Correlation between auditory brainstem response and hearing prognosis in idiopathic sudden sensorineural hearing loss patients.

OBJECTIVE: To investigate the latency and amplitude of auditory brainstem response (ABR) and hearing prognosis in patients with idiopathic sudden sensorineural hearing loss (ISSNHL). METHODS: Patients with ISSNHL were classified into four different recovery groups. All patients' clinical and demographic features were analyzed. Two-channel ABRs were collected in response to click stimuli at 90dB nHL. ABR amplitudes for wave I and ABR latency for waves I, III, and V were analyzed. RESULTS: One hundred and two patients (54 men and 48 women) were included in the study. Hearing recovery was observed in 72 cases (70.6%). Waves I, III, and V latencies were significantly prolonged in the affected ears compared with the unaffected ears. A smaller wave I amplitude was found in the affected ear compared with the unaffected ear in the three recovery groups. There was a significant association between wave I latency and hearing outcome (p=0.009) with a prolonged trend from complete to slight hearing recovery group. CONCLUSIONS: There was a significant correlation between wave I latency and hearing outcome in patients with ISSNHL. The finding may provide diagnostic information and serve as a potential prognostic indicator in patients with ISSNHL.

The universal newborn hearing screening program of Taipei City.

OBJECTIVES: To establish a hearing screening program with high coverage, low referral rate, high follow-up rate, and early intervention in Taipei City. METHODS: From September 2009 to December 2010, 85% delivery units in Taipei City, which includes 20 hospitals and 14 obstetrics clinics, were recruited into the screening program in two stages. A total of 15,930 babies were born in these participating hospitals and clinics during the program period. Among these neonates, 15,790 underwent hearing screening test with automatic auditory brainstem response (AABR). The screening was free of charge to the parents. The hearing screening examination was performed 24-36 h after birth. The same test was repeated between 36 and 60 h of age if the baby failed the first hearing test. The neonate was referred to the diagnostic hospitals for further investigations if he failed the second test. RESULTS: The screening coverage rate was 99.1% (15,790/15,930). The incidence of bilateral moderate to severe and unilateral hearing loss was 1.4 per 1000 (22/15,790) and 1.5 per 1000 (24/15,790), respectively. Four percent (626/15,790) of newborns failed to pass the initial screening test and 1.0% of newborns failed to pass the second screening test. Therefore, 1.0% newborns were referred for diagnostic assessments. The follow-up rate was 94.4% (151/160). Sixty-four percent (14/22) of babies with bilateral hearing loss completed the full diagnostic hearing tests within 3 months of birth. CONCLUSIONS: The universal newborn hearing screening program is an adequate program for Taipei City with high coverage, low referral rate, and good follow-up rate. Screening fees covered by third parties, two-stage screening steps with AABR strategy, and the stringent monitoring system proved to be effective. LEVEL OF EVIDENCE: 2b, individual cohort study.

Dysregulated brain creatine kinase is associated with hearing impairment in mouse models of Huntington disease.

Huntington disease (HD) is a degenerative disorder caused by expanded CAG repeats in exon 1 of the huntingtin gene (HTT). Patients with late-stage HD are known to have abnormal auditory processing, but the peripheral auditory functions of HD patients have yet to be thoroughly assessed. In this study, 19 HD patients (aged 40-59 years) were assessed for hearing impairment using pure-tone audiometry and assessment of auditory brainstem responses (ABRs). PTA thresholds were markedly elevated in HD patients. Consistent with this, elevated ABR thresholds were also detected in two mouse models of HD. Hearing loss thus appears to be an authentic symptom of HD. Immunohistochemical analyses demonstrated the presence of mutant huntingtin that formed intranuclear inclusions in the organ of Corti of HD mice, which might interfere with normal auditory function. Quantitative RT-PCR and Western blot analyses further revealed reduced expression of brain creatine kinase (CKB), a major enzyme responsible for ATP regeneration via the phosphocreatine-creatine kinase (PCr-CK) system, in the cochlea of HD mice. Treatment with creatine supplements ameliorated the hearing impairment of HD mice, suggesting that the impaired PCr-CK system in the cochlea of HD mice may contribute to their hearing impairment. These data also suggest that creatine may be useful for treating the hearing abnormalities of patients with HD.