DBS can substantially improve arm tremor (e.g. by over 80%) and, to a lesser extent, midline tremor such as voice and head tremor (e.g. by around 50%). DBS can thereby improve function such as eating, drinking and writing. DBS can reduce or eliminate the need to take anti-tremor medication. DBS is not a cure for tremor and tremor returns when the DBS is switched off. However, DBS almost always remains beneficial for the rest of a patient’s life. DBS can be turned up over time if the underlying tremor worsens over time due to progression of the underlying condition of Essential tremor. We usually recommend turning off stimulation at night to spare battery life and to minimise any potential for side effects to build up or tremor suppression to decay over time.

The major target for tremor is a zone encompassing the motor thalamus (VOP/VIM) and below (posterior subthalamic area). We target both regions in a single trajectory and choose the most effective location to apply stimulation for the individual.

Side effects include slurred speech, imbalance when walking and a tingling sensation. These side effects (if they occur) usually disappear when stimulation is turned down or switched off. Occasionally, a compromise may be necessary between the level of stimulation (and thus tremor control) and any side effect. Occasionally, balance can worsen with the implantation of DBS, and persists when DBS is turned off.

Overall, DBS for arm and leg tremor is usually very effective and can greatly improve function. Head and voice tremor is less responsive to DBS but the benefit can still be substantial. Side effects, if they occur, are typically temporary and can be reversed by reducing stimulation.