Wendy D'haenens

Short-term Auditory Effects of Listening to an MP3 Player

OBJECTIVES To determine the output levels of a commercially available MPEG layer-3 (MP3) player and to evaluate changes in hearing after 1 hour of listening to the MP3 player. DESIGN First, A-weighted sound pressure levels (measured in decibels [dBA]) for 1 hour of pop-rock music on an MP3 player were measured on a head and torso simulator. Second, after participants listened to 1 hour of pop-rock music using an MP3 player, changes in hearing were evaluated with pure-tone audiometry, transient-evoked otoacoustic emissions, and distortion product otoacoustic emissions. PARTICIPANTS Twenty-one participants were exposed to pop-rock music in 6 different sessions using 2 types of headphones at multiple preset gain settings of the MP3 player. MAIN OUTCOME MEASURES Output levels of an MP3 player and temporary threshold and emission shifts after 1 hour of listening. RESULTS The output levels at the full gain setting were 97.36 dBA and 102.56 dBA for the supra-aural headphones and stock earbuds, respectively. In the noise exposure group, significant changes in hearing thresholds and transient-evoked otoacoustic emission amplitudes were found between preexposure and postexposure measurements. However, this pattern was not seen for distortion product otoacoustic emission amplitudes. Significant differences in the incidence of significant threshold or emission shifts were observed between almost every session of the noise exposure group compared with the control group. CONCLUSIONS Temporary changes in hearing sensitivity measured by audiometry and otoacoustic emissions indicate the potential harmful effects of listening to an MP3 player. Further research is needed to evaluate the long-term risk of cumulative noise exposure on the auditory system of adolescents and adults.

Impact of newborn hearing screening: comparing outcomes in pediatric cochlear implant users.

To evaluate the impact of a newborn hearing screening program on the management and outcome of deaf children and to identify underlying factors that may be responsible for the differences between high and low performing implanted children.

Transient-evoked and distortion product otoacoustic emissions: A short-term test-retest reliability study

Abstract Knowledge regarding the variability of transient-evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) is essential in clinical settings and improves their utility in monitoring hearing status over time. In the current study, TEOAEs and DPOAEs were measured with commercially available OAE-equipment in 56 normally-hearing ears during three sessions. Reliability was analysed for the retest measurement without probe-refitting, the immediate retest measurement with probe-refitting, and retest measurements after one hour and one week. The highest reliability was obtained in the retest measurement without probe-refitting, and decreased with increasing time-interval between measurements. For TEOAEs, the lowest reliability was seen at half-octave frequency bands 1.0 and 1.4 kHz; whereas for DPOAEs half-octave frequency band 8.0 kHz had also poor reliability. Higher primary tone level combination for DPOAEs yielded to a better reliability of DPOAE amplitudes. External environmental noise seemed to be the dominating noise source in normal-hearing subjects, decreasing the reliability of emission amplitudes especially in the low-frequency region. Sumario Es esencial conocer la variabilidad de las emisiones otoacústicas evocadas por transitorios (TEOAEs) y por productos de distorsión (DPOAEs) en ambientes clínicos para mejorar su utilidad en el monitoreo de la condición auditiva en el tiempo. En este estudio se midieron TEOAEs y DPOAEs con equipo de OAE comercialmente disponible en 56 oídos normales durante tres sesiones. La confiabilidad se analizó en el retest sin re-colocar la sonda, en el retest inmediato con recolocación de la sonda y con mediciones después de una hora y una semana. La mayor confiabilidad se obtuvo en el retest sin recolocación de la sonda y disminuyó a aumentar el intervalo entre mediciones. Con TEOAEs la confiabilidad más baja se observó en bandas de frecuencia en 1.0 y 1.4 kHz mien-tras que para las DPOAEs también la banda de frecuencia de media octava de 8 kHz tuvo también confiabilidad pobre. La combinación de niveles tonales primarios superiores con DPOAEs, llevó a una mejor confiabilidad de las amplitudes de las DPOAEs. El ruido ambiental externo parece ser la fuente de ruido dominante en sujetos normales, disminuyendo la confiabilidad de las amplitudes de la emisión, especialmente en la región de las frecuencias graves.

