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Thursday, January 31, 2008

Deep Brain Stimulation for Alzheimers Disease.

Electrical stimulation of areas deep within the brain could improve memory, early research suggests. A team of doctors in Canada were attempting to treat a morbidly obese man through deep brain stimulation (DBS) for his obesitas. Their long-standing interest in functional neurosurgery and DBS made them consider the possibility of a neurosurgical treatment. They wanted to stimulate the hypothalamus for appetite control. Hypothalamic lesion surgery had been used previously to treat obesity. Hypothalamic stimulation was proposed based on experimental studies of appetite control in rodents, dogs, and nonhuman primates.

DBS electrodes were implanted bilaterally in the ventral hypothalamus with the patient receiving local anesthesia without sedation.
During stimulation the patient vividly remembered a situation from the past:

being in a park with friends, a familiar scene to him. He felt he was younger, around 20 years old. He recognized his epoch-appropriate girlfriend among the people. He did not see himself in the scene, but instead was an observer. The scene was in color; people were wearing identifiable clothes and were talking, but he could not decipher what they were saying. As the stimulation intensity was increased from 3.0 to 5.0 volts, he reported that the details in the scene became more vivid.

These recollections were tested under double blind conditions.
The effects of stimulation on memory were further characterized using recognition tasks with high sensitivity and specificity for hippocampus-dependent retrieval processes. Each task was performed twice, with the stimulator on or off in a double-blinded fashion.

Shortly after recovery of the operation as well as after a year the patient performed better in memory tests than he had previously done.

The patient performed well in memory tests when the electrodes were stimulated, but less well when they were switched off.

The results suggest it might be possible to use deep brain stimulation directly to boost memory.

Maybe a new treatment for Alzheimer? Sounds to good to be true. I remember ECT and Morbus Parkinson. ECT can help but as the disease progresses the results diminishes.

The conclusion of the authors:

Electrical stimulation in this high-density area could be affecting a number of neural elements. We cannot be sure how much of the effect is related to stimulation of nuclei versus axons coursing in the hypothalamus. At this time, we believe that the results are consistent with driving the activity of the hippocampal memory circuit through stimulation of the fornix. The effects of hypothalamic stimulation on memory shown here represent an unanticipated collateral effect in the context of a putative treatment for morbid obesity.

Thanks to BBC News Health
Hamani, C., McAndrews, M.P., Cohn, M., Oh, M., Zumsteg, D., Shapiro, C.M., Wennberg, R.A., Lozano, A.M. (2008). Memory enhancement induced by hypothalamic/fornix deep brain stimulation. Annals of Neurology, 63(1), 119-123. DOI: 10.1002/ana.21295

1 comment:

The Shrink said...


Intuitively it makes sense, I suppose. We know that the diencephalon is damaged in Alzheimer's disease before we see cortical loss and clinical symptoms of dementia.

As such, the thalamus (and hypothalamus, amygdala, hippocampal gyrus) of the limbic system, being the first bit of the brain to show damage and atrophic change, could sensibly profit from stimulation and drive in MCI/early dementia.

What would really excite me is if this could be shown to delay neurodegenerative disease progression, rather than provide symptom relief whilst the underlying disease process continues on, unchanged.