What Researchers Did
Researchers compared how patients with sudden hearing loss after a blast injury responded to hyperbaric oxygen therapy combined with oral steroids, compared to patients whose sudden hearing loss came from noise exposure alone.
What They Found
This study of 598 ears from 387 patients, all treated with one 90-minute hyperbaric oxygen session at 2.5 ATA given daily plus oral prednisone, found that the 259 blast-injured ears had a significantly smaller improvement in hearing after treatment than the 339 noise-exposed ears (6 plus or minus 17 dB vs 10 plus or minus 14 dB, p = 0.022). Before treatment, blast-injured patients already had worse hearing measures, including a higher pure-tone average (18 plus or minus 11 dB vs 12 plus or minus 9 dB, p less than 0.001), higher speech reception thresholds (16 plus or minus 14 dB vs 10 plus or minus 8 dB, p less than 0.001), and more abnormal otoscopy findings (87% vs 95%, p = 0.003). After treatment, blast-injured ears still had worse pure-tone thresholds than noise-exposed ears at every frequency tested, with differences ranging from 3.2 to 6.8 dB (all p less than 0.05).
What This Means for Canadian Patients
For Canadian patients being treated for sudden hearing loss after an explosion versus after noise exposure, this study suggests blast-related hearing loss responds less well to the combination of hyperbaric oxygen therapy and oral steroids than noise-related hearing loss does. Blast-injured patients started with more abnormal hearing measures and ended treatment with less improvement and more persistent hearing loss across all frequencies tested.
Canadian Relevance
No direct Canadian connection identified.
Study Limitations
The abstract does not describe a comparison group that received oral prednisone alone or no treatment, so it is not possible to tell how much of the change in hearing came from the hyperbaric oxygen therapy versus the steroids, and exposure to blast or noise was classified by patient history rather than an objective measure.