Voice monitoring to measure emotional load during short-term stress.
It is well known that there is a relationship between the voice the human emotional status. Previous studies have demonstrated that changes of fundamental frequency ( f(0)), in particular, have a significant relationship with emotional load. The aim of the present study was to investigate how f(0) changes in response to an unknown emotionally stressful task under real-life conditions. A further question was whether repetitions of this task lead to an adaptation of f(0), indicating a lower emotional load. The participants of this study included 26 healthy males. f(0) and heart rate ( f(c)) were recorded for baseline testing (BLT) under relaxed laboratory conditions. Then the participants were asked to negotiate a natural obstacle by way of sliding down a rope hanging from a handlebar without any safety provisions, thus being exposed to the danger of a fall from a height of up to 12 m into shallow water (guerrilla slide I, GSI). The task was repeated after 30 min (GSII) and after 3 days of physical strain (GSIII). Immediately before starting the task the participants were asked to give a standardised speech sample, during which f(c) was recorded. The mode value of f(0) ( f(0,mode)) of the speech samples was used for further analysis. The mean (SD) value of f(0,mode) at BLT was 114.9 (14.8) Hz; this increased to 138.8 (19.6) Hz at GSI ( P<0.000), decreased to 135.9 (19.6) Hz at GSII and to 130.0 (21.5) Hz at GSIII ( P=0.012). The increase in f(c) was significantly different from BLT to GSI ( P<0.000). The repetitions of the task did not produce significant changes in f(c). It was shown that f(0,mode) is a sensitive parameter to describe changes in emotional load, at least in response to short-term psychoemotional stress, and seems to throw light upon the amount of adaptation caused by increased experience.
Wittels
Peter
P
Forschungsgruppe Leistungsmedizin, Heeresspital, Brünnerstrasse 238, A 1210 Wien, Austria. wittels@bmlv.gv.at
Johannes
Bernd
B
Enne
Robert
R
Kirsch
Karl
K
Gunga
Hanns-Christian
HC
D000328:Adult; D004644:Emotions; D015444:Exercise; D005583:Fourier Analysis; D006339:Heart Rate; D006801:Humans; D007318:Inservice Training; D008297:Male; D008889:Military Personnel; D010806:Physical Education and Training; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography / Q000379:methods; D013223:Statistics as Topic; D013315:Stress, Psychological / Q000503:physiopathology* / Q000523:psychology*; D014705:Verbal Behavior; D014831:Voice; D014833:Voice Quality