Target identification using relative level in multi-talker listening

Cortical and Sensory Causes of Individual Differences in Selective Attention Ability Among Listeners With Normal Hearing Thresholds

PURPOSE

This review provides clinicians with an overview of recent findings relevant to understanding why listeners with normal hearing thresholds (NHTs) sometimes suffer from communication difficulties in noisy settings.

METHOD

The results from neuroscience and psychoacoustics are reviewed.

RESULTS

In noisy settings, listeners focus their attention by engaging cortical brain networks to suppress unimportant sounds; they then can analyze and understand an important sound, such as speech, amidst competing sounds. Differences in the efficacy of top-down control of attention can affect communication abilities. In addition, subclinical deficits in sensory fidelity can disrupt the ability to perceptually segregate sound sources, interfering with selective attention, even in listeners with NHTs. Studies of variability in control of attention and in sensory coding fidelity may help to isolate and identify some of the causes of communication disorders in individuals presenting at the clinic with "normal hearing."

CONCLUSIONS

How well an individual with NHTs can understand speech amidst competing sounds depends not only on the sound being audible but also on the integrity of cortical control networks and the fidelity of the representation of suprathreshold sound. Understanding the root cause of difficulties experienced by listeners with NHTs ultimately can lead to new, targeted interventions that address specific deficits affecting communication in noise.

PRESENTATION VIDEO

http://cred.pubs.asha.org/article.aspx?articleid=2601617.

Predicting the effect of hearing loss and audibility on amplified speech reception in a multi-talker listening scenario

Auditive and cognitive influences on speech perception in a complex situation were investigated in listeners with normal hearing (NH) and hearing loss (HL). The speech corpus used was the Nonsense-Syllable Response Measure [NSRM; Woods and Kalluri, (2010). International Hearing Aid Research Conference, pp. 40-41], a 12-talker corpus which combines 154 nonsense syllables with 8 different carrier phrases. Listeners heard NSRM sentences in quiet, background noise, and in background noise plus other "jammer" NSRM sentences. All stimuli were linearly amplified. A "proficiency" value, determined from the results in quiet and the quiet-condition speech intelligibility index (SII), was used with the SII in predicting results in the other conditions. Results for nine of ten NH subjects were well-predicted (within the limits of binomial variability) in the noise condition, as were eight of these subjects in the noise-plus-jammers condition. All 16 HL results were well-predicted in the noise condition, as were 9 of the HL in the noise-plus-jammers condition. Hierarchical regression partialling out the effects of age found proficiency in noise-plus-jammers significantly correlated with results of "trail-making" tests, thought to index processing speed and attention-deployment ability, and proficiency in quiet and noise was found significantly correlated with results from a backward digit-span memory test.