C. P. Maguire

Letter and Category Fluency in Alzheimer's Disease: A Prognostic Indicator of Progression?

This study investigated differential patterns of performance by 40 Alzheimers disease (AD) patients on standardised letter and category fluency tests. The performance of 24 age and education matched controls was used to classify patients as relatively more letter fluency impaired (L < C, n = 15) or more category fluency impaired (C < L, n = 25), and clinical features distinguishing these patient subgroups were investigated. Category performance was equally impaired in both patient subgroups, whereas the L < C subgroups were particularly impaired on letter fluency. The subgroups differed significantly in duration of illness (24 months for L < C group, 47 months for C < L group; t = 2.69, p = 0.01) but did not differ in global dementia severity, age, education, general language ability, or functional status. Data on annual rate of change (ARC) on the Mini-Mental State Examination were available for 26 patients. While not statistically significant, subgroup ARC differences were suggestive of more rapid decline in the L < C patients, consistent with the finding of shorter duration of illness in this group. Word fluency tests may have potential as early predictors of rate of progression in AD.

Distinguishing between Patients with Depression or Very Mild Alzheimer's Disease Using the Delayed-Word-Recall Test

The present study investigated the accuracy of an extended version of the Delayed Word Recall (DWR) test in distinguishing patients with very mild Alzheimers disease (AD) (Mini Mental State Examination score > or = 23) from community-dwelling depressed/dysthymic patients. The DWR test was administered to 26 non-depressed patients who, at the time of DWR administration or on follow-up, fulfilled NINCDS/ADRDA criteria for probable AD, and to 20 age-matched non-dementing patients with a diagnosis of major depression (n = 12) or dysthymia (n = 8) according to DSM-III-R criteria. Sensitivity and specificity were, respectively, 96 and 100% for DWR free recall, and 92 and 100% for DWR recognition. In this study both DWR free recall and recognition measures were highly sensitive and specific in distinguishing very-mild-AD patients from depressed/dysthymic patients. The investigation of more severely depressed patients is warranted.

Memory impairment in Alzheimer's disease: replication and extension of the delayed word recall (DWR) test

Objective: The original DWR test, which measured delayed free recall, was reported to have high predictiveaccuracy in discriminating Alzheimers disease (AD) patients from control subjects (overall accuracy of 95%).Comparison of differential performance in free recall and recognition of the same material may be of clinical interest. In the present study a delayed recognition component was added to the DWR test and the utility of both measures in discriminating AD patients from control subjects was evaluated. Procedure: This extended version of the DWR test was administered to 66 patients meeting NINCDS/ADRDA criteria for probable AD and 42 control subjects. Results: In a comparison between 42 of these patients (MMSE range 18–29), and 42 age matched healthy controls, both the delayed free recall and recognition measures were highly accurate in distinguishing patients from controls. The free recall measure achieved 98% sensitivity, specificity and overall accuracy, while the recognition measure yielded 98% sensitivity, 95% specificity, and 96% overall accuracy. The recognition performance of all 66 patients, ranging in severity from very mild to severe (MMSE range 11–29), was also evaluated to determine its relationship, if any, to measures of global cognitive impairment. While therecognition measure correlated poorly with MMSE and CAMCOG there was a modest but significant correlation with the CAMCOG memory subscale. Conclusions: In this study of highly selected AD patients both the free recall and recognition measures were sensitive and specific indicators of AD compared to control subjects. Recognition performance appears to be more closely related to degree of amnesia than to degree of global cognitive impairment.