Acoustic correlates of laryngeal-muscle fatigue: findings for a phonometric prevention of acquired voice pathologies

This presentation focuses on the problem of defining valid acoustic correlates of vocal fatigue seen as a physiological condition that can lead to voice pathologies. Several findings are reported based on a corpus of recordings involving electromyography (EMG) of laryngeal muscles and voice acoustics. The recordings were obtained in sessions of vocal effort extending across 12-14 hours. A known technique for estimating muscle fatigue is applied involving “spectral compression” of EMG potentials. The results show critical changes at given times of day. In examining the effects of these changes on voice acoustics, there is no linear correlation with respect to conventional acoustic parameters, but peaks in voice tremor occur at points of critical change in muscle fatigue. Further results are presented showing the need to take into account compensatory muscle actions in defining phonometric signs of vocal fatigue.