Neuroimaging and neurophysiological evaluation of severity of Parkinson's disease.

Objectives: Parkinson's disease (PD) is a neurodegenerative disease presenting characteristic motor features. Severity is usually assessed by clinical symptoms; however, few objective indicators are available. In this study, we evaluated the utility of dopamine transporter (DAT) imaging and subthalamic nucleus (STN) activities as indicators of PD severity.

Materials And Methods: Twelve hemispheres of ten patients with PD who underwent deep brain stimulation (DBS) were included in this study. Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part 3 scores were used to evaluate clinical severity. The relationship between specific binding ratio (SBR) of DAT imaging and the root mean square (RMS) of STN micro-electrode recording (MER) was evaluated.

Results: A negative correlation was detected between the MDS-UPDRS part 3 scores and SBR (N = 20, R = 0.418; P = 0.002). With respect to subscores, rigidity (R = 0.582; P < 0.001) and bradykinesia (R = 0.378; P = 0.004) showed negative correlation with SBR, whereas tremor showed no correlation (R = 0.054; P = 0.324) (N = 20). On the other hand, no correlation was found between MER and the MDS-UPDRS part 3 scores in ten hemispheres of six patients.

Conclusion: DAT findings may be useful in evaluating PD severity, especially rigidity and bradykinesia.