Freya Swinnen

The vestibular evoked myogenic potential: A test–retest reliability study

OBJECTIVE The purpose of this study was to evaluate the reliability of the vestibular evoked myogenic potential (VEMP) response in a clinical setting when only a feedback mechanism is available for monitoring background EMG. METHODS Sixty-one healthy subjects participated in the investigation of the within-session reliability, whereas fourteen of them were retested after one week for examination of the between-session reliability. VEMPs were recorded using 500 Hz tone bursts with the subjects in a sitting position and their heads turned away from the test ear to the contralateral shoulder, thereby pushing their chin against the inflatable cuff of a blood pressure manometer, serving as feedback method. RESULTS The feedback method revealed latency and amplitude values comparable to other data in the literature where different test conditions were applied. Excellent reliability with ICC values ranging from 0.78 to 0.96 and CV(ME) values ranging from 4% to 36%, was achieved for P1 and N1 latency, threshold and interpeak amplitude. Good reliability with ICC values of 0.65 and 0.68 and CV(ME) values of 170% and 189%, was obtained for the asymmetry ratio. CONCLUSIONS A unilateral muscle contraction controlled by a feedback mechanism resulted in reliable response parameters, comparable right to left and corresponding to literature data obtained in different test conditions. SIGNIFICANCE The use of a blood pressure manometer as feedback mechanism combined with a meticulously controlled positioning of the head and contraction of the SCM muscle provides a reliable alternative in clinical settings, when the background muscle contraction cannot be measured or software related correction algorithms are not accessible.

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.

Association between bone mineral density and hearing loss in osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a heritable connective tissue disorder, predominantly characterized by bone fragility. In half of the patients, progressive hearing loss develops, which is associated with abnormal bony changes involving the middle ear ossicles and stapes footplate. In the present study, we investigated whether the development of hearing loss in OI may be related to the overall aberrant bone quality.

Determination and evaluation of clinically efficient stopping criteria for the multiple auditory steady-state response technique

OBJECTIVE The present study aimed at establishing clinically efficient stopping criteria for a multiple 80-Hz auditory steady-state response (ASSR) system. METHODS In Experiment 1, data of 31 normal-hearing subjects were analyzed off-line to propose stopping rules. Consequently, ASSR recordings will be stopped when (1) all 8 responses reach significance and significance can be maintained for 8 consecutive sweeps; or (2) the mean noise levels were 4nV (if p-values were between 0.05 and 0.1, measurements were extended once by 8 sweeps); or (3) a maximum amount of 48 sweeps was attained; whichever occurred first. In Experiment 2, these stopping criteria were applied on 10 normal hearing and 10 hearing-impaired adults to assess the efficiency. RESULTS The application of these stopping rules resulted in ASSR threshold values that were comparable to other ASSR research. Furthermore, preliminary analysis of the response and noise amplitudes demonstrated slightly higher values for hearing impaired than normal-hearing subjects. CONCLUSIONS The proposed stopping rules can be used in adults to determine accurate ASSR thresholds within a time-frame of about 1h. SIGNIFICANCE The use of these a priori stopping criteria might assist the clinician in their decision to terminate ASSR recordings.

Osteogenesis imperfecta: the audiological phenotype lacks correlation with the genotype

BackgroundOsteogenesis Imperfecta (OI) is a heritable connective tissue disorder mainly caused by mutations in the genes COL1A1 and COL1A2 and is associated with hearing loss in approximately half of the cases. The hearing impairment usually starts between the second and fourth decade of life as a conductive hearing loss, frequently evolving to mixed hearing loss thereafter. A minority of patients develop pure sensorineural hearing loss. The interindividual variability in the audiological characteristics of the hearing loss is unexplained.MethodsWith the purpose of evaluating inter- and intrafamilial variability, hearing was thorougly examined in 184 OI patients (type I: 154; type III: 4; type IV: 26), aged 3-89 years, with a mutation in either COL1A1 or COL1A2 and originating from 89 different families. Due to the adult onset of hearing loss in OI, correlations between the presence and/or characteristics of the hearing loss and the underlying mutation were investigated in a subsample of 114 OI patients from 64 different families who were older than 40 years of age or had developed hearing loss before the age of 40.ResultsHearing loss was diagnosed in 48.4% of the total sample of OI ears with increasing prevalence in the older age groups. The predominant type was a mixed hearing loss (27.5%). A minority presented a pure conductive (8.4%) or pure sensorineural (12.5%) loss. In the subsample of 114 OI subjects, no association was found between the nature of the mutation in COL1A1 or COL1A2 genes and the occurrence, type or severity of hearing loss. Relatives originating from the same family differed in audiological features, which may partially be attributed to their dissimilar age.ConclusionsOur study confirms that hearing loss in OI shows a strong intrafamilial variability. Additional modifications in other genes are assumed to be responsible for the expression of hearing loss in OI.

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.