This study aimed (1) to investigate the feasibility of recording the electrically evoked auditory event–related potential (eERP), including the onset P1-N1-P2 complex and the electrically evoked auditory change complex (EACC) in response to temporal gaps, in children with auditory neuropathy spectrum disorder (ANSD); and (2) to evaluate the relationship between these measures and speech-perception abilities in these subjects.
Fifteen ANSD children who are Cochlear Nucleus device users participated in this study. For each subject, the speech-processor microphone was bypassed and the eERPs were elicited by direct stimulation of one mid-array electrode (electrode 12). The stimulus was a train of biphasic current pulses 800 msec in duration. Two basic stimulation conditions were used to elicit the eERP. In the no-gap condition, the entire pulse train was delivered uninterrupted to electrode 12, and the onset P1-N1-P2 complex was measured relative to the stimulus onset. In the gapped condition, the stimulus consisted of two pulse train bursts, each being 400 msec in duration, presented sequentially on the same electrode and separated by one of five gaps (i.e., 5, 10, 20, 50, and 100 msec). Open-set speech-perception ability of these subjects with ANSD was assessed using the phonetically balanced kindergarten (PBK) word lists presented at 60 dB SPL, using monitored live voice in a sound booth.
The eERPs were recorded from all subjects with ANSD who participated in this study. There were no significant differences in test–retest reliability, root mean square amplitude or P1 latency for the onset P1-N1-P2 complex between subjects with good (>70% correct on PBK words) and poorer speech-perception performance. In general, the EACC showed less mature morphological characteristics than the onset P1-N1-P2 response recorded from the same subject. There was a robust correlation between the PBK word scores and the EACC thresholds for gap detection. Subjects with poorer speech-perception performance showed larger EACC thresholds in this study.
These results demonstrate the feasibility of recording eERPs from implanted children with ANSD, using direct electrical stimulation. Temporal-processing deficits, as demonstrated by large EACC thresholds for gap detection, might account in part for the poor speech-perception performances observed in a subgroup of implanted subjects with ANSD. This finding suggests that the EACC elicited by changes in temporal continuity (i.e., gap) holds promise as a predictor of speech-perception ability among implanted children with ANSD.
This study aimed 1) to investigate the feasibility of recording the electrically evoked auditory event-related potential (eERP), including the onset P1-N1-P2 complex and the electrically evoked auditory change complex (EACC) in response to temporal gaps, in children with auditory neuropathy spectrum disorder (ANSD); and 2) to evaluate the relationship between these measures and speech perception abilities in these patients. eERPs were recorded from 15 children with ANSD who had various speech perception performance. There was a robust correlation between the PBK word scores and the EACC thresholds for gap detection. Subjects with poorer speech performance showed larger EACC thresholds in this study.
Department Otolaryngology—Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
The authors thank Alexandra Gery for her assistance with subject recruitment. The authors also thank all the auditory neuropathy spectrum disorder subjects and their parents for participating in this study. The authors also express their great appreciation to Professors Carolyn J. Brown and Paul J. Abbas for generously providing the custom-designed stimulating software.
This work was supported by grants from the National Institutes of Health/National Institute on Deafness and Other Communication Disorders (1R21DC011383) and the Deafness Research Foundation.
Portions of this article were presented at the Objective Measures in Auditory Implants—6th International Symposium in September of 2010.
Dr. Craig A. Buchman is a member of Cochlear Corporation Surgeon’s Advisory Board, and Dr. Holly F.B. Teagle is a member of a Cochlear Corporation Audiology Advisory Board. The remaining authors have no disclosures to report.
Address for correspondence: Shuman He, G190 Physicians Office Building, 170 Manning Drive, Department of Otolaryngology—Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. E-mail: firstname.lastname@example.org