Deep brain stimulation and tremor.

Deep brain stimulation (DBS) has been used to treat various tremor disorders for several decades. Medication-resistant, disabling essential tremor (ET) is the most common tremor disorder treated with DBS. The treatment has been consistently reported to result in significant benefit in upper extremity, as well as head and voice tremor, all of which were improved more dramatically with bilateral procedures. These benefits have been demonstrated to be sustained for up to 7 years. DBS has also been shown to be beneficial for the tremor associated with multiple sclerosis and post-traumatic tremor; however, fewer cases have been reported and the benefit is less consistent, less dramatic, and more transient than that seen with ET. The ventral intermediate nucleus of the thalamus is the most common DBS target for tremor disorders, but more recent studies have demonstrated benefits in tremor from DBS of the subthalamic area, primarily the zona incerta. Surgical complications are relatively uncommon and are generally less frequent than those seen with thalamotomy. Stimulation-related effects are usually mild and resolve with adjustment of stimulation parameters. DBS is thus a relatively safe and effective treatment for tremor disorders, particularly for medication-resistant, disabling ET, but may also have some role in medication-resistant, disabling tremor associated with multiple sclerosis and traumatic head injury.