Novel solutions for non-invasive detection of circulating cortisol from sweat: first-in-human with chronic concussion symptoms.

Research Objectives: To validate a novel method for non-invasively detecting biochemistry relevant to rehabilitation outcomes (i.e., circulating cortisol) among adults with chronic mild traumatic brain injury (mTBI).

Design: Validation (first-in-humans with mTBI) of resonance circuit-based, wireless biochemical sensing.

Setting: PM&R outpatient mTBI clinic

Participants: Adults with mTBI symptoms > 3 months post-injury

Interventions: AdapTango dance, a movement-to-music activity (Hackney (2010); Worthen-Chaudhari (2019)).

Main Outcome Measures: Primary: detection of circulating cortisol within the normative range, 0.5 – 120 ng/ml (Steckl (2018); Samson (2020); Parlak (2018); Torrente-Rodríguez (2020)), as measured by both experimental and standard methods (enzyme-linked immunoabsorbent assay (ELISA)) from a single sample.

Secondary: feasibility of generating sufficient sweat sample volume among adults with mTBI (criteria: >50% success rate among attempted sessions (Worthen-Chaudhari, 2013)). A session was deemed "successful" if participants completed 15+ minutes of AdapTango activity and researchers collected target sample volume (>40 uL).

Tertiary: (1) maximum rating of perceived exertion (maxRPE) for successful vs unsuccessful sessions; (2) mean symptom change during successful sessions (measured by the Sports Concussion Assessment Tool symptom (SCAT) score).

Results: Both experimental and ELISA methods detected circulating cortisol within normative range for all successful sessions. Four participants completed 10 sessions total (1-3 each), meeting feasibility criteria by achieving target sample volume within 9 (90%). MaxRPE was "hard" (16 of 20) for sessions that achieved target sample volume and "somewhat hard" (14 of 20) for one session that did not. When AdapTango was performed at RPE of "hard", symptoms improved (p=0.031; mean(SD) pre = 40.1(25.7) vs post = 28.2(12.7); Cohen's d = 0.66).

Conclusions: The experimental method detected circulating cortisol among adults with mTBI. Study of sensitivity, specificity, and cost vs ELISA is required. Through AdapTango dance activity performed at RPE level "hard", we completed the validation protocol and reduced symptoms within-session.

Author(s) Disclosures: This research was supported by the Ohio State University Center for Medical Engineering and Innovation. Non-presenting author Jinghua Li is an inventor on a related, pending patent filed by The Ohio State University (application No.: 63/171,694, filed on 04/07/2021).