All of the following audiometric findings are characteristic of sensorineural hearing loss EXCEPT:

Explanation

## Sensorineural Hearing Loss: Audiometric Patterns ### Core Audiometric Features of SNHL **Key Point:** In sensorineural hearing loss (SNHL), both air conduction (AC) and bone conduction (BC) thresholds are elevated **equally**, resulting in an **air-bone gap of ≤10 dB**. This is the hallmark finding that distinguishes SNHL from conductive hearing loss (CHL). ### Analysis of Each Option | Feature | SNHL | CHL | |---------|------|-----| | **Air-bone gap** | ≤10 dB (closed) | >15 dB (open) | | **AC threshold** | Elevated | Normal or elevated | | **BC threshold** | Elevated equally with AC | Normal (better than AC) | | **Carhart's notch** | Present in otosclerosis (mechanical artifact) | Classic in otosclerosis | | **Speech discrimination** | Disproportionately poor | Proportionate to loss | ### Why Option C Is the Exception (Correct Answer) **Clinical Pearl:** In SNHL, bone conduction thresholds are **NOT** better than air conduction thresholds. Both AC and BC are elevated to a similar degree (air-bone gap ≤10 dB). Bone conduction being **better than** air conduction — i.e., a significant air-bone gap — is the defining feature of **conductive hearing loss**, not SNHL. In CHL, the cochlea is intact so BC remains normal while AC is impaired. Option C therefore describes a finding characteristic of **conductive** (or mixed) hearing loss, making it the exception in the context of SNHL. ### Why the Other Options Are Characteristic of SNHL 1. **Option A (air-bone gap closure with both AC and BC elevated equally):** ✓ This is the defining audiometric hallmark of SNHL — both thresholds rise together, closing the gap. 2. **Option B (Carhart's notch at 2 kHz):** ✓ Carhart's notch is a mechanical artifact seen on bone conduction audiometry, classically at **2 kHz**, in otosclerosis. It can also appear in other forms of SNHL and represents a dip in BC thresholds due to impaired ossicular resonance. It is a well-recognized audiometric finding associated with SNHL/mixed loss patterns. *(Dhingra 7e, Ch 8)* 3. **Option D (speech discrimination disproportionately poor):** ✓ In SNHL, cochlear hair cell damage leads to **disproportionately poor speech discrimination** relative to the pure-tone average — a key distinguishing feature from CHL, where discrimination remains proportionate because the cochlea is intact. ### Mnemonic: SNHL Audiogram **"SNHL = Same (AC & BC), Speech Sucks"** - **Same:** AC and BC thresholds elevated equally → no air-bone gap - **Speech Sucks:** Discrimination disproportionately poor **High-Yield:** The presence of an air-bone gap (BC better than AC) always points toward a **conductive component**. Pure SNHL never produces a significant air-bone gap. *(Dhingra ENT 7e; Scott-Brown's Otorhinolaryngology)*