Nosography of the "essential": volitional palatal tremor.

A 19-year-old heavy metal singer with a history of congenital micrognathia, post-traumatic stress disorder, and anxiety developed isolated movements of the soft palate after lower mandible corrective surgery (osteotomy and genioplasty). He endorsed ear clicks and control over the movements. On examination, there were rhythmic movements of the distal soft palate, characteristic of essential palatal tremor (EPT). However, their change in frequency and amplitude on command (video on the Neurology(R) Web site at www.neurology.org) indicated volitional control. Unlike psychogenic EPT, whereby variability and entrainability must be present(1) and endorsed as involuntary ("a-volitional"), patients with volitional EPT admit to full control and no disability (figure). They have also been categorized as the "voluntary/special skill" EPT variant.(2) No neurologic investigations are warranted in patients with volitional EPT.