Investigation of the effects of stress on microtremor's activity and vocal fold's physiology

Stress directly affects the function of body organs, such as muscles. Vocal folds are also among the muscles which can be impressed by being stressed out. Sound production is directly influenced by the vocal folds’ function. Thus, the present study aimed to investigate stress using the infrasonic sound signals. The results of the investigation can be used in lie detection processes.
The study sample included 16 volunteers who were in normal or imposed stress conditions. The subjects were assessed regarding the amplitude average and zero crossing.
The results showed a decrease in the average amplitude and number of zero crossings in the stressed subjects compared to the normal ones. Besides, the mean of decrease in the amplitude average and the number of zero crossings was 24% and 5.7%, respectively.
The results showed that this procedure could be used in stress assessment and deception detection with acceptable accuracy.