Audiology and Speech Disorders — MCQs

Question 1: Brainstem Evoked Response Audiometry (BERA) can be most accurately performed from which gestational age?

• A. 30 weeks
• B. 32 weeks
• C. 34 weeks (Correct Answer)
• D. 28 weeks

Explanation: **Explanation:** Brainstem Evoked Response Audiometry (BERA), also known as ABR, is an objective electrophysiological test used to assess the integrity of the auditory pathway from the cochlear nerve to the brainstem. **Why 34 weeks is correct:** The auditory system undergoes significant maturation during the third trimester. While the inner ear (cochlea) reaches adult size by 20 weeks of gestation, the **myelination** of the auditory nerve and the brainstem pathways—essential for conducting electrical impulses—is only sufficiently developed to produce a consistent, reproducible, and interpretable BERA waveform by **34 weeks of gestation**. Before this period, the waves are often absent, inconsistent, or have excessively prolonged latencies. **Analysis of Incorrect Options:** * **28 & 30 weeks:** At this stage, the fetus may show a startle response to loud sounds, but the neural pathways are too immature (lack of myelination) to yield a reliable BERA recording. * **32 weeks:** While some rudimentary waves may appear, they are often unstable. 34 weeks is the clinically accepted threshold for "accurate" and standardized testing. **High-Yield Clinical Pearls for NEET-PG:** * **Waveforms:** BERA consists of 7 waves, but **Waves I, III, and V** are the most clinically significant. * **Wave V:** This is the most robust wave and is used to determine the **hearing threshold** (the lowest intensity at which Wave V is visible). * **Site of Origin:** Wave I (Distal 8th Nerve), Wave II (Proximal 8th Nerve), Wave III (Cochlear Nucleus), Wave IV (Superior Olivary Complex), Wave V (Lateral Lemniscus/Inferior Colliculus). * **Indications:** Newborn hearing screening (gold standard), diagnosing acoustic neuroma (retrocochlear lesions), and determining hearing thresholds in uncooperative patients.