CENTRAL AUDTIORY DEVELOPMENT IN CHILDREN WITH HEARING LOSS: CLINICAL RELEVANCE OF THE P1 CAEP BIOMARKER IN HEARING-IMPAIRED CHILDREN WITH MULTIPLE DISABILITIES

Abstract

Objective: First, we review the development and plasticity of the central auditory pathways in infants and children with hearing loss who are fitted with cochlear implants (CIs). Second, we describe case studies demonstrating the clinical utility of the P1 central auditory evoked potential (CAEP) for evaluating cortical auditory maturation in the rapidly increasing number of cochlear-implanted children who have multiple disabilities.

Study design: Children who receive CIs provide a platform to examine the trajectories of deprivation-induced and experience-dependent plasticity in the central auditory system. We review the evidence for, and time limits of sensitive periods for cortical auditory maturation framing an optimal period for cochlear implantation. Finally, we evaluate the use of the P1 biomarker as an objective assessment tool in the special case of children with multiple disabilities.

Results: The P1 response was useful in assessing central auditory maturation in patients with CHARGE association, ANSD, and Pallister-Killian Syndrome concomitant with hearing loss.

Conclusion: The presence of co-existing disabilities in addition to hearing loss poses unique challenges regarding both pre-intervention evaluation and post-intervention rehabilitation for children with multiple disabilities. When combined with a standard audiological test battery, the P1 CAEP biomarker has a useful role in objectively evaluating the maturation of central auditory pathways to determine the effectiveness of various intervention strategies in hearing-impaired children with multiple disabilities.

Keywords: P1 Cortical auditory evoked potential; cochlear implant; multiple disabilities; sensitive period.

Figures

Figure 1

Audiogram of behavioral unaided and aided thresholds for Case 1 (1A), Grand average CAEP response for Case 1 obtained after intervention via bilateral hearing aids (1B), and average P1 latency as a function of child’s age plotted against the 95% confidence limits for normal-hearing children for Case 1 (1C).

Figure 2

Audiogram of behavioral unaided thresholds and aided thresholds post-bilateral cochlear implantation for Case 2 (2A), Grand average CAEP response for Case 2 obtained post-bilateral cochlear implantation (2B), and average P1 latency as a function of child’s age plotted against the 95% confidence limits for normal-hearing children pre- and post-implantation for Case 2 (2C).

Figure 3

Audiogram of behavioral unaided thresholds, aided thresholds, and thresholds post-left ear cochlear implantation for Case 3 (3A), Grand average CAEP response for Case 3 obtained in the left ear post- unilateral cochlear implantation (3B), non-replicable grand average CAEP responses obtained in the unaided right ear (3C), and average P1 latency for the implanted left ear and unaided right ear as a function of child’s age plotted against the 95% confidence limits for normal-hearing children both pre- and post-implantation in Case 3 (3D).

Figure 4

Audiogram of behavioral unaided and bilateral aided thresholds for Case 4 (4A), Grand average CAEP response for Case 4 obtained after bilateral hearing aid intervention (4B), and average P1 latency as a function of child’s age plotted against the 95% confidence limits for normal-hearing children after hearing aid intervention for Case 4 (4C).

Figure 5

Audiogram of aided thresholds for Case 5 (5A), Grand average CAEP response for Case 5 obtained after bilateral hearing aid intervention (4B), and average P1 latency as a function of child’s age plotted against the 95% confidence limits for normal-hearing children after hearing aid intervention for Case 5 (4C).