Rene Hugo

High frequency immittance for neonates : a normative study

Conclusion. High frequency immittance measurements demonstrate promise in clarifying middle ear status for neonates but age- and gender-specific norms should be consulted. Objective. To describe high frequency immittance measurements using a 1000 Hz probe tone for a sample of 278 neonatal ears (0–4 weeks of age) in order to compile normative tympanometric and acoustic reflex criteria. Subjects and methods. Assessment of neonatal ears included 1000 Hz probe tone immittance measurements (tympanograms and ipsilateral acoustic reflexes), and distortion product oto-acoustic emission (DPOAE) screening. Results were compared and normative values were compiled for immittance measures in ears controlled for normal middle ear functioning (n=250). Results. Comparison of immittance results to OAE screening outcome provides estimates of sensitivity and specificity for middle ear fluid with tympanometry of 57% and 95%, and 57% and 90% for acoustic reflex presence, and 58% and 87% for combined tympanogram and acoustic reflex results, respectively. Normative data indicate that static peak admittance values differ significantly across gender and age with the 5th percentile cut-off value for the entire sample at 1.4 mmho. The 90% range of tympanic peak pressure normative values increases with increasing age from 140 daPa for neonates 1 week of age to 210 daPa for neonates 2–4 weeks of age. Acoustic reflexes were elicited at 93±9 dB with a 90% normality range of 80–105 dB.

A novel service delivery model for infant hearing screening in developing countries

Newborn hearing screening is the procedure of choice for ensuring optimal outcomes for infants with hearing loss, whether in a developed or developing country. Unfortunately, apart from a small number of recent exceptions, newborn hearing screening has been a practice reserved for the developed world. Despite the prevailing challenges towards implementing hearing screening in developing countries, there are existing structures in these countries that need to be investigated as possible platforms from which programs can be actualized. Immunization clinics, constituting part of a primary healthcare approach characteristic of developing countries, offer one such a platform. A novel service delivery model, based on initial results from a pilot study, was developed for infant hearing screening at immunization clinics in South Africa as an integrated part of primary, secondary, and tertiary levels of healthcare. This type of model is a first step toward ensuring that infants with hearing loss in developing communities are afforded opportunities for optimal development and societal integration through accountable and contextually relevant early hearing detection and intervention services.

Estimations of auditory sensitivity for young cochlear implant candidates using the ASSR: preliminary results

This paper presents preliminary results obtained with the use of the auditory steady-state response (ASSR) technique as part of a cochlear implant candidacy assessment protocol for infants. Fifteen infants (30 ears), between 10 and 60 months of age, with severe-to-profound hearing loss participated in the study. ASSR measurements were performed for 0.5, 1, 2 and 4 kHz at intensities up to 120–128 dB HL. The ASSR thresholds were obtained in 74% of the measurements, and exceeded the maximum auditory brainstem response (ABR) intensity output in 91% of cases and the maximum free-field behavioral intensity output in 84% of cases. Eighty-seven per cent of ASSR threshold measurements were measured at intensities of 100 dB HL or higher, and almost half (47%) were measured at intensities of 115 dB HL and higher. Preliminary results indicate that absent ABR and behavioral thresholds do not preclude the possibility of residual hearing, making the ASSR a primary source of information regarding profound levels of hearing loss. Sumario Este trabajo presenta los resultados preliminares obtenidos con el uso de la técnica de respuestas auditivas de estado estable (ASSR) como parte de un protocolo de evaluación de elegibilidad de candidatos infantiles para implante coclear. Participaron en el estudio quince infantes (30 oídos) entre los 10 y los 60 meses de edad, con hipoacusia severa a profunda. Se realizaron mediciones de ASSR en 0.5, 1, 2 y 4 kHz, a intensidades de 120–128 dB HL. Los umbrales de las ASSR se obtuvieron en el 74% de las mediciones, y excedieron la intensidad máxima de salida para las respuestas auditivas de tallo cerebral (ABR) en el 91% de los casos y la intensidad máxima de salida para el campo libre conductual en el 84% de los casos. Ochenta y ocho por ciento de los umbrales de las ASSR se midieron a intensidades de 100 ó más dB HL, y casi la mitad (47%) fue medida a intensidades de 115 ó más dB HL. Los estudios preliminares indican que la ausencia de ABR y de umbrales conductuales no excluye la existencia de audición residual, convirtiendo las ASSR en una fuente primaria de información para pérdidas auditivas de nivel profundo.

