Auditory and Visual Evoked Potentials: Diagnostic Techniques and Interpretation

Introduction

Evoked potentials (EPs) are electrophysiological tests used to measure electrical responses of the nervous system to auditory and visual stimuli. They are valuable diagnostic tools in ophthalmology and neurology, aiding in the detection of various disorders.

Types of Evoked Potentials

Auditory Evoked Potentials (AEPs)

• Brainstem Auditory Evoked Responses (BAERs): Evaluate auditory nerve and brainstem function.
• Middle Latency Responses (MLRs): Assess the auditory cortex.
• Long Latency Responses (LLRs): Measure cognitive processing of auditory stimuli.

Visual Evoked Potentials (VEPs)

• Pattern-Reversal VEPs: Used for diagnosing optic nerve diseases like multiple sclerosis.
• Flash VEPs: Suitable for patients with poor visual acuity.
• Steady-State VEPs: Applied in research and complex diagnostic evaluations.

Clinical Applications

AEPs and VEPs are critical for assessing auditory and visual pathway integrity in conditions such as:

• Multiple Sclerosis
• Optic Neuritis
• Glaucoma
• Brainstem Lesions
• Auditory Neuropathy

Interpretation and Limitations

EPs require expert analysis to differentiate normal and abnormal waveforms. Factors such as age, attention, and technical settings can impact test results, requiring careful interpretation by specialists.

Conclusion

Evoked potential testing remains an essential component in ophthalmology and neurology, providing valuable diagnostic insights into sensory pathway integrity.