Computer vision based algorithm to support correct electrode placement for home-based non-invasive electric brain stimulation

Non-invasive brain stimulation (NIBS), such as transcranial electrical stimulation (tES), has been proposed as a promising treatment strategy for neuropsychiatric pathologies in addition to conventional methods. To achieve a larger outreach and ensure regular, high-frequency treatment exposure, home-based, self-applied solutions have been promoted as a new strategy.

There are currently no available solutions to assess the correct placement of tES electrodes at home or to guide patients during the self-application process. To address these challenges, we have developed and tested an easy-to-use and cost-effective tool to monitor cap placement performance and support patients at home.

Thirty-six healthy participants took part in this study. We compared their cap placement performance with the performance of a NIBS-expert investigator, testing participants’ placement accuracy with instructions before (Pre) and after the investigator’s placement (Post), as well as using the computer vision tool (Algorithm). For feasibility evaluation of this novel technique, user experience (UX) and confidence levels were tested.

Permutation tests showed that cap placement accuracy performed with the Algorithm were significantly closer in 3D space to the expert investigator’s placement compared with the Pre. The UX questionnaire and subjective measures of ease of use and usefulness of the algorithm were satisfactory. The algorithm decreases the variability of performance, ensures placement within the suggested maximum of deviation, and supports confidence of correct placement.

We conclude that this novel technology adds distinguishable value to home-based self-applied set-ups in helping patients achieve correct electrode placement and guide them with real-time feedback. It also induces confidence in the patients and provides an exciting opportunity to further promote home-based, self-applied tES as cost-effective and safe adjunct treatment strategy, that can ensure high frequency treatment exposure while being easily integrated in patients’ daily life.