Flickering lights and sound to tackle Alzheimer’s

For the past few years, Annabelle Singer and her collaborators have been using flickering lights and sound to treat mouse models of Alzheimer’s disease, and they’ve seen some dramatic results. Now they have results from the first human feasibility study of the flicker treatment, and they’re promising, with Qiliang He, a postdoctoral fellow in the School of Psychology, serving as first author for the study. “We looked at safety, tolerance, and adherence, and several different biological outcomes, and the results were excellent — better than we expected,” said Singer, assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory. Singer shared preliminary results of the feasibility study in October at the American Neurological Association annual meeting. Now she is a corresponding author with Emory neurology researcher James Lah of a paper outlining their findings in the journal Alzheimer’s & Dementia: Translational Research & Clinical Interventions.

The flicker treatment stimulates gamma waves, manipulating neural activity, recruiting the brain’s immune system, and clearing pathogens — in short, waging a successful fight against a progressive disease that still has no cure. Previous research already had shown that sensory areas in the human brain will entrain to flickering stimuli for seconds to hours. But this was the first time Singer and her team were able to test gamma sensory stimulation over an extended period of time. The study included 10 patients with Alzheimer’s-associated mild cognitive impairment, which required them to wear an experimental visor and headphones that exposed one group to light and sound at 40 hertz for an hour a day over eight weeks, and another group for four weeks after a delayed start. “We were able to tune the devices to a level of light and sound that was not only tolerable, but it also successfully provoked an underlying brain response,” Lah said. As they hoped and expected, Singer said, “there was widespread entrainment.” That is, brain activity – in this case, gamma waves – synchronized to the external stimulation.

Gamma waves are associated with high-level cognitive functions, like perception and memory. Disruptions to these waves have been found in various neurological disorders, not just Alzheimer’s. The human feasibility study showed that the gamma flicker treatment was safe and tolerable. And perhaps most surprising, patients followed the full treatment schedule. Adherence rates hovered around 90 percent, with no severe adverse effects reported during the study or the 10-month open label extension (some patients even volunteered to continue being monitored and assessed after the study, though this data wasn’t part of the published research). Some participants reported mild discomfort that could have been flicker related — dizziness, ringing in the ears, and headaches. But overall, Singer said, the device’s safety profile was excellent. She also reported some positive biological outcomes.

Source: Georgia Tech news release