Speech Recognition Materials and Ceiling Effects: Considerations for Cochlear Implant Programs

Abstract

Cochlear implant recipients have demonstrated remarkable increases in speech perception since US FDA approval was granted in 1984. Improved performance is due to a number of factors including improved cochlear implant technology, evolving speech coding strategies, and individuals with increasingly more residual hearing receiving implants. Despite this evolution, the same recommendations for pre- and postimplant speech recognition testing have been in place for over 10 years in the United States. To determine whether new recommendations are warranted, speech perception performance was assessed for 156 adult, postlingually deafened implant recipients as well as 50 hearing aid users on monosyllabic word recognition (CNC) and sentence recognition in quiet (HINT and AzBio sentences) and in noise (BKB-SIN). Results demonstrated that for HINT sentences in quiet, 28% of the subjects tested achieved maximum performance of 100% correct and that scores did not agree well with monosyllables (CNC) or sentence recognition in noise (BKB-SIN). For a more difficult sentence recognition material (AzBio), only 0.7% of the subjects achieved 100% performance and scores were in much better agreement with monosyllables and sentence recognition in noise. These results suggest that more difficult materials are needed to assess speech perception performance of postimplant patients – and perhaps also for determining implant candidacy.

A comparison of the speech recognition and pitch ranking abilities of children using a unilateral cochlear implant, bimodal stimulation or bilateral hearing aids

“…Unexpectedly, we also found no significant difference between the mean CNC scores of the CI-only (M = 71.87%) and BMS groups (M = 76.45%; SD = 14.79). This result is contrary to the findings of Gifford and colleagues [27], who reported that the CNC word recognition scores of a group of 36 adults using BMS (M = 71.8% correct) were significantly higher than those of a group of 162 adult using a unilateral CI (M = 55.7%). They are also not in agreement with the general consensus of within-group comparison studies, which indicate that CI recipients with residual hearing in their non-implanted ear obtain higher word recognition scores using BMS than when only using their CI [8,24,34].…”

“…Consistent with our second hypothesis, there were no significant differences between the sentence recognition in quiet scores of the CI-only, HA-only, and BMS groups. This is consistent with the results of several studies which reported no significant differences in the sentence recognition in quiet scores of adults using a unilateral CI and BMS [5,27], nor between users of a unilateral CI recipients and HA users with a severe hearing loss [35].…”

“…Recently, two studies compared the speech recognition performance of separate groups of participants using a unilateral CI or BMS [5,27]. Gifford and colleagues [27] found no significant difference in the speech recognition in noise performance of 112 unilateral CI recipients and 11 BMS users.…”

“…Recently, two studies compared the speech recognition performance of separate groups of participants using a unilateral CI or BMS [5,27]. Gifford and colleagues [27] found no significant difference in the speech recognition in noise performance of 112 unilateral CI recipients and 11 BMS users. Similar results were found by Dorman et al [5] who assessed 65 adults using a unilateral CI and 15 using BMS on a sentence recognition in noise task (10 dB SNR) and an arrhythmic melody recognition task.…”

“…At present the HINT sentences are the only sentence recognition test materials available with a New Zealand accent. Gifford and colleagues [27] recently examined the validity of the HINT sentences as a measure of open-set speech recognition in quiet. CI-only and BMS users were assessed using HINT and AzBio sentences, and CNC words in quiet.…”