Comparing statistics for objective detection of transient and steady-state evoked responses in newborns.

OBJECTIVE: Receiver operating characteristic (ROC) methodology was used to compare the performance of different statistics in the automatic detection of multiple auditory steady-state responses (MSSR) and click auditory brainstem responses (cABR). STUDY SAMPLE: Thirty-five healthy newborns tested within the first two weeks of birth. DESIGN: In each case cABR and MSSR (0.5 and 2 kHz) were recorded with and without acoustic stimulation, using AUDIX equipment. With this test sample of recordings, ROC curves were evaluated separately for each statistic evaluated: (1) the standard deviation ratio (SDR) and the correlation coefficient ratio (CCR) for the cABR; (2) the Hotelling T2 (HT2) and circular T2 (CT2) for the MSSR. RESULTS: All objective detection methods performed well (areas under ROC (AUC) > 0.9). The MSSR statistics showed significantly larger AUCs at both frequencies (HT2: 0.98 and 1; CT2: 0.96 and 0.99) than the cABR measures (SDR: 0.91 and CCR: 0.92). The HT2 hits rate was the highest (97-100% at 0.5 and 2 kHz) for fixed false alarms rates of both 10 and 20%. CONCLUSIONS: This superiority of performance of T2-like statistics, reflecting inherent advantages of MSSR analysis for automation, warrants serious consideration for further development of newborn screening technology.

Caracterización electrofisiológica del potencial evocado auditivo de seguimiento a la modulación del estímulo acústico / Electrophysiological characterisation of envelope-following responses

Introducción: Comprender el lenguaje implica percibir adecuadamente los cambios temporales que se producen en la amplitud de modulación de los sonidos del habla. La detección de estos cambios disminuye en las afecciones neurológicas como la esclerosis múltiple, la neuropatía auditiva, las hipoacusias neurosensoriales, la presbiacusia y el retraso primario del lenguaje. El potencial evocado auditivo de seguimiento a la envolvente (PEA-SE) permite estudiar electrofisiológicamente la respuesta auditiva a los cambios en la modulación de un estímulo acústico. Objetivos: Caracterizar el PEA-SE en adultos sanos y estudiar los efectos del sueño sobre este potencial. Métodos: Se estudiaron 11 sujetos, 6 en condiciones de vigilia y 5 en sueño espontáneo. Se registró el PEA-SE obtenido con un ruido blanco al que se le hizo un barrido de frecuencias de modulación entre 20-200Hz a 50dB HL de intensidad. Resultados: El PEA-SE mostró una morfología similar en todos los sujetos, caracterizándose por presentar dos componentes principales. La amplitud del primer componente (localizado entre 30-50Hz de modulación) fue significativamente mayor que la del segundo componente (entre 80-110Hz) tanto en los sujetos despiertos como en los dormidos. Existió además un efecto significativo del estado de vigilia sobre la amplitud del PEA-SE para las frecuencias entre 88-110Hz, 155-165Hz y 190-200Hz. Sin embargo, no hubo un efecto significativo del sueño sobre los componentes principales del PEA-SE. Conclusiones: En este trabajo se corrobora el patrón morfológico del PEA-SE sustentándose su utilidad para el estudio objetivo del procesamiento temporal del sistema auditivo (AU)

Introduction: The auditory ability to discriminate rapid changes in the envelope of language sounds is essential for speech comprehension. This ability is deteriorated in some neurological diseases such as multiple sclerosis, auditory neuropathy, sensorineural hearing loss, presbycusis, and primary developmental language disorder. Envelope-following responses (EFRs) in humans are useful in objective measurement of temporal processing in the auditory nervous system. Objectives: To evaluate EFRs in healthy younger subjects and to investigate the effects of subject states on the EFRs recorded. Methods: Eleven young subjects were included; 6 of them were awake and 5 were asleep. EFRs were evoked by white noise carrier stimuli with a sweep of modulation frequencies from 20 to 200Hz presented at 50dB HL. Results: The EFRs we recorded were similar in all subjects. There were two principal components. During both subject sleep and wakefulness, the first component (located between 30 and 50Hz) was significantly larger than the second component (located between 80 and 110Hz). There was also a significant effect of sleep on the EFR amplitude for the modulation frequencies between 88 and 110Hz, 155 and 165Hz, and 190 and 200Hz. However, there were no significant effects of sleep on the principal EFR components. Conclusions: These results corroborate the usefulness of the EFR technique for objective measurement of human auditory temporal processing (AU)

[Electrophysiological characterisation of envelope-following responses]. / Caracterización electrofisiológica del potencial evocado auditivo de seguimiento a la modulación del estímulo acústico.

