"Last year in an operating room at the University of Toronto a yearold woman with Alzheimers disease experienced something she hadnt for  years a memory of her yearold self playing with her siblings on their family farm in Scotland.   The woman is a patient of Dr. Andres Lozano httpneurosurgery.utoronto.cafacultylistlozano.htm a neurosurgeon who is among a growing number of researchers studying the potential of deep brain stimulation to treat Alzheimers and other forms of dementia. If the approach pans out it could provide options for patients with fading cognition and retrieve vanished memories. Right now deep brain stimulation is used primarily to treat Parkinsons disease and tremor for which its approved by the Food and Drug Administration. DBS involves delivering electrical impulses to specific areas of the brain through implanted electrodes. The technique is also approved for obsessivecompulsive disorder and is being looked at for a number of other brain disorders including depression chronic pain and as in Lozanos work dementia. In  Lozanos group published a study in which an obese patient was treated with deep brain stimulation of the hypothalamus. Though no bigger than a pea the hypothalamus is a crucial bit of brain involved in appetite regulation and other bodily essentials such as temperature control sleep and circadian rhythms. It seemed like a reasonable target in trying to suppress excessive hunger. To the researchers surprise following stimulation the patient reported a sensation of deja vu. He also perceived feeling  years younger and recalled a memory of being in a park with friends including an old girlfriend. With increasing voltages his memories became more vivid including remembering their clothes. Using a dimensional brain mapping technique called standardized lowresolution brain electromagnetic tomography or sLORETA http Lozanos group uncovered an explanation for the unexpected findings. They found that stimulating the hypothalamus was in turn driving increased brain activity in the hippocampus a key cog in the brains memory circuitry. As Alzheimers progresses not only does the hypothalamus atrophy but electrical communication between neurons in the region also gradually becomes impaired. That our memories  so entwined with our personalities and senses of self  might be so vulnerable to a brown out is existentially speaking rather alarming. Theres something palpably dehumanizing about reducing our past selves to the exchange of electricity between neurons and also about retrieving memories by hotwiring the brain. Yet the prospect of the latter is undeniably intriguing. Given that Alzheimers affects  in  people over the age of  and that current therapies are in many patients dismally ineffective Lozano felt all but obligated to dig further. His group launched a test in six patients and published the results http in the Annals of Neurology in . The study included patients with mild and severe disease who received stimulation in the fornix continuously for  year. The fornix is like the highway leading into the hippocampus explains Lozano. Its easier to stimulate than the hippocampus itself and crucial to memory function. As expected those with more severe disease continued to mentally deteriorate however it appeared that in those with mild disease cognitive decline slowed with stimulation. Next Lozano launched a randomized trial involving  patients from the US and Canada all of whom had electrodes implanted in the fornix on both sides of the brain. In half the patients the stimulation was turned on right away. In the other half the stimulation wasnt turned on for a year though they didnt know it. Preliminary results httpthejns.orgdoiabs...JNSurl_verZ.rfr_idoriAridAcrossref.orgrfr_datcr_pubDpubmed published in December  in the Journal of Neurosurgery were mixed but encouraging. Given that so few people have had electrical stimulation applied to memory circuits perhaps the most significant finding was that both the surgery itself and DBS of the fornix appear safe. No serious longterm neurological side effects were seen in either patient group supporting future research in the field. In terms of efficacy however after one year there were no significant differences in cognition between the groups as measured by two scales commonly used to measure Alzheimers disease symptoms the ADASCog https and CDRSB. Alzheimers tends to progress slowly and reversing or slowing the neurodegeneration associated with condition may take time to become noticeable. Lozanos final results wont be reported until four years out. More intriguing for now were comparisons of glucose utilization. Glucose is our brains primary fuel. The degree to which glucose is burned is a commonly used measure of brain activity. Patients with Alzheimers typically have reduced glucose activity in their brains as well as again shrinking memory circuits. The older patients in Lozanos study who had stimulation turned on exhibited markedly increased glucose use in the brains memory regions. Not only that the hippocampus of some study patients who received DBS actually increased in size. Reversing withering hippocampi by encouraging the growth of new neurons is seen as a holy grail in Alzheimers research and Lozanos finding is supported by a recent animal study http demonstrating that DBS in rats causes the release of growth factors that induce neuronal growth in the hippocampus. Lozano acknowledges that retrieving childhood memories which he says has occurred in about onethird of his patents  requires lofty voltages that he would be uncomfortable sending patients home on. Yet hes encouraged by the early findings that suggest the procedure is safe. We also know that in patients who receive stimulation there is an increase in glucose utilization in memory areas of the brain he says a finding that could mean theres a way to overcome some of the damage from Alzheimers. Evidence supporting DBS in dementia is emerging from other research groups as well. A  study http published in the New England Journal of Medicine reported that in seven patients receiving DBS to a brain region called the entorhinal cortex spatial memory improved  meaning they could more easily remember the locations of newly learned landmarks. The entorhinal cortex works in concert with the hippocampus to solidify memories. A group at the University of Cologne in Germany is instead focusing on delivering DBS to a part of the brain called the nucleus basalis of Meynert another region in which impaired neuron function is thought to contribute to Alzheimers. Last year they published a study http in Molecular Psychiatry in which four of six patients either remained cognitively stable or improved in response to DBS as measured by the ADAScog. Like in Lozanos study no serious side effects were seen. Despite the mounting evidence for DBS not everyone is convinced. Referring to Lozanos second clinical study Dr. Nader Pouratian a neurosurgeon and DBS researcher at UCLA comments The recent deep brain stimulation trial for Alzheimers disease clearly demonstrates the safety of this approach for trying to treat the progression of disease. Unfortunately the findings suggest that the therapy may not be as robust as initially proposed. However he acknowledges Lozanos results suggest that DBS to the fornix might be promising for a subgroup of patients those being older people with less severe disease. The most promising areas are likely the fornix or the entorhinal area he says. But I believe further studies are necessary to better elucidate the efficacy of this treatment before proceeding to a larger scale randomized trial. In a  episode of the medical television drama House the shows main character Dr. Gregory House survives a bus crash that leaves his memory murky. In an attempt to remember the medical history of a fellow collision victim  and inspired by Lozanos initial paper  House voluntarily undergoes deep brain stimulation. Following the procedure the grouchy TV doctors memory returns. As is customary on the show he cracks the case. DBS for treatment of Alzheimers and other dementias is a field in its infancy. Unlike on TV in all likelihood it wont be widely used anytime soon to retrieve specific memories. Even though House did this were not doing it yet cautions Lozano. Yet the fact that the therapy can in some people rescue recollections  albeit random ones  and possibly induce new neuron growth in memory regions of the brain seems reason enough to pursue it further. Were hoping to use electricity to drive activity in areas of the brain involved in memory and cognition says Lozano. We want to turn these brain networks back on. Bret Stetka is a writer based in New York and an editorial director at Medscape http His work has appeared in Wired Scientific American and on The Atlantic.com. He graduated from University of Virginia School of Medicine in . Hes also on Twitter BretStetka httpstwitter.comBretStetka."