December 18, 2012 News

Research Trends: Gerontology

Hearing Loss and Aging Degrade Speech Perception

Advancing age and sensorineural hearing loss combine to produce diminished gap detection in older adults, according to results of an American Journal of Audiology paper in press. The Gaps-in-Noise test is used to assess a listener's auditory temporal resolution, which predicts one's ability to identify words in noise, information that can help audiologists identify an auditory processing disorder.

Researchers compared the Gaps-in-Noise test results of three groups of participants: older adults with hearing loss, older adults with normal hearing, and young adults with normal hearing. Variance analyses and regression modeling were used to determine the effects of age and audibility on Gaps-in-Noise performance.

Results indicated varying gap thresholds across all groups, with the poorest thresholds exhibited by adults with sensorineural hearing loss, and the best thresholds demonstrated by young adults with normal hearing. Across the three groups, the strongest predictor of a decrease in Gaps-in-Noise performance was an increased audibility index score, but age was also identified as a significant factor.

The study's findings posit the Gaps-in-Noise test as a promising clinical measure of temporal resolution. But researchers caution that clinicians should be aware that age and audibility affect performance on the test, which may create discrepancies between test anlyses and interpretation and published normative data. Search doi: 10.1044/1059-0889(2012/11-0023).

Using Tone Discrimination to Detect Acoustic Perceptual Deficits

People with Parkinson's disease may have less ability to notice changes in frequency and amplitude when compared to other older adults, according to a study published in the American Journal of Speech-Language Pathology. The study's findings also lend further credence to data implicating frontal regions of the brain in auditory perception, due to connections between the frontal lobe and the basal ganglia.

Deficits in auditory perception can compromise a range of linguistic processes in people with Parkinson's disease, including speech perception and sensitivity to affective and linguistic prosody. But researchers wanted to find out whether these deficits exist only at the level of speech perception, or extend also to the more pervasive level of auditory perception. They suspected that Parkinson's may produce a selective impairment of the perception of an acoustic feature, such as frequency, amplitude, or duration.

Researchers investigated auditory perception in in people with Parkinson's disease using a tone-discrimination task. Twelve clients and 15 age-matched controls judged pairs of pure tones as the same or different. The tones were varied by acoustic features (frequency, amplitude, or duration) combined with perceptual distance (close or far).

Relative to healthy, age-matched control participants, clients with Parkinson's showed marked impairment in tone discrimination. People with Parkinson's experienced deficits in the detection of frequency and amplitude differences for perceptually near tones, supporting the hypothesis that these clients have decreased sensitivity to changes in at least some features of speech. Search doi: 10.1044/1058-0360(2012/11-0007).

Aging With Parkinson's Affects Speech Rhythms 

As people age, changes in breath pausing patterns, syntax, and punctuation of speech occur due to changes in respiratory physiology. But according to an American Journal of Speech-Language Pathology paper in press, aging patients with Parkinson's disease may experience speech changes resulting from a combination of altered physiology and cognition.

Researchers studied 30 young adults, 25 typically aging older adults, and 15 people with Parkinson's disease. Fifteen participants were matched by age and gender with the participants with Parkinson's disease. After asking participants to read a passage aloud twice, the researchers recorded utterance lengths, the points at which participants paused relative to punctuation and syntax, and noted the number of disfluencies and "mazes"—multiple word repetitions, restarted utterances, and other deviations from the text.

For all groups, breaths correlated closely with punctuation. In general, older adults produced shorter utterances, a smaller percentage of breaths at major syntactic boundaries (e.g., commas, periods), and a greater percentage of breaths at minor boundaries (e.g., verb or noun phrases) than young adults. There was, however, no significant difference between older adults and people with Parkinson's disease on these measures.

People with Parkinson's disease took more breaths at locations unrelated to syntactic boundaries than the control group, and they also produced more mazes. The results suggest that clinicians should focus on training people with Parkinson's to breathe at major and minor syntactic boundaries—not only major. Additionally, note the researchers, it seems advisable to delay direct treatment of breath pausing patterns until moderate speech impairment becomes evident. But the researchers caution that breath patterns should be monitored at all stages of Parkinson's disease, given the preliminary nature of their data. Search doi: 10.1044/1058-0360(2012/11-0059).  


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