Calibration of clinical cerebellar and deep brain stimulation systems.

The increasing use of electrical stimulation of the brain for relief of pain, spasticity and epilepsy has introduced unfamiliar techniques into clinical neurological and neurosurgical practice. In view of the evidence that excessive levels of stimulation can damage brain tissue, it is of great importance to monitor the dose of stimulation. A review of recent clinical papers suggests that many centres do not measure the dose accurately, relying on arbitrary dial settings on external transmitters. This paper reviews that factors that affect the dose received by the patient and suggests methods of measuring them, at operation and subsequently, which should routinely be employed by clinicians implanting stimulators.