P1 CAEPs, Auditory Maturation and Auditory Neuropathy Spectrum Disorder
The P1 cortical auditory-evoked potential (CAEP) can be used to assess maturation of the central auditory nervous system (CANS) in children younger than 3 to 4 years. The P1 CAEP is a robust, easily identified, positive response that typically occurs between 100 and 300 milliseconds post-stimulus onset. Of note, in older children, the P1 waveform changes and becomes the P1-N1-P2 complex. The P1-N1-P2 complex can be more difficult to identify in cases of auditory deprivation. Sharma and Dorman (2006) note the overall morphology of the CAEP reflects the maturational status of the central pathways and positive changes (such as improved morphology and decreased latency) in the CAEP reflects central auditory development (see Nash, Sharma, Martin).
Cardon and Sharma (2013) examined CAEPs and behavioral outcomes in 24 children (15 females, 9 males, age range 1.4 to 12.6 years, mean = 3.8 years). The group’s mean pure tone average (PTA) was 81 dB HL and each child was diagnosed with auditory neuropathy spectrum disorder (ANSD). All children were fitted with cochlear implants (CIs). The P1 CAEPs were present in all children post-implantation and the P1 CAEP latency was statistically significantly correlated with the child’s Infant Toddler–Meaningful Auditory Integration Scale (IT-MAIS) score. Further, more of the children implanted prior to age two years demonstrated normal P1 latencies (within 6 months post implantation) while children implanted after age 2 years (primarily) demonstrated delayed P1 latencies. Cardon and Sharma suggest these results possibly indicate a "sensitive period for cortical auditory development" for children with ANSD.
The authors note that when one considers previous and current work, and when one considers hearing aid amplification as compared to CIs (with respect to ANSD and P1), indeed, hearing aids "may be a viable treatment for a small subset of, but certainly not all, children with ANSD…." Further, they state "Thus, it would appear that CIs are more effective at providing the auditory stimulation needed for central auditory maturation in children with severe disruptions in neural synchrony, while hearing aids may only benefit children with milder cases of dys-synchrony…."
For More Information, References, and Recommendations
Cardon G, Sharma A. (2013) Central auditory maturation and behavioral outcome in children with auditory neuropathy spectrum disorder who use cochlear implants. International Journal of Audiology 52:577-586.
Nash A, Sharma A, Martin K, Biever A. Clinical Applications of the P1 Cortical Auditory Evoked Potential (CAEP) Biomarker.
Sharma A, Dorman MF.(2006) Central auditory development in children with cochlear implants: clinical implications. Advances in Oto-Rhino-Laryngology 64: 66–88.