A STS in hearing is defined as a change in at least one ear noted between the test of interest and reference audiogram as either an average at 2000 Hz, 3000 Hz, and 4000 Hz of [+ or -] 10dBHL or more, or [+ or -] 15 dBHL or more at 1000 Hz, 2000 Hz, 3000 Hz, or 4000 Hz.
Lew et al reported an average 10 dBHL difference between blast-exposed and nonblast TBIs, with the more significant hearing loss occurring within the blast-exposed TBI group.
Abbreviations: C&P = Compensation and Pension, CAP = central auditory processing, CAPD = central auditory processing disorder, dBHL
= decibels hearing loss, DPOAE = distortion product otoacoustic emission, IED = improvised explosive device, NSI = Neurobehavioral Symptom Inventory, OAE = otoacoustic emission, RPG = rocket-propelled grenade, SD = standard deviation, TBI = traumatic brain injury, VA = Department of Veterans Affairs, VHA = Veterans Health Administration.
Each list was presented monaurally (right ear) starting at 0 dBHL and ascending in 5 dBHL steps until 100% recognition was achieved.
Although at 12 dBHL SNR normal speech was about 85% intelligible for both groups, esophageal speech was only about 34%.
The prevalence of hearing loss was calculated in percentage distribution for the worse ear (the ear with the greater hearing loss compared with the other ear of the same person) with loss of [less than or equal to] 25 dBHL, 26-39 dBHL, 40-54 dBHL, and [greater than or equal to] 55 dBHL, respectively, for a) rayon workers with noise exposure [less than or equal to] 85 dB(A); b) rayon workers with noise exposure > 85 dB(A); c) workers with noise-only exposure in the adhesive tape and electronic industries; and d) the rayon plants administrative workers with low noise exposure.
The prevalence of overall hearing loss of > 25 dBHL was calculated for each group, based on measures using a three-division method for sound levels of 0.
Workers in the rayon industry with noise exposure [less than or equal to] 85 dB(A) exhibited a higher prevalence (18%) of hearing loss of 40-54 dBHL than did subjects with noise exposure (4%).
Compared with the administrative personnel, the overall OR for hearing loss of > 25 dBHL was 6.
Of the 40 participants, 10 who had threshholds 30 dBHL or higher at any frequency were asked to return for a repeated test free of charge.
These percentages were computed by calculating the percentage of the participants that presented with a hearing threshold of 25 dBHL or higher and 24 dBHL or lower.
Although there is statistical significance, the clinical difference shows only minimal variation in dBHL levels.