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Biomedical subjects

S A Cavallo

Publications and source records attributed to S A Cavallo.

5 recordsLinked to original sources
PubMed1985

Prephonatory laryngeal and chest wall dynamics.

The timing of prephonatory movements of the larynx, rib cage, and abdomen was examined in order to gain insight into the contribution of the vocal folds to the posturing of the chest wall. A simple stimulus-response paradigm was used in eliciting brief utterances--/a/ and /ha/--from six adult males. Chest wall movements were observed using mercury strain gages while simultaneous electroglottographic and airflow records provided information about vocal fold behavior. Independence of prephonatory laryngeal and chest wall behavior was demonstrated. Laryngeal adjustment preceded the start of vocal fold oscillation by a constant amount of time, whereas the time of onset of the chest wall adjustment varied as a function of the utterance type. The qualitative characteristics of prephonatory chest wall posturing were unaffected by altering glottal configuration requirements. Rib cage enlargement occurred during postural adjustment while the vocal folds were abducted (in preparation for /h/). This implies that rib cage enlargement during prephonatory chest wall posturing was not a passive response to abdominal compression.

Adult↗
PubMed1984

Frequency perturbation characteristics of pulse register phonation.

Examination of some acoustic characteristics of sustained pulse register phonation in normal adults confirmed the existence of two distinct waveform patterns. Trains of similar, highly damped waves with relatively uniform spacing predominated, but the "dicrotic" pattern previously described accounted for about 15% of the total sample. Average differences in the periods of continguous cycles (jitter) were extremely large--on the order of 20% of the fundamental period. Jitter did not vary with fundamental frequency according to the pattern documented in modal register and, thus, jitter ratio is not a useful normalizing descriptor of pulse register perturbation.

Adult↗
PubMed1983

Prephonatory chest wall posturing in stutterers.

The possibility that prephonatory chest wall posturing is abnormal in stutterers was explored by observing rib cage and abdominal hemicircumference changes during the interval between the presentation of a stimulus and the production of/alpha/by a group of stutterers (N = 5). It was found that the patterns of chest wall adjustment for phonation were qualitatively identical in the stutterers and in a comparable group of normal men studied previously. There was, however, a significant difference in the way in which lung volume changed during the execution of the chest wall adjustment. This was considered to be indicative of delayed glottal closure among the stutterers rather than representative of a primary ventilatory disturbance.

Abdominal Muscles↗
PubMed1979

Chest wall movements prior to phonation.

Movements of the chest wall during the interval between an acoustic stimulus and the subject's vocal response were examined and timed in eight normal males. The reaction-time interval was divisible into two phases, a latency period with duration independent on chest wall status at the time of stimulus and an adjustment period during which the rib cage and abdomen usually moved oppositionally to achieve a prephonatory postural set. The time required for this adjustment varied significantly with lung volume, but was independent of the ventilatory phaze previously in progress.

Abdomen↗