Payam Ezzatian

The Effect of Priming on Release From Informational Masking Is Equivalent for Younger and Older Adults

Objective: Previous studies have shown that presenting younger listeners with all but the last word of a target anomalous sentence immediately before presenting the full sentence in a noisy background produces a greater release from masking when the masker is two-talker anomalous speech than when it is speech-spectrum noise, thereby demonstrating that an auditory prime can produce a release from informational masking. The purpose of this study was to investigate whether older adults could gain the same benefit from auditory primes as younger adults and what bottom-up auditory factors contribute to the advantage provided by auditory primes in releasing speech from informational masking. Design: A total of 76 younger adults (university students) and 76 older adults (volunteers from the local community) participated in this study. All participants spoke English as a first language and had normal hearing below 4 kHz. Results: In experiment 1, younger adults performed better in the presence of the speech masker, whereas older adults performed equivalently under both types of masking, but auditory priming produced an equivalent amount of release from informational masking in both younger and older adults. To examine the degree to which familiarity with the target talkers voice contributed to the priming effects observed in the first experiment, in experiment 2, we primed individuals with sentences that were spoken by the target talker but with lexical content that was unrelated to the target sentences. There was no release from informational masking for either age group. Next, to investigate the extent to which the release from informational masking in the first experiment was due to the amplitude envelope cues provided by the prime, in experiment 3, we noise vocoded the prime (using 3 bands) to remove semantic content while retaining some cues about the primes amplitude envelope. When the primes were noise vocoded, there was no release from informational masking for either younger or older adults. Finally, to examine whether older adults performance in the presence of the speech masker in the first experiment was due to an age-related decline in the ability to take advantage of dips in the amplitude envelope of the speech masker, in experiment 4, we noise vocoded the speech masker. We found a significant improvement in performance, but the amount of improvement was equivalent for both age groups. Conclusions: Auditory priming resulted in equivalent amounts of release from informational masking in both younger and older adults. The benefit provided by auditory primes was not due to cues provided in the prime about the target talkers voice or cues provided in the prime about fluctuations in the amplitude envelope of the target sentences. Importantly, there was an age-related decline in performance in the presence of a two-talker masker relative to a continuous speech-spectrum noise masker; however, this age-related decline in performance cannot be attributed to age-related differences in the ability to take advantage of fluctuations in the amplitude envelope of the speech masker.

Parent-of-origin effects in attention-deficit hyperactivity disorder

The goal of the present study was to investigate parent-of-origin effects in attention-deficit hyperactivity disorder (ADHD). Parent-of-origin effects in ADHD may be due to differences in the relative quantity of risk factors transmitted by each parent. Alternatively, parent-of-origin effects may be produced by qualitative differences in the risks transmitted, such as those carried on the sex chromosomes or regulated by genomic imprinting. 60 children with maternal-only history of ADHD and 131 children with paternal-only history of ADHD were compared on three domains for which prior evidence suggested parent-of-origin effects may exist: core symptoms, disruptive behaviours and depression. Dependent variables were derived from previously validated, age-appropriate and standardized parent and teacher interviews and questionnaires. Depression levels were rated using the Child Depression Inventory. Consistent with previous research and the predictions derived from threshold models of ADHD etiology, the maternal history group received higher ratings of behavioural disorder (ADHD, conduct disorder and oppositional symptoms) than the paternal history group. Parent-of-origin effects were also observed for depression, with the paternal history group rating themselves as significantly more depressed than children in the maternal history group, particularly girls. Heightened paternal transmission relative to maternal is suggestive of genomic imprinting, and the interaction with proband sex indicates the involvement of the sex chromosomes or sex-specific physiological or hormonal factors. Interpretations of these data in terms of environmental and genetic factors, including epigenetic and sex-linked hypotheses, are explored.

Delayed Stream Segregation in Older Adults: More Than Just Informational Masking.

Objective: To determine whether the time course for the buildup of auditory stream segregation differs between younger and older adults. Design: Word recognition thresholds were determined for the first and last keywords in semantically anomalous but syntactically correct sentences (e.g., “A rose could paint a fish”) when the target sentences were masked by speech-spectrum noise, 3-band vocoded speech, 16-band vocoded speech, intact and colocated speech, and intact and spatially separated speech. A significant reduction in thresholds from the first to the last keyword was interpreted as indicating that stream segregation improved with time. Results: The buildup of stream segregation is slowed for both age groups when the masker is intact, colocated speech. Conclusions: Older adults are more disadvantaged; for them, stream segregation is also slowed even when a speech masker is spatially separated, conveys little meaning (3-band vocoding), and vocal fine structure cues are impoverished but envelope cues remain available (16-band vocoding).

