Cerebral blood flow and cognitive function in Parkinson's disease

Abstract

To evaluate visual cognitive and memory function in patients with Parkinson's disease (PD), we performed the Rey–Osterrieth complex figure (ROCF) test in 24 patients with PD and 12 normal control subjects. In the ROCF test, the copy score (copy 0) was used to evaluate visuospatial constructive function; the recall score (recall 30) 30 min after copying the ROCF and the percentage recall score (%recall 30=100×{1−[copy 0–recall 30]/copy 0}) was used to evaluate visuospatial memory function. Regional cerebral blood flow (rCBF) in the PD patients was measured using single-photon emission computed tomography (SPECT) and 123I-iodoamphetamine as a tracer. Measurement of rCBF was performed semiquantitatively using the RI count ratio to the cerebellar region. The recall 30 and %recall 30 scores were significantly lower in the PD patients than the normal controls. The copy 0 score was correlated with rCBF in the lateral and medial prefrontal cortex. Both the recall 30 score and the %recall 30 score were correlated with rCBF in the posterior parietal cortex. In addition, the %recall 30 score was correlated with the lateral occipital cortex. The present study suggests that the impairment of visuospatial constructive function in PD patients may be related to a reduction in rCBF in the frontal cortex, while impairment of visuospatial memory function may be related to a reduction in rCBF in the posterior parietal and occipital cortex.