Abstract
BackgroundIntellectual disability (ID) and dementia reflect disturbed cortical function during and after developmental age, respectively. Due to the wide heterogeneity of ID population the decline in cognitive and adaptive skills may be different in distinct genetic subgroups.MethodsUsing the British Present Psychiatric State–learning Disabilities assessment (PPS‐LD) questionnaire the dementia signs were screened in 62, 22 and 44 individuals (> 35 year of age) with Down (DS, OMIM number 190685), Williams (WS, OMIM number, 194050), and Fragile X syndrome (FXS, OMIM number 309550), respectively. The median age of those with FXS (59 years) was higher than of those with DS (50 years) and WS (53 years).ResultsMost study participants with DS (80%) and FXS (89%) were or had been moderately or severely intellectually disabled while most participants with WS (73%) were or had been mildly or moderately disabled at adolescent age. The adolescent (premorbid) level of ID did not correlate with the dementia score. The median scores were 11/27, 1/27, and 0/27 in DS, WS, and FXS subgroups, respectively. Dementia that was confirmed by brain imaging, manifested as Alzheimer disease and as moya‐moya disease associated vascular dementia in DS and as vascular dementia in WS.ConclusionsThis survey suggests that the risk of dementia varies depending on the cause of ID and that the severity of ID in adolescence does not predict the development of dementia at a later age. Consequently, the ID and dementia should be understood as separate clinical entities that need to be taken into account in the health management of intellectually disabled people. This is important for the arrangement of appropriate and timely interventions, which can be expected to delay the need for institutionalization.
Highlights
Intellectual disability (ID) and dementia reflect disturbed cortical function during developmental age and after developmental age, respectively
Intellectually disabled persons form an extremely heterogeneous population with different neuropsychiatric and somatic characteristics depending on the etiology of ID
All individuals (>35 years of age) with DS, WS, and FXS living in the South‐Häme district and all individuals with WS and FXS living in Pirkanmaa, Northern Ostrobothnia, and Southwest Finland districts were invited to participate
Summary
Intellectual disability (ID) and dementia reflect disturbed cortical function during developmental age and after developmental age, respectively. Down syndrome represents the most common genetic, cerebral palsy‐ID the most common acquired, and autism spectrum‐ID the most common multi‐factorial ID syndrome These three most common entities represent only 40%–55% of all people with IDs the remaining 45%–60% represent numerous smaller entities (Arvio & Sillanpää, 2003). DS (caused by trisomy 21) and WS (caused by hemizygosity at chromosomal site 7q11.23) affect both genders while FXS (caused by a mutation in the FMR1 gene located on the long arm of the X chromosome) affects mainly males Those with DS and WS represent 10%–15% and approximately 0.5% of intellectually disabled population, respectively, and males with FXS represent approximately 2% of all males with an ID (Arvio & Sillanpää, 2003). We recruited new individuals in order to compare the signs of dementia between these three genetic ID syndromes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
