[Memory deficit in patients with subcortical vascular cognitive impairment versus Alzheimer-type dementia: the sensitivity of the 'word list' subtest on the Wechsler Memory Scale-III]

Abstract

Introduction: Memory deficits are frequent in mild subcortical vascular pathology and in the early stage of Alzheimer's disease.

Aim: To study the memory deficits in patients with subcortical vascular cognitive impairment (SVCI) vs. mild stage Alzheimer's disease patients (AD), using the Weschler Memory Scale-III (WMS-III) word lists test, to examine the adequacy of this test to show the different memory patterns in this population, that could contribute to early differential diagnosis.

Patients and methods: Three groups of patients were compared: AD (n = 25), SVCI-leukoaraiosis (n = 17) and SVCI-multi infarct (n = 16). The three groups did not differ in age, education or severity of illness.

Results: Patients with SVCI showed a memory impairment in free recall with an improvement in their performance on the recognition task. The AD group, however, showed low scores in free recall as in recognition tasks, with a major number of false positive errors. Significant differences were also found between the SVCI-leukoaraiosis and SVCI-multi infarct groups, with the latter showing the best performance in long term retention and a minor trend to respond with false positive errors.

Conclusions: The WMS-III word lists test is a good instrument to differentiate the memory profile between SVCI and AD, with the recognition task being the most discriminative one. The worst impairment in leukoaraiosis patients in comparison to the multi infarct group, suggests that white matter diffuse lesion could affect more directly the recall processes mediatised by the frontal lobe.