Patient Selection Criteria for Deep Brain Stimulation for Parkinson Disease

Patient selection is critical for optimizing clinical outcomes after deep brain stimulation (DBS) surgery. Patient expectations need to be addressed before DBS surgery to avoid disappointment. There are generally accepted criteria for DBS candidacy for treatment of Parkinson disease (PD), essential tremor (ET), and dystonia. For PD, selection criteria include a diagnosis of idiopathic PD and the presence of disabling or troubling motor symptoms such as motor fluctuations or dyskinesia (despite optimized pharmacologic treatment). Medication-resistant tremor is also an indication. The response of problematic motor symptoms to dopaminergic drugs is an important predictor of DBS response, favoring selection of patients for whom levodopa substantially improves tremor, bradykinesia, and rigidity. Rarely, gait is improved with DBS, and in some cases freezing can improve, although this is not a predictable post-DBS feature. Exclusion criteria include serious medical comorbidities, uncontrolled psychiatric illness (thought and mood disorders), and dementia. Preoperative magnetic resonance imaging with extensive white matter changes, vascular malformations, severe cerebral atrophy, or hydrocephalus can also be exclusions. The patient should clearly understand the risks and benefits of DBS, which should be assessed using a preoperative multidisciplinary evaluation (neurology, neurosurgery, neuropsychology, psychiatry, and rehabilitation). Use of a social worker and/or nutritionist can also be helpful in select cases.