Susan L. Phillips

Prevalence of noise-induced hearing loss in student musicians

Abstract This study describes the prevalence and characteristics of noise-induced hearing loss (NIHL) in student musicians (N = 329) aged 18–25 years. Students completed a questionnaire regarding exposures before a hearing assessment. NIHL was defined by the presence of a notch 15 dB in depth at 4000 or 6000 Hz relative to the best preceding threshold. Overall prevalence of NIHL was 45%, with 78% of notches occurring at 6000 Hz. The proportion of the total population with bilateral notching at any frequency was 11.5%, mostly occurring at 6000 Hz. There was a significant increase in the frequency of notching in students who reported more than two hours per day of personal practice. There were no significant associations for instrument group or other noise exposures. The data suggest that susceptibility to NIHL among students of music is not uniform and cannot be ascribed solely to the instrument played and other exposures. Students with bilateral losses tend to have deeper notches and may represent a group that has an inherent predisposition to NIHL. Sumario Este estudio describe la prevalencia y las características de la hipoacusia inducida por ruido (NIHL) en estudiantes de música (N = 329) con edades entre 18 y 25 años. Los estudiantes completaron un cuestionario sobre exposición a ruido antes de la evaluación auditiva. Se definió NIHL como la presencia de una muesca de 15dB en 4000 o 6000Hz con relación al mejor umbral precedente. La prevalencia general de NIHL fue de 44%, con 78% de las muescas en 6,000 Hz. La proporción de la población total con muescas bilaterales en cualquier frecuencia fue de 11.5%, en su mayoría a 6,000 Hz. Hubo un incremento significativo en la frecuencia de la muescas en los estudiantes que reportaban más de dos horas al día de práctica profesional. No hubo una asociación significativa con grupos de instrumentos u otra exposición a ruido. Los datos sugieren que la susceptibilidad a NIHL entre los estudiantes de música no es uniforme y no puede atribuirse solamente al instrumento tocado o a otras exposiciones. Los estudiantes con pérdida bilateral tienden a tener muescas más profundas y pueden representar un grupo que tenga una predisposición inherente a la NIHL.

The effect of silence on tinnitus perception

OBJECTIVE The effect of sustained silence was studied on the emergence of tinnitus perception in 120 normal hearing young adult Caucasians and African Americans. STUDY DESIGN AND SETTING After sitting in a sound booth for a period of 20 minutes, participants were asked to complete a questionnaire documenting whether they perceived sounds in the silent setting and descriptions of the sounds they heard. RESULTS: Tinnitus-like sounds were perceived in 64% of listeners overall. No significant differences in tinnitus perception were observed between males and females. However, there was a significant difference in tinnitus perception between Caucasian and African American subjects, with tinnitus sounds emerging in sustained silence less frequently in African American listeners. Tinnitus emerged quickly in a majority of subjects (less than 4 minutes) and African American subjects who perceived tinnitus heard a greater number of individual tinnitus-like sounds than did Caucasian subjects. Ring (57%), buzz (21%), pulse (22%), heartbeat (21%), and hum (14%) were the most common sounds heard, with ring being the most common overall tinnitus perception. CONCLUSIONS AND SIGNIFICANCE Few investigators have documented at the emergence of tinnitus in normal hearing subjects. Results of the current study found significant differences in tinnitus perception between Caucasian and African American subjects, but found no significant differences when comparing males and female subjects. EBM rating: C.

Student's music exposure: Full-day personal dose measurements

Previous studies have shown that collegiate level music students are exposed to potentially hazardous sound levels. Compared to professional musicians, collegiate level music students typically do not perform as frequently, but they are exposed to intense sounds during practice and rehearsal sessions. The purpose of the study was to determine the full-day exposure dose including individual practice and ensemble rehearsals for collegiate student musicians. Sixty-seven college students of classical music were recruited representing 17 primary instruments. Of these students, 57 completed 2 days of noise dose measurements using Cirrus doseBadge programed according to the National Institute for Occupational Safety and Health criterion. Sound exposure was measured for 2 days from morning to evening, ranging from 7 to 9 h. Twenty-eight out of 57 (49%) student musicians exceeded a 100% daily noise dose on at least 1 day of the two measurement days. Eleven student musicians (19%) exceeded 100% daily noise dose on both days. Fourteen students exceeded 100% dose during large ensemble rehearsals and eight students exceeded 100% dose during individual practice sessions. Approximately, half of the student musicians exceeded 100% noise dose on a typical college schedule. This finding indicates that a large proportion of collegiate student musicians are at risk of developing noise-induced hearing loss due to hazardous sound levels. Considering the current finding, there is a need to conduct hearing conservation programs in all music schools, and to educate student musicians about the use and importance of hearing protection devices for their hearing.

Feasibility of a bilateral 4000–6000 Hz notch as a phenotype for genetic association analysis

Abstract Objective: Noise-induced hearing loss (NIHL) is a worldwide health problem and a growing concern among young people. Although some people appear to be more susceptible to NIHL, genetic association studies lack a specific phenotype. We tested the feasibility of a bilateral 4000–6000 Hz audiometric notch as a phenotype for identifying genetic contributions to hearing loss in young adults. Design: A case-control-control study was conducted to examine selected SNPs in 52 genes previously associated with hearing loss and/or expressed in the cochlea. A notch was defined as a minimum of a 15-dB drop at 4000–6000 Hz from the previous best threshold with a 5-dB ‘recovery’ at 8000 Hz. Study sample: Participants were 252 individuals of European descent taken from a population of 640 young adults who are students of classical music. Participants were grouped as No-notch (NN), Unilateral Notch (UN), or Bilateral Notch (BN). Results: The strongest evidence of a genetic association with the 4000–6000 Hz notch was a nonsynonymous SNP variant in the ESRR– gene (rs61742642:C> T, P386S). Carriers of the minor allele accounted for 26% of all bilateral losses. Conclusion: This study indicates that the 4000–6000 Hz bilateral notch is a feasible phenotype for identifying genetic susceptibility to hearing loss.

A polymorphism in human estrogen-related receptor beta (ESRRβ) predicts audiometric temporary threshold shift

Abstract Objective: A non-synonymous single nucleotide polymorphism (rs61742642; C to T, P386S) in the ligand-binding domain of human estrogen-related receptor beta (ESRRβ) showed possible association to noise-induced hearing loss (NIHL) in our previous study. Design: This study was conducted to examine the effect of the ESRRβ rs61742642 T variant on temporary threshold shift (TTS). TTS was induced by 10 minutes of exposure to audiometric narrow-band noise centered at 2000 Hz. Hearing thresholds and distortion product otoacoustic emissions input output function (DP IO) at 2000, 3000, and 4000 Hz were measured before and after the noise exposure. Study sample: Nineteen participants with rs61742642 CT genotype and 40 participants with rs61742642 CC genotype were recruited for the study. Results: Participants with the CT genotype acquired a significantly greater TTS without convincing evidence of greater DP IO temporary level shift (DPTLS) compared to participants with the CC genotype. Conclusion: The results indicated that the ESRRβ polymorphism is associated with TTS. Future studies were recommended to explore molecular pathways leading to increased susceptibility to NIHL.