Cross-Modal and Intra-Modal Characteristics of Visual Function and Speech Perception Performance in Postlingually Deafened, Cochlear Implant Users.

Evidence of visual-auditory cross-modal plasticity in deaf individuals has been widely reported. Superior visual abilities of deaf individuals have been shown to result in enhanced reactivity to visual events and/or enhanced peripheral spatial attention. The goal of this study was to investigate the association between visual-auditory cross-modal plasticity and speech perception in post-lingually deafened, adult cochlear implant (CI) users. Post-lingually deafened adults with CIs (N = 14) and a group of normal hearing, adult controls (N = 12) participated in this study. The CI participants were divided into a good performer group (good CI, N = 7) and a poor performer group (poor CI, N = 7) based on word recognition scores. Visual evoked potentials (VEP) were recorded from the temporal and occipital cortex to assess reactivity. Visual field (VF) testing was used to assess spatial attention and Goldmann perimetry measures were analyzed to identify differences across groups in the VF. The association of the amplitude of the P1 VEP response over the right temporal or occipital cortex among three groups (control, good CI, poor CI) was analyzed. In addition, the association between VF by different stimuli and word perception score was evaluated. The P1 VEP amplitude recorded from the right temporal cortex was larger in the group of poorly performing CI users than the group of good performers. The P1 amplitude recorded from electrodes near the occipital cortex was smaller for the poor performing group. P1 VEP amplitude in right temporal lobe was negatively correlated with speech perception outcomes for the CI participants (r = -0.736, P = 0.003). However, P1 VEP amplitude measures recorded from near the occipital cortex had a positive correlation with speech perception outcome in the CI participants (r = 0.775, P = 0.001). In VF analysis, CI users showed narrowed central VF (VF to low intensity stimuli). However, their far peripheral VF (VF to high intensity stimuli) was not different from the controls. In addition, the extent of their central VF was positively correlated with speech perception outcome (r = 0.669, P = 0.009). Persistent visual activation in right temporal cortex even after CI causes negative effect on outcome in post-lingual deaf adults. We interpret these results to suggest that insufficient intra-modal (visual) compensation by the occipital cortex may cause negative effects on outcome. Based on our results, it appears that a narrowed central VF could help identify CI users with poor outcomes with their device.

Benefit From Directional Microphone Hearing Aids: Objective and Subjective Evaluations.

OBJECTIVES: The aims of this study were to find and compare the effect of directional (DIR) processing of two different hearing aids via both subjective and objective methods, to determine the association between the results of the subjective and objective evaluations, and to find out individual predictive factors influencing the DIR benefit. METHODS: Twenty-six hearing aid users fitted unilaterally with each two different experimental hearing aid performed modified Korean Hearing in Noise Test (K-HINT) in three DIR conditions; omnidirectional (OMNI) mode, OMNI plus noise reduction feature, fixed DIR mode. In order to determine benefits from DIR benefit within a hearing aid and compare performance of the DIR processing between hearing aids, a subjective questionnaire was administrated on speech quality (SQ) and discomfort in noise (DN) domain. Correlation analysis of factors influencing DIR benefit was accomplished. RESULTS: Benefits from switching OMNI mode to DIR mode within both hearing aids in K-HINT were about 2.8 (standard deviation, 3.5) and 2.1 dB SNR (signal to ratio; SD, 2.5), but significant difference in K-HINT results between OMNI and OMNI plus noise reduction algorithm was not shown. The subjective evaluation resulted in the better SQ and DN scores in DIR mode than those in OMNI mode. However, the difference of scores on both SQ and DN between the two hearing aids with DIR mode was not statistically significant. Any individual factors did not significantly affect subjective and objective DIR benefits. CONCLUSION: DIR benefit was found not only in the objective measurement performed in the laboratory but also in the subjective questionnaires, but the subjective results was failed to have significant correlation with the DIR benefit obtained in the K-HINT. Factors influencing individual variation in perceptual DIR benefit were still hard to explain.

Objective and Subjective Improvement of Hearing in Noise After Surgical Correction of Unilateral Congenital Aural Atresia in Pediatric Patients: A Prospective Study Using the Hearing in Noise Test, the Sound-Spatial-Quality Questionnaire, and the Glasgow Benefit Inventory.

