Fine structure processing improves telephone speech perception in cochlear implant users

The objective of this study was to compare telephone speech perception and subjective preferences in cochlear implant users with two different speech-processing strategies: high-definition continuous interleaved sampling (HDCIS) and fine structure processing (FSP). A randomized double-blind study was designed for intra-individual comparison of HDCIS and FSP. Twenty-five post-lingually deafened patients with either the PulsarCI¹⁰⁰ or SonataTI¹⁰⁰ and Opus2 acoustic processor were tested consecutively with both coding strategies, assigned in a random order. Disyllabic word speech perception was tested 6 weeks after each fitting under the following conditions: landline use with (LWN) and without (LWoN) background noise, mobile use with (MWN), and without (MWoN) background noise and mobile use with a Bluetooth magnetic field transmitter necklace (MB). Changes in health-related quality of life (QoL) were assessed using the Glasgow Benefit Inventory (GBI) and Faber’s questionnaire. Personal preferences between strategies were surveyed upon completion of the study. All subjects included in this study performed better with FSP in the landline tests. There was an improvement of 11.5 % in LWN use (p = 0.014; CI 95 % = 3–20 %) and 10 % in LWoN use (p = 0.001; CI 95 % = 5–15 %). MWoN showed an improvement of 6.3 % with FSP (p = 0.03; CI 95 % = 0–13 %). MB tests showed an improvement of 11 % with FSP (p < 0.05; CI 95 % = 1.5–22 %). Quality of life was significantly better using FSP. Eighty-four percent of participants preferred FSP. The FSP speech coding strategy improved the speech recognition of cochlear implant users when using the telephone compared to HDCIS. Cochlear implantation with FSP coding improved QoL.