INTRODUCTION: The auditory ability to discriminate rapid changes in the envelope of language sounds is essential for speech comprehension. This ability is deteriorated in some neurological diseases such as multiple sclerosis, auditory neuropathy, sensorineural hearing loss, presbycusis and primary developmental language disorder. Envelope-following responses (EFRs) in humans are useful in objective measurement of temporal processing in the auditory nervous system. OBJECTIVES: To evaluate EFRs in healthy younger subjects and to investigate the effects of subject states on the EFRs recorded. METHODS: Eleven young subjects were included; six of them were awake and five were asleep. EFRs were evoked by white noise carrier stimuli with a sweep of modulation frequencies from 20 to 200Hz presented at 50dB HL. RESULTS: The EFRs we recorded were similar in all subjects. There were two principal components. During both subject sleep and wakefulness, the first component (located between 30-50Hz) was significantly larger than the second component (located between 80-110Hz). There was also a significant effect of sleep on the EFR amplitude for the modulation frequencies between 88-110, 155-165 and 190-200Hz. However, there were no significant effects of sleep on the principal EFR components. CONCLUSIONS: These results corroborate the usefulness of the EFR technique for objective measurement of human auditory temporal processing.

Cribado auditivo neonatal con potenciales evocados auditivos de estado estable a múltiples frecuencias / Newborn hearing screening test with multiple auditory steady-state responses

Introducción: Las técnicas más utilizadas en los programas de cribado auditivo presentan limitaciones reconocidas en la detección de las pérdidas auditivas. Se presenta una nueva alternativa de cribado auditivo basada en el uso de potenciales evocados de estado estable. Objetivo: Evaluar la factibilidad de una prueba semiautomática de cribado auditivo en una población de recién nacidos sanos. Métodos: Se estudiaron 50 neonatos (7-18 días de nacidos) sin factores clínicos de riesgo y con respuesta detectable bilateral a 40 db nHL con potenciales evocados auditivos de tronco cerebral. A cada uno se le realizó una prueba con potenciales evocados auditivos de estado estable a múltiples frecuencias (PEAee-MF) (500 y 2.000Hz) y un registro sin estímulo para simulación de sordera. Resultados: Los umbrales auditivos se encontraron entre 25 y 50dB HL para ambas frecuencias (42,5±7dB HL para 500Hz y 35,5±6dB HL para 2.000Hz). Los tiempos medios de registro fueron de 2,6±1,6min por cada oído y la duración total del procedimiento (incluyendo preparación y colocación de electrodos) fue de 17,8±3,7min. Con la prueba de cribado se obtuvo una adecuada eficiencia diagnóstica (sensibilidad, 100%, y especificidad, 96%). Conclusiones: Los resultados descritos sugieren que los PEAee-MF (estimulación simultánea con múltiples frecuencias) pudieran ser utilizados como prueba de cribado auditivo en una población de recién nacidos sanos. Para esto, es necesario seguir perfeccionando la técnica combinando una metodología válida y sencilla con determinadas facilidades de automatización (AU)

