Pure-tone auditory threshold in school children

Significant influence of prelingual deafness but less impact of elderly age at implantation on long-term psychoacoustic CI programming parameters

OBJECTIVE

This study aimed to elucidate the long-term impact of prelingual deafness and elderly age at cochlear implantation on cochlear implant (CI) programming parameters and CI thresholds METHODS: We retrospectively reviewed patients who underwent cochlear implantation less than 5 years (Prelingual group) and equal and more than 18 years in our institute. The latter group was further divided into Adult and Elderly groups according to whether the patient was younger or older than 65 at implantation. From 152, 69, and 55 patients in the Prelingual, Adult, and Elderly groups, 242, 92, and 58 ears were included. We compared CI thresholds and CI programming parameters, including impedances, T/C levels, and dynamic ranges for 8 years after implantation between the Prelingual, Adult, and Elderly groups.

RESULTS

The Prelingual group showed consistently lower CI thresholds than the Adult and Elderly groups during the postoperative 2-8 years, but no difference was detected between the Elderly and Adult groups, except at the postoperative 4 years. The elderly group's CI thresholds did not deteriorate until postoperative 8 years. The Prelingual group showed consistently larger T/C levels (minimum/maximum current strength from CI), especially C levels, than the other two groups. At the same time, there was no significant difference between the Elderly and Adult groups except for smaller dynamic ranges in the Elderly group until postoperative 2 years. These results in the CI programming parameters might explain the lower CI thresholds in the Prelingual group than in the other groups. Focusing on CI maps 1 and 3 years after implantation, the strength of the T/C levels was similar for all channels in the Prelingual group, but the Adult and Elderly groups showed larger electrical stimuli in channels responsible for the middle frequencies than those for the lower or higher frequencies.

CONCLUSIONS

Our results suggest a significant influence of prelingual deafness but less impact of elderly age at implantation on long-term CI programming parameters and CI thresholds. The larger C levels and lower CI thresholds in the Prelingual group than in the Adult and Elderly groups implied that CI children with prelingual deafness tolerate and prefer larger CI stimuli, which may reflect the CI-dependent development of their auditory system before the critical period. No age-related reduction in hearing thresholds was observed in the Elderly group, probably because the CI compensates for age-related dysfunction of the peripheral auditory system.

Effects of Self-Generated Noise on Quiet Threshold by Transducer Type in School-Age Children and Adults

Purpose Low-frequency detection thresholds in quiet vary across transducers. This experiment tested the hypothesis that transducer effects are larger in young children than adults, due to higher levels of self-generated noise in children. Method Listeners were normal-hearing 4.6- to 11.7-year-olds and adults. Warble-tone detection was measured at 125, 250, 500, and 1000 Hz with a sound-field speaker, insert earphones, and supra-aural headphones. Probe microphone recordings measured self-generated noise levels. Results Thresholds were similar across ages for speaker measurements. Transducer effects were larger for children than adults, with mean child-adult threshold differences at 125 Hz of 3.4 dB (insert earphones) and 6.6 dB (supra-aural headphones). Age effects on threshold were broadly consistent with noise levels measured in the ear canal. Conclusions Self-generated noise appears to elevate children's low-frequency thresholds measured with occluding transducers. These effects could be particularly relevant to the diagnosis of minimal and mild hearing loss in children.

Hearing in Schoolchildren After Neonatal Exposure to a High-Dose Gentamicin Regimen

OBJECTIVE

To assess the association between gentamicin exposure in the neonatal period and hearing in school age.

METHODS

This study included children exposed to a high-dose (6 mg/kg) gentamicin regimen as neonates (2004-2012), invited for follow-up at school age, and a healthy age-matched control group. We assessed hearing with pure tone audiometry including the extended high-frequency (EHF) range. Outcomes were average hearing thresholds in the midfrequencies (0.5-4 kHz) and the EHFs (9-16 kHz). The measures of gentamicin exposure were cumulative dose and highest trough plasma concentration. We used linear regression models to assess the impact of gentamicin exposure, and other peri- and postnatal morbidities, on hearing thresholds.

RESULTS

A total of 219 gentamicin-exposed and 33 healthy-control children were included in the audiological analysis. In the gentamicin cohort, 39 (17%) had a birth weight <1500 g. Median cumulative doses and trough plasma concentrations were 30 (interquartile range 24-42) mg/kg and 1.0 (interquartile range 0.7-1.2) mg/L, respectively. Median hearing thresholds for the midfrequencies and the EHFs were 2.5 (0 to 6.3) dB hearing level and -1.7 (-5.0 to 5.0) dB hearing level, both of which were within the normal range. In an adjusted analysis, increasing hearing thresholds were associated with lower birth weight and postnatal middle-ear disease but not level of gentamicin exposure. After adjusting for birth weight, there was no difference in hearing threshold between the gentamicin-exposed cohort and healthy controls.

CONCLUSIONS

Exposure to a high-dose gentamicin regimen in the neonatal period was not associated with an increase in hearing thresholds in schoolchildren being able to complete audiometry.

