Appendix 2 Prevalence for conditions associated with use of AAC
Autistic Spectrum Disorder
The Scottish Government consultation document 'Towards an Autism Strategy for Scotland'55 presented a detailed analysis of the prevalence data for autistic spectrum disorder in Scotland. Current estimates suggest an incidence rate for autistic spectrum disorder of 42 children per 10,000 as the most accurate figure. For adults, a rate of 5.1 per 100,000 is considered the most accurate estimate.
The incidence of cerebral palsy is reported to be around 1 in every 500 births. Data from the United Kingdom collaborative network of Cerebral palsy registers56 (UK-CP) reported 6900 children with cerebral palsy registered in 2006. This equates to approximately 345 children in Scotland. The database in some regions is voluntary and there is a history of poor maintenance in some areas. Accordingly, it currently provides an indication rather than actual numbers of children with cerebral palsy.
Cerebral palsy is a long-term condition where AAC needs evolve and change throughout early developmental years and into adulthood. A further study57 reports that the survival rates for cerebral palsy are linked to severity of condition. If a child with cerebral palsy lives to age 18 then they are more likely to live beyond age 40. Adults with cerebral palsy die of the same diseases as the rest of the population - heart disease, stroke and cancer.
A multi-centred European study58 of 818 children with cerebral palsy identified that 43% of the children in the study had impaired or no speech and therefore may potentially benefit from AAC. In addition, 65% of children participating in the study had difficulty with fine motor skills suggesting that these children may have difficulty with writing and accessing a standard keyboard.
Dementia primarily affects cognitive function. The number of people with dementia in Scotland is reported as approximately 71,000 people within the total population.59 As a consequence of the changing demographics within the Scottish population this number is predicted to double over the next 25 years.59 Cognitive communication difficulties are a recognised feature of dementia.
The same as you?60 report estimates that 20 people per 1,000 have a mild or moderate learning disability in Scotland while 3 to 4 people per 1,000 have a profound or multiple disability. The same as you? further reports that the number of people with learning disabilities is predicted to grow by over 1% a year as survival rates improve,
Motor Neurone Disease
Motor neurone disease is a progressive neurological disorder that primarily affects motor function and, for some individuals, cognitive function. Standardised incidence in Scotland is reported as 2.4 per 100,00061 while the incidence for over 80s is 7.3 per 100,000.62
In Scotland incidence rates are higher than reported elsewhere63,64 and survival rates are lower.62,63,65,66,67 While this trend may be a consequence of artefact it does represent a possible 30% reduction in survival rate when compared to other countries. The median survival time for motor neurone disease in Scotland is 25 months.68
Although a national motor neurone disease register provides data on prevalence and survival rates for MND, the number of people in Scotland with MND who use AAC is unknown. For a life-limiting and rapidly deteriorating illness like motor neurone disease response rates for AAC must be timeous and appropriately supported. In Scotland, people with motor neurone disease are the second largest group with whom speech and language therapists report using AAC.11
Multiple sclerosis is a neurological disease that affects motor and cognitive function. The course of the disease varies and can be rapidly or slowly progressing. The number of people with multiple sclerosis in Scotland is estimated at 10,000, with caveats. Information Services Division: Scotland report incident cases numbering 623 in 2008/9 (based on projected mid year population). Further data for 2008/9 reports a total of 5,600 individuals with MS consulting their primary care team. (These figures have a wide confidence interval as they are based on only a limited number of practice figures.) Reported incidence of dysarthria and communication difficulties for people with multiple sclerosis ranges from 23% to 51%.68
Parkinson's Disease is a progressive neurological condition that affects both motor and cognitive function. In Scotland, there are between 120 and 230 people with Parkinson's disease per 100,000 population. It is reported that the age related incidence of Parkinson's disease means that the number of cases will increase by 25% to 30% over the next 25 years if the population of Scotland remains stable.69
Stroke is the main cause of disability in Scotland. Of the 80% of people who survive stroke at least half of these individuals will remain dependent after six months and consequently strokes result in life-long disability. There are reports that around 8,500 first-ever-in-a-lifetime strokes occur per annum in Scotland.70 What is unknown is how many of these individuals use AAC as a consequence of a resulting dysarthria or aphasia.
Dysarthria, a motor speech impairment more readily associated with AAC use, reportedly occurs following 20% to 30% of strokes. Prevalence rates for aphasia, an impairment of language, following a stroke have been reported as ranging from 20% to 38% of individuals70 to 15% of stroke survivors at 6 months morbidity.71 Unlike dysarthria, where language functions remain intact and literacy is unaffected, aphasia results in loss of language with varying severity and can affect all communication modalities. For a person with aphasia, AAC may offer solutions to impairment of both spoken and written communication.
Several other neurological conditions including Huntington's Disease, Ataxia, and Progressive Supranuclear Palsy are low-incidence conditions where communication difficulties are common and AAC may offer potential solutions.
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