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1. Angelman's Syndrome & AAC

The history of medicine is full of interesting stories about the discovery of illnesses. The saga of Angelman Syndrome is one such story. Dr. Harry Angelman reflects:

"It was purely by chance that nearly 30 years ago, three handicapped children were admitted at various times to my children's ward in England. They had a variety of disabilities; and although at first sight they seemed to be suffering from different conditions, I felt that there was a common cause for their illness. The diagnosis was purely a clinical one because in spite of technical investigations, which today are more refined, I was unable to establish scientific proof that the three children all had the same handicap. In view of this, I hesitated to write about them in the medical journals.

However, when on holiday in Italy, I happened to see an oil painting in the Castelvecchio museum in Verona called a Boy with a Puppet. The boy's laughing face and the fact that my patients exhibited jerky movements gave me the idea of writing an article about the three children with a title of Puppet Children. It was not a name that pleased all parents but it served as a means of combining the three little patients into a single group. Later the name was changed to Angelman syndrome."

This article was published in 1965 and, after some initial interest, lay almost forgotten until the early 1980s. In fact many doctors denied that such a condition existed. In the past ten years, American and English doctors have placed the syndrome on a firm footing with the ability to establish the diagnosis beyond doubt. . . "¹ Reading Dr. Angelman's story leads us to note that:

1. Observations by practicing clinicians often are ignored (or devalued) by academicians and researchers, but are critical to perceiving and unraveling important questions and information. In this case, Dr. Angelman's hunch that three children shared a common cause for their disabilities was right, but not confirmed for almost two decades.
2. New technology and medical procedures now exist that can confirm the existence of syndromes caused by chromosomal and genetic abnormalities. This means the field of behavioral neurogenetics, which combines areas of genetics, neuropsychology and neuropsychiatry, is leading us toward an understanding of the biological basis of behavior. The field is of growing interest because it provides a "window to the understanding of a broader spectrum of learning and developmental disabilities."²
3. Identification of congenital conditions that place children at high risk for severe communication impairments (like AS) should compel AAC professionals to develop plans that result in better communication outcomes across the life span.^{3, 4} Successful AAC interventions are likely to enhance other outcomes as well, e.g., social relationships, independence, community participation, employment and the individual's sense of well-being

Characteristics of AS

AS is always associated with mental retardation (functionally severe), a nearly total lack of speech, a movement or balance disorder (unsteady, widely based gait, stiff, ataxic movements, fine motor problems), and unique behaviors, e.g., inappropriate bursts of laughter and hyperactivity. ^2,5-8 Individuals with AS usually are microcephalic by age three years. Many have seizures and abnormal EEGs. Other characteristics are:

• hypo-pigmented skin

• light hair and eye color

• heat intolerance; excessive sweating
• flattened back of head
• protrusion of the tongue with prominent jaw, wide mouth
• small, widely spaced teeth
• drooling and oral motor problems
• feeding problems during infancy
• strabismus (crossed eye)

Prevalence

The incidence and prevalence of AS remains unknown. Reasons are: (a) the diagnosis often isn't made until after age three, (b) many professionals are still unaware of the syndrome and (c) confirming the diagnosis requires identification of clinical findings, EEG studies, chromosome analysis using in situ hybridization techniques, and molecular studies.²

To date, more than 300 patients with AS are reported in the literature.⁶ According to the AS Foundation, over 800 individuals with AS have been identified in the US and Canada. It seems likely that thousands more people remain undiagnosed or misdiagnosed as having cerebral palsy, Rhett syndrome, autism or other developmental disorders.⁵

Genetics

Males and females are equally affected. Four classes of AS are identified.^{8, 9}

• Type I (60-70%) - a deletion on chromosome #15, of maternal origin
• Type II (2-5%) - two copies of chromosome #15, from their fathers (uniparental disomy)
• Type III (2-5%) - abnormal DNA methylation pattern
• Type IV (20-35%) - genetic change not yet identified

Familial cases exist in Types III and IV. Some types seem to be associated with higher cognitive and better motor functioning than others.^{8, 9}

Note: Prader-Willi Syndrome (PWS) also results from deletions on chromosome 15, of paternal origin. PWS is associated with mild to moderate mental retardation, obesity, short stature and hypogonadism. Prevalence is 1 in 10,000 births.¹⁰

Communication challenges

People with AS have greater receptive than expressive language abilities. Both speech and nonverbal communication are affected. Dysarthria and atypical facial expressions, intonation and gestures can make communication acts difficult to interpret. A recent review article noted:

In AS, the absence of speech is not solely dependent on the level of MR. It is also related to social interaction and oral-motor development.¹¹

Researchers also report variations in cognitive, language; social and oral-motor abilities in severely retarded adults with AS.⁴ Some articles mention the use of AAC techniques, e.g., language boards and manual signs. ^11,12 However, despite the well-documented existence of severe communication impairments, we were unable to find any article that discusses the AAC management of communication problems in persons with AS across their life span.

This article appears in ACN Volume 8, # 3.

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