Chronic Conductive Hearing Loss Is Associated With Speech Intelligibility Deficits in Patients With Normal Bone Conduction Thresholds.
Masahiro Okada, D Bradley Welling, M Charles Liberman and 1 others
PMID 31490800WHAT IT FOUND
Adults with chronic unilateral conductive hearing loss and normal bone conduction thresholds had significantly poorer word recognition on the affected side.
This deficit was linked to the degree and duration of the conductive loss, not inner ear sensitivity. Amplification may be needed even when standard thresholds appear normal.
Key findings
01Word recognition scores were significantly poorer on the affected side in patients with chronic conductive hearing loss and pure-tone averages greater than 40 dB HL.
02There was no significant correlation between bone conduction thresholds and word recognition scores, suggesting the deficit is not driven by measurable sensorineural hearing loss.
03Both the degree and duration of the conductive hearing loss were significant factors in the decrement of word recognition scores.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study is retrospective, relying on existing clinical records rather than controlled experimental conditions. Patients with acute conductive hearing loss were significantly older than those with chronic conditions, introducing potential age-related confounds, though the authors argue age did not drive the observed deficits. Word recognition was tested in quiet; deficits may be more pronounced in noise, which was not assessed. The study excluded patients with bone conduction thresholds worse than 25 dB HL, so findings do not apply to those with mixed hearing loss.
Declared interests
The research was funded by the NIH – NIDCD P50 DC015857. No conflicts of interest were declared by the authors.
The easy way to misread this
Do not assume that normal bone conduction thresholds guarantee normal speech recognition in adults with chronic conductive hearing loss. The study shows that word recognition can be significantly impaired on the affected side when the conductive loss is moderate to severe and chronic, even if inner ear sensitivity appears normal.