Establishing normal hearing with the dichotic multiple-frequency auditory steady-state response compared to an auditory brainstem response protocol

Objective To determine the clinical usefulness of the dichotic multiple-frequency (MF) auditory steady-state response (ASSR) technique for estimating normal hearing compared to a 0.5-kHz tone burst and broadband click auditory brainstem response (ABR) protocol in a sample of adults. Material and Methods A comparative experimental research design was selected in order to compare estimations of normal hearing obtained with the dichotic ASSR technique at 0.5, 1, 2 and 4 kHz with a 0.5-kHz tone burst and broadband click ABR protocol. The recording times required for each procedure were also compared. Normal-hearing subjects (n = 28) were selected according to immittance values within normal limits and pure-tone behavioural thresholds of < 25 dB HL across frequencies. Results The dichotic MF ASSR estimated normal hearing to be, on average, 30–34 dB HL across the range 0.5–4 kHz. The mean estimate of normal hearing for 0.5 kHz using tone burst ABRs was 30 dB nHL and the mean click ABR threshold was 16 dB nHL, i.e. 14–18 dB better than the ASSR thresholds. The dichotic MFASSR technique recorded 8 thresholds (4 in each ear) in a mean time of 23 min. The ABR protocol recorded 4 thresholds (2 in each ear) in a mean time of 25 min. Conclusions Both the dichotic MF ASSR and ABR protocols provided a time-efficient estimation of normal hearing. There was no significant difference between the tone burst ABR and MF ASSR techniques in terms of estimation of normal hearing at 0.5 kHz. The dichotic MF ASSR technique proved more time-efficient by determining more thresholds in a shorter time compared to the ABR protocol.

Relationship Patterns Between Central Auditory Processing Disorders and Language Disorders, Learning Disabilities, and Sensory Integration Dysfunction:

Central auditory processing disorders often present with language disorders, sensory integration dysfunction, and learning disabilities (LD). In this study, a multimodal assessment of children with LD was used to identify certain problem areas. Phylogenetic analyses established the nature of the relationship among these areas and grouped them according to shared problem areas. The majority of children presented with deficits involving both the visual and auditory modalities, as well as problems with motor abilities and concentration skills. Within this majority group, further subgroups of problem areas were found to occur together. The results suggest that a multimodal perceptual approach is useful for enhancing diagnosis of and choosing interventions for these children.

A novel service delivery model for infant hearing screening in developing countries: Un modelo novedoso para la prestación de servicios de tamiz auditivo infantil en países en desarrollo

Newborn hearing screening is the procedure of choice for ensuring optimal outcomes for infants with hearing loss, whether in a developed or developing country. Unfortunately, apart from a small number of recent exceptions, newborn hearing screening has been a practice reserved for the developed world. Despite the prevailing challenges towards implementing hearing screening in developing countries, there are existing structures in these countries that need to be investigated as possible platforms from which programs can be actualized. Immunization clinics, constituting part of a primary healthcare approach characteristic of developing countries, offer one such a platform. A novel service delivery model, based on initial results from a pilot study, was developed for infant hearing screening at immunization clinics in South Africa as an integrated part of primary, secondary, and tertiary levels of healthcare. This type of model is a first step toward ensuring that infants with hearing loss in developing communities are afforded opportunities for optimal development and societal integration through accountable and contextually relevant early hearing detection and intervention services.

Screening for middle-ear disease in schools for hearing-impaired children

The aim of the study was to determine the prevalence of middle-ear dysfunction in a group of hearing-impaired children attending schools for the deaf. Two groups of subjects between the ages of 4 and 16 years were selected. Group 1 consists of Caucasian and Group 2 of Negroid children. Otoscopic examinations, impedance and pure tone testing were performed on each child. The results indicated a prevalence of 43% failures on the impedance tests in the Caucasian group and 18% failures in the Negroid group. Chronic problems like perforations, otorrhoea, etc. were more common in Group 2. The results also suggest the existence of differences in the prevalence of middle-ear dysfunction between normal and hearing-impaired children.

A Novel Service Delivery Model for Infant Hearing Screening in South Africa

Newborn hearing screening is the procedure of choice for ensuring optimal outcomes for infants with hearing loss, whether in a developed or developing country. Unfortunately, apart from a small number of recent exceptions, newborn hearing screening has been a practice reserved for the developed world. Despite the prevailing challenges towards implementing hearing screening in developing countries, there are existing structures in these countries that need to be investigated as possible platforms from which programs can be actualized. Immunization clinics, constituting part of a primary healthcare approach characteristic of developing countries, offer one such a platform. A novel service delivery model, based on initial results from a pilot study, was developed for infant hearing screening at immunization clinics in South Africa as an integrated part of primary, secondary, and tertiary levels of healthcare. This type of model is a first step toward ensuring that infants with hearing loss in developing communities are afforded opportunities for optimal development and societal integration through accountable and contextually relevant early hearing detection and intervention services.