High coupling efficiency to a low dispersion slow light-supporting photonic crystal waveguide

In this paper, we design a waveguide on photonic crystal slab for propagation of low-dispersion slow light. By shifting the air holes adjacent to the waveguide, we obtain a photonic crystal waveguide with a group index of 25 in 25 nm bandwidth which results in a group index bandwidth product of 0.366. To take the advantages of low dispersion slow light generated in this engineered waveguide, we next focus on low coupling efficiency limitation. A low group index coupler is proposed to increase the transmission of the light to the slow mode in the low dispersion bandwidth. By using the proposed coupler and adjusting the structural parameters, the coupling efficiency to low dispersion slow light is improved 11 dB compared to the transmission without the coupler

Impact of Acamprosate on Chronic Tinnitus: A Randomized-Controlled Trial

Objectives: Tinnitus is a common and distressing otologic symptom, with various probable pathophysiologic mechanisms, such as an imbalance between excitatory and inhibitory mechanisms. Acamprosate, generally used to treat alcoholism, is a glutaminergic antagonist and GABA agonist suggested for treating tinnitus. Thus, we aimed to evaluate the efficacy and safety of acamprosate in the treatment of tinnitus. Methods: The current randomized-controlled trial study included 20 subjects with chronic tinnitus. After performing psycho-acoustic, psychometric and electrophysiological evaluations, all studied tinnitus subjects were randomly divided into two groups of acamprosate and placebo. The first group received oral acamprosate (two tablets of 333 mg/d, three times a day), whereas the second group was given placebo treatment (two tablets, three times a day). After the first 30 days, all evaluations were repeated for the studied groups just in the same manner before the study. Subsequently, the final results of each evaluation were compared together with the baseline values. Results: Nine studied subjects randomly received acamprosate, whereas eleven others received a placebo. There was no significant improvement in the psycho-acoustic tests, except a decrease was observed in the pitch match of tinnitus (P =.039). For those subjects who were receiving acamprosate, a significant reduction was observed in tinnitus handicap inventory (P =.006), tinnitus questionnaire scores (P =.007), and the visual analog scores (P =.007) compared to the placebo group. There was a significant reduction in Action Potential latency (P =.048) as well as an increase in the amplitude of distortion product otoacoustic emissions at 4 kHz (P =.048). Conclusions: The study results indicated a subjective relief of tinnitus as well as some degree of the electrophysiological improvement at the level of the cochlear and the distal portion of the auditory nerve among the subjects who received the acamprosate. Clinical trial registration code: IRCT2013121115751N1. © The Author(s) 2020

Cochlear implantation in children with auditory neuropathy spectrum disorder: A multicenter study on auditory performance and speech production outcomes

Objectives: To evaluate the auditory performance and speech production outcome in children with auditory neuropathy spectrum disorder (ANSD). The effect of age on the outcomes of the surgery at the time of implantation was also evaluated. Methods: Cochlear implantation was performed in 136 children with bilateral severe-to- profound hearing loss due to ANSD, at four tertiary academic centers. The patients were divided into two groups based on the age at the time of implantation; Group I: Children �24 months, and Group II: subjects >24 months. The categories of auditory performance (CAP) and speech intelligibility rating (SIR) scores were evaluated after the first and second years of implantation. The differences between the CAP and SIR scores in the two groups were assessed. Results: The median CAP scores improved significantly after the cochlear implantation in all the patients (p value < 0.001). The improvement in the CAP scores during the first year in Group II was greater than Group I (p value: 0.007), but the improvement in CAP scores tended to be significantly higher in patients who were implanted at �24 months (p value < 0.001). There was no significant difference between two groups in SIR scores at first-year and second-year follow-ups. The evaluation of the SIR improvement revealed significantly higher values for Group I during the second-year follow-up (p value: 0.003). Conclusion: The auditory performance and speech production skills of the children with ANSD improved significantly after cochlear implantation, and this improvement was affected by age at the time of implantation. © 2018 Elsevier B.V

Cochlear implantation in children with inner ear malformation: A multicenter study on auditory performance and speech production outcomes

Objectives: This multicenter study evaluated the auditory performance and speech production outcomes of cochlear implantation in children with inner ear anomaly and compared the outcomes of patients with different kinds of malformation. Methods: Cochlear implantation was performed in 107 children with inner ear malformation at four tertiary academic centers. The categories of auditory performance (CAP) and speech intelligibility rating (SIR) scores were evaluated preoperatively and one year and two years postoperatively. Results: Types of inner ear malformation and their frequencies were: incomplete partition type-I, 19 (17.8) patients; incomplete partition type-II, 31 (29), common cavity, 17 (15.9), cochlear hypoplasia, 17 (15.9), and isolated enlarged vestibular aqueduct (isolated EVA), 23 (21.5) patients. EVA was the coexisting anomaly in 27(25.2) subjects. The median CAP and SIR scores improved significantly during the first two years after cochlear implantation in all groups (p-values <0.001 and < 0.001, respectively). No significant difference was seen in CAP and SIR scores of children with different inner ear malformations (p-value = 0.147 and 0.570, respectively) or in patients with isolated EVA compared to coexisting EVA (p-value = 0.538 and 0.075, respectively). Conclusion: The median CAP and SIR scores two years after surgery were 5 (Understanding of common phrases without lip-reading) IQR: 4�6, and 3 (Connected speech is intelligible to a listener who concentrates and lip-reads within a known context) IQR: 3�4, respectively. Auditory performance and speech production were significantly improved in all inner ear malformation patient groups, and no significant difference was observed between the scores of patients with different types of anomaly. © 2020 Elsevier B.V

Cochlear implantation in children with auditory neuropathy spectrum disorder: A multicenter study on auditory performance and speech production outcomes

Objectives: To evaluate the auditory performance and speech production outcome in children with auditory neuropathy spectrum disorder (ANSD). The effect of age on the outcomes of the surgery at the time of implantation was also evaluated. Methods: Cochlear implantation was performed in 136 children with bilateral severe-to- profound hearing loss due to ANSD, at four tertiary academic centers. The patients were divided into two groups based on the age at the time of implantation; Group I: Children �24 months, and Group II: subjects >24 months. The categories of auditory performance (CAP) and speech intelligibility rating (SIR) scores were evaluated after the first and second years of implantation. The differences between the CAP and SIR scores in the two groups were assessed. Results: The median CAP scores improved significantly after the cochlear implantation in all the patients (p value < 0.001). The improvement in the CAP scores during the first year in Group II was greater than Group I (p value: 0.007), but the improvement in CAP scores tended to be significantly higher in patients who were implanted at �24 months (p value < 0.001). There was no significant difference between two groups in SIR scores at first-year and second-year follow-ups. The evaluation of the SIR improvement revealed significantly higher values for Group I during the second-year follow-up (p value: 0.003). Conclusion: The auditory performance and speech production skills of the children with ANSD improved significantly after cochlear implantation, and this improvement was affected by age at the time of implantation. © 2018 Elsevier B.V