A review of literature on the prevalence of dysphagia in people with intellectual disability reveals that dysphagia is underdiagnosed.
The link between dysphagia, health complications and risk of mortality seems to be stronger in persons suffering from intellectual disability. Dysphagia in these people is further complicated by medical, psychiatric and behavioural comorbidity. Until now, few studies have examined the prevalence of this pathology in this group. However, more information would help address the problem and raise awareness among patients and their entourage. British academics recently began alerting public opinion on the underestimation of dysphagia. Their findings were published in the latest issue of Intellectual and Developmental Disabilities.
Prevalence varies from one survey to another
Twenty studies relating to the prevalence of dysphagia in people with intellectual disability published from 1990 to July 2016 were identified: eight in the US, four in the Netherlands, three in the UK and one each in Belgium/Netherlands, Ireland, Israel, Japan and Spain.
The prevalence of dysphagia varies considerably, from 1% of adults with intellectual deficiency without cerebral palsy to 99% of children with intellectual disability and severe cerebral palsy. Two studies were conducted on representative groups of people with intellectual disabilities. One estimates the prevalance of dysphagia at 11.5% and the other at 8.1%. In all, 94% of subjects suffered from oral dysphagia, 51.5% pharyngeal, 25.7% esophageal and 58.4% combined several types.
Prevalence was found to be higher in studies not based on people with intellectual disabilities: 52.1% in subjects over 50 and 69.7% in adults and children.
Three factors affect dysphagia
Estimates differ because three factors are not taken into account:
– The prevalence of dysphagia in people with intellectual disability increases according to the severity of the disability, increasing twofold in those with severe deficiencies.
– The prevalence of dysphagia also increases with the presence of cerebral palsy. Some studies reveal an eightfold increase.
– A Japanese survey of a population of people with intellectual and physical disabilities suggested a link between the prevalence of dysphagia and the frequency of epileptic fits.
Age-related surveys are rare but seem to indicate a higher prevalence of dysphagia in subjects aged 46-60 and over compared to subjects aged 16-45.
A serious underestimation of dysphagia
The review concludes that “dysphagia in people with intellectual disability appears to be associated with more severe levels of intellectual disability, comorbid cerebral palsy, and motor impairments”. Increased awareness and treatment of dysphagia could help prevent other health issues, premature deaths and avoid hospitalisation. The authors acknowledge that “further research with representative samples of people with intellectual disability using adequate methods of assessment are required in order to provide more precise prevalence estimates and clarify factors that may be associated with dysphagia in this population”.
Prevalence of Dysphagia in People With Intellectual Disability: A Systematic Review. Robertson J, Chadwick D, Baines S, Emerson E, Hatton C. Intellect Dev Disabil. 2017 Dec;55(6):377-391. doi: 10.1352/1934-9556-55.6.377. https://www.ncbi.nlm.nih.gov/pubmed/29194030