A recent study reports that deep brain stimulation of a region of the brain called the nucleus basalis of Meynert (NBM) could potentially be used to treat mild to moderate Alzheimer’s disease. The results of this pilot study were published in Molecular Psychiatry on May 6, 2014. The NBM region of the brain is rich in a neurotransmitter that is important for cognition. This study suggests that stimulating this area of the brain may slow the progression of Alzheimer’s in some patients. This is the first Phase-I clinical study to explore the technical feasibility of deep brain stimulation of the NBM in Alzheimer’s disease.
Alzheimer’s disease is an irreversible form of dementia that slowly destroys memory and thinking skills. Alzheimer’s is the most common cause of dementia among older people. There are an estimated 70,000 people aged 65 and older living with Alzheimer's disease in Connecticut (5.2 million in the U.S.). Projected estimates indicate this number will rise to 91,000 (7.1 million in the U.S.) by the year 2025. Alzheimer’s is characterized by the loss of neurons in specific areas of the brain, including the NBM. The NBM is a major site of acetylcholine activity (the neurotransmitter acetylcholine plays an important role in cognitive performance).
Researchers studied six patients with Alzheimer’s disease to determine the effects of deep brain stimulation of the NBM. The six patients were all diagnosed with mild-to-moderate Alzheimer’s disease (diagnostic criteria based on the DSM-IV, ICD-10, and NINCDS-ADRDA scales). Stereotactic surgery is a minimally invasive form of surgery which makes use of a three-dimensional coordinate system to locate small targets inside the body. Electrodes were stereotactically implanted into the NBM of each patient under general anesthesia. All patients received stimulation through these electrodes for one year. Cognitive functioning was measured one week prior to implantation of the stimulator, and at multiple time points throughout the following year.
The study found that four of the six patients’ cognitive abilities remained stable or improved. The remaining two patients showed some decline in cognitive abilities. There were no severe side-effects and patients’ average quality of life did not decline. Overall, the results suggest that Alzheimer’s patients who receive deep brain stimulation show a less pronounced decline in cognitive ability compared to Alzheimer’s patients who don’t receive this treatment. Though it’s unclear which patients this treatment may be effective in, the researchers conclude that deep brain stimulation of the NBM is well tolerated and technically feasible in Alzheimer’s patients. Larger studies are needed to confirm these preliminary findings.