Epilepsy, dementia and adaptive behaviour in Down's syndrome.
First-time seizures after 35 in adults with Down syndrome flag likely dementia and fast adaptive skill loss.
01Research in Context
What this study did
The team looked at adults with Down syndrome. They split them into three groups: no seizures, early seizures, or new seizures after age 35.
They then compared adaptive behavior scores and dementia rates across the groups.
What they found
Adults who had new seizures after age 35 scored much lower on daily-living skills.
They also showed higher rates of dementia than the other two groups.
How this fits with other research
Matson et al. (1999) saw the same pattern in a wider ID sample: seizures link to lower adaptive skills, not more problem behavior.
Hagopian et al. (1999) and Dall et al. (1997) later confirmed that dementia itself lowers adaptive scores in older adults with Down syndrome.
Huang et al. (2014) seemed to disagree: dementia explained only 3 % of daily-living decline. The gap comes from method: the 2014 study added controls for disability severity and other illnesses, so dementia’s unique slice looked small. The 1993 study kept the lens simple, showing the raw clinical signal you see at first glance.
Why it matters
If an adult with Down syndrome has a first seizure after 35, expect a sharp drop in self-care and a high chance of dementia. Start cognitive supports early, simplify routines, and teach caregivers to watch for further decline.
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02At a glance
03Original abstract
Widespread inquiry identified 378 adults with Down's syndrome resident in Leicestershire, England. The immediate carer of 351 of these (92.8%) was interviewed for the purpose of establishing a past history of seizures, including the age at which the seizures began. The immediate carer was also invited to provide information to enable the completion of an Adaptive Behaviour Scale (A.B.S.) rating. Individuals with a history of seizures were divided into two groups on the basis of whether or not seizures commenced prior to or after age 35 years. Two control groups of individuals with Down's syndrome, but without a history of seizures were selected. Adaptive Behaviour Scale scores for those in whom seizures commenced at a younger age were similar to those who had no recorded history of seizures. However, in those in whom seizures began in later life, scores on all domains of the A.B.S. were significantly reduced compared to both young epileptic patients and their controls. Adaptive Behaviour Scale scores for the older control group held an intermediate position, suggesting that late-onset epilepsy may be a late manifestation of a dementing process. A clinical diagnosis of dementia recorded in the case records was significantly associated with the presence of late-onset epilepsy. This is supportive of the hypothesis that late-onset epilepsy in individuals with Down's syndrome is associated with Alzheimer's disease.
Journal of intellectual disability research : JIDR, 1993 · doi:10.1111/j.1365-2788.1993.tb00582.x