Assessment of Interaural Attenuation in Infants and Young Children Using Bone-Conducted Auditory Brainstem Response.

OBJECTIVES: In hearing assessment, the term interaural attenuation (IAA) is used to quantify the reduction in test signal intensity as it crosses from the side of the test ear to the nontest ear. In the auditory brainstem response (ABR) testing of infants and young children, the size of the IAA of bone-conducted (BC) stimuli is essential for the appropriate use of masking, which is needed for the accurate measurement of BC ABR thresholds. This study aimed to assess the IAA for BC ABR testing using 0.5 to 4 kHz narrowband (NB) CE-chirp LS stimuli in infants and toddlers with normal hearing from birth to three years of age and to examine the effects of age and frequency on IAA. DESIGN: A total of 55 infants and toddlers with normal hearing participated in the study. They were categorized into three age groups: the young group (n = 31, infants from birth to 3 mo), middle-aged group (n = 13, infants aged 3-12 mo), and older group (n = 11, toddlers aged 12-36 mo). The participants underwent BC ABR threshold measurements for NB CE-chirp LS stimuli at 0.5 to 4 kHz. For each participant, one ear was randomly defined as the "test ear" and the other as the "nontest ear." BC ABR thresholds were measured under two conditions. In both conditions, traces were recorded from the channel ipsilateral to the test ear, whereas masking was delivered to the nontest ear. In condition A, the bone oscillator was placed on the mastoid of the test ear, whereas in condition B, the bone oscillator was placed on the mastoid contralateral to the test ear. The difference between the thresholds obtained under conditions A and B was calculated to assess IAA. RESULTS: The means of IAA (and range) in the young age group for the frequencies 0.5, 1, 2, and 4 kHz were 5.38 (0-15) dB, 11.67 (0-30) dB, 21.15 (10-40) dB, and 23.53 (15-35) dB, respectively. Significant effects were observed for both age and frequency on BC IAA. BC IAA levels decreased with age from birth to 36 mo. In all age groups, smaller values were observed at lower frequencies and increased values were observed at higher frequencies. CONCLUSIONS: BC IAA levels were both age and frequency dependent. The study found that the BC IAA values for lower stimulus frequencies were smaller than previously assumed, even in infants younger than 3 mo. These results suggest that masking should be applied in BC ABR threshold assessments for NB CE-chirp LS stimuli at 0.5, 1, and 2 kHz, even in young infants. Masking may not be necessary for testing at 4 kHz if a clear response is obtained at 15 dB normal-hearing level (nHL) in infants younger than 3 mo.

Assessment of Risk Indicators for Targeted Cytomegalovirus Screening in Neonates.

BACKGROUND: In the absence of universal screening for congenital cytomegalovirus (cCMV) infection, the aim of this study was to assess the outcomes of a targeted screening protocol based on maternal and neonatal risk indicators. METHODS: The medical records of 2,623 neonates born in our maternal hospital between June 2016 and December 2018 and screened for cCMV infection were reviewed. Among those of the included neonates, the records of 380 CMV-negative and 19 CMV-positive neonates were randomly assigned to obtain additional comparative data. RESULTS: During the study period, a total of 63 neonates were identified as positive for cCMV, comprising 0.2% of the total birth cohort (63/28,982) and 2.4% of all neonates screened for cCMV (63/2,623). The comparative data analysis showed that suspected or confirmed CMV infection during pregnancy, maternal age, and maternal diabetes mellitus were found to be significantly associated with a positive cCMV diagnosis. Although symmetric small for gestational age and hearing screening failure contributed to the detection of some of the CMV-positive infants, these factors were not specific to this group. The results of the logistic regression model showed that the only factor that was significantly associated with an increased risk for a cCMV diagnosis was maternal serology suspected of CMV infection during pregnancy, with a regression coefficient estimate of 2.657 (adjusted p < 0.001). CONCLUSIONS: A targeted neonatal screening protocol based on multiple maternal and neonatal risk indicators is feasible but provides limited information. Our study emphasizes the importance of universal neonatal screening for the detection of neonates with cCMV.

The impact of conductive hearing loss on balance.

