Event related potentials – are they useful in paediatric cochlear implant patients?

Abstract

Background. The use of cochlear implants in profoundly deaf children is increasing with a trend towards earlier implantation. However, tools used at present to assess outcome are primarily based on behavioural tests, which are difficult to use effectively in young children. Event related potentials (ERP) such as Mismatch Negativity (MMN) have been proposed to have potential in assessing central processing in cochlear implant patients.1 Objective. The main objective of this study was to assess the correlation of ERP measures with behavioural assessment data to identify if they can be used to predict performance in cochlear implant patients. Methods. We carried out a prospective, blinded, non‐randomised study investigating auditory ERPs to speech stimuli in 35 cochlear implanted children. We compared P1, N2 and MMN parameters with behavioural outcome, assessed at the time of recording ERPs and 2 years later. Results. Auditory ERPs were identifiable in 30 out of 35 patients. MMN was recorded in 85% of star performers but in only 20% of poor performers. At behavioural reassessment 2 years later, 50% of poor performers who had demonstrated a MMN progressed to achieve ‘star’ performance in comparison to 25% of those who had not. Conclusion. These results indicate that MMN can be used to assess the functional status of auditory cortex in young children with cochlear implants and may provide an objective measure to predict future performance. However a large longitudinal study is needed to establish its sensitivity and specificity before using it as a clinical tool. Reference 1 Singh S., Liasis A., Towell A., et al. (2004) Event related potentials in cochlear implant patients. Ear and Hearing25(6), 598‐‐610

The Role of Event-Related Brain Potentials in Assessing Central Auditory Processing

“…Our review of the literature shows that MMN amplitude is highly sensitive to discrimination deficits in different clinical populations including individuals suffering from learning disabilities and/or hearing impairment. For example, the MMN can be used to assess the functional status of auditory cortex in people with hearing loss and who wear cochlear implants (Kraus et al, 1993;Ponton and Don, 1995;Singh et al, 2004;Kelly et al, 2005;Roman et al, 2005;Singh et al, 2006). Moreover, in healthy young adults near threshold stimuli can elicit reliable MMN responses (Alain et al, 2004).…”