Cognitive and vestibulo-proprioceptive components of spatial ability in Parkinson's disease

Visual-spatial deficits are often associated with Parkinson's Disease (PD). Recent theories suggest that frontal-basal ganglionic dysfunction affects cognition in PD. Although this hypothesis does not entirely explain spatial deficits in PD, the inappropriate utilization of cues associated with exec utive dysfunction may induce spatial deficits. Alternatively, the vestibula r system is also involved in spatial cognition, and vestibular dysfunction may affect visual-spatial ability in PD. To test these hypotheses. we admin istered the Water Jar Test, while perturbing vestibulo-proprioceptive input . Non-demented PD patients were significantly less accurate than controls i n judging horizontal, and appeared to inappropriately utilize cues. No grou p effect was found for head tilt. These findings suggest the visual-spatial difficulties seen in PD are related to executive dysfunction that is assoc iated with a disruption of the frontal-basal ganglionic and frontal-parieta l systems. Published by Elsevier Science Ltd.