“Sound” Approach to Treating Alzheimer’s Disease
Alzheimer’s patients can present with impairments in brain waves, specifically in gamma-frequency oscillations in the range of 25–80 Hz, that are important for attention, perception, and memory.
In 2016, Iaccarino et al demonstrated that visual stimuli presented at 40 Hz, but not other frequencies reduced levels of beta-amyloid plaques in mice; beta-amyloid plaques are a pathogenic marker for Alzheimer Disease. However, the results were limited to the visual cortex.
In their new study published in Cell, the researchers (Martorell et al, 2019) examined the application of a 10 kHz tone presented at 40 Hz rate for 1 hour per day for 7 days in mice. They found that the treatment drove gamma frequency neural activation not only in the auditory cortex but also in the hippocampus. This also resulted in reduced beta-amyloid plaques and improved spatial and recognition memory. Further, combined auditory and visual stimulation decreased amyloid in the medial prefrontal cortex, which was not observed in single stimuli conditions.
Though in an early study, the application of sound therapies for Alzheimer Disease represents an intriguing treatment pathway. For more information see the full article.
Iaccarino et al. (2016) Gamma frequency entrainment attenuates amyloid load and modifies microglia. Nature 540 (7632):230–235.
Martorell et al. (2019) Multi-sensory gamma stimulation ameliorates Alzheimer’s-Associated Pathology and Improves Cognition. Cell 177:1–16.