Not all of the variance in speech-recognition performance of cochlear implant (CI) users can be explained by biographic and auditory factors. In normal-hearing listeners, linguistic and cognitive factors determine most of speech-in-noise performance. The current study explored specifically the influence of visually measured lexical-access ability compared with other cognitive factors on speech recognition of 24 postlingually deafened CI users. Speech-recognition performance was measured with monosyllables in quiet (consonant-vowel-consonant [CVC]), sentences-in-noise (SIN), and digit-triplets in noise (DIN). In addition to a composite variable of lexical-access ability (LA), measured with a lexical-decision test (LDT) and word-naming task, vocabulary size, working-memory capacity (Reading Span test [RSpan]), and a visual analogue of the SIN test (text reception threshold test) were measured. The DIN test was used to correct for auditory factors in SIN thresholds by taking the difference between SIN and DIN: SRTdiff. Correlation analyses revealed that duration of hearing loss (dHL) was related to SIN thresholds. Better working-memory capacity was related to SIN and SRTdiff scores. LDT reaction time was positively correlated with SRTdiff scores. No significant relationships were found for CVC or DIN scores with the predictor variables. Regression analyses showed that together with dHL, RSpan explained 55% of the variance in SIN thresholds. When controlling for auditory performance, LA, LDT, and RSpan separately explained, together with dHL, respectively 37%, 36%, and 46% of the variance in SRTdiff outcome. The results suggest that poor verbal working-memory capacity and to a lesser extent poor lexical-access ability limit speech-recognition ability in listeners with a CI.
The primary objective of the study was to investigate the feasibility, reliability, and validity of the Dutch digits in noise (DIN) test for measuring speech recognition in hearing aid and cochlear implant users and compare results to the standard sentences-in-noise (SIN) test.The relation between speech reception thresholds for DIN test and SIN test was analysed to determine the validity of the DIN test. As linguistic skills were expected to make different contributions in these tests, their influence was analysed.Participants were 12 normal-hearing listeners, 24 hearing aid users, and 24 cochlear implant users.The DIN test was feasible for more participants than the SIN test. Intraclass correlation coefficients showed high reliability. The standard error of measurement was smaller for the DIN test than for the SIN test. DIN test and SIN test were highly correlated (r = 0.95 and r = 0.56 for NH+ HA and CI users respectively). In the regression analysis no significant contribution of basic linguistic skills or personal factors was found.In the assessment of speech recognition in noise of aided hearing-impaired listeners with hearing aids or cochlear implants, the DIN test is a feasible, reliable and valid test.
The aim of the present study was to investigate whether prediction models built by de Graaff et al. (2020 ) can be used to improve speech recognition in experienced adult postlingual implanted Cochlear CI users. de Graaff et al. (2020 ) found relationships between elevated aided thresholds and a not optimal electrical dynamic range (<50 CL or >60 CL), and poorer speech recognition in quiet and in noise. The primary hypothesis of the present study was that speech recognition improves both in quiet and in noise when the sound processor is refitted to match targets derived from the prediction models from de Graaff et al. (2020 ). A second hypothesis was that subjectively, most of the CI users would find the new setting too loud because of an increase in C levels, and therefore, prefer the old settings.
The main objective was to investigate the effect of linguistic abilities (lexical-access ability and vocabulary size) on different measures of speech-in-noise recognition in normal-hearing listeners with various levels of language proficiency.Speech reception thresholds (SRTs) were measured for sentences in steady-state (SRTstat) and fluctuating noise (SRTfluc), and for digit-triplets in steady-state noise (DIN). Lexical-access ability was measured with a lexical-decision test and a word-naming test. Vocabulary size was also measured. For the SRT, keyword scoring and sentence scoring were compared.To introduce variation in linguistic abilities, three groups of 24 young normal-hearing listeners were included: higher-educated native, lower-educated native, and higher-educated non-native listeners.Lexical-access ability was most accurately measured with combined results of lexical decision and word naming. Lexical-access ability explained 60% of the variance in SRT. The effect of linguistic abilities on SRTs was up to 5.6 dB for SRTstat and 8 dB for SRTfluc. Using keyword scoring reduced this effect by approximately 1.5 dB. For DIN the effect of linguistic ability was less than 1 dB.Lexical-access ability is an important predictor of SRTs in normal-hearing listeners. These results are important to consider in the interpretation of speech-in-noise scores of hearing-impaired listeners.
Objectives: The objective of this study was to identify parameters which are related to speech recognition in quiet and in noise of cochlear implant (CI) users. These parameters may be important to improve current fitting practices. Design: Adult CI users who visited the Amsterdam UMC, location VUmc, for their annual follow-up between January 2015 and December 2017 were retrospectively identified. After applying inclusion criteria, the final study population consisted of 138 postlingually deaf adult Cochlear CI users. Prediction models were built with speech recognition in quiet and in noise as the outcome measures, and aided sound field thresholds, and parameters related to fitting (i.e., T and C levels, dynamic range [DR]), evoked compound action potential thresholds and impedances as the independent variables. A total of 33 parameters were considered. Separate analyses were performed for postlingually deafened CI users with late onset (LO) and CI users with early onset (EO) of severe hearing impairment. Results: Speech recognition in quiet was not significantly different between the LO and EO groups. Speech recognition in noise was better for the LO group compared with the EO group. For CI users in the LO group, mean aided thresholds, mean electrical DR, and measures to express the impedance profile across the electrode array were identified as predictors of speech recognition in quiet and in noise. For CI users in the EO group, the mean T level appeared to be a significant predictor in the models for speech recognition in quiet and in noise, such that CI users with elevated T levels had worse speech recognition in quiet and in noise. Conclusions: Significant parameters related to speech recognition in quiet and in noise were identified: aided thresholds, electrical DR, T levels, and impedance profiles. The results of this study are consistent with previous study findings and may guide audiologists in their fitting practices to improve the performance of CI users. The best performance was found for CI users with aided thresholds around the target level of 25 dB HL, and an electrical DR between 40 and 60 CL. However, adjustments of T and/or C levels to obtain aided thresholds around the target level and the preferred DR may not always be acceptable for individual CI users. Finally, clinicians should pay attention to profiles of impedances other than a flat profile with mild variations.
To assess the impact of cochlear implantation (CI) and speech perception outcomes on the quality of life (QoL) of adult CI users and their communication partners (CP) one-year post-implantation. This research is part of a prospective multicenter study in The Netherlands, called SMILE (Societal Merit of Intervention for hearing Loss Evaluation). Eighty adult CI users completed speech perception testing and the Nijmegen Cochear Implant Questionnaire (NCIQ). Fifty-four CPs completed the Hearing Impairment Impact - Significant Other Profile (HII-SOP). CI resulted in a large improvement in the QoL of both users and CPs. Despite this, some users still reported difficulties in the NCIQ sub-domains Social Interactions, Activity Limitations and Self-esteem. Similarly, some CPs still reported moderate and severe third-party disability on the HII-SOP. Additionally, the correlation between speech perception results and self-reported QoL was weak to negligible for both groups. Speech perception in quiet is not an accurate measure of real-life success with a CI. A subset of CI users and CPs still experience substantial QoL challenges regardless of speech perception performance. To improve counselling and intervention, QoL measures should be a standard part of the CI care pathway for CI users and their CPs.
