Marc A. Fagelson

The Association Between Tinnitus and Posttraumatic Stress Disorder

PURPOSE Posttraumatic stress disorder (PTSD) affects nearly 10% of the population, a prevalence comparable with that of tinnitus. Similarities between the way PTSD and tinnitus influence auditory behaviors include exaggerated startle responses and decreased loudness tolerance. Tinnitus loudness is often exacerbated by sounds that trigger PTSD-related anxiety. This report addresses physical and psychological relations between PTSD and tinnitus. METHOD A chart review of veterans seen over a 4-year period for tinnitus services was conducted. Case history and self-assessments of tinnitus handicap were examined in all patients. A review of the literature related to triggers and effects of PTSD was conducted to explore potential consequences related to the presence of PTSD in the Veterans Affairs Medical Center (VAMC) tinnitus population. RESULTS Chart review confirmed that 34% of the first 300 patients enrolled in the VAMC Tinnitus Clinic also carried a diagnosis of PTSD. Patient reports citing tinnitus severity, suddenness of tinnitus onset, sound-tolerance problems, and sound-triggered exacerbation of tinnitus were more common for patients with a PTSD diagnosis than patients with tinnitus only. CONCLUSIONS Several neural mechanisms linked to both tinnitus and PTSD affect auditory behaviors. Audiologists should be aware that patients with tinnitus and PTSD will require test protocols and referrals that address these powerful responses.

MUSICAL TRAINING INFLUENCES AUDITORY TEMPORAL PROCESSING

Background: A link between musical expertise and auditory temporal processing abilities was examined. Material and methods: Trained musicians (n=13) and non-musicians (n=12) were tested on speech tasks (phonetic identification, speech recognition in noise) and non-speech tasks (temporal gap detection). Results: Results indicated musicians had shorter between-channel gap detection thresholds and sharper phonetic identification functions, suggesting that perceptual reorganization following musical training assists basic temporal auditory processes. Conclusions: In general, our results provide a conceptual advance in understanding how musical training influences speech processing, an ability which, when impaired, can affect speech and reading competency.

Bone Conduction Transmission and Head‐Shadow Effects for Unilateral Hearing Losses Fit with Transcranial Cic Hearing Aids

Bone conduction transmission and head‐shadow effects were determined with transcranial completely‐in‐the‐canal (TCCIC) CROS hearing aids. Five subjects with documented profound unilateral hearing loss and experience with traditional CROS/BICROS fittings (TCROS) were tested with a CIC hearing aid placed in their poorer ear. Peak SPL was measured at the tympanic membrane and ranged from 105–115 dB SPL at 2000 Hz. Pure‐tone crossover thresholds and functional gain tested at frequencies from 250–8000 Hz varied considerably more than the SPL measures. The pure‐tone results indicated that sensitivity in the better ear was moderately associated with functional gain across frequency. Speech recognition was then tested in the sound field in two conditions: direct (noise in the poorer ear, speech in the better ear) and indirect (noise in the better ear, speech in the poorer ear) at S/Ns of −6, 0, +6, +12, and quiet. The TCCIC fittings were more effective than TCROS aids across S/Ns, particularly in the direct condi...

Gap discrimination and speech perception in noise

The relation between discrimination of silent gaps and speech‐in‐noise perception was measured in 20 normal‐hearing listeners using speech‐shaped noise as both the gap markers and the noise source for speech testing. In the gap discrimination experiment, subjects compared silent gaps marked by 60 dB SPL 250‐ms noise bursts to standards of either 5, 10, 20, 50, 100, or 200 ms. The gap results were most similar to those reported by Abel [S. M. Abel, J. Acoust. Soc. Am. 52, 519–524 (1972)] as ΔT/T decreased non‐monotonically with increased gap length. In a second experiment, the California Consonant Test (CCT) was administered at 50 dB HL via CD in three conditions: quiet, +10 S/N, and 0 S/N. Results from both experiments were correlated and the association between ΔT/T and CCT scores was generally negative. Listeners who discriminated the gaps with greater acuity typically had higher speech scores. The relation was strongest for the smaller gap standards at each S/N, or when performance for any gap duration was compared to the CCT results obtained in quiet.

Correlations between auditory‐filter shape parameters measured at proximal center frequencies

Auditory‐filter shape parameters in 20 normal‐hearing listeners were determined at center frequencies (CFs) of 913, 1095, 3651, and 4382 Hz using the five‐point roex (p,r) method. Slopes of the filters’ skirts were correlated for the CFs in each frequency region at both low and high stimulus levels. In the λ=1000‐Hz region, the auditory filters’ low‐frequency slopes were significantly correlated at the low and high stimulus levels, while the high‐frequency slopes were associated at the high, but not the low level. In the λ=4000‐Hz region the relationships were clearer as the low‐frequency and high‐frequency filter skirts diverged at the low level, but were significantly correlated at high stimulus levels. Level dependencies in auditory‐filter shapes indicated subtle differences in cochlear frequency analysis at proximal places along the basilar membrane diminished as signal level was increased. Conversely, in those situations most likely to be affected by active processing along the partition, such as the low‐level and high‐frequency conditions, auditory filters centered at neighboring frequencies often did not resemble one another. This suggests that active cochlear mechanisms are not uniformly distributed throughout the length of the basilar membrane. [Work supported by the College of Communication (Jamail Grant) and NIDCD.]