Vowel amplitude variation associated with the heart cycle.
Modulation of the acoustic amplitude of a sustained vowel across the cardiac (ECG) cycle was examined by signal-averaging techniques. Ten normal men prolonged [a] at a comfortable Fo maintained within three SPL ranges: 60-68, 70-78, and 80-88 dB. Peak-to-peak amplitude variation associated with the heart cycle averaged 8.5% (s.d. = 5.4) re: mean, varying from about 14% at low SPLs to approximately 3% at high SPLs. The amplitude modulation was estimated to account for 11.8% of the measured short-term amplitude perturbation (shimmer), ranging from about 5% to almost 22% for individual samples. The mean deterministic shimmer (Sd) was 0.036 dB (s.d. = 0.019), with a trend toward decreasing Sd with increasing SPL. Additionally, fundamental frequency variation across the heart cycle within these phonations was comparable to that observed by Orlikoff and Baken [J. Acoust. Soc. Am. 85, 888-893 (1989)], and was shown to be uninfluenced by vocal SPL, although deterministic jitter (Jd) did decrease with vocal intensity. The results are discussed in terms of how the phonovascular relationship may affect the reliability and interpretation of acoustic shimmer measures.
Orlikoff
R F
RF
Department of Audiology and Speech Pathology, Memphis State University, Tennessee 38105.
D000328:Adult; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology; D013018:Sound Spectrography; D013061:Speech Acoustics; D014827:Vocal Cords / Q000098:blood supply; D014833:Voice Quality / Q000502:physiology*