Fig. 4.

Relationship between symptom asymmetry and neural asymmetry. Asymmetry of UPDRS/MDS-UPDRS symptoms is shown on the y-axis, while asymmetry of right hand beta ERD power in the primary motor cortices is shown on the x-axis. Negative UPDRS asymmetry values reflect patients who had symptoms that were left-dominant, while positive values reflect patients whose symptoms were right-dominant. Negative neural asymmetry values reflect relatively greater beta ERD in the left (contralateral to movement) primary motor cortex, while positive neural asymmetry values reflect relatively greater beta ERD in the right (ipsilateral to movement) primary motor cortex. There was a significant relationship between symptom asymmetry and neural asymmetry, r(15) = 0.486, p = 0.048, such that the more left-lateralized the symptomatology, the more left-lateralized the beta ERD, and in contrast, the more right-lateralized the symptomatology, the more right-lateralized the beta ERD response, controlling for symptom severity.