Masters Theses

Date of Award

12-1989

Degree Type

Thesis

Degree Name

Master of Arts

Major

Audiology

Major Professor

Carl W. Asp

Committee Members

Patricia Earl, Niel Field

Abstract

Fourteen full term (36-41 weeks gestational age) normal nursery infants (28-118 hours old) served as subjects in this study. Seven normal infants with low (below 8 mg/dl) serum bilirubin concentration and seven infants with high (above 12 mg/dl) serum bilirubin concentration formed the two groups under investigation.

A pain cry, elicited by a heelstick, was tape recorded while a blood sample was taken. The tape recordings were presented in their entirety to a panel of five nurses from the newborn nursery at The University of Tennessee Medical Center. The nurses rated their perceptions of the infants' cries by using a 1-5 point rating scale. The perceptual parameters included: urgent to not urgent, pleasing to grating, healthy to sick, soothing to arousing, piercing to not piercing, comforting to discomforting, aversive to nonaversive, and distressing to not distressing. An overall profile of the bilirubin infants' cries was seen from the ratings of the nurses. The bilirubin cries were more urgent, grating, sick, arousing, aversive, and distressing than the normal infants' cries. The cries of the bilirubin infants were also rated significantly more piercing than the cries of normal infants. The parameter of piercing was thought to be the parameter most closely related to the acoustic characteristic of pitch.

The 14 mothers of the infants identified the cry of their infant from the cries of two other infants. Seventy-one percent of the mothers identified their infant's cry correctly from the cries of others. No correlation was found between the amount of time the mother had spent with her infant and the ability to correctly identify her infant's cry. It was speculated that the ability to identify cry might be hormonally mediated or the result of some intrauterine imprinting.

The 14 cries were analyzed on both narrow and wide band spectrograms according to; cry latency (msec), 2nd pause (msec), minimum Fo for the first and second cry segments (Hz) , peak Fo for the first and second cry segments, (Hz) , the presence of continuity in the first and second cry segments, and the presence of furcation in the entire cry signal. The feature of fraction was present in all of the hyperbilirubinemic infant cries, but was not present in any of the normal infant cries. Furcation was identified when a split in the Fo was seen resulting in small branching of the Fo.

Correlations were examined between the physical state of the infant at the time of the recording and the acoustic characteristics. A statistically significant correlation was determined between cry latency and the infants' state of wakefulness.

Based on the results of technical and interactive evaluation of the infants' cries, the utility of cry analysis might prove to be a powerful tool for early intervention. Cry analysis could be used in the evaluation of subclinical and clinical repercussions of hyperbilirubinemia and other neonatal disorders. Even at a moderate serum bilirubin level (8-12 mg/dl), which traditionally has not been implicated as a cause of overt pathology, infants may experience subacute or subclinical changes that might indicate a need for ongoing evaluation.

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