Relationships between constructional and visuospatial abilities in normal subjects and in focal brain-damaged patients.

We tested 125 normal subjects and 24 right and 22 left focal brain-damaged patients (RBD and LBD) on the Rey figure copying test and on a battery of perceptual and representational visuospatial tasks, in search of relationships between constructional and visuospatial abilities. Selected RBD and LBD were not affected by severe aphasia, unilateral spatial neglect or general intellectual defects. Both RBD and LBD showed defective performances on the constructional task with respect to normal subjects. As regards visuospatial tasks, both patient groups scored lower than normal subjects in judging angle width and mentally assembling geometrical figures; moreover, RBD, but not LBD, achieved scores significantly lower than healthy controls in judging line orientation and analyzing geometrical figures. Post-hoc comparisons did not reveal any significant differences between RBD and LBD. Multiple regression analysis showed that visuospatial abilities correlate with accuracy in copying geometrical drawings in normal subjects and in RBD, but not in LBD. From a theoretical perspective, these findings support the idea that visual perceptual and representational abilities do play a role in constructional skills

Frontal dysfunction contributes to the genesis of hallucinations in non-demented Parkinsonian patients.

BACKGROUND: Hallucinations occur in patients with Parkinson's disease (PD) with reported prevalence ranging from 8% to 40%. Hallucinations are significantly associated with dementia in PD, but little is known about possible distinctive cognitive features of non-demented PD patients who develop hallucinations. OBJECTIVE: The aim of the study was to assess selected cognitive abilities in non-demented PD patients with and without hallucinations in order to identify specific neuropsychological correlates of such phenomena. METHODS: Forty-eight consecutive patients with PD and Mini Mental State Examination (MMSE) > or = 23 were examined for the presence of hallucinations and assessed on standardized neuropsychological tasks for semantic and phonological fluency, verbal learning and logical abstract thinking; disease severity was staged according to Hoehn and Yahr scale. RESULTS: Fourteen (29.2%) of 48 patients experienced hallucinations. There was no difference between hallucinators and non-hallucinators on demographic variables, disease severity and dose of any pharmacological treatment. Disease duration was significantly longer in hallucinator vs non-hallucinator patients (p = 0.02). Patients with hallucinations scored significantly lower than patients without hallucinations only on verbal learning-immediate recall task (p = 0.0324), and semantic and phonological fluency tasks (p = 0.0005 and p = 0.0036, respectively). CONCLUSIONS: Our results suggest that PD patients with hallucinations show reduced performance on tasks that explore executive functioning as compared with non-hallucinators. Therefore, executive dysfunction may be considered as a risk factor for the development of hallucinations in non-demented PD patients