Use of Audiometric Measurement for Assessment of Vocal-Fold Function in Postextubation Infants

Infants with vocal-fold motion impairment (VFMI) have an increased risk of aspiration and pulmonary complications. Flexible nasolaryngoscopy (FNL) is the gold standard for evaluation of vocal-fold mobility. Although safe, FNL causes measurable physiologic changes. Noxious stimuli, especially in neonates in the cardiovascular intensive care unit, may cause imbalance between the pulmonary and systemic circulations and potentially circulatory collapse.

To examine whether bedside measurement of infant cry volume using a smartphone application can be a screening tool for vocal-fold movement in FNL.

This case-control study performed from December 1, 2013, through January 31, 2015, included 42 infants in the intensive care unit at Texas Children's Hospital, Houston.

Patient cry volume in decibels was recorded using a smartphone application placed 12 in from their mouth.

Forty-two infants were identified at the intensive care unit (median age, 33 days; 20 [48%] female and 22 [52%] male), 21 with VFMI and 21 without, based on FNL findings. A statistically significant difference was found in the mean cry volume of infants with (76.60 dB) and without (85.72 dB) VFMI. The absolute difference in the mean cry volume was 9.12 dB (95% CI, 2.74-15.50 dB). A cry volume of 90 dB or greater had a sensitivity of 90.4% (95% CI, 71%-97%) for identification of normal vocal-fold mobility. A cry volume of 75 dB or less had a specificity of 90.5% (95% CI, 71%-97%) for the identification of VFMI. The mean (SE) area under the receiver operating characteristic curve was 0.721 (0.080) (95% CI, 0.565-0.877). The cry volume, however, was not a good screen for aspiration.

Bedside measurement of the cry volume with a smartphone application can be used by untrained health care professionals to screen patients for further evaluation of vocal-fold mobility using FNL.