40 Hz sound, in mice

• In a 2019 study in mice, listening to 10 kHz tone pulses repeated 40 times a second, one hour a day for seven days, improved performance on memory tasks; sound together with light reached wider brain areas.^[1]
• In a 2024 study in mice, combined 40 Hz sound and light increased the brain’s fluid clearance.^[2]
• A 2022 pilot study in 15 patients with mild probable Alzheimer’s dementia found daily 40 Hz sound and light stimulation safe and well tolerated.^[3]
• ARK Sounds does not play 40 Hz tones.

Who took part

Mostly mice. One small pilot in 15 patients with mild probable Alzheimer’s dementia.

Funding

Li-Huei Tsai and Ed Boyden co-founded Cognito Therapeutics, which makes a 40 Hz device, and advise it.^[2][3] The 2022 pilot was NIH-funded.^[3]

References

1. Martorell AJ, Paulson AL, Suk HJ, et al. Multi-sensory gamma stimulation ameliorates Alzheimer’s-associated pathology and improves cognition. Cell. 2019;177(2):256-271. pubmed.ncbi.nlm.nih.gov/30879788/ · Mice.
2. Murdock MH, Yang CY, Sun N, et al. Multisensory gamma stimulation promotes glymphatic clearance of amyloid. Nature. 2024;627(8002):149-156. pubmed.ncbi.nlm.nih.gov/38418876/ · Mice.
3. Chan D, et al. Gamma frequency sensory stimulation in mild probable Alzheimer’s dementia patients: results of feasibility and pilot studies. PLoS One. 2022;17(12):e0278412. pubmed.ncbi.nlm.nih.gov/36454969/ · Small pilot.