BACKGROUND: Balance is a complex process involving the coordinated activities of multiple sensory, motor and biomechanical components. Balance function may be disturbed in subjects suffering from hearing loss but the impairment has been attributed to the pathology underlying the hearing loss. AIM: The purpose of the study was to investigate the possible interference of simulated conductive hearing loss with the ability to maintain postural balance. METHODS: Twenty normal-hearing subjects, 20-30 years old, underwent the computerised dynamic posturography test battery before and after plugging their external ear canals with earplugs, thus simulating a 40dB conductive hearing loss. RESULTS: Eighteen females and two males were tested before and after plugging their ear canals. Average CHL was 40 ± 4.9dB. The composite equilibrium score was significantly diminished after plugging the ears with an average sway score of 73.5% (P < .05, T = 2.27). The fourth test condition was specifically affected with an average sway score of 72.85% with earplugs (P < .05, T = 2.37). CONCLUSIONS: Conductive hearing loss has a negative effect on balance. This can be theoretically explained by the association between hearing loss and saccular dysfunction.

Frequency-specific auditory brainstem response testing with age-appropriate sedation.

OBJECTIVE: Auditory brainstem response (ABR) testing is the gold-standard procedure for hearing evaluation in pediatric patients who cannot complete a behavioral hearing test. The amount of audiological information obtained depends on the quality of the patient's sleep during the test. In this retrospective database review, we aimed to assess the amount and the characteristics of the audiological information obtained in ABR testing in pediatric patients with age-appropriate sedation. METHODS: A retrospective chart review was conducted on 501 consecutive ABR sedation sessions performed between January 2014 and June 2016 at the Tel Aviv Medical Center. Oral triclofos was used for the sedation of younger patients (3-24 months) and intravenous propofol for older patients (>24 months). The dataset included 370 triclofos sessions (in 337 patients) and 131 propofol sessions (in 126 patients). RESULTS: None of the children developed complications, and all were discharged on the same day of the evaluation. Among the hearing-impaired children, a mean of 10 (1.8 SD) ABR threshold measurements was obtained from propofol-sedated patients and 9.4 (2.8 SD) measurements from those sedated with triclofos (P = 0.039). The major characteristics of the hearing loss, including its degree, type, and configuration, were obtained from all propofol-sedated patients and from 95% of those sedated with triclofos. CONCLUSIONS: A comprehensive evaluation of hearing status can be obtained in ABR testing with age-appropriate sedation. An average number of ∼10 threshold measurements were obtained during ABR testing with age-appropriate sedation, thus allowing for the evaluation of the degree, type and configuration of the hearing loss.

Sensitivity of the Automated Auditory Brainstem Response in Neonatal Hearing Screening.

BACKGROUND: In a 2-stage neonatal hearing screening protocol, if an infant fails the first-stage abstract screening with an otoacoustic emissions test, an automated auditory brainstem response (ABR)test is performed. The purpose of this study was to estimate the rate of hearing loss detected byfirst-stage otoacoustic emissions test but missed by second-stage automated ABR testing. METHODS: The data of 17 078 infants who were born at Lis Maternity Hospital between January 2013 and June 2014 were reviewed. Infants who failed screening with a transient evoked otoacoustic emissions (TEOAE) test and infants admitted to the NICU for more than 5 days underwent screening with an automated ABR test at 45 decibel hearing level (dB HL). All infants who failed screening with TEOAE were referred to a follow-up evaluation at the hearing clinic. RESULTS: Twenty-four percent of the infants who failed the TEOAE and passed the automated ABR hearing screening tests were eventually diagnosed with hearing loss by diagnostic ABR testing (22/90). They comprised 52% of all of the infants in the birth cohort who were diagnosed with permanent or persistent hearing loss .25 dB HL in 1 or both ears (22/42).Hearing loss .45 dB HL, which is considered to be in the range of moderate to profound severity, was diagnosed in 36% of the infants in this group (8/22), comprising 42% of the infants with hearing loss of this degree (8/19). CONCLUSIONS: The sensitivity of the diverse response detection methods of automated ABR devices needs to be further empirically evaluated.