Diagnosing dementia in the oldest-old

Abstract

The “oldest-old” comprise the fastest growing segment of the population in much of the world. Rates of dementia are extremely high in this age group and will present a major public health burden as the numbers of these individuals quadruple by the middle of the century. Studies in this age group are rare and frequently have small numbers of participants. In research studies and the clinic, the diagnosis of dementia and determination of the etiology of the disorder are challenging. In this review, we include some of our experiences in a population-based longitudinal investigation, The 90+ Study. Oldest-old individuals are more likely to suffer from medical comorbidities and have high rates of sensory loss, psychoactive medication usage, frailty and fatigue. Moreover, social and cultural expectations affect the reporting and interpretation of behavioral changes. These and other factors make it difficult to determine the relative contributions of cognitive losses and non-cognitive losses in the development of functional disability. Contributing further to the complexities of diagnosis, current research suggests that dementia in the oldest-old, compared to younger people, is more likely to be related to mixed disease pathologies. Frequent cerebral neuropathologies include Alzheimer’s disease neurodegeneration, small and large vessel vascular disease, and hippocampal sclerosis. More research is necessary in the oldest-old to better understand the etiologies of dementia in this age group, and factors that may affect the expression of disease as we age.

Alzheimer disease pathology and longitudinal cognitive performance in the oldest-old with no dementia

“…For instance, 72% of participants in The 90ϩ Study have sensory deficits (i.e., vision loss) and at least 20% of participants report being fatigued. 26 Fourth, we did not examine comorbid pathologies such as hippocampal sclerosis or cerebrovascular disease given the low prevalence of these pathologies in our participants without dementia. Hippocampal sclerosis is not found in the brains of our participants without dementia and less than 12% have infarcts at autopsy.…”

Prognostic Significance of Dementia in Older Adults with Solid Tumors

“…From 3,460 patients, 132 patients fulfilled the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) for dementia which requires 2 main components: (1) loss of memory and at least 1 other cognitive domain, and (2) a decline in social or occupational performance [6]. The diagnosis of dementia was made at any time before or after the diagnosis of solid tumors.…”

Investigating Discontinuity of Age Relations in Cognitive Functioning, General Health Status, Activity Participation, and Life Satisfaction between Young-Old and Old-Old Age

“…For example, in contrast to young-old age there are losses in cognitive functioning such as plasticity, some aspects of learning, and memory in old-old age [4,5,6,7]. While prevalence rates of Alzheimer’s disease are rather low in young-old age (about 2%–3%), they are substantially increased in old-old age (about 40%–50% [8,9]). Overall, functioning seems to be to a degree lower in old-old compared to young-old age, for which a simple linear progression across the entire old-age lifespan would not be sufficient to explain [10,11,12].…”