The brain cells function by electrically encoding, processing and transmitting information. Deep brain stimulation affects the electrical functions of neurons, but the mechanism by which it alters those functions, are unknown. According to some hypothesis, the reduction of the effects of an abnormal neuronal activity occurs because of inhibition, depolarization blockade or the adjustment of neuronal activity to a constant rate.
Inhibition – The depolarization of axons terminating in target structure by deep brain stimulation causes these terminals to discharge and release neurotransmitters. Deep Brain Stimulation may cause a flood of inhibitory neurotransmitters that effectively shuts down neurons in the target structures.
Depolarization blockade – If a neuron is constantly depolarized but below the threshold need to produce an action potential, the threshold for producing an action potential increases. Neurons firing are difficult as the threshold increases.
Altering erratic neuronal activity – Deep Brain Stimulation alters the abnormal discharge activity that results from the disease. It has been suggested that irregular or chaotic firing of neurons may be more disruptive of normal function than a constant and regular pattern of activity. Deep Brain Stimulation drives the abnormally discharging neurons into a pattern of more regular firing that is less deleterious.
Indications – Deep brain stimulation (DBS) has become an effective therapy option for several different neurologic and psychiatric conditions, including PD. It currently has the US Food and Drug Administration approval for Parkinson’s disease, essential tremor, dystonia and obsessive-compulsive disorder. For PD treatment, it is currently approved specifically for those patients suffering from complications of pharmacotherapy, including motor fluctuations or dyskinesia and a disease process of at least 4 years of duration. Studies have demonstrated DBS and medical management is superior to medical management alone in selected PD patients.
Deep brain stimulation (DBS) is done in patients with a variety of neurologic conditions such as:
- Essential tremor
- Parkinson’s disease
- Tourette syndrome
- Chronic pain
- Obsessive compulsive disorder
- Major depression
It is been studied on an experimental basis for the treatment for stroke recovery, addiction and dementia.