OBJECTIVES: The aim of this study was to assess the objective and subjective long-term binaural benefits of surgical correction in children with unilateral congenital aural atresia, using an open-set sentence test in noise and subjective questionnaires. DESIGN: A prospective study was performed between August 2010 and February 2013. This study included pediatric patients who had unilateral conductive hearing loss (normal bone conduction hearing) on the atretic side but normal air conduction hearing on the normal side and were scheduled to undergo a primary canaloplasty. Pure-tone audiometry, the hearing in noise test (HINT), and questionnaires (Sound-Spatial-Qualities of Hearing Scale; Glasgow Benefit Inventory [GBI]) were administered preoperatively and at 6 and 12 months postoperatively. RESULTS: Among 34 consecutive patients who initially met enrollment criteria, 26 subjects (23 boys and 3 girls) aged 10 to 16 years (mean 12.3 years) completed this study. Canaloplasty and hearing restoration procedures were performed uneventfully in all patients. The mean air conduction thresholds were significantly improved from 63.9 to 35.0 dB (6 months) and 39.4 dB (12 months) after surgery (p < 0.001). In HINT, speech understanding in noise that was presented toward the newly opened atretic ear significantly improved at 1 year postoperatively (p = 0.014). In noise toward the normal ear, speech understanding significantly improved after surgery, from -0.1 dB preoperatively to -2.0 dB at 6 months (p = 0.002) and -1.8 dB at 12 months (p = 0.005) (p for quadratic trend = 0.036). The composite score improved from -2.6 dB preoperatively to -3.4 dB at 6 months and -3.6 dB at 12 months (p = 0.045; p for linear trend = 0.005). The Sound-Spatial-Qualities of Hearing Scale scores in all domains significantly improved 1 year after surgery (p < 0.034). The mean GBI scores in each domain ranged from 14.2 to 49.4. Total GBI score was correlated with better signal to noise ratio in noise toward the atretic ear as measured by HINT at postoperative 1 year (Spearman ρ = 0.482, p = 0.013). CONCLUSIONS: Teenaged patients with unilateral congenital aural atresia showed satisfactory hearing improvement after canaloplasty with hearing restoration surgery. In a serial long-term follow-up, speech understanding in noise measured by HINT improved over time. One year after surgery, teenaged children acquired binaural hearing (binaural squelch), as measured by the HINT with noise presented to the newly opened atretic ear. Subjective questionnaires also showed improvements in binaural hearing function and quality of life.

Clinical effectiveness of wireless CROS (contralateral routing of offside signals) hearing aids.

This study evaluated the clinical effectiveness of wireless contralateral routing of offside signals hearing aids (CROS) in patients with severe to profound unilateral sensorineural hearing loss (USNHL). Twenty-one patients with USNHL were enrolled in this prospective study. The change of subjective satisfaction was evaluated using three questionnaires (K-HHIE, K-IOI-HA, K-SSQ). Changes in objective measurements were evaluated with sound localization test (SLT) and hearing in noise test (HINT). These tests were performed at pre-CROS fitting, 2 and 4 weeks after use of CROS. Subjects were grouped according to the age: young (<40 years) vs. old (≥40 years) group. The average K-HHIE and K-SSQ scores significantly improved with the use of CROS. SLT result revealed that hit rate and error degree improved in the young group and lateralization ability improved in both groups. In quiet environments, the reception threshold for speech also indicated a significant benefit in the young group. When the noise was presented to the normal ear, HINT revealed benefit of CROS, while loss of performance with CROS use was significant when noise was presented to the impaired ear. Wireless CROS provided increased satisfaction and overall improvement of localization and hearing. Although true binaural hearing cannot be obtained, CROS is a practical option for rehabilitation of USNHL.

Sound localization performance improves after canaloplasty in unilateral congenital aural atresia patients.

OBJECTIVE: To investigate the changes in sound localization ability in the horizontal plane after canaloplasty in unilateral congenital aural atresia (CAA) patients. STUDY DESIGN: Prospective interventional study. SETTING: Tertiary referral center. PATIENTS: Twenty-eight patients with unilateral CAA were enrolled. All patients had unilateral conductive hearing loss. INTERVENTIONS: Canaloplasty. MAIN OUTCOME MEASURES: Pure tone audiometry, sound localization test, and the Speech, Spatial, and Quality questionnaire (SSQ) were administered preoperatively, 6 and 12 months postoperatively. For the sound localization test, 8 loudspeakers were positioned in a circle at 45-degree intervals, and patients were instructed to identify the speaker from which sound was coming. Mean correct response rate and mean error degree were calculated for each patient. The correct lateralization rate to the ipsilesional/contralesional stimuli was also calculated. RESULTS: Mean hearing threshold decreased from preoperatively 63.8 to 39.4 dB 12 months after canaloplasty. Mean correct response rate and error degree at preoperative evaluation were 26.0% and 60.7 degrees, respectively, and these were respectively improved to 58.5% and 27.8 degrees postoperatively. Respective mean correct lateralization rate to ipsilesional stimuli after canaloplasty improved from 20.6% to 84.0%, and that to contralesional stimuli slightly improved from 93.8% to 98.8%. Patients with good postoperative hearing (<40 dBHL) showed better sound localization results. In addition, self-assessment scores of spatial domain in the SSQ questionnaire were significantly improved after the operation. CONCLUSION: Sound localization performance improved significantly after canaloplasty. Canaloplasty could provide better localization benefit and subjective improvement in spatial sensation to unilateral CAA patients.