The Effect of Age on the Sinusoidal Harmonic Acceleration Test, Pseudorandom Rotation Test, Velocity Step Test, Caloric Test, and Vestibular-evoked Myogenic Potential Test

Objectives: Age-related anatomical and morphologic vestibular deterioration has already been elaborated. Demonstrating a corresponding degradation in physiologic function, however, entails a much higher challenge. The objective of this study was to investigate age-related changes using rotational tests, caloric tests, and the vestibular-evoked myogenic potentials (VEMP) test. Design: Eighty healthy human subjects (38 men and 42 women) ranging in age from 18 to 80 yrs participated in this study and were subjected to an extensive vestibular test battery. Function tests included sinusoidal harmonic acceleration tests, a pseudorandom rotation test, velocity step tests, a caloric test, and a VEMP test. Results: No significant age trends were noted for the sinusoidal harmonic acceleration test and velocity step tests response parameters, in contrast to subtle decreasing gain values with advancing age for the pseudorandom rotation test. Increasing slow-component velocity values were measured with the caloric test, whereas the frequency parameter showed no relevant age changes. The largest age trends were detected with the VEMP, with decreasing amplitudes, increasing thresholds, and decreasing N1 latencies. All asymmetry parameters remained stable across the different age categories. Conclusions: Only subtle age changes could be demonstrated with the rotational and caloric tests, in contrast to more pronounced age trends with the VEMP.

Auditory steady-state responses in normal hearing adults: a test-retest reliability study.

The test-retest reliability of the auditory steady-state response (ASSR) has received limited attention. Therefore, the aim was to assess the test-retest reliability of an 80-Hz multiple-ASSR system in normal-hearing subjects by a comprehensive set of statistical methods. Twenty-nine participants (15 females) aged between 18 and 30 years contributed to two sessions (test-retest), and the ASSR thresholds were determined with a descending search protocol using a 10-dB precision. The test-retest reliability was assessed by a three-layered approach which consisted of Pearson product-moment correlation, analysis of variance (ANOVA), and standard error of measurement (SEM). The correlations for ASSR thresholds ranged from poor (0.34) for 500 Hz CF to moderate (0.55) for 1000, 2000, and 4000 Hz CF. A two-way ANOVA of the difference scores (ASSR threshold minus behavioral threshold) demonstrated no significant difference between test and retest. The SEM determined the normal tolerance for clinical error of repeated thresholds and the ASSR SEM values fell well within ±10 dB HL. This investigation shows that the multiple ASSR-technique produces a clinically acceptable test-retest reliability for normal-hearing adults.

Effectiveness of hearing protector devices in impulse noise verified with transiently evoked and distortion product otoacoustic emissions

This study aimed to evaluate the effect of impulse noise on otoacoustic emissions (OAEs) while a passive non-linear earplug or an active level-dependent earmuff was worn. Since none of the standardized attenuation measurement techniques, REAT (real ear at threshold), ATF (acoustic test fixture), or MIRE (microphone in real ear), is designed to test both types in real-wearing condition, OAEs, suitable for detecting subtle changes in the functional integrity of the cochlear outer hair cells, are used. First, DPOAEs (distortion product) and TEOAEs (transiently evoked) of 24 subjects were compared before, immediately after gunfire practice, and after one hour of non-exposure. Secondly, both types of OAEs were evaluated in 31 subjects before and after exposure during a five-day military practice. Significant differences existed between the ears in most cases; the emissions from the right ear had a tendency to be more robust. There were no significant changes in OAEs either before and after exposure, or in the second experiment over multiple days. These findings suggest that the HPDs are able to prevent cochlear damage.

Water irrigation versus air insufflation: a comparison of two caloric test protocols.

The aim of the present study was to construct and compare two caloric test protocols, one for water irrigation, and one for air insufflation. A set of reference data was constructed and tabulated as well as the intersubject variability. The effect of age, sex, ear, and temperature, as well as a possible priming effect and order effect were investigated. Forty-seven subjects (18–58 years) without otological or vestibular history participated. Four response parameters were investigated: slow component velocity (SCV), frequency, unilateral weakness (UW), and directional preponderance (DP). Statistically higher SCV values were obtained for water compared to air, with statistically higher standard deviations for SCV water values. No influences of age, sex, ear, or temperature could be demonstrated on any of the response parameters. The same applied for the presence of an order effect and a priming effect. Comparing the two protocols to one another led the present authors to favour water as the standard irrigation medium, and air only in situations where water is contra-indicated.

