Measuring Vocal Efficiency in Daily Life in Patients with Voice Disorders Using Wireless Accelerometer and Microphone Sensors.

Voice disorders are linked to inefficient phonation, with vocal efficiency (VE) measured in clinic. We studied ecological vocal efficiency (EVE) by estimating daily-life VE as SPL/Ps (dB/dB) using a wireless dual-sensor voice monitor: subglottal pressure (Ps) predicted from a neck-surface accelerometer (ACC) and sound pressure level (SPL) from a microphone. 14 females participated (7 with vocal fold nodules; 7 matched controls). In lab, VE was computed via a /p/-vowel sequence (loud-to-soft; 3 pitch levels). Participants completed 3 days of ambulatory monitoring (12 h/day), and EVE was computed. Patients showed lower EVE and reduced variability than controls in daily life (4.1 vs 4.7, effect size r = 0.67; SD 0.4 vs 1.0, r = 0.91); variability metrics separated groups better in field than in lab. Patients spent significantly more time outside the EVE normative range than controls (92 vs 36%; p = 0.03; r = 0.81). Preliminary results support EVE as an ecological marker of vocal function.