current communication needs. (Box (a), Figure 1). The SLP first determines the type, severity, and anticipated course of the individual’s communication impairment. This portion of the assessment process confirms the diagnosis of severe dysarthria, apraxia, or aphasia. In addition, the SLP seeks to identify the individual’s daily communication needs in order to establish functional communication goals for treatment. The scope of an individual’s communication needs may range from simple expressions of wants and needs to a caregiver, to the communication of complex thoughts and ideas to family, friends, and services providers across multiple settings. The product of the assessment will be an individualized profile of communication needs with an indication of the importance for each need category (Yorkston, 1999; Beukelman and Mirenda, 1998; Blackstone, 1985).
Assess communication effectiveness. (Box (b), Figure 1). Using the individualized communication needs profile, the SLP considers whether, given the severity of the individual’s current level of speech and language impairment, the daily communication needs can be met using natural modes of communication. The assessment determines whether an individual is able to communicate effectively using natural speech in typical conversations and other communication occurrences that arise throughout the individual’s daily activities.
Assess potential for deterioration in natural communication skills. (Box (c), Figure 1). The SLP determines the likelihood that there will be deterioration in communication effectiveness due to the natural course of the individual’s condition. For example, after noting that an ALS individual’s speech intelligibility has worsened, the SLP may predict that communication through natural modes will become impossible and recommend AAC treatment in anticipation of this deterioration.
When communication needs are met, no treatment is recommended. (Box (d), Figure 1). When the assessment process shows that individuals are able to meet their communication needs through natural communication methods, and their condition is not expected to deteriorate further, then no treatment is recommended.
Identify functional communication goals. (Box (e), Figure 1). When recommending AAC treatment, the SLP defines a list of functional communication goals. According to Medicare guidance, functional communication goals ‘reflect the final level the patient is expected to achieve, are realistic, and have a positive effect on the quality of the patient’s everyday functions.’ Functional goals may be a ‘small, but meaningful change that enables the beneficiary to function more independently in a reasonable amount of time.’ Medicare Intermediary Manual (HCFA Pub. 13) (‘MIM’) § 3905.3(A); Medicare Hospital Manual (HCFA Pub. 10) (‘MHM’) §446(a)(3)(A). Functional communication goals may range from an ability to: indicate yes/no responses; communicate basic physical needs or emotional status; communicate self-care and medical needs; use a basic spoken vocabulary and short phrases; engage in social communication with family and friends; engage in communicative interactions in the community; utilize conversational language skills; talk on the telephone; or respond to emergencies. MIM §3905.3(A); MHM, §446(a)(3)(A).
Assess potential to improve natural communication methods. (Box F, Figure 1). The purpose of this assessment is to determine whether functional communication goals can be achieved using speech, writing, or gestures. Where natural communication methods have the potential to meet communication needs, an SLP will recommend treatment to improve natural speech or language performance. (Box G, Figure 1). For some individuals, sustained treatment to improve their natural speech and language capability is sufficient to return them to communication effectiveness, and AAC treatment is not recommended. However, when individuals with severe dysarthria, apraxia, and/or aphasia do not demonstrate the potential to meet their communication needs using natural methods, the SLP will recommend AAC treatment approaches to improve communication effectiveness and achieve functional communication goals. (Box H, Figure 1).
At this point of the clinical decision making process, the SLP has determined that an individual will require treatment involving AAC treatment techniques. This judgment is based on the individual’s diagnosis of severe dysarthria, apraxia, and/or aphasia and his/her inability to meet current or future communication needs using natural communication methods. The next portion of the clinical decision making process leads the SLP, often in collaboration with other allied-health professionals, determines the type of AAC treatment required, the type of AAC device and device accessories needed, and the specific treatment plan that will be implemented.
Select AAC treatment options. (Box (I), Figure 1) AAC treatments may include three different approaches to augmenting spoken communication: (1) speech output AAC devices (also known as ‘high technology’ devices); (2) non-electronic aids such as alphabet, word, and picture boards; and (3) unaided communication strategies such as gestures, listener-supported AAC techniques, and sign language. Most individuals use a combination of these approaches.
