Deep Brain Stimulation for Essential Tremor

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We have already blogged about “benign” essential tremor.

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Here is a recap of the patient featured in one of those previous posts. He has a long history of worsening essential tremor, which has not responded to oral medications, and has made it impossible for him to hold a cup or write with a pen:

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He decided to undergo deep brain stimulation, a procedure where tiny electrodes are placed into deep nuclei inside the brain. When these electrodes are activated, they cause an interruption in the brain circuits which cause tremor:

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Here he is, after surgery, with the electrodes switched off:

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Here he is with the electrodes to both sides of the brain switched on, see how much better his tremor is, particularly on the right side:

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He can write and hold a cup for the first time in >10 years.

These same pathways can be inactivated by gamma knife radiosurgery in tremor patients who cannot undergo deep brain stimulation because of blood thinners, dementia or some other medical problem.

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Stereotactic radiosurgery for obsessive compulsive disorder, Phineas Gage meets the Jetsons.

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Small studies have shown that gamma knife stereotactic radiosurgery can relieve symptoms in as many as 50% of patients with obsessive-compulsive disorder (OCD) who got no help from conventional behavioral or medical therapies.

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What is OCD?

OCD is an anxiety disorder in which people have unwanted and repeated fearful thoughts (obsessions) that drive them to perform repeated behaviors (compulsions) to temporarily relieve the associated anxiety.

Examples of OCD include excessive hand washing or cleaning, repeated checking and nervous obsessive rituals like such as opening and closing a door a certain number of times before entering or leaving a room.

Anxiety from OCD and the resultant obsessive ritualistic behaviors can be alienating and time-consuming, leading to emotional and financial distress.

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Symptoms of OCD can be ameliorated by medications, such as serotonin reuptake inhibitors, and behavioral therapy.  However, many severely affected patients remain unable to function normally despite these interventions, leading them to look for more effective or permanent solutions to this difficult problem.

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Surgery for psychiatric disorders.

Phineas Gage (1923-1960) survived an accident in which a pole impaled his head going through his left cheek, destroying his eye, through the frontal part of his brain, and back out the right top part of his skull.
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Before the accident, he was described by his friends as a friendly, calm, caring man.  After the accident, he became bad mannered, aggressive, foul-mouthed, and anti-social to the point where he could no longer hold a job and none of his friends wanted to associate with him anymore.

His skull was saved and later analyzed to plot the trajectory of this pole through his skull, finding that the rod mostly damaged the middle region of the frontal lobes.

This and other cases of medial frontal lobe lesions causing similar changes in behavior led to the conclusion that this part of the brain’s function is related to normal social  social behavior

Surgical frontal lobotomy was first performed in the 1935, and lobotomized patients showed a decrease in agitation, anxiety, and depression.  Walter Freeman and James Watts spread the technique of lobotomy across America in the 1930 and 40s, and it became considered as a quick fix for dealing with overcrowded insane asylums.

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Ultimately the procedure was conducted using an “ice pick” inserted into the frontal lobe through the orbit under a brief period of unresponsiveness induced by ECT.

However, with the advent of psychotherapeutic drugs and increasing evidence for the horrors and limited therapeutic effects of lobotomy, the surgery lost popularity, almost becoming completely extinct.

Nevertheless, the important influence of the frontal lobes on social behavior was not forgotten, and more recent PET studies have further reinforced the influence of this brain region area in OCD:

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PET study showing increased activity in the frontal lobes in a OCD patient compared to a normal control.

There has been a limited comeback of psychosurgery, initially the form of less invasive non destructive  surgical techniques like the anterior cingulotomy (designed just to sever the connections between the frontal lobes and the underlying subcortical structures) still used for patients with severe OCD and depression refractory to conventional therapies.

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Gamma knife for OCD.

Activated deep brain stimulation electrodes placed into the anterior limb of the internal capsule can also interrupt the circuits than connect the frontal lobes to the rest of the brain and ameliorate OCD behavior:

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Gamma knife radiosurgery can create permanent lesions in these same regions of the brain, leading to Permanent lesions resulting in long-lasting benefit to OCD patients without the need for implanted hardware.

A recent study published in Neurosurgery by Kondziolka et al (click here for link) demonstrated the long-term benefit of bilateral gamma knife lesioning to the internal capsule in three patients with OCD intractable to conventional medical therapies.

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Gamma knife radiosurgery for OCD. Left – MRI showing the lesions resulting from the procedure. Right – clinical improvement in na OCD rating score in all three patients after surgery (lower score = better).

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Where can you get help and more information?

The International OCD Foundation has a website with more information on medical therapies, psychosurgery, DBS and gammaknife radiosurgery for OCD.