A retrospective study of audiological characteristics of hyperacusis versus misophonia in children with auditory processing disorder (APD).

OBJECTIVES

This study aimed to evaluate in children with developmental auditory processing disorder (APD): STUDY DESIGN: Retrospective study comparing outcomes of pure-tone thresholds from .25 to 12.5 kHz, ipsilateral stapedial reflex thresholds (SRTs), uncomfortable loudness levels (ULLs), past history of OME and tinnitus between those with and without DST.

STUDY SAMPLE

The study included 278 children with a diagnosis of APD, aged 6-16 years (mean age: 11.68 years, SD: 2.21) with nonverbal IQ ranging from 80 to 128 (mean: 98.74, SD: 9.92). Three groups of participants included i). Hyperacusis only (n = 107), ii). Misophonia with hyperacusis (n = 35) and iii). No DST (n = 136).

RESULTS

The pure-tone average for 8, 10 and 12.5 kHz (High PTAvg) was lower than the .25, .5, 1, 2 and 4 kHz pure-tone average (Low PTAvg) in all the three groups in both the ears, with significantly larger High-Low PTAvg difference in the 'Misophonia with hyperacusis' group compared to the 'No DST group in the right ear. SRTs elicited by 1 and 4 kHz tones were similar in all the groups. ULLs were significantly lower for both 1 and 4 kHz tones in both 'Misophonia with hyperacusis' and 'Hyperacusis only' groups compared to the 'No DST' group, with higher level of significance for 4 kHz (p < .001) compared to 1 kHz (p < .01). ULLs did not reflect the severity of impact of DST on daily life. Despite higher prevalence of misophonia in females, the frequency of significant impact was similar in both males and females. Males had higher prevalence of hyperacusis but the frequency of significant impact on life was more in females.Tinnitus prevalences were 30.47 %, 45.7 %, and 18.18 % in the 'Hyperacusis only', 'Misophonia with hyperacusis', and 'No DST' groups respectively. The 'Misophonia with hyperacusis' group was older than the other two groups irrespective of tinnitus. Tinnitus was more prevalent in older children in the 'Hyperacusis only' and the 'no DST' groups. The presence or absence of tinnitus did not influence any of the audiological characteristics in the 'Hyperacusis only' and the 'Misophonia with hyperacusis' groups. Participants with tinnitus in the 'No DST' group had significantly lower ULL at 4 kHz, with a significant difference between 4 and 1 kHz in their right ear compared to those without tinnitus.The prevalences of past OME history were similar in the three groups.

CONCLUSION

Routine audiological evaluations cannot differentiate between misophonia and hyperacusis. Normal SRTs and low ULLs in DST and in those with tinnitus without DST indicate that higher order brain networks influence ULL, suggesting a need of evaluation for DST in children presenting with tinnitus. The higher high frequency sensitivity in the right ear needs further exploration. DST is unrelated to previous OME history, and the study suggests that DST and tinnitus are considered as auditory disabilities in addition to different types of listening difficulties in APD.