Alleviating Depression and Dementia with Transcorneal Electrical Stimulation

A joint research team in Hong Kong discovered that stimulation of the eye surface can reduce depressive symptoms and improve cognitive functions in animals, leading to the possibilities of novel therapeutic applications for patients with chronic depression and neurological diseases such as Alzheimer’s. 

The scientists from LKS Faculty of Medicine, University of Hong Kong, and City University of Hong Kong published their findings in Brain Stimulation and Annals of the New York Academy of Sciences, as a result of the effort to develop alternative neuropsychiatric diseases treatments without the need of invasive deep brain stimulation.

Instead of implanting electrodes into the brain, the team achieved therapeutic effects by a non-invasive stimulation of the eye’s corneal surface (transcorneal electrical stimulation, TES), the technique resulted in antidepressant-like effects and reduced stress hormones in an animal model. Additionally, this technique induced gene expression involved in the development and growth of brain cells in the hippocampus, a region crucial for memory and learning.

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Electrical Stimulation of Eye May Cure Alzheimer’s 

Alongside encouraging hippocampal cells’ growth, the scientists observed that TES reduced beta-amyloid buildups, a characteristic of Alzheimer’s disease in a related study. Dr. Leanne Chan Lai-hang, co-author of this research shared: “Transcorneal electrical stimulation is a non-invasive method initially developed to treat eye diseases, and it would be a major scientific breakthrough if it could be applied to treat neuropsychiatric diseases.”

Treatment with TES effectively reduced blood stress hormone (corticosterone) levels in stressed test subjects, while upregulating neurogenesis-related markers. The team found that the expression of neurogenesis-related gene Ki67 is lower in stressed rats, subsequent treatment by TES restored expression to normal level.

“These research findings pave the way for new therapeutic opportunities to develop novel treatment for patients suffering from treatment-resistant depression and dementia. Nevertheless, clinical trials must be conducted to validate the efficacy and safety,” said Professor Chan Ying-shing.

Author

Fujie Tham