May 1, 2013 Departments

From the Journals: May 2013

Usability Testing Shows Flaws in Hearing Aid Instructions

Some hearing aid instruction booklets contain information that users may find difficult to locate, understand and follow, according to a study in the December 2012 issue of the American Journal of Audiology. These limitations may negatively affect hearing aid satisfaction and use.

The study examined whether people could use two hearing aid instruction booklets to carry out basic maintenance tasks and to find and understand key facts. Using a cross-sectional study design, researchers recruited 40 participants (25 women and 15 men, age 46–72 years) with no experience of hearing aids or audiology services to test instruction booklets for either a Danalogic or a Unitron hearing aid (20 participants each). Researchers asked participants to follow the instructions provided in the booklets to complete common tasks—for example, cleaning the hearing aid and mold, and changing the battery—and demonstrate understanding of information. Then a short individual interview captured participants' views of the booklets.

Participants experienced problems in completing all tasks while following instructions provided by both booklets. Individual interviews highlighted further issues regarding layout, diagrams and content, including missing information. Researchers recommend that written information for clients be evaluated prior to use. This study supports the premise that performance-based usability and literature testing are appropriate methods.

Audiologists' Professional Satisfaction Remains Stable

Audiologists' satisfaction with their careers, averaged across settings and types of degrees earned, stands at 3.9 on a five-point scale, a rating that has not changed since 1997, according to survey results published in the December 2012 issue of the American Journal of Audiology. These results have implications for goal setting and planning within the profession, and for audiologists' career choices.

The authors asked 382 randomly chosen, practicing audiologists to evaluate their professional satisfaction, and compared the results to their similar 1997 survey. Audiologists responded to 38 statements on a five-point Likert scale (5 = strong agreement with a statement, 1 = strong disagreement with a statement). The respondents were broken down into demographic subgroups, and statements were divided into subgroups reflecting six core reward areas that contribute to overall professional satisfaction. The authors found statistically significant correlations between how average core reward areas were rated and mean group satisfaction.

Mean group satisfaction was 3.9, which has remained unchanged since 1997. The 80 private practice audiologists in the survey showed a mean group satisfaction of 4.31, higher than for other practice settings. AuD private practice owners' mean group satisfaction of 4.52 was higher than for other degrees and practice settings.

Cochlear Implants' Processing Limitations Most Pronounced in Quiet

Cochlear implant processing limitations primarily take their toll on signal recognition in quiet, and account for poor speech recognition and language/phonological deficits in children who use them, according to a study published in the February 2013 issue of the Journal of Speech, Language, and Hearing Research. The results suggest that teachers and clinicians should teach language and phonology directly, and maximize signal-to-noise levels in the classroom.

Common wisdom suggests that listening in noise poses disproportionately greater difficulty for listeners with cochlear implants than for peers with normal hearing. This study examined phonological, language and cognitive skills that might help explain speech-in-noise abilities for children with cochlear implants. Researchers tested three groups of kindergartners—19 with normal hearing, eight with hearing aids, and 27 with cochlear implants—on speech recognition in quiet and noise, and on tasks thought to underlie the abilities of phonological awareness, general language and cognitive skills. These last measures were used as predictor variables in regression analyses with speech-in-noise scores as dependent variables.

Compared to children with normal hearing, children with cochlear implants did not perform as well on speech recognition in noise or on most other measures, including recognition in quiet. Two surprising results were that noise effects were consistent across groups, and scores on other measures did not explain any group differences in speech recognition.

Noise Hampers Children's Expressive Word Learning

Noise limits expressive vocabulary growth in children and reduces the quality of word form representation in the lexicon, according to research published in the July 2012 issue of Language, Speech, and Hearing Services in Schools. The results imply that clear speech input can aid expressive vocabulary growth in children, even in noisy environments.

Researchers sought to determine the effects of noise and speech style on word learning in typically developing school-age children. Thirty-one participants age 9–11 attempted to learn two sets of eight novel words and their referents. They heard each word 13 times within meaningful narrative discourse. The authors manipulated signal-to-noise ratio (noise vs. quiet) and speech style (plain vs. clear) so that half the children heard the new words in broadband white noise and half heard them in quiet. Within those conditions, each child heard one set of words produced in a plain speech style and another set in a clear speech style.

Children trained in quiet learned to produce the word forms more accurately than those who were trained in noise. Clear speech resulted in more accurate word form productions than plain speech, whether the children had learned in noise or quiet. Learning from clear speech in noise and plain speech in quiet produced comparable results.

Lifelong Bilingualism Linked to Neural Efficiency in Older Adults

Recent behavioral data suggest that lifelong bilingualism can help preserve cognitive strength in aging. Now a study in the January 2013 issue of The Journal of Neuroscience provides the first direct evidence of a neural basis for this bilingual cognitive control boost among older adults.

Researchers conducted two experiments using a perceptual task-switching paradigm with 110 participants. In the first experiment, older adults (mean age of 64.1 years) who are bilingual showed better perceptual switching performance than their monolingual peers.

In the second experiment, younger and older adult monolinguals and bilinguals completed the same perceptual task-switching experiment. As expected, researchers observed typical age-related performance reductions and functional magnetic resonance imaging activation increases.

However, like younger adults, bilingual older adults outperformed their monolingual peers while displaying decreased activation in the left lateral frontal cortex and cingulate cortex. Critically, this decrease of age-related overrecruitment of brain regions associated with bilingualism correlated directly with better task-switching performance. In addition, the lower blood oxygenation level-dependent response in frontal regions accounted for 82 percent of the variance in the bilingual task-switching reaction time advantage. These results may suggest that lifelong bilingualism offsets age-related declines in the neural efficiency for cognitive control processes.


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