Brent J. Small

Cognitive predictors of incident Alzheimer's disease: a prospective longitudinal study.

The present study examined whether cognitive variables measured at baseline could predict incident cases of Alzheimers disease (AD) after a 3-year follow-up period. Twenty-six incident AD adults and 179 very old (M = 83.5 years) adults without dementia participated in a population-based study. Cognitive performance was indexed by the Mini-Mental State Examination (MMSE) and multiple indices of memory and visuospatial and verbal performance. A logistic regression analysis that controlled for age, gender, and education indicated that MMSE scores were reliable indicators of who would develop AD. In addition, recall of organizable words, recognition of faces, and letter fluency were reliable predictors of subsequent dementia status after differences in MMSE performance were partialed out. Thus, although the MMSE is useful in predicting dementia, there is an additional advantage of assessing specific indices of cognitive functioning. Further, supportive episodic memory tasks may be more salient predictors of incident AD than tasks that offer less supportive encoding or retrieval conditions.

Three-year changes in cognitive performance as a function of apolipoprotein E genotype : Evidence from very old adults without dementia

This study examined whether baseline cognitive performance and 3-year longitudinal changes were influenced by apolipoprotein E epsilon 4 (APOE-epsilon 4) allele. Participants consisted of 20 APOE-epsilon 4 (2 epsilon 2/epsilon 4; 17 epsilon 3/epsilon 4; 1 epsilon 4/epsilon 4) and 54 non-epsilon 4 (12 epsilon 2/epsilon 3; 42 epsilon 3/epsilon 3) very old adults without dementia (M = 81.82 +/- 5.06 years) participating in a population-based longitudinal study. Cognitive performance was indexed by the Mini-Mental State Examination and multiple indexes of memory, visuospatial, and verbal performance. The results indicated no significant baseline differences between the 2 APOE groups in any cognitive performance measure. However, analyses revealed that the APOE-epsilon 4 group experienced greater negative change in recognition memory for faces and words. Changes in tasks assessing other abilities did not vary as a function of APOE status. The authors concluded that APOE-epsilon 4 status may not influence cognitive performance in adults without dementia and speculated that when such effects do occur (e.g., decline in recognition memory), these may be related to impending dementia, rather than to the influence of the specific genotype on cognition in normal aging.

Cognitive correlates of mortality: evidence from a population-based sample of very old adults.

The authors examined performance on memory, visuospatial, and verbal tasks and subsequent mortality in adults 75-95 years. The sample consisted of 178 living and 44 deceased participants. Mean-level analyses revealed mortality group differences for all domains of cognitive functioning. A Cox regression analysis, independent of age, gender, education, functional ability, and chronic illness, indicated that measures of word recognition and category fluency were significant predictors of mortality status. The results indicate a relationship between cognitive performance and subsequent mortality status in very old age and suggest that episodic memory and verbal skill may be particularly sensitive in predicting such effects.

Cognitive changes in very old persons with dementia: the influence of demographic, psychometric, and biological variables.

Longitudinal changes in global cognitive functioning, indexed by the Mini-Mental State Examination (MMSE), in subjects with dementia (Alzheimers disease and vascular dementia) were examined. The roles of several demographic, psychometric, and biological indices in predicting cognitive deterioration were also examined. The sample consisted of 36 very old (M age at entry = 83.0 years, range = 75-95) adults with dementia from a community-based study. Subjects were tested on two occasions separated by approximately 2.5 years. Results indicated significant longitudinal decline in MMSE scores over the retest interval; the average decline was estimated as 2.43 (SD = 1.81) points per year. Several factors were associated with cognitive deterioration. Higher initial MMSE scores were associated with greater deterioration, whereas superior forward digit span and Block Design at entry were associated with attenuated decline, once differences in baseline severity were accounted for. By contrast, a variety of other putatively important variables exhibited no relationship to decline, including age, gender, education, onset age, dementia type, backward digit span, as well as a number of biological parameters (e.g., vitamin B12, folic acid). The results suggest that although the magnitude of cognitive deterioration in dementia is highly variable, several indicators may be useful predictors of future changes in cognitive functioning.

Predictors of Longitudinal Changes in Memory, Visuospatial, and Verbal Functioning in Very Old Demented Adults

Longitudinal changes in memory, visuospatial and verbal functioning in a sample of demented persons were examined. The role of several demographic, psychometric, and biological indices in predicting the rate of cognitive deterioration was also investigated. The sample consisted of 31 very old (mean age at entry = 83.5 years, range = 75–95) persons with Alzheimer’s disease (n = 22) and vascular dementia (n = 9) from a community-based study. Subjects were tested on two occasions separated by approximately 2.5 years. Results indicated significant longitudinal decline in verbal fluency and visuospatial ability, but only on 1 of 3 measures of episodic memory. Results from regression analyses indicated that a variety of putatively important variables, including age, gender, education, digit span, as well as a number of biological (vitamin B12, TSH), dementia etiology, and psychometric (digit span) indicators, exhibited no relationship to rate of memory, visuospatial, or verbal decline. The results suggest that the rate of cognitive deterioration in dementia is highly variable, and this variability in change appears to include a variety of characteristics. A possible reason thereof may be that the role of individual-difference variables for cognitive functioning in dementia is overshadowed by the pathogenetic process itself.

7.10 – Cognitive Development in Alzheimer's Disease: Charting the Decline Process

Research on cognitive functioning in Alzheimer´s disease is reviewed with regard to preclinical identification, early clinical detection, and staging. Methodological problems associated with research targeting these specific stages of the disease are addr