Introduction: The techniques most frequently used within a screening context (otoacoustic emissions and click auditory brainstem response) have well-known limitations in hearing loss detection. Objective: This study examines the feasibility of a semi-automated multiple auditory steady-state responses (MSSR) system designed for neonatal hearing screening. Methods: A sample of 50 newborns without risk factors (well-babies) was tested within two weeks of birth. All had detectable auditory brainstem responses to clicks down to 40dB nHL in both ears. Two amplitude modulated carrier tones of 500 and 2,000Hz were mixed together and presented simultaneously. Each infant (and ear) was screened with the MSSR system; to simulate a hearing loss, a recording without stimulation was also obtained. Results: Mean auditory thresholds were 42.5±7dB HL at 500Hz and 35.5±6dB HL at 2,000Hz. The average duration of the MSSR recording was 2.6±1.6minutes for each tested ear and the overall duration of the screening procedure (including electrode fitting and infant preparation) was 17.8±3.7minutes. The diagnostic sensibility and the positive predictive values of the MSSR semi-automatic screening system was 100% and 96% respectively, with specificity of 96% and negative predictive values of 100%. Conclusions: Although the diagnostic efficiency of the semi-automated MSSR system was found adequate, further technological improvements are still necessary to facilitate its use in the context of universal newborn hearing screening program (AU)

[Newborn hearing screening test with multiple auditory steady-state responses]. / Cribado auditivo neonatal con potenciales evocados auditivos de estado estable a múltiples frecuencias.

INTRODUCTION: The techniques most frequently used within a screening context (otoacoustic emissions and click auditory brainstem response) have well-known limitations in hearing loss detection. OBJECTIVE: This study examines the feasibility of a semi-automated multiple auditory steady-state responses (MSSR) system designed for neonatal hearing screening. METHODS: A sample of 50 newborns without risk factors (well-babies) was tested within two weeks of birth. All had detectable auditory brainstem responses to clicks down to 40dB nHL in both ears. Two amplitude modulated carrier tones of 500 and 2,000Hz were mixed together and presented simultaneously. Each infant (and ear) was screened with the MSSR system; to simulate a hearing loss, a recording without stimulation was also obtained. RESULTS: Mean auditory thresholds were 42.5±7dB HL at 500Hz and 35.5±6dB HL at 2,000Hz. The average duration of the MSSR recording was 2.6±1.6 minutes for each tested ear and the overall duration of the screening procedure (including electrode fitting and infant preparation) was 17.8±3.7 minutes. The diagnostic sensibility and the positive predictive values of the MSSR semi-automatic screening system was 100% and 96% respectively, with specificity of 96% and negative predictive values of 100%. CONCLUSIONS: Although the diagnostic efficiency of the semi-automated MSSR system was found adequate, further technological improvements are still necessary to facilitate its use in the context of universal newborn hearing screening program.

Test accuracy and prognostic validity of multiple auditory steady state responses for targeted hearing screening.

The test accuracy and prognostic validity of Multiple Auditory Steady State Responses (MSSR) and click Auditory Brainstem Responses (cABR) was compared within the context of a targeted screening protocol. A sample of 508 high-risk babies was first screened using cABR and MSSR (500 and 2000 Hz). All children (failed/ pass) were called back at three to four years of age to determine their hearing status (pure-tone audiometry). Although both methods showed an equally good test performance in the first screen (sensitivity: 100% and specificity: 92-95%), the MSSR may have some potential advantage to identify low-frequency hearing loss. Furthermore, the confirmatory audiometry with MSSR predicted the child hearing status more accurately than the cABR. In conclusion, the MSSR can provide valuable information for the diagnosis and management of infants earlier detected by a screening protocol and further developed might be also useful as a screening test.

Estimating audiometric thresholds using auditory steady-state responses.

Human auditory steady-state responses (ASSRs) were recorded using stimulus rates of 78-95 Hz in normal young subjects, in elderly subjects with relatively normal hearing, and in elderly subjects with sensorineural hearing impairment. Amplitude-intensity functions calculated relative to actual sensory thresholds (sensation level or SL) showed that amplitudes increased as stimulus intensity increased. In the hearing-impaired subjects this increase was more rapid at intensities just above threshold ("electrophysiological recruitment") than at higher intensities where the increase was similar to that seen in normal subjects. The thresholds in dB SL for recognizing an ASSR and the intersubject variability of these thresholds decreased with increasing recording time and were lower in the hearing impaired compared to the normal subjects. After 9.8 minutes of recording, the average ASSR thresholds (and standard deviations) were 12.6 +/- 8.7 in the normal subjects, 12.4 +/- 11.9 dB in the normal elderly, and 3.6 +/- 13.5 dB SL in the hearing-impaired subjects.