A Comparison of Cognitive Impairments in Dementia of the Alzheimer Type and Depression in the Elderly

Abstract

General cognitive function and specific language and memory processing abilities were compared in dementia of the Alzheimer type (DAT), depressed and normal control subjects. Several tests clearly differentiated between DAT and depressed subjects including a verbal fluency task, several components of a word memory test, an IQ deterioration index, and the Mini-Mental State Examination. The inability of DAT subjects to take advantage of semantic cues in both the verbal fluency and in the memory test contrasted with the performance of depressed and normal subjects, who were able to benefit from semantic cues. Depressed patients displayed deficits compared with normal controls on the more effortful verbal fluency task but not on the memory test. Tasks that are least effortful, rely on semantic associations, and require declarative memory are most likely to discriminate between DAT and depression.

Negligible Effects of Depression on Verbal and Spatial Performance in Alzheimer’s Disease

“…The results demonstrate that it did not: no differences between the AD and AD/D groups were observed in letter fluency, category fluency, block design or clock drawing. The lack of additional effect of depression on verbal and visuospatial performance in AD should be viewed in light of the fact that depression-related deficits have been observed in these cognitive domains among nondemented individuals [17 [20][21][22]32]. Moreover, the nonexistent effects of depression in this study may not be attributable to measurement artifacts; no floor or ceiling effects were apparent in the data.…”

“…There is some evidence to suggest that verbal skill is more compromised in depression than is episodic memory [20,32]. Thus, it is possible that effects of depression on cognitive performance in AD may be more easily detected for language-oriented tasks than for memory tasks.…”

Psychometric Analysis of the Selective Reminding Procedure in a Sample from the General Elderly Population

“…When memory performance was compared between groups of patients with different brain disorders by means of the SRP, no differential deficits were found with the SRP scores, although differential memory deficits have been described with other memory tests (e.g. depression vs. dementia [27][28][29]; Alzheimer vs. multi-infarct dementia [26]). …”

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

“…who took a detailed history, performed a mental state and physical examination and administered the MMSE and the 21-item Hamilton Depression Rating Scale (HAM-D) [26]. Mean severity of depression on the HAM-D was 18.5 (standard deviation = 2.97, range [14][15][16][17][18][19][20][21][22][23][24][25]. At the time of assessment 12 depressed patients were taking benzodiaze pines and 4 were taking antidepressant medication (see table 1 for mean age and MMSE scores).…”

“…In this context, depressed patients present a useful comparison group, as the clinical differentiation of depression and dementia remains problematic, particu larly when dementia is very mild [12,13]. Although global cognitive screening tests such as the Mini Mental State Examination (MMSE) [14] can differentiate between de pression and modcrate-to-severe AD [15], such tests are [12,17], In contrast to the characteristic memory deficits already outlined for AD, memory impair ments in depression seem mostly due to defects in atten tion and motivation [17] and the rate of forgetting within the first 10 min appears to be normal [ 18]. As the extended DWR test appears to be highly sensitive for AD, the present study sought to evaluate both its sensitivity and specificity in discriminating depressed patients and AD patients with very mild cognitive impairment.…”