Acoustic Analysis of Speech of Cochlear Implantees and Its Implications

ObjectivesCochlear implantees have improved speech production skills compared with those using hearing aids, as reflected in their acoustic measures. When compared to normal hearing controls, implanted children had fronted vowel space and their /s/ and /∫/ noise frequencies overlapped. Acoustic analysis of speech provides an objective index of perceived differences in speech production which can be precursory in planning therapy. The objective of this study was to compare acoustic characteristics of speech in cochlear implantees with those of normal hearing age matched peers to understand implications.MethodsGroup 1 consisted of 15 children with prelingual bilateral severe-profound hearing loss (age, 5-11 years; implanted between 4-10 years). Prior to an implant behind the ear, hearing aids were used; prior & post implantation subjects received at least 1 year of aural intervention. Group 2 consisted of 15 normal hearing age matched peers. Sustained productions of vowels and words with selected consonants were recorded. Using Praat software for acoustic analysis, digitized speech tokens were measured for F1, F2, and F3 of vowels; centre frequency (Hz) and energy concentration (dB) in burst; voice onset time (VOT in ms) for stops; centre frequency (Hz) of noise in /s/; rise time (ms) for affricates. A t-test was used to find significant differences between groups.ResultsSignificant differences were found in VOT for /b/, F1 and F2 of /e/, and F3 of /u/. No significant differences were found for centre frequency of burst, energy concentration for stops, centre frequency of noise in /s/, or rise time for affricates. These findings suggest that auditory feedback provided by cochlear implants enable subjects to monitor production of speech sounds.ConclusionAcoustic analysis of speech is an essential method for discerning characteristics which have or have not been improved by cochlear implantation and thus for planning intervention

Constricting and Validating Hindi Monosyllabic Speech Perception Test Material for Hearing Impaired Children

The current study aimed to compare speech perception score of children with Hearing impairment using CI and HA. The Hindi speech perception test was designed for children aged between two to six years-old. A total of 226 normal hearing children consisting four groups from 2 years to 6 years participated as normative sample. Test items were selected on the basis of familiarity & frequent consonants occurred in daily uses. Test consists of each set of 40 pictorial stimuli which scored 2 for auditory response, 1 for auditory and visual cues, zero for no response even after auditory and visual stimulation. Similarly in experimental groups, 30 subjects with HI using HA were recruited with mean age 8.083 years consisting of 13 female and 17 male. Other group comprises of 30 subjects with HI using CI with mean age 8.231 years and consisting of 14 female & 16 male. Both the group had exposure to aural –oral therapy for at least 3 years. After‘t’ tail test analysis it was seen that both the group had statistically significant difference in speech perception score. Subjects with CI showed significant higher score in speech perception ability. This research article further discussed the HA technical short coming over C

Long Latency Responses in Children with Learning Disorder

The purpose of the study was to investigate long latency response from the children with LD and compare the findings with controlled subjects (i.e. age-gender matched). LLR responses were recorded from 30 subjects with LD (experimental group) and 30 control groups, age range from 10 -14 year with means age of 11.2 years. The LLR responses were recorded by using the click stimulus. P1, N1, P2, N2 latency and amplitude were used for analysis. Result of the study indicates that both the group had statistically significant difference in latency. P1 and N1 amplitude were found to be significantly different between the two test groups. The present study findings suggest that click evoked auditory late latency response is easily traceable in all children with LD and typically developing children. However, prolonged latency responses in the present study suggest that the auditory stimulus processing at auditory cortex level is different in LD children compared to typical children. This functioning difference in the auditory cortical area results in altered auditory cortical recording. The present study has discussed how LLR test can be effective test tool to use clinically that differentiates between individuals with and without LD

A novel locus DFNA59 for autosomal dominant nonsyndromic hearing loss maps at chromosome 11p14.2-q12.3

Autosomal dominant nonsyndromic hearing loss (ADNSHL) accounts for about one-fifth of hereditary hearing loss in humans. In the present study, we have analyzed a three-generation family with 14 of its members manifesting ADNSHL, using a genome-wide linkage mapping approach. We found a novel locus DFNA59 between the D11S929 and D11S480 markers in the chromosome location 11p14.2-q12.3. The highest two-point lod score of 5.72 at recombination fraction = 0 was obtained for D11S4152, D11S4154, D11S1301, D11S905 and D11S1344. The critical genomic region comprising about 37 megabases of DNA is proposed to carry a gene for ADNSHL in the family. About 50 cochlear-expressed genes mapping to the region are strong candidates which we propose to examine to identify the gene responsible for the hearing impairment

Implications in disclosing auditory genetic mutation to a family: a case study

The aim of the study is to understand the implications of disclosing the results of connexin26 (Cx26) gene testing to the concerned family with hearing impaired individuals. The department of biotechnology is funding a multicentric multidisciplinary team from Jawaharlal Nehru Center for Advanced Scientific Research (Bangalore), AYJNIHH (Mumbai), PGIBMS (Chennai), and MAMC (New Delhi) to profile mutations of deafness genes in India. Under this program, blood samples were taken from various centers and were sent to JNCASR for genetic analysis (screening for Cx26 mutations). This case study is an attempt to bring out issues encountered when disclosing the implications of genetic diagnosis to the concerned family

Contribution of connexin26 (GJB2) mutations and founder effect to non-syndromic hearing loss in India

This article does not have an abstract

Functional consequences of novel connexin 26 mutations associated with hereditary hearing loss

In a study of 530 individuals with non-syndromic, sensorineural hearing loss, we identified 18 mutations at connexin 26 (Cx26), four of which are novel (-23G>T, I33T, 377_383dupTCCGCAT, W172R) and the remaining 14 (ivs1+1G>A, M1V, 35delG, W24X, I35S, V37I, R75W, W77X, 312del14, E120del, Q124X, Y136X, R143W, R184P) being mutations previously described. To gain insight into functional consequences of these mutations, cellular localization of the mutant proteins and their ability to permit lucifer yellow transfer between cells was studied in seven of them (W24X, I33T, I35S, R75W, E120del, W172R and R184P). I35S and R184P showed impaired trafficking of the protein to the plasma membrane. I33T, R75W, E120del and W172R showed predominantly membrane localization but did not form functional gap junction channels. Surprisingly, W24X, a protein-truncating mutation, apparently permits formation of a full-length protein, perhaps due to a stop codon read-through mechanism. These results provide further evidence that Cx26 mutations affect gap junction activity by mis-regulation at multiple levels