ABCs of Brain Stimulation Therapies
November 7, 2018
Brain Stimulation has been used as treatment for various mental disorders by using direct electricity to activate or inhibit areas of the brain. Electricity is applied either directly to the brain via electrode implants, or non-invasively via external electrode on the scalp. More recently the electricity is induced via magnetic fields applied to the head like during Transcranial Magnetic Stimulation. While these treatments typically are not employed until after trying other first line treatments like medication, they have a positive success rate when medication fails to treat the issue. The proper treatment should be based on an individual’s medical situation and needs, under a physician's supervision.
Electroconvulsive Therapy (ECT) is the original brain stimulation therapy, and in turn the best studied. It is typically reserved for severe mental disorders and only consider if other first line treatments like medication are unsuccessful or if immediate response in needed, like in cases of suicide risk.
ECT is used as treatment for the following:
- Severe treatment resistant depression, bipolar disorder, or schizophrenia which is unresponsive to medication and / or therapy
- Catatonia, when a patient is unresponsive to the outside world
- Suicidal thoughts
- Severe depression causing malnuritionment
The main advantage to ECT is how quickly it can work, often producing results within the first week.
How it Works
- Patients are put under anesthesia and given a muscle relaxer to prevent movement during the procedure
- Electrodes are precisely place on the scalp
- An electric current passes from the electrodes to the brain causing a seizure that lasts about one minute.
- Patients wake approximately ten minutes after treatment, often feeling groggy from anesthesia, but can typically resume normal activities within an hour.
- Treatment typically lasts 6-12 session over the course of two to 4 weeks until depression improves.
- Follow up treatment is sometimes needed to prevent depression from returning. Patients typically take some form of medication in addition to ECT treatment.
The most common side effects for ECT include:
- Upset Stomach
- Muscle Aches
- Memory loss
Memory loss in patients typically impacts memories from around the treatment and usually improve within a few days or weeks of treatment. Research shows the transition from traditional bilateral application (electrodes on both sides of the heads) to unilateral application (electrodes only one the right side of the head, opposite of the side of the brain responsible for memory) has reduction instances of memories issues after treatment.
Repetitive Transcranial Magnetic Stimulation
Developed more recently, Repetitive Transcranial Magnetic Stimulation (rTMS) uses a magnet to activate areas of the brain to treat depression psychosis, anxiety and other disorders. Treatment can target very specific areas of the brain, compared to ECT, reducing the likelihood and severity of side effects.
rTMS was approved in 2008 by the FDA as treatment for major depressive disorder unresponsive to other first line treatments like medications. NIMH’s first large clinical trial on rTMS results found 14% achieved remission, increasing up to 30% if patients moved on to complete the second phase.
How it Works
- Electromagnetic coils are held against forehead near the area of the brain associated with mood regulation.
- Short electromagnetic pulses are administered causing small electrical currents that stimulate the targeted nerve cells. The currants only reach about 2 inches so other areas of the brain are not affected.
- Patients report the sensation of a knocking or tapping sensation on their heads during treatment.
- Treatment typically lasts 30 to 60 minutes and does not require anesthesia
Side effects are mild and less frequent than ECT, and can include:
- Slight discomfort at administration point
- Mild headaches
- Brief lightheadedness
Vagus Nerve Stimulation
Originally developed to treat epilepsy, Vagus Nerve Stimulation (VNS) is administered via an implant that sends electrical impulse through the left vagus nerve.
After being used for treatment of epilepsy, by stimulating the electric messages from the brain to body parts, scientists noticed VNS also had a positive impact on mood, particularly depression by affecting the area of the brain responsible for mood regulation. VNS can increase production of various neurotransmitters like norepinephrine, serotonin, and GABA.
VNS is only approved for use for treatment of depression if a specific set of circumstances is met:
- Patient must be 18;
- And illness has last over two years;
- And symptoms are severe and recurrent;
- And symptoms have not improved after four other different treatments
How it Works
A pulse generator device is implanted in the upper left region of the chest, which connects to the vagus nerve via an electrical lead wire
Every five minutes, 30 second pulses are sent to the vagus nerve
After receiving the pulse, the vagus nerve sends those signals to the brain.
It should be noted results may take several months to be noticed and additional treatment such as medication should be given during VNS.
In addition to possible complications with the device such as implantation infection or device displacement or malfunction, possible side effects include:
- Condition worsens instead of improves
- Neck Pain
- Cough or sore throat
- Trouble swallowing
- Trouble breathing particularly during exercise
- Pain at implantation site