Table 4 below lists nine clinical indicators for speech output AAC device selection. Their use in the AAC assessment process lead to the selection of an AAC device from among the three categories delineated in Section 5. In addition, these clinical indicators are used as coverage criteria for AAC devices as proposed in Section 6.
Table 4: Clinical Indicators Required for AAC Device Selection
Clinical Indicators |
Category |
Category |
Category |
|
| 1
|
The individual has a communication disability with a diagnosis of severe dysarthria, apraxia, and/or aphasia. |
Y |
Y |
Y |
2 |
The individual’s communication needs that arise in the course of current and projected daily activities cannot be met using natural communication methods. |
Y |
Y |
Y |
3 |
The individual requires a speech output communication device to meet his/her functional communication goals. |
Y |
Y |
Y |
4 |
The individual possesses the linguistic capability to formulate language (messages) independently. |
N |
Y |
Y |
5 |
The individual will produce messages most effectively and efficiently using spelling. |
N |
Y |
Y or N |
6 |
The individual will require an AAC device with extensive language storage capacity and rate enhancement features. |
N |
N |
Y |
7 |
The individual will access the AAC device most effectively and efficiently by means of a physical contact direct selection technique, such as with a finger, other body part, stylus, hand held pointer, head stick or mouth stick.. |
Y or N |
Y |
Y or N |
8 |
The individual will access the AAC device most effectively and efficiently by means of an electronic accessory that permits direct selection. |
Y or N |
N |
Y or N |
9 |
The individual will access the AAC device most effectively and efficiently by means of an indirect selection technique (e.g., scanning, Morse Code). |
Y or N |
N |
Y or N |
The first two clinical indicators lead to consideration of AAC treatment approaches as described above: The individual has a communication disability with a diagnosis of severe dysarthria, apraxia, and/or aphasia to which a positive response is required. And, the individual’s communication needs that arise in the course of current and projected daily activities cannot be met using natural communication methods. To which a positive response is required. The third clinical indicator the individual requires a speech output communication device to meet his/her functional communication goals requires a positive response. Some functional communication goals only can be met if a person has access to a speech output communication device.
After considering the remaining clinical indicator, the SLP will select from among the three categories of AAC devices described in Section 5.
Determine message formulation capability: (Box (J), Figure 1). The individual possesses the linguistic capacity to formulate language (messages) independently. Some individuals who are unable to meet their communication needs through natural speech are able to spell and/or sequence words or symbols in ways that allow them to generate sentences and narratives independently. If the response to the fourth clinical indicator is no, then the individual will require a ‘whole message’ AAC device. (Box (K), Figure 1). Individuals who experience cognitive or language impairments and are unable to formulate their messages by spelling or word-by-word development may include persons with aphasia due to cortical stroke as well as those with congenital (mental retardation) and acquired conditions (Huntington’s disease, progressive aphasia, and some individuals with severe traumatic brain injury). These individuals typically use AAC devices from the first category (digitized speech output). These systems provide the user with an entire phrase, sentence, or narrative with a single selection on their communication device.
Alternately, if the response to the fourth clinical indicator is yes, then the individual will require a device from the synthesized AAC device categories. (Box (L), Figure 1). Typically, these individuals have dysarthria secondary to primary physical impairments caused by ALS, cerebral palsy, brain stem stroke, multiple sclerosis, and Parkinson disease, and those persons with traumatic brain injury who have relatively preserved linguistic and cognitive skills. These individuals can generate messages independently using words, letters, or graphic symbols.
Determine need to generate messages by use of spelling: (Box (M), Figure 1). The individual will produce messages most efficiently and effectively using spelling. The AAC assessment process determines whether a person can spell sufficiently well to generate messages. If the answer is yes, then the individual will require a synthesized speech device because they can generate spoken messages using spelling. The assessment determines whether the individual has sufficient spelling abilities to generate messages independently.
Determine if person generates language most efficiently and effectively with a system that has extensive storage and rate enhancement features : (Box (N), Figure 1). The individual will require an AAC device that provides extensive language storage capacity. The AAC assessment process determines whether an individual who can generate language independently has the need to store and retrieve a large amount of language to meet their functional communication goals. For example, individuals wishing to prepare messages in advance, as well as those who need to provide large amounts of information such as to describe changes in the individual’s medical condition or reactions to medication to a doctor at a periodic appointment, or to be able to quickly ask questions related to a shopping list, require AAC devices with the capacity to store previously created messages and enable them to retrieve their stored messages efficiently and effectively. These features are described in Section 5. The assessment determines whether an individual has the need to use an AAC device with extensive language storage and retrieval capacity. AAC devices in category 3 offer these options.
