Onset of seizures as a poor indicator of longevity in people with down syndrome and dementia

✍ Scribed by Dr. V. P. Prasher; J. A. Corbett

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 375 KB
• Volume: 8
• Category: Article
• ISSN: 0885-6230
• DOI: 10.1002/gps.930081106

✦ Synopsis

An association between Down syndrome and dementia of Alzheimer type is well established. This study demonstrates that late onset seizures in people with Down syndrome are a strong indicator of a dementing process. Further, late onset seizures in people with Down syndrome may be used as a prognostic indicator, indicating life expectancy of less than a further 2 years, probable death within 3 years and death almost invariably within 5 years of onset.

KEY woms-Down syndrome, dementia, seizures, longevity.

During the latter half of this century the life expectancy of people with Down syndrome (DS) has increased considerably (Oliver and Holland, 1986;Prasher, 1992). Many individuals will live into middle age and beyond (Baird and Sadovnick, 1988). However, above the age of 40 years there is a dramatic rise in the mortality rate for individuals compared to those below this age (Thase, 1982). This is in part related to the increase in neuropathological changes of Alzheimer disease in the brain and the onset of clinical dementia (Mann, 1988;Prasher, 1993;Prasher and Krishnan, 1993).

Studies of longevity in adults without mental handicap but with the presence of dementia suggest longevity may range from a few months to several decades, with an average life span from time of diagnosis to death of 7 years (Sjogren et al., 1952). Between 25 and 30% live over 10 years, and some may live as long as 20 years (Corsellis, 1976; Katzman et al., 1978). For people with DS, Prasher and Krishnan (1993) recently reviewed the published case reports of 98 people with DS with respect to the age of onset and duration of clinical dementia. They found a mean age of onset of 5 1.7 years (range 31-68 years) and a mean duration of dementia of 6 years (range 0.5-21 years).