HSC Section 3 - Trauma, Critical Care and Sleep Medicine

Sun et al

If 90% degeneration is reached within 14 days of onset of paralysis, EMG is per- formed to rule out deblocking. If EMG also shows the absence of motor action po- tentials, the patient is a candidate for surgical decompression. If 90% degeneration is not reached by 14 days, testing is stopped because the patient is likely to have a Fig. 1. ENoG/EMG testing. ( A ) ENoG testing using an evoked, supramaximal impulse to stim- ulate the facial nerve as it exits the stylomastoid foramen and surface electrodes placed over the orbicularis oris to measure the compound muscle action potential (CMAP). ( B ) Sample CMAPs generated during ENoG testing for facial palsy. ( C ) EMG testing with needle elec- trodes placed in the facial muscles.

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