This article includes Supplementary Video, available online at .

jws-mds.20737.mpg11589K Position-sensitive jaw tremor activated by slight opening of jaw and sipping from an empty cup. Two channel needle electromyography demonstrates 5 Hz rhythmic jaw tremor with alternating pattern of activity in right masseter and digastric muscles. This video presentation has been abbreviated. The full version will appear on theMovementDisorders DVD Supplement, which is issued bi-annually.

Please note: Wiley Blackwell is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.