Impulse control disorder in PD: A lateralized monoaminergic frontostriatal disconnection syndrome?

• We studied Impulse Control Disorder (ICD) in Parkinson’s disease.
• We evaluated striatal and extrastriatal DATSCAN uptake.
• PD-ICD + showed a significant reduction in left putamen and left inferior frontal gyrus.
• Impairment of inter- and intra-hemispheric binding in PD-ICD + patients was evident.
• Left basal ganglia was key in an asymmetric molecular frontostriatal network breakdown.

BackgroundImpulse Control Disorder symptoms (ICD) in Parkinson’s disease (PD) has been recently associated by magnetic Resonance imaging with impaired cortico-striatal connectivity, especially between left putamen and frontal associative areas.Methods84 patients entered the study (21 PD-ICD+ and 64 PD-ICD-) and underwent DATSCAN imaging. The striatal tracer uptake was evaluated using BRASS software (Hermes, Sweden). The whole-brain analysis was performed with Statistical Parametric Mapping (SPM).ResultsPD-ICD+ showed a significant reduction of left putaminal and left inferior frontal gyrus tracer uptake compared to PD-ICD-. Functional covariance analysis using left putamen as the seed point showed that, in contrast to ICD-patients, ICD+ patients had no functional covariance with contralateral basal ganglia and ipsilateral cingulate cortex, as index of an impaired inter- and intra-hemispheric dopamine binding in PD-ICD+.Discussionthe results support and expand the concept of a functional disconnection syndrome linked to ICD symptoms in PD patients through an asymmetric molecular frontostriatal network breakdown with left basal ganglia as central hub.