New Insights Into Dementia Testing

According to an article published in the August 20 issue of JAMA,
there is likely an association between within-person variability on
neuropsychological testing and the development of dementia in older
adults.



Roee Holtzer, Ph.D. (Albert Einstein College of Medicine, Yeshiva
University, New York) and colleagues write that, "Developing strategies
to improve the prediction and diagnoses of dementia has paramount
therapeutic and public health implications." They add: "When
neuropsychological tests are used for diagnostic purposes, an
individual's level of performance on specific tests is measured against
healthy normative samples to determine cognitive impairment. However,
this approach does not take into account intra-individual variability
in cognitive function." This means that standard approaches fail to
deal with inconsistency in cognitive performance within a
person.



The study consisted of 897 individuals, age 70 or older, who are part
of The Einstein Aging Study - a longitudinal study taking place in
Bronx County, New York that focuses on aging and dementia. Every 12 to
18 months, participants had follow-up visits and underwent detailed
neurological and neuropsychological evaluations. Participants were
tested for verbal IQ, attention/executive function, and memory. The
researchers were interested in finding out if within-person
across-neuropsychological test variability could be used to predict
future dementia.



"Of the 897 participants," the authors find, "there were 61 cases of
incident dementia (6.8 percent) ??¦ identified during the follow-up
period (mean [average] 3.3 years)." They also report that, "On the
basis of the consensus clinical diagnostic procedures, 47 participants
developed incident dementia of the Alzheimer type and 18 participants
developed incident vascular dementia. During the study, 128 individuals
died, as expected for the age of this cohort. Of these, 18 had
developed incident dementia."



"In summary, within-person across-neuropsychological test variability
was associated with development of dementia independently of
performance of the neuropsychological tests. This finding needs to be
replicated in different populations before it is applied in a clinical
setting," conclude the authors.



Within-Person Across-Neuropsychological Test Variability and
Incident Dementia

Roee Holtzer; Joe Verghese; Cuiling Wang; Charles B. Hall;
Richard B. Lipton

JAMA(2008).
300[7]: pp. 823-830.

Click
Here to View Abstract



Written by: Peter M Crosta