The role of the somatosensory cortex in self-paced movement impairment in Parkinson's disease.

OBJECTIVE

The aim of this work was to study the differences at the whole-brain level between self-paced and cued movement processing in Parkinson's disease (PD).

METHODS

High density electroencephalogram (HD-EEG) was recorded during the performance of self-paced movements (Bereitschaftspotential - BP) and visually cued movements (VMT) in PD patients (n = 38) and in a group of healthy controls (HC, n = 23). Oscillatory changes in the alpha, beta, and gamma frequencies were evaluated and correlated to the clinical scales- MDS-UPDRS and Freezing of Gait Questionnaire (FOGQ).

RESULTS

The main difference in the alpha range was an activation in the basal ganglia area during VMT performance as compared to BP performance; this activation was present only in HC. The most important finding was observed in the high beta range: a higher activation of the right postcentral area during BP performance in PD subjects as compared to HC, correlating to the severity of FOG. Moreover, PD patients had lower gamma activation of the right frontal areas.

CONCLUSION

A simplification of motor circuits and a hyperactivation of the right somatosensory cortex were observed in PD subjects.

SIGNIFICANCE: Future studies should be focused on this area to confirm or disprove its role in FOG.