DIFFERENCES BETWEEN MULTI-INFARCT DEMENTIA AND SMALL-VESSEL DISEASE DEMENTIA IN ATTENTION AND WORKING MEMORY DEFICITS

Abstract

Attention and working memory deficit are significantly impaired in patients with small vessel disease dementia, but little is known about diferences in these cognitive domains between subtypes of vascular dementia. 60 patients were studied, 28 were randomised as multi infarct dementia (MID) and 32 in small vessel disease dementia (SVD), according to NINDS- AIREN (National Institute of Neurological Disorders and Stroke and Association Internationale pour la Recherché et l'Enseignement en Neurosciences) neuroradiological criteria. Patients with MMSE (Mini Mental State Examination) score 15–25 were included. Groups have been matched by sex, age and education. Patients with severe aphasia, depression, and hand weakness were excluded. Trail Making Test (TMT) A and B form was used to evaluate: processsing information speed, visuo- conceptual functions, visuo-motor tracking and attention. WMS- R(Wechsler Memory Scale – Revised) visual span subtest and digit-symbol coding subtest on the Wechsler Test of Intelligence was used to measure visual abilities and digit span for verbal capacities of attention and working memory. Processing information speed was significantly slower, and conceptual skills were more impaired in MID than in SVD group (p = 0,012), with coefficient of discrimination between reaction time 0,068 for TMTA and 0,022 for TMT B. There were no differences between groups in verbal and visual span WMS-R scores forward, but either verbal or visual backward scores and Digit Symbol Test score were significantly lower in MID (p=0,002). Coefficient of discrimination for verbal span backward was 0.122, for visual span backward was 0.109, for verbal span forward was 0,066 and for visual span forward was 0,064. The most predicatable scores were proposed for each group of vascular dementia patients (MID ˂2, SVD 3 and ˃3 for verbal span backward; MID ˂2, SVD 4 and ˃4 for visual span forward, MID ˂ 4, SVD 6 and ˃6 for visual span forward MID ˂3, SVD 4 and ˃4 for visual span forward; MID 0, SVD 1–6, and ˃6 for digit symbol coding). Attention and working memory deficit are more severe in MID than SVD.