Auditory steady-state responses to MM and exponential envelope AM2/FM stimuli in normal-hearing adults

The present study utilized a commercially available multiple auditory steady-state response (ASSR) system to test normal hearing adults (n=55). The primary objective was to evaluate the impact of the mixed modulation (MM) and the novel proposed exponential AM2/FM stimuli on the signal-to-noise ratio (SNR) and threshold estimation accuracy, through a within-subject comparison. The second aim was to establish a normative database for both stimulus types. The results demonstrated that the AM2/FM and MM stimulus had a similar effect on the SNR, whereas the ASSR threshold results revealed that the AM2/FM produced better thresholds than the MM stimulus for the 500, 1000, and 4000 Hz carrier frequency. The mean difference scores to tones of 500, 1000, 2000, and 4000 Hz were for the MM stimulus: 20±12, 14±9, 10±8, and 12±8 dB; and for the AM2/FM stimulus: 18±13, 12±8, 11±8, and 10±8 dB, respectively. The current research confirms that the AM2/FM stimulus can be used efficiently to test normal hearing adults.

Clinical usefulness of the rotatory, caloric, and vestibular evoked myogenic potential test in unilateral peripheral vestibular pathologies

Abstract Objective: The aim of this study was to investigate the diagnostic capacity of three different rotatory tests, and to investigate the clinical effectiveness of the caloric, rotatory, and vestibular evoked myogenic potential (VEMP) test. Design and study sample: Several rotatory tests—sinusoidal harmonic acceleration test (SHAT), pseudorandom rotation test (PRRT), velocity step test (VST)—and a caloric and a VEMP test, were given to 77 patients (mean age 52 years) with a unilateral peripheral vestibular pathology, and 80 control subjects (mean age 48 years). Results: For the rotatory test, the highest diagnostic capacity was obtained with the 0.01 Hz SHAT frequency, followed by 0.1 and 0.05 Hz. A higher diagnostic accuracy was reached for the caloric and VEMP test. The caloric test demonstrated high sensitivity and specificity values, but the 0.01 Hz SHAT rotation appeared more sensitive, and the VEMP more specific, than the caloric test. Conclusion: A selection of the 0.01, 0.05, and 0.1 Hz SHAT rotations is suggested as the most ideal rotatory test protocol, and a combination of rotatory, caloric, and VEMP testing will result in a more complete examination of our vestibular system. Sumario Objetivos: El objetivo de este estudio fue investigar la capacidad diagnóstica de tres diferentes pruebas rotatorias e investigar la efectividad clínica de las pruebas calóricas, rotatorias y de potenciales evocados vestibulares biogénicos (VEMP). Diseñ: Se aplicaron algunas pruebas rotatorias (prueba de aceleración sinusoidal armónica (SHAT), prueba de rotación pseudo-aleatoria (PRRT), prueba de velocidad de pasos (VST), prueba calórica y VEMP, a setenta y siete pacientes (edad promedio de 52 añs) con patología vestibular periférica unilateral y a 80 sujetos de un grupo control (edad media de 48 añs). Resultados: Para la prueba rotatoria, la más alta capacidad diagnóstica se obtuvo con la frecuencia SHAT 0.01, seguida por 0.1 y 0.05 Hz. La máxima precisión diagnóstica se alcanzó con las pruebas calórica y VEMP. La prueba calórica demostró altos valores de sensibilidad y especificidad, pero la de rotación SHAT en 0.01 pareció más sensitiva y el VEMP, más específico que la prueba calórica. Conclusiones: Se sugiere una selección de rotaciones SHAT de 0.01, 0.05 y 0.1 como protocolo ideal de pruebas rotatorias y una combinación de las pruebas rotatorias, calóricas y de VEMP, para lograr un examen más completo del sistema vestibular.