Deep Brain Stimulation in Patients with Traumatic Brain Injury; Facts and Figures.

eep brain stimulation (DBS) is a functional neurosurgery procedure being performed by inserting two specific pace-making probes into specific deep brain nuclei and sending electrical stimulations in order to suppress or stimulate different nerve groups in the nuclei [1]. Currently DBS has been approved by Food and Drug Administration (FDA) for treatment of essential tremor, Parkinson’s disease, dystonia and obsessive-compulsive disorder (OCD) [2]. DBS has also been used in research studies to treat chronic pain and has been used to treat various affective disorders, including major depression; neither of these applications of DBS have yet been FDA-approved [1]. While DBS has proven helpful for some patients, there is potential for serious complications and side effects. Patients suffering from severe traumatic brain injuries (TBI) have several complications attributable to involvement of deep brain nuclei such as tremor, dystonia, behavioral changes, cognitive impairments and somatic symptoms [3]. According to previous successful results of treatment of such impairments using DBS in other population groups (Primary dystonia, Parkinson disease, Alzheimer disease, Multiple Sclerosis) [1], this idea came into existence that DBS can also be effective in patients with severe traumatic brain injuries to treat tremor, dystonia and emotional and cognitive impairments. In this regards, some limited studies have been performed with controversial results. In 1990, Tsubokawa and co-workers [4] in Japan reported results of chronic DBS (stimulation target: the mesencephalic reticular formation and/or non-specific thalamic nucleus) in 8 patients with persistent vegetative state (PVS) after severe TBI. They found that chronic DBS was effective in alleviation of EEG patterns and behavioral arousal responses. After months of treatment, 4 (50.0%) patients emerged successfully from PVS and were able to communicate and express their demands by voice [4]. These researchers followed their study and in 2002 they reported their results in 20 patients [mesencephalic reticular formation in 2 cases and centre median nucleus/parafascicular (CM/PF) complex in 18 cases]. Seven of the patients emerged from the PVS, and became able to obey verbal commands. However, they remained in a bedridden state. These 7 cases revealed a desynchronization or slight desynchronization pattern on continuous EEG frequency analysis [5]. In 2007, a group in USA leaded by Schiff et Ar ch ive of S ID