Clinical characteristics of essential tremor
The first segment shows a 65-year-old woman with mild bilateral slightly asymmetric postural tremor affecting the arms, most significantly in amplitude at the wrist joint, rather than more proximal or distal joints. Generally, the tremor involves wrist flexion-extension rather than rotation-supination. The kinetic component is observed during a dot approximation task. The next segment shows a 60-year-old man with a similar asymmetric postural arm tremor. The final segment reveals the out-of-phase character seen in some patients (seesaw effect seen when arms are held in the wing-beating position). When a bimanual task is performed (not shown in the video), the movement direction of one side could potentially cancel the out-of-phase direction of the other side; this can be leveraged by the patients during a functional task.