ORIENTING OF VISUAL-ATTENTION IN ALZHEIMERS-DISEASE - ITS IMPLICATIONIN FAVOR OF THE INTERHEMISPHERIC BALANCE

Visual attention in dementia of Alzheimer's disease (AD) has not been investigated as extensively as memory or language. The aim of this res earch was to study the orienting of attention in patients with AD (whi ch temporo-parietal areas are primarily affected) compared with patien ts with Parkinson-Dementia, Parkinson's disease, and normal controls, using the Posner paradigm, Subjects were instructed to respond by pres sing a response key after the appearance of a target at the same locat ion (valid trial) or at the opposite location (invalid trial) indicate d by a central cue (arrow). According to the experimental procedure de veloped by Posner, ii has been hypothesized that parietal lobes are in volved In ''disengagement operation'' (when attention has to move from one location to another in the controlateral field). Results showed n o differences between AD and the other groups and between left and rig ht hemifield. In conclusion. the authors did not find any sign of diff iculty with disengagement, and results are discussed in terms of Kinsb ourne's interpretation of a balance between hemispheres.