Effects of Presentation Level on Spatial Hearing With and Without Bone-Conduction Amplification in Congenital Unilateral Aural Atresia

Parent-Reported Ease of Listening in Preschool-Aged Children With Bilateral and Unilateral Hearing Loss

OBJECTIVES

Evidence from school-aged children suggests that the ease with which children listen varies with the presence of hearing loss and the acoustic environment despite the use of devices like hearing aids. However, little is known about the ease of listening in preschool-aged children with hearing loss-an age at which rapid learning occurs and increased listening difficulty or effort may diminish the required capacity to learn new skills. To this end, the objectives of the present study were to (i) assess parent-reported aided ease of listening as a function of hearing loss configuration (hearing loss in one versus both ears) and device configuration among children with hearing loss in one ear (unilateral hearing loss), and (ii) investigate factors that influence children's ease of listening.

DESIGN

Parents of 83 children with normal hearing, 54 aided children with bilateral hearing loss (hearing loss in both ears), and 139 children with unilateral hearing loss participated in the study. Of the 139 children with unilateral loss, 72 were unaided, 54 were aided with a device on the ear with hearing loss (direct aiding) and 13 were aided with a device that routed signals to the contralateral normal hearing ear (indirect aiding). Mean age of children was 40.2 months (1 SD = 2.5; range: 36 to 51). Parents completed the two subscales of the Parents' Evaluation of Aural/Oral Performance of Children+ (PEACH+) questionnaire, namely functional listening and ease of listening. Individual percent scores were computed for quiet and noisy situations. Linear mixed-effects models were used to assess the effect of hearing loss configuration and device configuration in children with unilateral hearing loss. Multiple regression was used to assess factors that influenced ease of listening. Factors included hearing thresholds, age at first device fit, consistency in device use, condition (quiet/noise), presence of developmental disabilities, and functional listening abilities.

RESULTS

Children with direct aiding for their hearing loss, either unilateral or bilateral, had similarly lower functional listening skills and ease of listening than their normal hearing peers. Unaided children with unilateral hearing loss had lower functional listening skills and ease of listening than their normal hearing peers in noise but not in quiet. All aided children with unilateral hearing loss, irrespective of direct or indirect aiding had lower functional listening skills and ease of listening relative to normal hearing children in both quiet and noise. Furthermore, relative to unaided children with unilateral hearing loss, those with indirect aiding had lower functional listening and ease of listening. Regression analyses revealed functional listening as a significant predictor of ease of listening in all children with hearing loss. In addition, worse degrees of hearing loss and presence of noise reduced ease of listening in unaided children with unilateral hearing loss.

CONCLUSIONS

Bilateral hearing loss is associated with poorer-than-typical ease of listening in preschoolers even when aided. The impact of unilateral hearing loss on ease of listening is similar to that observed in children with bilateral hearing loss, despite good hearing in one ear and aiding. Given increased difficulties experienced by children with unilateral loss, with or without a device, additional strategies to facilitate communication abilities in noise should be a priority.

Asymmetry in Cortical Thickness of the Heschl's Gyrus in Unilateral Ear Canal Atresia

HYPOTHESIS

Unilateral congenital conductive hearing impairment in ear canal atresia leads to atrophy of the gray matter of the contralateral primary auditory cortex or changes in asymmetry pattern if left untreated in childhood.

BACKGROUND

Unilateral ear canal atresia with associated severe conductive hearing loss results in deteriorated sound localization and difficulties in understanding of speech in a noisy environment. Cortical atrophy in the Heschl's gyrus has been reported in acquired sensorineural hearing loss but has not been studied in unilateral conductive hearing loss.

METHODS

We obtained T1w and T2w FLAIR MRI data from 17 subjects with unilateral congenital ear canal atresia and 17 matched controls. Gray matter volume and thickness were measured in the Heschl's gyrus using Freesurfer.

RESULTS

In unilateral congenital ear canal atresia, Heschl's gyrus exhibited cortical thickness asymmetry (right thicker than left, corrected p = 0.0012, mean difference 0.25 mm), while controls had symmetric findings. Gray matter volume and total thickness did not differ from controls with normal hearing.

