Impaired intentional content learning but spared incidental retention of contextual information in non-demented patients with Parkinson's disease.
We investigated the incidental and intentional learning performance of 29 patients with idiopathic Parkinson's disease (PD) and 20 healthy volunteers. Measures of incidental and intentional memory were assessed with a spoken verbal recall task followed by a temporal word order task, a picture recall task followed by a spatial picture location task, and a written word recall task followed by a judgement of word frequency task. A multivariate analysis of variance and appropriate post hoc tests revealed significant differences for all intentional learning variables. In all cases, PD patients performed worse than normal controls. No group differences were found for the incidental retention of contextual information. The results indicate that PD patients have a selective problem of intentional learning, whereas incidental learning of contextual information remains intact. Elaborate processing, attentional and organizing strategies in the systematic encoding, and recollection of information have been attributed to dorsolateral prefrontal activation. Preferential dysfunction of dorsolateral prefrontal cortex-associated memory processes is consistent with the previously reported uneven patterns of dopamine loss in the striatum of patients with idiopathic PD showing most severe dopamine depletion in the portion of the caudate nucleus that is anatomically connected to the dorsolateral frontal cortex.
Vingerhoets
Guy
G
Laboratory for Neuropsychology, Ghent University, De Pintelaan 185-4K3, B-9000 Ghent, Belgium. guy.vingerhoets@ugent.be
Vermeule
Els
E
Santens
Patrick
P
D000368:Aged; D001245:Association Learning / Q000502:physiology; D005260:Female; D006801:Humans; D033182:Intention; D007859:Learning Disabilities / Q000503:physiopathology*; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology*; D012153:Retention, Psychology / Q000502:physiology*; D014706:Verbal Learning / Q000502:physiology