Objectives/Hypothesis: Visible light spectroscopy (VLS) is the technology behind the Food and Drug Administrationapproved TSTAT device that is used to monitor tissue oxygen (StO 2 ) and relative total hemoglobin (rtHb) levels by measuring reflected visible light. The purpose of this novel, pilot study was to determine if VLS is a reliable and valid method of measuring StO 2 and rtHb levels in the human thyroarytenoid/lateral cricoarytenoid (TA-LCA) muscle complex, thus providing information about vocal fold muscle physiology.
Study Design: Pre-test/post-test with mulitple baselines and two conditions. Methods: VLS measurements were taken at baseline, during exercise, and following recovery on six subjects using both noncontact channel-port endoscope (endo-probe) and laryngeal electromyography (LEMG) needle-guided techniques.
Results: The average baseline StO 2 was 69% (standard deviation [SD] ΒΌ 3.6%) for the LEMG-guided probe and was 71.5% (SD ΒΌ 2.8%) for the endo-probe. During phonation, the StO 2 for the LEMG-guided probe dropped to 59% (SD ΒΌ 7%; P ΒΌ .04). Mean rtHb measured by the LEMG probe rose from a baseline of 144 lM (SD ΒΌ 165 lM) to 214 lM (SD ΒΌ 166 lM, P ΒΌ .34) during phonation and back to 149 lM (SD ΒΌ 139 lM, P ΒΌ .85) after recovery. Mean rtHb as measured using the endo-probe at baseline and after recovery was 104 lM (SD ΒΌ 30 lM, P ΒΌ .76).
Conclusions: VLS can be used to measure changes in StO 2 and rtHb levels pre-and postexercise in the human TA-LCA muscle complex.