**Core Concept:** Hearing loss in neonates is a crucial aspect of early diagnosis and intervention. A variety of investigations are available to assess hearing loss, including auditory brainstem response (ABR), otoacoustic emissions (OAE), and transient evoked otoacoustic emissions (TEOAE).

**Why the Correct Answer is Right:** The correct answer, **Auditory Brainstem Response (ABR)**, is the most reliable and widely used test for evaluating hearing loss in neonates. ABR measures the electrical response of the auditory pathway, including the cochlea, brainstem, and cortex, to clicks or pure tones. This test is non-invasive, objective, and capable of detecting both conductive and sensorineural hearing loss.

**Why Each Wrong Option is Incorrect:**

A. **Otoacoustic Emissions (OAE)** are useful for screening purposes, detecting reversible conductive hearing loss, and monitoring the effects of treatment. However, they are less accurate than ABR in detecting sensorineural hearing loss.

B. **Transient Evoked Otoacoustic Emissions (TEOAE)** are similar to OAE but are more sensitive to detect cochlear pathology and are essential for screening purposes. However, they are not as sensitive as ABR in detecting sensorineural hearing loss.

C. **Venous Pulse Oximetry (VPT)** is a non-invasive test that measures oxygen saturation of blood. It is not a reliable method for assessing hearing loss in neonates.

**Clinical Pearl:** Early identification and intervention for neonatal hearing loss are essential for optimal language and cognitive development. ABR is the gold standard investigation for assessing hearing loss in neonates and should be performed within the first few days of life for infants at risk.