Vocal Fold Perturbation Rates: Comparison Between Multiple Sclerosis and Normal Subjects
The literature contains limited information concerning the voice characteristics of Multiple Sclerosis (M.S.) patients. Vocal fold perturbation values have been found to be an effective means in determining normal vocal fold status, yet no research has been reported for the M.S. population. Fifteen M.S. subjects were matched with fifteen normal subjects by age and gender. All subjects prolonged la.l and /i:/, and repeated the utterances. /hi:d/. /hfl:d/. /pi:d/ and /pa:6/, prolonging the medial sound. The data were tape recorded digitally, analyzed and compared in terms of differences in fundamental frequency, jitter, and shimmer rates. Results did not show significant differences between the normal and M.S. groups for fundamental frequency and jitter. One significant finding (.015 level of confidence) was discovered for shimmer in the speech utterance /hi:d/. All other speech utterances did not yield significant. The results were similar to previous studies conducted when comparing fundamental frequency; however, perturbation results appeared variable and inconsistent with previous studies.