Normal Hearing Age Research Articles

Perception of alternated speech operates similarly in young and older adults with age-normal hearing.

When speech is rapidly alternated between the two ears, intelligibility declines as the rate of alternation approaches 3 to 5 switching cycles per second, and then, paradoxically, returns to a good level beyond that point. We tested intelligibility when shadowing was used as a response measure (Experiment 1), when recall was used as a response measure (Experiment 2), and when time-compression was used to vary the speech rate of the presented materials (Experiment 3). In spite of claims that older adults are generally slower in switching attention, younger and older adults did not differ in the critical alternation rates producing minimal intelligibility. We suggest that the point of minimal intelligibility in alternated speech reflects an interaction between (1) the rate of disruption induced by breaking the speech stream between two sound sources, (2) the amount of contextual information per ear, and (3) the size of the silent gaps separating the speech elements that must be perceptually bridged.

Increased Frequencies of Cochlin-Specific T Cells in Patients with Autoimmune Sensorineural Hearing Loss

Autoimmune sensorineural hearing loss (ASNHL) is the most common cause of sudden hearing loss in adults. Although autoimmune etiopathogenic events have long been suspected in ASNHL, inner ear-specific Ags capable of targeting T cell autoreactivity have not been identified in ASNHL. In this study, we show by ELISPOT analysis that compared with normal hearing age- and sex-matched control subjects, ASNHL patients have significantly higher frequencies of circulating T cells producing either IFN-gamma (p = 0.0001) or IL-5 (p = 0.03) in response to recombinant human cochlin, the most abundant inner ear protein. In some patients, cochlin responsiveness involved both CD4+ and CD8+ T cells whereas other patients showed cochlin responsiveness confined to CD8+ T cells. ASNHL patients also showed significantly elevated cochlin-specific serum Ab titers compared with both normal hearing age- and sex-matched control subjects and patients with noise- and/or age-related hearing loss (p < 0.05 at all dilutions tested through 1/2048). Our study is the first to show T cell responsiveness to an inner ear-specific protein in ASNHL patients, and implicates cochlin as a prominent target Ag for mediating autoimmune inner ear inflammation and hearing loss.

Personal and Social Conditions Potentially Influencing Women’s Hearing Loss Management

Little gender-specific data related to hearing loss and hearing loss management are available. The purpose of this investigation was to examine personal and social conditions affecting women at selected stages of the adult life course that may influence hearing loss management. In all, 191 women in three age groups, ranging from 35 to 85 years old, participated. None reported hearing problems. Participants completed a demographic data form and were given a standard audiometric evaluation to confirm age-normal hearing. Each completed assessments of speech understanding in quiet and noise, auditory signal duration discrimination, and binaural processing. Measures of hearing knowledge, behaviors, and attitudes; health-related locus of control; ego strength; and, social support were administered. Results revealed that although some variables deteriorate among subsequent age groups (i.e., hearing thresholds, central auditory processing, and ego strength), the reverse is true for others (i.e., social interaction and satisfaction with income). Age-specific sociodemographic burdens that may interfere with hearing loss management were noted. New psychosocial data are revealed against which women and men with impaired hearing may be compared.

Analysis of narrative ability in children with cochlear implants.

The purposes of this study were to: 1) develop a scoring system to assess narrative ability in children; 2) evaluate the impact of auditory speech perception with a cochlear implant on narrative ability; and 3) evaluate the importance of narrative ability to reading comprehension in deaf children. Narrative productions prompted from an eight-picture sequence story were elicited from 8 and 9 yr olds; 87 who had at least 4 yr of cochlear implant experience and 28 who had normal hearing. The stories were transcribed and a scoring system for narrative ability was developed based on the use of complete narrative structure, conjunctions linking semantic relations, and referents that served to identify and distinguish characters in the narrative. Narrative ability scores of cochlear implant users were examined in relation to their age, IQ, speech perception, language, and reading test scores. In addition, narrative ability scores for children with normal hearing were compared with two groups of cochlear implant users, those with above average speech perception scores and those with below average speech perception scores. Within the sample of hearing-impaired children, narrative ability scores correlated significantly with speech perception, language syntax, and reading test scores. A multiple regression analysis was conducted to predict reading comprehension scores from four predictor variables (age, IQ, language syntax, and narrative ability). Results reflected the independent contribution of discourse-level language skills, as measured by the narrative ability score, as well as sentence-level language skills in predicting reading test scores. Analysis of stories obtained from 8- and 9-yr-old children with normal hearing revealed the classic pattern that included a high point, a resolution, and one or more evaluative statements. Their stories achieved cohesion from correct use of both conjunctions and referents. Deaf children who received above-average speech perception scores with a cochlear implant (i.e., scored above 48% on the Word Intelligibility by Picture Identification speech perception test) told narratives that were similar in structure and use of referents to those of age mates with normal hearing. Although their use of subordinate conjunctions was not as well developed as normal-hearing children, it was significantly above that of deaf children who received less speech perception benefit after a similar period of implant use. These below-average speech perceivers exhibited significantly poorer use of narrative structure and cohesive devices than either normal-hearing age mates or children who achieved above average speech perception with a cochlear implant. Narrative ability is an important predictor of reading comprehension ability in deaf children above and beyond IQ and syntactic competence. Children who receive a cochlear implant under 5 yr of age and obtain above average speech perception benefit from the device construct narratives that are similar in structure and cohesion to those of their hearing age mates by age 8 to 9.