Auditory system dysfunction in Brazilian gasoline station workers.
Simone Mariotti Roggia, Aline Gomes de França, Thais C Morata and 2 others
PMID 31017499WHAT IT FOUND
Gas station workers showed auditory dysfunction on specialized tests even when standard hearing thresholds were normal.
Audiologists should use a full battery including acoustic reflexes and otoacoustic emissions, not just pure-tone audiometry, to detect early damage.
Key findings
01Workers with normal hearing thresholds still showed significantly poorer results on acoustic reflex tests, otoacoustic emissions, and auditory brainstem responses compared to non-exposed controls.
02Longer duration of gasoline exposure was associated with worsening auditory brainstem response latencies and decreasing otoacoustic emission signals, particularly in workers who had developed hearing loss.
03P300 auditory evoked potentials did not differ significantly between exposed workers and controls, suggesting this specific test may not be sensitive to gasoline-related auditory damage.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study lacked detailed individual data on solvent uptake and specific exposure levels, making it difficult to precisely quantify the contribution of gasoline versus other factors. The control group was recruited from volunteers via ads and word of mouth, which may introduce selection bias compared to the worker group. The study did not include behavioral tests for central auditory processing disorder, which the authors suggest might be more sensitive than the electrophysiological P300 test used.
Declared interests
The authors report no conflicts of interest.
The easy way to misread this
Do not assume that normal pure-tone audiometry results mean a patient is free from auditory damage. This study shows that workers with 'normal' hearing thresholds still had significant dysfunction in acoustic reflexes, otoacoustic emissions, and brainstem responses. Relying solely on standard hearing tests may miss early ototoxic effects from chemical exposure.