The P300 component of the auditory event-related potential in adult psychiatric and neurologic disorders: a narrative review of clinical and experimental evidence

The auditory P300 wave, also known as P3b, is an event-related potential component thought to reflect central information processes involved in stimulus evaluation or categorization. It is typically elicited using the oddball paradigm, which involves mixing low-probability target items with high-probability standard stimuli. Its latency is associated with the timing of cognitive processes such as stimulus evaluation and response preparation, while its amplitude is related to the amount of attentional resources engaged during the task. Despite decades of use in research settings, its application in clinical practice has been limited. Prolongation of latencies and reduction of amplitudes in the auditory P3b have been observed in both psychiatric and neurological conditions. This includes cases where traditional neuropsychological tests are challenging due to severe motor or speech dysfunctions, or in conditions characterized by subtle cognitive deficits. Additionally, specific laterality patterns in psychoses and a loss of P300 habituation in migraines have been described. The wealth of experimental evidence supports the use of this evoked potential, which can be elicited through a relatively simple paradigm, for objectively evaluating cognition in psychiatric and neurological patients, particularly in follow-up assessments. Therefore, the auditory P300 appears to be a valuable tool for monitoring the clinical course of patients with mental and neurological disorders in certain circumstances.