The High Value of External Anal- and Urethral-Sphincter Electromyography in Differential Diagnosis with MSA-P, PD, and PSP.

The average duration of MUPs and the ratio of the simple phase and simple-mix phase of EAS-EMG and US-EMG all can provide the basis for the differential diagnosis between MSA-P and PD. US-EMG can be used as a supplement to differentiate MSA-P from PD when EAS-EMG is limited. The only discriminating indicator between MSA-P and PSP seems to be the average duration of MUPs of EAS-EMG and US-EMG. There is still a lack of diagnostic electromyography indicators between PD and PSP.