A home-based brain stimulation device appeared to boost cognition in patients with early Alzheimer's disease (AD), although the effect was small, a new study showed.
Patients who received active treatment with the device, which provides active gamma transcranial alternating current stimulation, showed improvements on several cognitive measures, including remembering faces and people’s names, said study author Barbara Borroni, MD, Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
“The effects we observed were modest but meaningful in everyday life,” Borroni told Medscape Medical News. “For example, patients showed improvements at being a bit quicker in recalling information or managing simple day-to-day tasks more independently.”
The study was reported on December 8 in JAMA Network Open.
Targeting Gamma Waves
Gamma wave activity plays a key role in cognitive processes such as attention, memory, and perception. Studies have shown that gamma oscillations are disrupted in patients with AD, and early evidence suggests gamma sensory stimulation may offer therapeutic benefits.
For the randomized, double-blinded, placebo-controlled study, 50 patients with prodromal or mild AD (mean age, 67 years; 50% women) received brain stimulation or sham treatment 5 days a week for 8 weeks. At the end of 8 weeks, all participants received brain stimulation for an additional 8-week open-label phase and an 8-week follow-up.
The brain stimulation device positioned saline-soaked sponge electrodes on the scalp via a customized helmet over the precuneus in the parietal lobe, one of the earliest regions affected by AD, Borroni said. As she explained, the device delivers very low-intensity sinusoidal electrical current.
“We targeted the gamma frequency range because Alzheimer’s disease is characterized by a slowing of brain rhythms and by a disruption of gamma-band activity, a type of fast brain oscillation that becomes progressively more impaired as the disease advances,” she said.
Patients’ caregivers received training in the operation of the device, which includes built-in safety checks to ensure proper use. The caregivers ran daily 60-minute sessions at home under remote supervision.
At the end of each 8-week time period, patients completed cognitive and behavioral assessments, received an EEG to monitor brain activity, and gave blood samples to measure blood biomarker activity. Patients also underwent an MRI at two time points.
‘Practical Gains’
In the sham group, marginal mean differences vs the active treatment group were significant for The Clinical Dementia Rating sum of boxes (0.35; P = .007), Alzheimer’s Disease Assessment Scale-cognitive subscale (0.93; P = .001), and Alzheimer’s Disease Cooperative Study-Activities of Daily Living (-0.55; P = .02).
Participants also showed substantial improvement in the Face-Name Association Test (-1.14; P ≤ .001).
“This real-world skill — remembering names and faces — affects social interactions and independence, which is something families immediately recognize as helpful,” Borroni said.
“This is not a reversal of Alzheimer’s disease,” she cautioned. But the improvements “represent practical gains that can make interactions, routines, and independence slightly easier. For patients and caregivers, even small improvements in these areas can have real value.”
Investigators said the at-home treatment was safe and well tolerated, with no major adverse events reported. The most common effect, reported only by a small number of participants, was a mild visual flickering sensation during stimulation, which did not affect treatment adherence.
Borroni declined to comment on how much treatment could cost.
Investigators now plan to study treatment effects over a longer period of time to better understand whether symptom improvement continues after treatment ends.
“It will be important to determine whether periodic booster sessions are needed, how often they should be given, and whether longer-term treatment can further enhance or stabilize the benefits,” Borroni said.
Encouraging but More Work Needed
Gamma stimulation is important “because we have 30, 40 years of research showing that the gamma wave and gamma synchrony can be helpful with cognition, learning, memory, etc.,” P. Murali Doraiswamy, MBBS, professor of psychiatry and medicine, Duke University School of Medicine, Durham, North Carolina, told Medscape Medical News.
“Our brain waves operate at different frequencies depending on how alert we are, whether we’re sleeping, we’re coordinated, performing tasks, meditating, so on and so forth. Depending on the frequency of external stimulation applied, the brain can be entrained to synchronize with that external device,” he said.
The improvement on the Alzheimer’s Disease Assessment Scale-cognitive was 1 point, while donepezil (Aricept) — a common AD drug – produces an improvement of 2.5-3 points. The improvement is “impressive,” said Doraiswamy, who was not part of the new study.
However, he cautioned that “it’s relatively easy to get a change at 1 month or 2 months out, but to sustain the benefits, that’s what’s really, really hard. That’s why Alzheimer’s drug discovery is like a graveyard of sunken drugs,” he said. “These guys have not yet shown that their device can do it. And certainly, when the device is turned off, as you see in the follow-up period, the improvement sort of goes away.”
Christopher Weber, PhD, senior director of global science initiatives, Alzheimer’s Association, Middleton Town, Wisconsin, told Medscape Medical News that the findings “are encouraging because they support a noninvasive, low-burden, home-based intervention that could potentially complement existing and future therapies,” Weber said. “However, the authors reported that there were no changes in plasma biomarkers.”
Moving forward, “much more evidence is needed before considering regulatory review and/or implementation into clinical practice,” he said. “The study was small, the treatment interval was relatively brief, and the treatment effects diminished during the 8-week follow-up post-treatment.”
This study was supported by the Italian Ministry of Health and the European Union-Next Generation. Borroni has a patent for transcranial direct current simulation in AD. Other authors reported various disclosures. Doraiswamy disclosed relationships with USC, Fordham, Columbia, National Institutes of Health, Cure Alzheimer’s Fund, Wrenn Trust, Gates Ventures, Lumos Labs, Keel Digital, Cornell, Transposon, Prospira, Alzheon, Neurology Live, uMETHOD, Evidation, MarvelBiome, AHEL, and Live Love Laugh Foundation. He is a co-inventor on patents for dementia. Weber had no disclosures.
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