Bilirubin and serial auditory brainstem responses in premature infants.

OBJECTIVES: To determine the usefulness of the bilirubin-albumin (B:A) molar ratio (MR) and unbound bilirubin (UB) as compared with serum total bilirubin (TB) in predicting bilirubin encephalopathy as assessed by auditory brainstem responses (ABR) in infants of 28 to 32 weeks' gestational age. STUDY DESIGN: During a 2-year period, serial ABRs were obtained on 143 infants of 28 to 32 weeks' gestational age during the first postnatal week. Waveforms were categorized on the basis of response replicability and the presence of waves III and V. Wave V latencies were also serially analyzed when measurable for individual infants. Maturation of the ABR was defined as abnormal when the waveform category worsened and/or latency increased during the study interval. Serum albumin was analyzed at 48 to 72 hours of age in all patients. Serum TB was analyzed as clinically indicated. Aliquots of the same samples were also analyzed for UB in a subset of infants. RESULTS: The mean peak TB concentration (10.1 +/- 1.7 mg/dL) for the 71 infants with normal ABR maturation was not significantly different from the mean peak TB (10.2 +/- 2.1 mg/dL) in the 24-hour period preceding the ABR's first showing abnormal maturation in the other 55 infants. However, in infants with UB analyzed, the mean peak UB (0.62 +/- 0.20 vs 0.40 +/- 0.15 microg/dL) was significantly higher in the infants with abnormal maturation (n = 25) than in infants with normal maturation (n = 20). The B:A MR results were equivocal. In the entire study population, there was no difference in B:A MR between infants with normal versus abnormal ABR maturation. However, in the subset of infants in whom UB was measured, although TB was not different, there was a significant difference in B:A MR. Based on receiver-operating characteristic curves, a UB level of 0.5 microg/dL was the best discriminator with a sensitivity of 70% and a specificity of 75%. The proportion of infants who had UB >0.5 microg/dL and UB 0.5 microg/dL compared with UB

Brainstem maturation in premature infants as a function of enteral feeding type.

OBJECTIVE: To determine whether brainstem maturation as measured by brainstem auditory-evoked responses (BAERs) in preterm infants is a function of dietary intake. STUDY DESIGN: We obtained serial BAERs on infants 28 to 32 weeks' gestation at birth, cared for in the neonatal intensive care unit of a regional referral center in Upstate New York. Waveforms were analyzed for replicability and for the presence of waves III and V. Absolute and interwave latencies were measured. Baseline and follow-up BAER measurements were compared, and the rates of change were calculated. Patient charts were reviewed for type of enteral feeding during the interval between BAERs. Student's t test was used to analyze continuous variables and chi(2) analysis was used to analyze categorical variables. RESULTS: Data from 37 study infants (17 fed breast milk and 20 fed commercial premature formula) revealed that there was no difference in absolute latencies of waves III and V at baseline; however, the rates of decrease of absolute latencies over the study interval were significantly greater in infants receiving human milk. CONCLUSIONS: Infants fed breast milk have faster brainstem maturation, compared with infants fed formula, based on the rate of maturation of BAERs. This effect may be attributable to the constituent composition of breast milk, compared with synthetic formulas.

Morphological changes in serial auditory brain stem responses in 24 to 32 weeks' gestational age infants during the first week of life.

OBJECTIVE: The purpose of this investigation was to describe and quantify the sequential morphological changes in the auditory brain stem response (ABR) during the first postnatal week of life in very premature infants < or = 32 wk gestational age. These normative data could be useful in predicting neurological outcome in infants with perinatal risk factors. DESIGN: Sequential ABRs were recorded on a total of 135 infants on 5 out of the first 7 days of life. For analysis, data were grouped by gestational age in 2 wk intervals. In addition, a unique system was devised to categorize waveform response types in premature infants: type 1, a response with normal morphology and replicable waves III and V; type 2, a replicable response with either a wave III or wave V; type 3, a replicable response with neither a wave III or wave V; type 4, a response with no replicable waveform. RESULTS: The frequency of detection of waves improves over the first week of life with the detectability of waves III and V being more frequent than wave I at all gestational ages. There was a gradual improvement in response types in infants > 26 wk with the greatest improvement occurring during the 28 to 29 wk gestation. ABRs were predominantly types 3 and 4 at 24 to 25 wk, type 3 at 26 to 27 wk, type 2 at 28 to 29 wk, and types 1 and 2 at 30 to 31 wk. Absolute wave latencies and interwave latencies also progressively decreased during the first postnatal week. In some infants there was a transient increase in latencies or worsening of response type on the second to third test day. CONCLUSIONS: There is progressive improvement in frequency of detection of waves I, III, and V with increasing gestational age. Response types gradually mature over the first postnatal week, particularly in premature infants 28 to 32 wk gestational age.

Characteristics of a "nonspecific" ENG population.

Fifty-one patients with "nonspecific" (nonlocalizing) electronystagmograms were studied both concurrently and retrospectively to determine the characteristics of this sample population. Data were gathered for the following categories: (1) vestibular signs/symptoms; (2) trauma; (3) aural signs/symptoms; (4) hearing loss; (5) psychosocial behavior; (6) other neurological findings; and (7) other medical problems. Analysis indicates that twice as many females have nonspecific electronystagmogram findings. The majority of these are in the menopausal age range. Most patients are uncertain about the onset, duration, and frequency of their vestibular problems. A high percentage of the population had a history of psychiatric treatment.

Users' satisfaction with hearing aids.

Seventy-one hearing aid users were surveyed two years after their initial fitting to determine whether they (1) wore the hearing aid(s) prescribed, (2) were satisfied with their aid(s), (3) had specific complaints about their aid(s), and (4) would recommend that a hearing-impaired friend or relative go through the same hearing aid selection process. Ninety-six percent of the respondents obtained that aid that we recommended. Eighty-eight percent were "very satisfied" or "satisfied" with the help that their aid(s) provided. Eighty-two percent would recommend that a hearing-impaired friend or relative go directly to a "hearing specialist" for assistance when selecting a hearing aid.