Purposely Induced Tics: Electrophysiology

Abstract

Tics are non-rhythmic movements that can be simple or complex. Clinically, they may appear as quick voluntary movements (50–200 ms), but can also be longer and more sustained (>300 ms). These movements are often described as being predictable. An inner tension builds which is relieved by the movement in most cases, and the movement can be suppressed for some time. Most patients report a feeling of relief once they release the movement, and therefore do not prolong the suppression. Thus, to some extent, the movement is under voluntary control. Tics have been called “unvoluntary”; a movement between voluntary and involuntary behavior.4 Here we present a person who can purposely induce tics. Simultaneous electroencephalography (EEG) and electromyographic (EMG) activity were recorded to capture the Bereitschaftspotential (BP) to explore the physiology of this phenomenon.