Within-patient longitudinal speech reception measures with continuous interleaved sampling processors for ineraid implanted subjects.

Abstract

To assess within-subject changes in speech reception over time in a group of Ineraid subjects fitted with continuous interleaved sampling (CIS) wearable processors fabricated in Geneva. To compare asymptotic performance between CIS and Ineraid processors for the same subjects. Twelve patients, all users of the 4-channel Ineraid cochlear implant system for several years and with no previous experience of CIS processors in daily life, were equipped with Geneva Wearable Processors programmed to implement a high-rate CIS sound processing strategy using four to six channels. Their speech reception performance with CIS processors was monitored over a period of 1 yr with consonant and vowel identification tests. For comparison, speech reception performance also was measured with Ineraid processors before switching to CIS and after 6 mo of non-use of Ineraid processors. At fitting, CIS processors produced significantly better consonant identification but no better vowel identification. Subsequently, consonant and vowel scores with CIS processors improved progressively to asymptote after 6 mo of daily use. At 6 mo and beyond, performance with CIS processors was significantly superior to that obtained with Ineraid processors on both consonant and vowel identification tests. Control tests made with Ineraid processors after 6 mo of non-use of the device yielded results that were indistinguishable from those obtained before the study. The full potential of the CIS strategy is not revealed at fitting. Accumulation of daily experience provides significant improvements, asymptotic performance being reached after about 4 to 6 mo of use. All Ineraid users might greatly benefit from CIS processors.