Cochlear Implant Results in Older Adults with Post-Lingual Deafness: The Role of "Top-Down" Neurocognitive Mechanisms.

To date, no clear specific cognitive predictors of speech perception outcome in older adult cochlear implant (CI) users have yet emerged. The aim of this prospective study was to increase knowledge on cognitive and clinical predictors of the audiological outcome in adult cochlear implant users. A total of 21 patients with post-lingual deafness, who were candidates for cochlear implantation, were recruited at the Department of Ear, Nose and Throat, University of Torino (Italy) and subjected to a pre-operatory neuropsychological assessment (T0) and an audiological examination after 12 months of implantation (T12). Patients who, at T12, had a 60 dB verbal recognition above 80%, were younger (z = -2.131, p = 0.033) and performed better in the Verbal Semantic Fluency Test at T0 (z = -1.941, p = 0.052) than subjects who had a 60 dB verbal recognition at T12 below 80%. The most significant predictors of the CI audiological outcome at T12 were age (ß = -0.492, p = 0.024) and patients' TMT-A performance at baseline (ß = -0.486, p = 0.035). We conclude that cognitive processing speed might be a good predictor of the level of speech understanding in older adult patients with CI after one year of implantation.

Evaluation of Italian Simplified Matrix Test for Speech-Recognition Measurements in Noise.

This study aimed at the evaluation of a simplified Italian matrix test (SiIMax) for speech-recognition measurements in noise for adults and children. Speech-recognition measurements with adults and children were conducted to examine the training effect and to establish reference speech-recognition thresholds of 50% (SRT50) and 80% (SRT80) correct responses. Test-list equivalency was evaluated only with adults. Twenty adults and 96 children-aged between 5 and 10 years-participated. Evaluation measurements with the adults confirmed the equivalence of the test lists, with a mean SRT50 of -8.0 dB and a standard deviation of 0.2 dB across the test lists. The test-specific slope (the average of the list-specific slopes) was 11.3%/dB, with a standard deviation of 0.6%/dB. For both adults and children, only one test list of 14 phrases needs to be presented to account for the training effect. For the adults, adaptive measurements of the SRT50 and SRT80 showed mean values of -7.0 ± 0.6 and -4.5 ± 1.1 dB, respectively. For children, a slight influence of age on the SRT was observed. The mean SRT50s were -5.6 ± 1.2, -5.8 ± 1.2 and -6.6 ± 1.3 dB for the children aged 5-6, 7-8 and 9-10 years, respectively. The corresponding SRT80s were -1.5 ± 2.7, -3.0 ± 1.7 and -3.7 ± 1.4 dB. High test-retest reliabilities of 1.0 and 1.1 dB for the SRT80 were obtained for the adults and children, respectively. This makes the test suitable for accurate and reliable speech-recognition measurements.

Monaural or binaural sound deprivation in postlingual hearing loss: Cochlear implant in the worse ear.

OBJECTIVES/HYPOTHESIS: To determine whether speech recognition scores (SRS) differ between adults with long-term auditory deprivation in the implanted ear and adults who received cochlear implant (CI) in the nonsound-deprived ear, either for hearing aid-assisted or due to rapidly deteriorating hearing loss. STUDY DESIGN: Retrospective study. METHODS: Speech recognition scores at evaluations (3 and 14 months postimplantation) conducted with CI alone at 60-dB sound pressure level intensity were compared in 15 patients (4 with bilateral severe hearing loss; 11 with asymmetric hearing loss, 7 of which had contralateral hearing aid), all with long-term auditory deprivation (mean duration 16.9 years) (group A), and in 15 other patients with postlingual hearing loss (10 symmetric, 5 asymmetric with bimodal stimulation) (controls, group B). RESULTS: Comparison of mean percentage of correctly recognized words on speech audiometry at 3 and 14 months showed improvement within each group (P < 0.05). Between-group comparison showed no significant difference at 3 (P = 0.17) or 14 months (P = 0.46). Comparison of SRSs in group A (bimodal stimulation [n = 7] and binaural sound deprivation [n = 4]) versus group B showed no significant differences at 3 (bimodal stimulation P = 0.16; binaural sound deprivation P = 0.19) or 14 months (bimodal stimulation P = 0.14; binaural sound deprivation P = 0.82). CONCLUSIONS: Speech recognition scores in monaural and binaural sound-deprived ears did not significantly differ from ears with unilateral cochlear implantation in nonsound-deprived ears when tested with CI alone. Improvement in the implanted worse ear indicates that it could be a potential candidate ear for cochlear implantation even when sound deprived. LEVEL OF EVIDENCE: 4. Laryngoscope, 126:1905-1910, 2016.

Cochlear Nerve Stimulation in the Internal Auditory Canal in Ossified Cochlea: A Case Study.

OBJECTIVE: To present the first reported case of intraneural direct cochlear nerve stimulation in a human being. STUDY DESIGN: This is a case report. RESULTS: A 23-year-old patient with bilateral progressive hearing loss associated with bilateral complete semicircular canal aplasia and ossified cochleas underwent cochlear implantation. During surgery, a patent cochlear lumen could not be found, and the array was positioned in the internal auditory canal adjacent to the cochlear nerve. Against our expectations, an assiduous rehabilitation and frequent fitting adjustments have led to a word recognition score, in open set speech with lip reading, of 18/25 and acceptable frequency discrimination. CONCLUSIONS: We are aware that this was an anomalous use of the cochlear implant, and it is not our aim to suggest a new indication for cochlear array positioning. However, this case shows that auditory perception, to some degree, can be obtained with intraneural direct cochlear nerve stimulation.

The role of the efferent auditory system in developmental dyslexia.

OBJECTIVE: To assess the role of the efferent auditory system by inhibition of contralateral otoacoustic emission in dyslexic children with auditory processing disorders. METHODS: The study sample was 34 children: 17 with dyslexia and 17 age-matched controls. Sensitive speech tests (low-pass filtered, time-compressed, distorted and dichotic) were performed to assess coexisting auditory processing disorder. Distortion-product otoacoustic emission (DPOAE) values were measured in basal condition and with contralateral broadband noise signal delivered via an earphone transducer at 60 dB SPL. RESULTS: The lower scores at sensitive speech testing confirmed the association of an auditory processing disorder in the dyslexic children. DPOAE values were significantly attenuated by contralateral inhibition only in the control group (p=0.001; dyslexics, p=0.19); attenuation was not significant at any frequency in the dyslexic group. CONCLUSIONS: The differences in DPOAE attenuation between the groups, although not statistically significant, suggest alterations in the auditory efferent system in the dyslexic population. These alterations may affect language perception. If confirmed in further studies with larger samples, these results could provide insight into a possible pathophysiological background of dyslexia.