Determine ability to use direct selection access. (Box (O), Figure 1). There are a range of access methods for AAC devices. Two involve direct selection: (1) direct physical contact using a finger, another body part, stylus, hand-held pointer, head stick, or mouth stick, or (2) direct selection techniques using an electronic accessory. A third access method utilizes indirect selection using switch-based scanning.
The AAC assessment process for the seventh clinical indicator the individual will access the AAC device most effectively by physical contact direct selection technique, such as with a finger, other body part, stylus, hand held pointer, head stick or mouth stick and the eighth clinical indicator: the individual will access the AAC device most effectively by means of an electronic accessory that permits direct selection often may require the knowledge and skills of other allied-health professionals to determine the most effective method of access. When a direct selection accessory is needed, the AAC assessment determines the type required. Section 5 discusses these options. If the individual is able to spell and does not have extensive needs for language storage and can use direct physical access, the SLP will recommend a device from Category #2. Devices in Categories #1 and #3 offer multiple options for direct access.
Determine ability to use indirect access (switches). (Box (P), Figure 1). When individuals have severe physical impairment that preclude access to AAC devices using direct selection, the SLP will consider alternative selection options. The ninth clinical indicator asks: the individual will access the AAC device most effectively and efficiently by means of an indirect selection technique (e.g., scanning, Morse Code). This portion of the AAC assessment is often conducted in collaboration with other allied-health professionals because of the motor impairments that preclude direct access to the AAC device. Section 5 provides information on scanning-based selection techniques, Morse code, and use of switches. The product of this assessment is the determination that an individual can use an indirect selection technique. All device categories except for Category #2 offer this option.
For Medicare reimbursement purposes, where the SLP has considered all the clinical indicators and made decisions about the category of AAC devices that is appropriate for the individual and the need for device accessories, if any (Box (Q), Figure 1) the process ends here, but for the SLP, the process continues. The SLP must recommend a specific device and address training needs. These determinations are based on all the facts gathered during the assessment but rely most directly on the nine key clinical indicators.
Specific AAC device recommendation. After determining that a voice output AAC device will be appropriate for the individual and identifying the appropriate category of AAC devices, the SLP matches the capabilities of the individual to the characteristics of a specific AAC device and device accessories. Typically, the matching process yields a short list of AAC device and accessory options from which the individual, family, and allied health professionals can select to enable the individual to achieve his or her functional communication goals and optimum level of communication independence.
Because of the complexity of human communication and the variation among people who benefit from using AAC devices, there is not a one-to-one relationship between the specific AAC device within any one category of devices and a group of end users. Within each category, specific AAC device choices will be made based on clinical factors as well as some individual preference factors. For example:
Finally, the SLP determines the extent to which specific no-tech strategies and low-tech aids will be used to complement the voice output AAC device and help the individual achieve his or her functional communication goals and ‘optimum communication independence.’ See MIM § 3905.3(A); see also MHM § 446(a)(3)(A).
Because AAC devices will be new to individuals with severe communication disorders, a period of instruction and practice is required if the individual is to become communicatively effective in using an AAC device. SLPs often encourage a trial use prior to recommending the purchase of an AAC device. A trial use period may be appropriate when decisions are being made between similar devices, when it is unclear whether the environment will support the use of an AAC device, or when the individual or family is uncertain about whether to use an AAC device.
After a device is purchased and delivered, and an initial instruction and practice period has been completed, the SLP will complete a new communication needs assessment to determine whether the individual’s current communication system, which now includes an AAC device, as well as residual natural communication and typically no-tech and low-tech AAC strategies, allows the person to communicate more effectively and achieve the functional communication goals. Over time, modifications of the configuration of the AAC device may be required to accomplish functional communication goals. Some individuals require follow-up to assist them with resolving technical difficulties, training new support personnel from time to time, and monitoring the achievement of functional communication goals.
Figure 1: AAC Treatment Clinical Decision Making Process Flow Chart(continued on next page)
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