Formant-frequency variation and its effects on across-formant grouping in speech perception

How speech is separated perceptually from other speech remains poorly understood. In a series of experiments, perceptual organisation was probed by presenting three-formant (F1+F2+F3) analogues of target sentences dichotically, together with a competitor for F2 (F2C), or for F2+F3, which listeners must reject to optimise recognition. To control for energetic masking, the competitor was always presented in the opposite ear to the corresponding target formant(s). Sine-wave speech was used initially, and different versions of F2C were derived from F2 using separate manipulations of its amplitude and frequency contours. F2Cs with time-varying frequency contours were highly effective competitors, whatever their amplitude characteristics, whereas constant-frequency F2Cs were ineffective. Subsequent studies used synthetic-formant speech to explore the effects of manipulating the rate and depth of formant-frequency change in the competitor. Competitor efficacy was not tuned to the rate of formant-frequency variation in the target sentences; rather, the reduction in intelligibility increased with competitor rate relative to the rate for the target sentences. Therefore, differences in speech rate may not be a useful cue for separating the speech of concurrent talkers. Effects of competitors whose depth of formant-frequency variation was scaled by a range of factors were explored using competitors derived either by inverting the frequency contour of F2 about its geometric mean (plausibly speech-like pattern) or by using a regular and arbitrary frequency contour (triangle wave, not plausibly speech-like) matched to the average rate and depth of variation for the inverted F2C. Competitor efficacy depended on the overall depth of frequency variation, not depth relative to that for the other formants. Furthermore, the triangle-wave competitors were as effective as their more speech-like counterparts. Overall, the results suggest that formant-frequency variation is critical for the across-frequency grouping of formants but that this grouping does not depend on speech-specific constraints.

Formant-frequency variation and its effects on across-formant grouping in speech perception

How speech is separated perceptually from other speech remains poorly understood. In a series of experiments, perceptual organisation was probed by presenting three-formant (F1+F2+F3) analogues of target sentences dichotically, together with a competitor for F2 (F2C), or for F2+F3, which listeners must reject to optimise recognition. To control for energetic masking, the competitor was always presented in the opposite ear to the corresponding target formant(s). Sine-wave speech was used initially, and different versions of F2C were derived from F2 using separate manipulations of its amplitude and frequency contours. F2Cs with time-varying frequency contours were highly effective competitors, whatever their amplitude characteristics, whereas constant-frequency F2Cs were ineffective. Subsequent studies used synthetic-formant speech to explore the effects of manipulating the rate and depth of formant-frequency change in the competitor. Competitor efficacy was not tuned to the rate of formant-frequency variation in the target sentences; rather, the reduction in intelligibility increased with competitor rate relative to the rate for the target sentences. Therefore, differences in speech rate may not be a useful cue for separating the speech of concurrent talkers. Effects of competitors whose depth of formant-frequency variation was scaled by a range of factors were explored using competitors derived either by inverting the frequency contour of F2 about its geometric mean (plausibly speech-like pattern) or by using a regular and arbitrary frequency contour (triangle wave, not plausibly speech-like) matched to the average rate and depth of variation for the inverted F2C. Competitor efficacy depended on the overall depth of frequency variation, not depth relative to that for the other formants. Furthermore, the triangle-wave competitors were as effective as their more speech-like counterparts. Overall, the results suggest that formant-frequency variation is critical for the across-frequency grouping of formants but that this grouping does not depend on speech-specific constraints. © Springer Science+Business Media New York 2013.

Illness perceptions and hearing difficulties in King-Kopetzky syndrome:what determines help seeking?

The present study explored illness perceptions of hearing difficulties amongst one hundred participants who reported experiencing hearing difficulties despite normal audiometric thresholds. This experience is referred to as King-Kopetzky syndrome (KKS), obscure auditory dysfunction (OAD), or auditory processing disorder (APD). Logistic regression was used to consider the associations between help-seeking and a range of audiological and illness perception measures. Results indicate that help-seekers present with poorer speech in noise thresholds than non help-seekers, and that coherent illness perceptions and a negative belief in the consequences of hearing difficulties are associated with help-seeking status, regardless of hearing sensitivity.

Measuring the impact of illness perception on NHS audiology service usage in presbycusis patients – a feasibility study

Objective: Coping behaviour in adult hearing loss is still not well understood. Despite the high prevalence of hearing loss in those over 65, many people do not seek help for hearing loss. The common sense model of illness perceptions suggests that illness perceptions are a strong predictor of adapted coping behaviours, including help-seeking and take-up of treatments. This study aimed to determine the feasibility of using the brief illness perceptions questionnaire (bIPQ) to measure the impact of illness perception in predicting usage of NHS audiology services. Study design: Twenty-four volunteers were recruited from a standard NHS audiology outpatient clinic and illness perception was measured using the bIPQ. Two different recruitment strategies were explored and compared in terms of recruitment and retention rates. Comprehensibility of the questionnaire was assessed by Think Aloud Analysis in a subset of participants, while possible risks and burdens were monitored in structured telephone interviews. Results: The questionnaire is a comprehensive and quick tool to measure individual illness perception at minimal cost. We suggested minor adaptations of three questionnaire items to increase comprehension. Participants preferred to complete the questionnaire after their appointment at the clinic facilities rather than at home prior to their hearing assessment appointment. There were no identified risks or burdens to participants in this study. Conclusions: This approach met our criteria for feasibility. Understanding the impact of illness perception on patients’ coping behaviour in presbycusis could improve treatment outcomes and increase patient satisfaction, while promoting a more efficient and individualized audiology service.