Does impaired executive functioning differentially impact verbal memory measures in older adults with suspected dementia?

The purpose of this study was to examine whether executive dysfunction differentially impacts list-learning and story recall tasks in a sample of older adults referred for suspected cognitive impairment. Older adults (N = 61) with mild cognitive impairment (MCI) or probable mild dementia, and those who did not meet criteria for diagnosis of dementia, were assessed using measures of executive function and verbal memory. Two groups were established based on performance on measures of executive function: (a) the No Executive Dysfunction group (NoED; n = 33) consisted of persons without impairment on any obtained measures of executive function; and (b) the Executive Dysfunction group (ED; n = 28) contained persons with impairment on at least one of the measures of executive function. The two groups were compared on performance on two measures of verbal memory, the California Verbal Learning Test-II (CVLT-II) and the Logical Memory (LM) subtest from the Wechsler Memory Scale-Revised (WMS-R). The NoED group performed significantly better than the ED group on the total learning and short delay free recall trials of the CVLT-II. However, there were no significant differences between the groups on the other indices of the CVLT-II (i.e., long delay free recall, recognition, recall repetitions, recall intrusions, or recognition false-positives) or on the immediate and delayed recall trials of the LM measure. These results support previous research demonstrating the impact of executive dysfunction on the acquisition of and short-delay retrieval of verbal information in older adults with suspected cognitive impairment.

Concurrent validity of abbreviated WAIS-III index scores in geriatric outpatients with suspected dementia.

Assessments of older adults with suspected dementia can be time limited and clinicians might consider using abbreviated versions of measures. The present study examined the concurrent validity of abbreviated WAIS-III index scores in a sample of geriatric patients referred for assessment of suspected dementia (N=43; mean age=63.8 years). All 2-subtest estimates of the Verbal Comprehension, Perceptual Organization, and Working Memory index scores accurately estimated more than 80% of cases within +/-2 standard errors of measurement (S.E.M.), and in most cases, more than 90% of cases were accurate at this level. While none of the 1-subtest estimates of these index scores were as accurate, both of the 1-subtest estimates of the Processing Speed index had high clinical accuracy. Abbreviated versions of the four index scores can be substituted in situations with this clinical population where testing time is limited or a patient fatigues easily.

Concurrent validity of WAIS-III short forms in a geriatric sample with suspected dementia: verbal, performance and full scale IQ scores.

Evaluation of intellectual abilities using the WAIS-III is a common component of neuropsychological assessments. However, clinicians might be interested in administering reliable and valid short forms due to practical and clinical reasons. The present study examined the concurrent validity of eight short forms of the WAIS-III with full form IQ scores in a sample (n=43) of geriatric outpatients referred for assessment of suspected dementia. There were no significant differences between the short and full form VIQ scores at P<.01, while half of the short form PIQ and FSIQ scores were significantly different from their respective full form scores at P<.01. Correlations between short and full form IQ scores ranged from .89 to .99. Seven-subtest short forms were able to accurately estimate over 80% of scores within +/-2 S.E.M.s. This study supports limited use of WAIS-III short forms when conducting evaluations of older adults with suspected dementia.