[How to use clinical neurophysiology in functional neurological disorders (FND)?]

I have reviewed the utility of clinical neurophysiological examinations in recently highlighted functional neurological disorders (FND) focusing mainly on functional movement disorders (FMD). There are many neurophysiological methods useful for diagnosis of FMD. I will hereafter summarize a few of them in the following part. Surface EMG: This is one of minimally required examinations for clinical analysis of movement disorders. It plays roles in the exclusion of organic disorders and showing positive findings to support FND, especially for functional tremor. The power spectral analysis of surface EMG clearly proves a few useful findings, such as entrainment, distraction and others. Somatosensory evoked potential (SEP): Giant SEP is critical because it proves organic disorders with hyperexcitability of the sensory cortex. Single pulse transcranial magnetic stimulation (TMS): Normal motor evoked potential (MEP) showing intact corticospinal tracts is a positive finding for functional paresis patients. It is also useful to exclude the corticospinal tracts organic dysfunction. Jerk-locked back averaging (JLA), bereitschaftspotential (BP), event related desynchronization (ERD): These are sometimes used for functional disorders, but their clinical validity remains to be determined.