The Effect of the Heartbeat on Vocal Fundamental Frequency Perturbation

Signal-averaging and autocorrelation analysis revealed that the cardiovascular system exerts a modest but consistent influence on vocal fundamental frequency (F₀), accounting for approximately 0.5% to 20% of the absolute F₀ perturbation (jitter) measured during a sustained phonation. There was also a marked trend for this percentage to decrease with increasing vocal F₀. Estimated mean "deterministic jitter" (J) values of 3.7 µsec (SD = 3.2) and 0.9 µsec (SD = 0.5) were derived from 6 normal male and 6 normal female subjects, respectively, with an overall mean of 2.3 µsec (SD =2.7). These values represent approximately 6.9% of the mean total jitter for men and 2.4% of the mean total jitter for women, or about 4.6% for all subjects. The results are discussed in terms of their significance regarding more reliable vocal jitter measurement.