Understanding audiogram patterns is essential for EHS managers who review occupational audiometric surveillance results. This guide covers conductive vs. sensorineural distinction: what it looks like on an audiogram, what it means clinically, what OSHA 1910.95 obligations it triggers, and the required employer response. Note that audiogram interpretation in the context of OSHA compliance always requires involvement of a licensed Professional Supervisor — a licensed audiologist, otolaryngologist, or other physician. The EHS manager's role is to understand the pattern well enough to act appropriately and ensure timely PS review.
Soundtrace provides audiometric testing supervised by a licensed audiologist who reviews all audiograms, identifies STSs, and makes clinical determinations — ensuring employer compliance with every 1910.95 audiometric obligation.
What Is Conductive vs. Sensorineural Distinction?
Sensorineural hearing loss results from damage to cochlear hair cells or the auditory nerve. It is permanent, the type caused by noise exposure, and the primary concern in occupational audiometric surveillance. Conductive hearing loss results from problems in the outer or middle ear (ear canal blockage, eardrum perforation, middle ear fluid, ossicular chain damage) that reduce sound transmission before it reaches the cochlea. A complete audiometric evaluation includes both air conduction and bone conduction testing to distinguish these types. Standard OSHA occupational audiograms use air conduction only.
Clinical Significance
Conductive hearing loss overlaid on a sensorineural audiogram can complicate STS interpretation. A worker who develops a middle ear infection before their annual audiogram will show apparent threshold elevation (worsening) at the STS frequencies that reflects the conductive component, not new cochlear damage. If this conductive loss is present at the time of testing, the annual audiogram may trigger an apparent STS that does not represent permanent noise-induced damage. Standard occupational audiometric testing with air conduction only cannot distinguish this situation without bone conduction testing.
All clinical interpretations of occupational audiograms — including determinations of audiogram pattern, work-relatedness, and STS confirmation — must be made by the Professional Supervisor (licensed audiologist, otolaryngologist, or other physician) under OSHA 1910.95(g)(3). EHS managers should understand these patterns to recognize when PS review is needed and to act on PS findings promptly, not to replace the PS role.
OSHA 1910.95 Implications
OSHA 1910.95 audiograms use air conduction testing. The STS calculation at 2000, 3000, and 4000 Hz applies to air conduction thresholds regardless of whether an underlying conductive component exists. However, the Professional Supervisor may determine that an apparent STS is due to a transient conductive condition and recommend retesting after the conductive condition resolves, before triggering STS follow-up actions. This is a clinical judgment that requires PS involvement — the employer should not independently decide that an STS is 'just conductive.'
Required Employer Response
When an annual audiogram shows an apparent STS, the Professional Supervisor reviews the audiogram to assess whether the shift is consistent with noise-induced sensorineural damage or may reflect a transient conductive condition. This review must occur before the 21-day notification deadline.
If the PS determines the apparent STS may reflect a transient conductive condition, they may recommend retesting after the condition resolves (typically 3–6 months) before finalizing the STS determination. The 21-day notification deadline is suspended during this retest window only with PS guidance.
Whatever the PS conclusion, it must be documented in the audiometric record with clinical rationale. Undocumented PS decisions are not defensible.
Audiologist-supervised audiometric testing with automatic STS detection
Soundtrace audiometric testing is supervised by a licensed audiologist who reviews every audiogram, identifies all STSs, and makes clinical determinations — ensuring your program meets every 1910.95 requirement.
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Sensorineural hearing loss results from damage to cochlear hair cells or the auditory nerve. It is permanent, the type caused by noise exposure, and the primary concern in occupational audiometric surveillance. Conductive hearing loss results from problems in the outer or middle ear (ear canal blockage, eardrum perforation, middle ear fluid, ossicu
OSHA 1910.95 audiograms use air conduction testing. The STS calculation at 2000, 3000, and 4000 Hz applies to air conduction thresholds regardless of whether an underlying conductive component exists. However, the Professional Supervisor may determine that an apparent STS is due to a transient condu. The Professional Supervisor must review all audiograms with significant findings to determine STS status and work-relatedness.
The Professional Supervisor — a licensed audiologist, otolaryngologist, or other physician — must review any audiogram with clinically significant findings. OSHA 1910.95(g)(3) requires PS involvement in all STS determinations and medical referral decisions. EHS managers should not attempt to interpret audiogram patterns independently.