CONCLUSION

We observed cortical thickness asymmetry in congenital unilateral ear canal atresia but no evidence of contralateral cortex atrophy. Further research is needed to understand the implications of this asymmetry on central auditory processing deficits.

The Role of Bone-Anchored Hearing Devices and Remote Microphones in Children with Congenital Unilateral Hearing Loss

Congenital unilateral hearing loss (UHL) represents a contemporary audiologic challenge. Children with UHL can struggle with understanding speech in noise, localizing sounds, developing language, and maintaining academic performance, leading to low self-esteem, anxiety, and decreased social support. Two specific conditions related to UHL in children are single-sided deafness (SSD) and unilateral auris atresia (UAA). This was a retrospective observational study on a group of children with UHL. The Simplified Italian Matrix Sentence Test was used for the assessment of speech reception threshold (SRT) in different conditions: speech and noise from the front (S0N0), speech at 45° from the side of the better ear and noise at 45° from the opposite side (SbNw), and vice versa (SwNb). Each test was conducted unaided, with a bone-anchored hearing device (BAHD), and with a remote microphone (RM) system. The use of a BAHD and RM led to an improvement in SRT in S0N0 and SwNb conditions. The SSD subgroup demonstrated significant benefits with both devices in SwNb, and the UAA subgroup from the use of BAHD in S0N0. In conclusion, the study underscores the potential benefits of both devices in enhancing speech perception for UHL children, providing insights into effective intervention strategies for these challenging cases.

A pilot study on spatial hearing in children with congenital unilateral aural atresia

Despite normal hearing in one ear, individuals with congenital unilateral aural atresia may perceive difficulties in everyday listening conditions typically containing multiple sound sources. While previous work shows that intervention with bone conduction devices may aid spatial hearing for some children, testing conditions are often arranged to maximize any benefit and are not very similar to daily life. The benefit from amplification on spatial tasks has been found to vary between individuals, for reasons not entirely clear. This study has sought to expand on the limited knowledge on how children with unilateral aural atresia recognize speech masked by competing speech, and how horizontal sound localization accuracy is affected by the degree of unilateral hearing loss and by amplification using unilateral bone conduction devices when fitted before 3 years of age. In a within-subject, repeated measures design, including 11 children (mean age = 7.9 years), bone conduction hearing device (BCD) amplification did not negatively affect horizontal sound localization accuracy. The effect on speech recognition scores showed greater inter-individual variability. No benefit from amplification on a group level was found. There was no association between age at fitting and the benefit of the BCD. For children with poor unaided sound localization accuracy, there was a greater BCD benefit. Unaided localization accuracy increased as a function of decreasing hearing thresholds in the atretic ear. While it is possible that low sound levels in the atretic ear provided access to interaural localization cues for the children with the lowest hearing thresholds, the association has to be further investigated in a larger sample of children.

Instant improvement in monaural spatial hearing abilities through cognitive feedback

Several studies report that sound localization performance of acute and chronic monauralized normal-hearing listeners can improve through training. Typically, training sessions are administered daily for several days or weeks. While this intensive training is effective, it may also be that monaural localization abilities improve instantly after providing explicit top-down information about the direction dependent change in timbre and level. The aim of the present study was to investigate whether cognitive feedback (i.e., top-down information) could instantly improve sound localization in naive acutely monauralized listeners. Forty-three normal-hearing listeners (experimental group), divided over five different centers, were tested. Two control groups, consisting of, respectively, nine and eleven normal-hearing listeners, were tested in one center. Broadband sounds (0.5-20 kHz) were presented from visible loudspeakers, positioned in azimuth (- 90° to 90°). Participants in the experimental group received explicit information about the noticeable difference in timbre and the poor localization in the monauralized listening condition, resulting in an instant improvement in sound localization abilities. With subsequent roving of stimulus level (20 dB), sound localization performance deteriorated immediately. The reported improvement is related to the context of the localization test. The results provide important implications for studies investigating sound localization in a clinical setting, especially during closed-set testing, and indicate the importance of top-down information.