Prevalence of hearing impairment amongst school going children in the rural field practice area of the institution

Worldwide, over 275 million people are estimated to have moderate to profound hearing loss in both ears. Children with hearing impairment often experience delayed development of speech and cognitive skills, which may result in slower learning and difficulty in progressing at school. Adequate hearing is one of the main factors for good psychosocial development, by which individuals may express their thoughts, feelings, and wishes, and acquire life experience and knowledge. Therefore, hearing impairment needs to be diagnosed early for prompt therapy. Primary objectives of this study was to know prevalence of hearing impairment amongst primary school children and secondary objective was to identify the common causes of hearing impairment amongst primary school children. The cross sectional study was conducted in the government and private schools of our rural field practice area in 2013-2014 for the duration of 4 months from November 2013 to February 2014. Prevalence of Hearing loss was 8.8%. Most common cause of Hearing loss was Impacted wax and Retracted Tympanic membrane. Otological conditions-Wax followed by otitis media with effusion and chronic suppurative otitis media were the common ear problems found in our study.

Effects of Self-Generated Noise on Estimates of Detection Threshold in Quiet for School-Age Children and Adults

OBJECTIVES

Detection thresholds in quiet become adult-like earlier in childhood for high than low frequencies. When adults listen for sounds near threshold, they tend to engage in behaviors that reduce physiologic noise (e.g., quiet breathing), which is predominantly low frequency. Children may not suppress self-generated noise to the same extent as adults, such that low-frequency self-generated noise elevates thresholds in the associated frequency regions. This possibility was evaluated by measuring noise levels in the ear canal simultaneous with adaptive threshold estimation.

DESIGN

Listeners were normal-hearing children (4.3 to 16.0 years) and adults. Detection thresholds were measured adaptively for 250-, 1000-, and 4000-Hz pure tones using a three-alternative forced-choice procedure. Recordings of noise in the ear canal were made while the listeners performed this task, with the earphone and microphone routed through a single foam insert. Levels of self-generated noise were computed in octave-wide bands. Age effects were evaluated for four groups: 4- to 6-year olds, 7- to 10-year olds, 11- to 16-year olds, and adults.

RESULTS

Consistent with previous data, the effect of child age on thresholds was robust at 250 Hz and fell off at higher frequencies; thresholds of even the youngest listeners were similar to adults' at 4000 Hz. Self-generated noise had a similar low-pass spectral shape for all age groups, although the magnitude of self-generated noise was higher in younger listeners. If self-generated noise impairs detection, then noise levels should be higher for trials associated with the wrong answer than the right answer. This association was observed for all listener groups at the 250-Hz signal frequency. For adults and older children, this association was limited to the noise band centered on the 250-Hz signal. For the two younger groups of children, this association was strongest at the signal frequency, but extended to bands spectrally remote from the 250-Hz signal. For the 1000-Hz signal frequency, there was a broadly tuned association between noise and response only for the two younger groups of children. For the 4000-Hz signal frequency, only the youngest group of children demonstrated an association between responses and noise levels, and this association was particularly pronounced for bands below the signal frequency.

CONCLUSIONS

These results provide evidence that self-generated noise plays a role in the prolonged development of low-frequency detection thresholds in quiet. Some aspects of the results are consistent with the possibility that self-generated noise elevates thresholds via energetic masking, particularly at 250 Hz. The association between behavioral responses and noise spectrally remote from the signal frequency is also consistent with the idea that self-generated noise may also reflect contributions of more central factors (e.g., inattention to the task). Evaluation of self-generated noise could improve diagnosis of minimal or mild hearing loss.

A Prevalence Study of Hearing Loss among Primary School Children in the South East of Iran

Hearing impairment substantially affects child's ability to normally acquire the spoken language. Such negative effects create problems for the child not only in terms of communication but also in terms of achievement in school as well as social and emotional growth. The aim of this research is to study the prevalence of hearing disorders and its relationship to age and gender among primary school students of Zahedan, Iran. In this cross-sectional and descriptive analytical study, 1500 students from elementary schools were screened for hearing loss. The selection of samples was performed using multistage sampling method. Primary information was obtained through direct observation, otoscopy, and audiometric and tympanometric screenings. Data was obtained and analyzed via ANOVA test. Statistical analysis showed a significant correlation between the age and the prevalence of middle ear abnormal function. Conductive hearing loss in males and females was 8.8% and 7.1%, respectively. In addition, 1% and 0.7% of male and female students, respectively, suffered from sensorineural hearing loss. Results indicated that 20.2% of students of elementary schools in Zahedan needed medical treatment for their problems. Therefore, it is recommended that the hearing screening of school-age children should be included in annual school health programs in this region.

Reversible audiometric threshold changes in children with uncomplicated malaria

Background. Plasmodium falciparum malaria, as well as certain antimalarial drugs, is associated with hearing impairment in adults. There is little information, however, on the extent, if any, of this effect in children, and the evidence linking artemisinin combination therapies (ACTs) with hearing is inconclusive. Methods. Audiometry was conducted in children with uncomplicated malaria treated with artesunate-amodiaquine (n = 37), artemether-lumefantrine (n = 35), or amodiaquine (n = 8) in Accra, Ghana. Audiometry was repeated 3, 7, and 28 days later and after 9 months. Audiometric thresholds were compared with those of a control group of children (n = 57) from the same area. Findings. During the acute stage, hearing threshold levels of treated children were significantly elevated compared with controls (P < 0.001). The threshold elevations persisted up to 28 days, but no differences in hearing thresholds were evident between treated children and controls after 9 months. The hearing thresholds of children treated with the two ACT regimens were comparable but lower than those of amodiaquine-treated children during acute illness. Interpretation. Malaria is the likely cause of the elevated hearing threshold levels during the acute illness, a finding that has implications for learning and development in areas of intense transmission, as well as for evaluating potential ototoxicity of new antimalarial drugs.