Teaching Video NeuroImages: Re-emergent jaw tremor in Parkinson disease.

A 77-year-old woman who was diagnosed with Parkinson disease at 51 years of age presented with a 4-year history of intermittent jaw tremor. This was present at rest and declined in amplitude during voluntary movements. Tremor reappeared after the patient bit a tongue depressor continuously for 10 seconds (video on the Neurology® Web site at Neurology.org). “Re-emergent tremor” is a postural hand tremor that appears after some delay while maintaining a posture and is similar to the classic resting tremor of Parkinson disease. Re-emergent jaw tremor may represent an additional type of tremor characteristic of Parkinson disease.