Speech Science Forum - Kinjal Mehta & Rajeev Mathew

Two Ear Institute speakers will each present their work at the next Speech Science Forum.

Kinjal Mehta, Ear Institute - The Role of Cortical Auditory Evoked Potentials (CAEP) in reducing the age at hearing aid fitting in Children with Hearing loss identified by Newborn Hearing Screening.

Abstract:
Free-field Cortical Auditory Evoked Potential (CAEP) measurements to speech tokens was introduced into the infant audiology pathways for permanent childhood hearing impairment (PCHI) in the UK. Children with bilateral PCHI were studied from two sequential cohorts. Thirty-five children followed a pathway prior to CAEP introduction and forty-four children followed the subsequent pathway with both unaided and aided CAEPs. Data analysis explored degree of loss, age at: diagnosis, hearing aid fitting and referral for cochlear implant (CI) assessment. CAEP offered a novel educative process for the parents and audiologists supporting rehabilitative decision-making for hearing aid fitting and CI referral.  Delays in hearing aid fitting or CI referral were categorised as either due to the audiologist’s recommendation or parental choice.   Results showed the median age at hearing aid fitting in the earlier cohort was significantly higher (9.2 months) than in the subsequent cohort (3.9 months). This change was attributed to children with mild-to-moderate losses, where the median age at fitting fell from 19 to 5 months.  The parents deferring fitting fell from 40% to 19% following educative CAEP assessment and delays due to audiologist recommendation fell from 40% to 12%.  Children with profound losses were referred for CI assessment at a significantly earlier age in the later cohort; in line with the UK national trend. However, it can be difficult to know if hearing aid intervention is appropriate for children with mild-to-moderate PCHI and this research demonstrates that it could be beneficial to introduce CAEPs into infant audiology pathways.

Rajeev Mathew, Ear Institute - Development and Significance of the Auditory Change Complex in Adult Cochlear Implant Users

Abstract:
The spatial auditory change complex (ACC) is a cortical response elicited by a change in place of stimulation.
There is growing evidence that it provides a useful objective measure of electrode discrimination in cochlear implant (CI) users. Early assessment of electrode discrimination could allow auditory stimulation to be optimized during a potentially sensitive period of auditory rehabilitation. A direct stimulation paradigm was used to measure the spatial ACC in both pre- and post-lingually deafened adults. We show that it is feasible to measure the spatial ACC in different CI devices and as early as 1-week after CI switch-on. The spatial ACC has a strong relationship with performance on a behavioural discrimination task and in some cases provides information over and above behavioural testing. In addition, longitudinal measurements of the spatial ACC provide evidence for central auditory plasticity. We suggest that it may be useful to measure the spatial ACC to guide auditory rehabilitation and improve hearing performance in CI users.