Author response: Therapeutic benefits of early electrophysiological testing in a functional neurology case.

Abstract

We entirely agree with the comments expressed by Professor Hallett et al. in response to our article1 regarding the use of electrophysiology to investigate probable functional neurologic disorders (FNDs). We point out in our article that electrophysiology is typically normal in FNDs and, indeed, is important evidence to support that diagnosis. However, we also mention that a small proportion of FNDs can demonstrate transient electrophysiologic abnormalities and that these seem consistent with other reported abnormal functional imaging, perfusion, and morphometric MRI studies in this group. FNDs are unlikely to be homogeneous disorders, and it may be that these exceptional cases provide insights into underlying mechanisms. This was precisely the reason for reporting this case of abnormal electrophysiology because, in our opinion, there was very robust evidence supporting a FND diagnosis: an incongruous clinical picture, pristine MRI imaging of whole spine and brain, absence of relevant signs, presence of positive phenomena, and rapid recovery.