Cognitive deficits and striatal dopaminergic denervation in Parkinson's disease: a single photon emission computed tomography study using 123iodine-beta-CIT in patients on and off levodopa.

Cognitive deficits affecting executive (frontal) functions have been widely described in Parkinson's disease (PD). However, dopa therapies are generally ineffective at reversing these deficits, except for tasks involving a sharing of attention such as working memory or simultaneous processing tasks. The aim of this study was to assess the relation between the nigrostriatal dopaminergic denervation in PD, as measured by SPECT with (123)Iodine-beta-CIT and the cognitive deficits, as measured by a simultaneous processing task, which had already been shown to be sensitive to dopa treatment.