New innovative treatments for Alzheimer’s disease (among others) are enabled by 40 Hz sensory neurostimulation and gamma entrainment. For example, research by Iaccarino & Singer et al. (2016), Adaikkan et al. (2019a), and Martorell et al. (2019) from MIT (Massachussetts Institute of Technology) have found a method that could curb the aggregation of insoluble amyloid-β plaques and phosphorylation of tau protein in neuron axons, thereby improving impaired memory in particular. To do this, brain waves in the gamma frequency, which are very important during wakefulness, are stimulated to synchronize by visual (light flickering at 40 Hz) and auditory (sound waves vibrating at 40 Hz) stimuli. The method has been successfully studied in Alzheimer’s mouse models and has now been investigated in humans as the next step (Chan & Tsai 2021a). Most remarkably, it was observed that in mice, brain immune cells called microglia underwent morphological changes under the influence of 40 Hz gamma stimulation, clustering around and dissolving both amyloid-β and neurofibrillary tau-tangles. Mice treated in this way were able to navigate again and “remembered” the neuronal maps stored in their place cells for routes to food and from mazes. This implies revitalization of their sense of smell in them. Adaikkan (2019b) speaks of the tremendous therapeutic potential of the procedure.
Extensive studies by researchers of MIT (Chan & Tsai 2021a) and of Emory University in Atlanta (Georgia, USA) (He & Singer 2021, Garza & Singer 2020) have shown that 40 Hz gamma neurostimulation is safe, has no negative side effects on health, and is well tolerated by subjects/patients. As results of human clinical trials, slowing of brain atrophy, significant improvement in memory, and improvement in sleep patterns were improved (Chan & Tsai 2021a). A good overview is provided by Chan & Tsai (2021b).
- Adaikkan, C., Middleton, S. J., Marco, A., Pao, P. C., Mathys, H., Kim, D. N., Gao, F., Young, J. Z., Suk, H. J., Boyden, E. S., McHugh, T. J., Tsai, L.-H. (2019a). Gamma entrainment binds higher-order brain regions and offers neuroprotection.Neuron, 102(5), 929-943. doi: https://doi.org/10.1016/j.neuron.2019.04.011
- Martorell, A. J., Paulson, A. L., Suk, H. J., Abdurrob, F., Drummond, G. T., Guan, W., Young, J. Z., Kim, D. N., Kriskiy, O., Barker, S. J., Mangena, V., Prince, S. M., Brown, E. N., Chung, K., Boyden, E. S., Singer, A. C., & Tsai, L. H. (2019). Multi-sensory gamma stimulation ameliorates Alzheimer’s-associated pathology and imrpoves cognition. Cell, 177(2), 256-271. doi: https://doi.org/10.1016/j.cell.2019.02.014
- Iaccarino H.F., Singer A.C., Martorell A. J., Rudenko A., Gao F., Gillingham T.Z., Mathys H., Seo J., Kritskiy O., Abdurrob F., Adaikkan C., Canter R.G., Rueda R. , Brown E. N., Boyden E.S., Tsai L.H. (2016). Gamma frequency entrainment attenuates amyloid load and modifies microglia. Nature. 2016 December 07; 540(7632): 230–235. doi: https://doi.org/10.1038/nature20587.
- Adaikkan C., Tsai L.H. (2019b). Gamma Entrainment: Impact on Neurocircuits, Glia, and Therapeutic Opportunities. Trends in Neurosciences. (2019) https://doi.org/10.1016/j.tins.2019.11.001
- Chan D., Tsai L.H. et al. (2021a). Gamma Frequency Sensory Stimulation in Probable Mild Alzheimer’s Dementia Patients: Results of a Preliminary Clinical Trial. (2021) https://doi.org/10.1101/2021.03.01.21252717
- He Q., Singer A. (2021). A feasibility trial of gamma sensory flicker for patients with prodromal Alzheimer’s disease. Alzheimer’s Dement. 2021;7:e12178. (2021). https://doi.org/10.1002/trc2.12178
- Garza K., Singer A. (2020). Gamma Visual Stimulation Induces a Neuroimmune Signaling Profile Distinct from Acute Neuroinflammation. The Journal of Neuroscience, February 5, 2020 • 40(6):1211–1225 • 1211. https://doi.org/10.1523/JNEUROSCI.1511-19.2019
- Chan D., Tsai L.H. et al. (2021b). Induction of specific brain oscillations may restore neural circuits and be used for the treatment of Alzheimer’s disease. 2021. The Association for the Publication of the Journal of Internal Medicine. https://doi.org/10.1111/joim.13329