DBS also helps with emotional processing, not just cognitive and motor issues. I wonder how it would affect semi conscious people.

Another article:

Deep-Brain Stimulation Sparks a Patient's Memory
By Crystal Phend, Staff Writer, MedPage Today
Published: January 30, 2008
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine.

TORONTO, Jan. 30 -- Vivid memories from 30 years earlier suddenly flooded back to a 50-year-old obese patient who was undergoing deep-brain stimulation of the hypothalamus to suppress appetite, researchers here reported.

Unexpectedly, three weeks of deep-brain stimulation significantly improved the patient's memory on verbal and spatial associative tests, reported Andres M. Lozano, M.D., Ph.D., of Toronto Western Hospital, and colleagues online in the Annals of Neurology.

This single-patient case study suggested a potential new application for deep-brain stimulation in patients with disorders such as early Alzheimer's disease, Dr. Lozano said.
Action Points

* Explain to patients who ask that deep-brain stimulation sends an electrical current into a localized area of the brain.

* Caution patients that deep-brain stimulation has been used successfully in patients with Parkinson's disease, but any benefits for those with Alzheimer's disease or other memory disorders are speculative.

"It tells us about the circuitry of memory," he said. "It tells us that the circuits can be modified by the application of electrical current. One could then visage that it might be possible to stimulate these same circuits in patients who have memory disorders to try to enhance memory function."

Deep-brain stimulation has most commonly been used in the motor cortex to improve motor function of patients with Parkinson's disease and other movement disorders.

Stimulation of the hypothalamus has also been used to treat cluster headaches and even aggressiveness, while animal models have shown it can influence feeding behavior as well.

Because of the potential effect on appetite, the researchers offered hypothalamic deep-brain stimulation to the 50-year-old man with a body mass index of 55.1 kg/m2.

"He refused gastric bypass and bariatric surgery feeling that he would continue eating excessively despite these interventions," the researchers said.

The patient had comorbid type II diabetes, hypertension, and obstructive sleep apnea but had failed treatment for obesity including diets, psychological interventions, group therapies, and medications.

Hypothalamic lesion surgery had been used to treat obesity, "but we felt that the safety and reversibility of deep-brain stimulation offered a significant advantage," Dr. Lozano and colleagues said.

The researchers implanted four electrodes on each side of the ventral hypothalamus under local anesthesia without sedation.

When they stimulated the first electrode in the operating room to identify potential sites to suppress appetite, the patient reported suddenly feeling what he described as "déjà vu."

He experienced being in a park with friends as a young man at around age 20. As an observer to the scene, he described color, people wearing identifiable clothes, and hearing talking, although he could not decipher the words.

With increasing intensity of stimulation from 3.0 V to 5.0 V, he described more vivid details. But higher stimulation at certain contacts produced an unpleasant warm feeling followed by facial hyperemia and sweating but no changes in vital signs.

The same occurred during blinded, sequential successive stimulation of four other individual electrodes.

Two months after hospital discharge, the implanted electrode stimulation generator was turned on and the patient again reported experiencing vivid memories of a nature and content that remained similar for electrodes on right and left sides independent of the contact or stimulation parameters used.

Chronic stimulation was left on at a setting that did not spark memory, behavioral, sensory, or autonomic effects.

Three weeks later, a comprehensive neuropsychological assessment showed significant improvements in scores on the California Verbal Learning Test and Spatial Associative Learning test compared with baseline.

The patients classified more of his responses on the memory tests as "remembered" when the stimulation was on than when it was off (70% versus 43%).

"The lack of global improvements across the various tests speaks against a non-specific enhancement in memory as a consequence of practice, learning, or increased attention or motivation with stimulation," the researchers said.

Brain imaging showed significantly increased activity in ipsilateral mesial temporal lobe structures, predominantly in the hippocampus and parahippocampal gyrus region.

However, no consistent effects on hunger were found during the operation and afterward only moderate benefits were seen for appetite suppression with no long-term weight loss.

Based on the findings, Dr. Lozano said his group has launched a pilot study of hypothalamic deep-brain stimulation in patients with early Alzheimer's disease.

He cautioned, though, that it's not clear whether the memory effects will be reproducible in other patients.

"We have to keep in mind that it's a single case report," Dr. Lozano said. "It is for now a very interesting observation, and we'll have to see whether it translates to other patients."

Primary source: Annals of Neurology
Source reference:
Hamani C, et al "Memory enhancement induced by hypothalamic/fornix deep brain stimulation" Ann Neurol 2008; 63: 119-123.

http://www.medpagetoday.com/Neurolog...rology/tb/8151