Benefits of Speech-based Audiometry and Low-gain Hearing Aids for Blast-exposed Veterans
Since 2000, at least 250,000 U.S. Service members have experienced a blast-related mild traumatic brain injury. A retrospective analysis of over 100,000 post-9/11 Veterans shows that blast injury more than doubles the risk of a diagnosed auditory problem. Many blast-exposed Veterans experience functional hearing difficulties (FHDs): problems in challenging listening environments despite clinically normal hearing as measured by the pure-tone audiogram. VA audiologists have begun using low-gain hearing aids to treat FHDs, but there are no concrete guidelines for this application given standard procedures rely on the pure-tone audiogram. This study proposes a data-driven approach called speech-based audiometry (SBA), which optimizes hearing aid gains from a patient's responses to speech stimuli in aided conditions. This trial will assess the behavioral (speech recognition in noise, subjective listening difficulty) and neurophysiological (functional neuroimaging during a speech recognition task) benefits of low-gain hearing aids programmed conventionally or with SBA among blast-exposed Veterans with FHDs.
⁃ Human subjects will be male or female Veterans selected without regard to race or ethnic background. All subjects will be 18 years of age or older and no more than 60 years old. On the QCuBE, all subjects must report at least one exposure to high-intensity blast (e.g., RPG, IED, mortar) close enough to feel the heat or pressure of the blast wave. All subjects must also score 20 or higher on the Hearing Handicap Inventory for Adults (HHIA). The remaining inclusion criteria for all subjects are:
• pure-tone average (PTA) at 0.5, 1, 2, 4 kHz of 35 dB HL or better in each ear;
• pure-tone thresholds no worse than 40 dB HL at any two audiometric frequencies up to 8 kHz;
• no differences in pure-tone thresholds exceeding 10 dB between the two ears at more than one audiometric frequency up to 4 kHz;
• native speaker of English; and
• a score of at least 25 on the Mini Mental State Exam.