Within-Patient Longitudinal Speech Reception Measures with Continuous Interleaved Sampling Processors for Ineraid Implanted Subjects

OBJECTIVE: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. DESIGN: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. RESULTS: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. CONCLUSIONS: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.