Subthalamic nucleus stimulation in Parkinson's disease.

Deep brain stimulation (DBS) is an effective surgical treatment for advanced Parkinson's disease (PD), with significant advantages in morbidity-mortality and quality of life when compared to lesion techniques such as thalamotomy and/or pallidotomy. The procedure is indicated in patients with severe resting tremor, unresponsive to conventional medical treatment or with motor complications. The most commonly reported complications in the intra- and post-surgical period are aborted procedure, misplaced leads, intracranial haemorrhage, seizures and hardware complications, whereas in the long-term period, cognitive and psychiatric complications can be observed. The most important eligibility criteria for DBS are: a correct diagnosis of idiopathic PD, severity of illness, a consistent levodopa response and absence of cognitive impairment. Chronological age and mood disorders may be relative contraindications to be individually evaluated. Tremor, rigidity dystonias and dyskinesias improve dramatically after DBS; freezing, postural instability and falls remain unchanged, whereas verbal fluency and dysarthria are known to worsen.