The loudness dependence of the auditory evoked potential (LDAEP) as an in vivo biomarker of central serotonergic function in humans: rationale, evaluation and review of findings
Article first published online: 18 APR 2008
Copyright © 2008 John Wiley & Sons, Ltd.
Human Psychopharmacology: Clinical and Experimental
Volume 23, Issue 5, pages 355–370, July 2008
How to Cite
O'Neill, B. V., Croft, R. J. and Nathan, P. J. (2008), The loudness dependence of the auditory evoked potential (LDAEP) as an in vivo biomarker of central serotonergic function in humans: rationale, evaluation and review of findings. Hum. Psychopharmacol. Clin. Exp., 23: 355–370. doi: 10.1002/hup.940
- Issue published online: 19 JUN 2008
- Article first published online: 18 APR 2008
- Manuscript Accepted: 22 FEB 2008
- Manuscript Received: 21 DEC 2007
- serotonin (5-HT);
- loudness dependence of auditory evoked potential (LDAEP);
- NMDA receptor;
- biological marker
The loudness dependence of the auditory evoked potential (LDAEP) has been proposed as a valid means of non-invasively assessing in vivo central serotonin (5-hydroxytryptamine, 5-HT) function in humans. The specificity and sensitivity of the LDAEP to changes in 5-HT neurotransmission have recently been explored directly in a number of pharmacological and genetic studies. Subsequently, this review was undertaken in an attempt to critically evaluate the potential role of the LDAEP as a marker of the central 5-HT function.
Findings from clinical, experimental animal and human studies examining the relationship between the LDAEP and the 5-HT system as well as other neurochemical systems including dopaminergic, glutamatergic and the cholinergic systems were reviewed.
The majority of evidence for an association between the LDAEP and 5-HT has come from animal studies. Indirect studies in clinical disorders of presumed serotonergic dysfunction have been circumstantial and inconsistent with more recent investigations utilising direct genetic association studies also providing conflicting reports. Pharmacological studies in humans provide overwhelming evidence that the LDAEP is insensitive to acute changes in 5-HT function, with additional evidence outlining sensitivity to other neurotransmitter systems including the glutamatergic system.
The available evidence suggests that the LDAEP lacks sensitivity and specificity to acute changes in serotonergic neurotransmission. Overall the findings do not provide strong support for its utility as a marker of central 5-HT function. However the LDAEP shows more promise as a potential predictor of antidepressant treatment response and this predictive ability may provide the basis for future research involving the LDAEP. Copyright © 2008 John Wiley & Sons, Ltd.