Thursday, February 23, 2012

DEMENTIA PREVALENCE IN EXTREME OLD AGE

Numerous researchers have extrapolated from dementia and AD prevalence rates in younger people that all centenarians should have at least some degree of cognitive impairment. Yet our studies, as well as those of other centenarian studies, indicate that approximately 20% to 30% are cognitively intact.
Dr. Silver, our lead neuropsychologist, examined a series of 74 centenarians during a 3-year period. Some of their characteristics are noted in Table 2.1, and Table 2.2 lists the neuropsychological tests performed. We are collaborating with other centenarian studies to establish norms for components of the Mattis Dementia Rating Scale and other tests.

The neuropsychological examination, as well as other phenotyping, is performed where the person lives. Specific maneuvers are performed to accommodate for hearing and vision deficits. Multiple visits are performed to prevent fatigue from factoring into the testing, and family is often invited to participate in order to help language barriers.

Table 2.3 summarizes Dr. Silver's neuropsychological test results of 74 subjects. The neuropathological findings for 14 of these participants are summarized in Table 2.4.

It is noteworthy that evidence of microvascular disease was conspicuously absent in the 14 cases found in Table 2.4. We have noted the absence of diagnoses and blood pressure measurements for many of our participants, which would predispose to vascular disease.
We are now in the process of recruiting individuals who are willing to eventually proceed to postmortem autopsy, following them longitudinally with annual detailed neuropsychological examinations. Our aim is to recruit 33 centenarians per year, who live in close enough proximity to the Massachusetts ADRC to ensure that the brain can be obtained within 4 hours of death.

TABLE 2.1 Centenarians Who Have Undergone Neuropsychological Testing
Age range 100-110 years
Gender 86% women, 14% men
Living situation 7% live alone, 26% with family, 67% in nursing homes
Country of origin 50% foreign born

Most frequent birthplaces Italy, Ireland, and Canada Education Mean = 11 years
Range = 1-20 years


TABLE 2.2 Neuropsychological Test Battery

Mini-Mental State Exam
• Mattis Dementia Rating Scale
• Boston Naming Test (CERAD)
• Trail Making Tests
A and B
• Clock Drawing
• Drilled Word Span
• Cowboy Story
(Boston-Rochester)
• Presidents since FDR
Inventory: Self report and Observer report
• Spiers' Calculations


Geriatric Depression Scale
* Telephone Interview for Cognitive Status
• Test for Severe Impairment
• Tactile Naming
• Cognition and Health History (Informant)
• Psychiatry History (Informant)
• Clinical Dementia Rating Scale
• NEO-Five Factor Personality

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