Audiological Profiling and Voice Characteristics in Individuals with Early and Late-Onset Auditory Neuropathy Spectrum Disorder (ANSD)

Abstract

The study aimed to describe onset-based differences using a new parameter, i.e., voice. The onset-based differences in audiological profiling and voice characteristics, the correlation between these two characteristics, and to predict those variables which best segregate the groups based on ANSD- onset is elucidated in the present study. Thirty-one participants (14-31 years) were recruited for the study and were divided into two groups based on onset reported- early-onset group (onset reported to be before 12 years) and late-onset group (onset reported to be during or after adolescence). Audiological profiling was done retrospectively by studying the case report. The participants were asked to record sustained phonation of three vowels (/a/, /i/ and /u/) on smartphones above specific configuration and send the voice sample over email to the experimenter. Acoustic parameters were assessed using Praat software. This was supplemented by perceptual evaluation (CAPE-V) by five speech-language pathologists. Results revealed that the early-onset group had significantly higher PTA and speech thresholds, with more chances of being presented as symmetrical hearing loss. Also, most participants in the early-onset group had a flat configuration of hearing loss, in contrast to the late-onset group, which had a rising type of configuration. The voice analysis results revealed significantly increased fundamental frequency for all vowels and decreased F2 and F3 of /i/ in the early-onset group compared to the late-onset group, which can be explained based on differences in the pathophysiology of the disorder. This could also be attributed to the perception-production link; that is, as the perception of high frequency is affected in long-standing ANSD participants, the production of high-frequency sounds is also affected. Although not statistically significant, mean perturbations (jitter and shimmer) and harmonic-to-noise ratio were more affected in the early-onset group reflective of lowered auditory feedback and periodicity in their voice samples. These differences were also complemented by perceptual evaluation findings, which revealed greater severity of pitch, breathiness, strain, hoarseness and overall severity in the early-onset group. It was also found out in the present study that the acoustic and perceptual parameters of voice was mild to moderately correlated with each other. The FLDA analyses revealed that PTA, speech thresholds and configuration were the best predictors of the group differences. In addition, high fundamental frequencies and greater severity in the perceptual rating of voice are predominantly seen in the early-onset group compared to the late-onset group. The presence of such indicators should alert audiologists to reflect on the possible onset of the disorder, which in turn can facilitate their rehabilitation choice.