Vocal Emotion Recognition in School-Age Children With Hearing Aids

In individuals with normal hearing, vocal emotion recognition continues to develop over many years during childhood. In children with hearing loss, vocal emotion recognition may be affected by combined effects from loss of audibility due to elevated thresholds, suprathreshold distortions from hearing loss, and the compensatory features of hearing aids. These effects could be acute, affecting the perceived signal quality, or accumulated over time, affecting emotion recognition development. This study investigates if, and to what degree, children with hearing aids have difficulties in perceiving vocal emotions, beyond what would be expected from age-typical levels.

We used a vocal emotion recognition test with non-language-specific pseudospeech audio sentences expressed in three basic emotions: happy, sad, and angry, along with a child-friendly gamified test interface. The test group consisted of 55 school-age children (5.4 to 17.8 years) with bilateral hearing aids, all with sensorineural hearing loss with no further exclusion based on hearing loss degree or configuration. For characterization of complete developmental trajectories, the control group with normal audiometric thresholds consisted of 86 age-matched children (6.0 to 17.1 years), and 68 relatively young adults (19.1 to 35.0 years).

Vocal emotion recognition of the control group with normal-hearing children and adults improved across age and reached a plateau around age 20. Although vocal emotion recognition in children with hearing aids also improved with age, it seemed to lag compared with the control group of children with normal hearing. A group comparison showed a significant difference from around age 8 years. Individual data indicated that a number of hearing-aided children, even with severe degrees of hearing loss, performed at age-expected levels, while some others scored lower than age-expected levels, even at chance levels. The recognition scores of hearing-aided children were not predicted by unaided or aided hearing thresholds, nor by previously measured voice cue discrimination sensitivity, for example, related to mean pitch or vocal tract length perception.

In line with previous literature, even in normal hearing, vocal emotion recognition develops over many years toward adulthood, likely due to interactions with linguistic and cognitive development. Given the long development period, any potential difficulties for vocal emotion recognition in children with hearing loss can only be identified with respect to what would be realistic based on their age. With such a comparison, we were able to show that, as a group, children with hearing aids also develop in vocal emotion recognition, however, seemingly at a slower pace. Individual data indicated a number of the hearing-aided children showed age-expected vocal emotion recognition. Hence, even though hearing aids have been developed and optimized for speech perception, these data indicate that hearing aids can also support age-typical development of vocal emotion recognition. For the children whose recognition scores were lower than age-expected levels, there were no predictive hearing-related factors. This could be potentially reflecting inherent variations related to development of relevant cognitive mechanisms, but a role from cumulative effects from hearing loss is also a possibility. As follow-up research, we plan to investigate if vocal emotion recognition will improve over time for these children.