Issues in Invisible Hearing Loss
Beck (2015) reported that when a patient presents with normal (or abnormal) pure-tone thresholds and their chief complaint is the inability to understand speech clearly in quiet or noise, a thorough diagnostic battery is called for. “The goal is not to simply document peripheral hearing loss, rather, the goal is to diagnose or describe the auditory-based communication disorder (i.e., a communication disorder manifested via audition).” He notes that a simple audiogram cannot document, estimate, reflect, or quantify speech-in-noise problems, neural or auditory processing difficulties, perceived distortions (loudness, spectral, or timing and more), attentional difficulties, etc. Beck reiterated “listening is where hearing meets the brain” (Beck and Flexer, 2011).
Bharadwaj et al (2015) report that “many listeners with normal hearing thresholds complain of communication difficulties….” In particular, they explored supra-threshold deficits related to the temporal structure of audible sounds and cochlear mechanical function. Statistically significant correlations were found regarding electrophysiological and behavioral measures of temporal coding fidelity. Conversely, Bharadwaj et al report these same differences were not related to variation in OAEs, cochlear tuning, or hearing thresholds. Electroencephalography (EEG) recordings revealed people with poor subcortical encoding were less sensitive to interaural timing differences (ITDs) and were less able to attend to specific competing speech signals. The authors conclude “hidden hearing deficits, likely originating at the level of the cochlear nerve, are part of “normal hearing.”
For More Information, References, and Recommendations
Beck DL. (2015) Invisible Hearing Loss March 11, 2015 Editorial.
Beck DL, Flexer C. (2011) Listening is where hearing meets brain…in children and adults. Hearing Review 18(2):30–35
Bharadwaj HM, Masud S, Mehraei G, Verhulst S, Shinn-Cunningham BS. (2015) Individual Differences Reveal Correlates of Hidden Hearing Deficits. The Journal of Neuroscience 35(5): 2161-2172.