Do nonnative listeners benefit as much as native listeners from spatial cues that release speech from masking

Since most everyday communication takes place in less than optimal acoustic settings, it is important to understand how such environments affect nonnative listeners. In this study we compare the speech reception abilities of native and nonnative English speakers when they are asked to repeat semantically anomalous sentences masked by steady-state noise or two other talkers in two conditions: when the target and masker appear to be colocated; and when the target and masker appear to emanate from different loci. We found that the later the age of language acquisition, the higher the threshold for speech reception under all conditions, suggesting that the ability to extract speech information from masking sounds in complex acoustic situations depends on language competency. Interestingly, however, native and nonnative listeners benefited equally from perceived spatial separation (an acoustic cue that releases speech from masking) independent of whether the speech target was masked by speech or noise, suggesting that the acoustic factors that release speech from masking are not affected by linguistic competence. In addition speech reception thresholds were correlated with vocabulary scores in all individuals, both native and nonnative. The implications of these findings for nonnative listeners in acoustically complex environments are discussed.

The effect of energetic and informational masking on the time-course of stream segregation: Evidence that streaming depends on vocal fine structure cues

To examine the effect of energetic and informational masking on the time-course of stream segregation, we presented listeners with semantically anomalous but syntactically correct target sentences (e.g., “A house should dash to the bowl”) that were masked by a two-talker speech masker or steady-state noise masker. To determine the effect of each masker on the time-course of stream segregation, we measured performance as a function of keyword position (key words in italics). The results from Experiment 1 showed that performance improved as a function of keyword position under speech masking, but was relatively stable across keyword positions under noise masking. The results of subsequent experiments showed that the variation in performance across keywords under speech masking was primarily due to the vocal similarities between the competing talkers, and that interference from the semantic content of the masker played a secondary role in undermining performance. Taken together, these results indicate that stream segregation takes longer to build up when a speech target is masked by other speech in the absence of cues that aid stream segregation (e.g., spatial separation), but that it takes little time to build up when a speech target is masked by a noise or when cues that aid stream segregation are available to listeners.

Do Circadian Rhythms Affect Adult Age-Related Differences in Auditory Performance?

Les effets de l’heure du jour ont été identifiés comme facteur de confusion potentiel dans la recherche portant sur la performance cognitive en fonction de l’âge. Les rythmes circadiens ont étés liés aux variations des mesures sensorielles en fonction de l’heure du jour; cependant, on en sait davantage sur l’effet des rythmes circadiens sur la vision que sur l’audition. On ne sait pratiquement rien en ce qui concerne les effets de l’heure du jour comme facteur de confusion potentiel dans les études portant sur le vieillissement auditif. L’objectif de la présente étude était de déterminer si les différences liées à l’âge observées dans l’exécution de tâches auditives étaient affectées par l’heure du jour. Un ensemble de quatre expériences auditives a été répété trois fois au cours d’une journée avec un groupe de jeunes adultes « du soir » et un groupe d’adultes aînés « du matin ». Les résultats reproduisent les constatations précédentes concernant les différences liées à l’âge, mais l’heure du jour n’affecte pas les résultats de base. Donc, l’heure du jour n’est pas un facteur de confusion sur les résultats observés dans des expériences de laboratoire typiques qui étudient le vieillissement auditif. Time-of-day effects have been identified as a possible confound in research on age-related differences in cognitive performance. Circadian rhythms have been related to time-of-day variations in sensory measures; however, more is known about the effect of circadian rhythms on vision than on hearing, and virtually nothing is known about whether time-of-day effects are potential confounds in studies of auditory aging. The purpose of the current study was to determine whether age-related differences in performance on auditory tasks are affected by time of day. A set of four auditory experiments was repeated three times over the course of one day with a group of Evening-type younger adults and a group of Morning-type older adults. The results replicated previous findings of age-related differences, but time of day did not affect the basic results. Thus, time of day does not confound the results observed in typical laboratory experiments investigating auditory aging.

Age-differences in the time course of stream segregation in informational masking of speech by speech

Ezzatian et al. (Lang. Cognitive Processes, 2011) determined thresholds for detecting three target-words(target-words in italics) in semantically-anomalous but syntactically-correct sentences (e.g., “A rose could paint a fish”) masked by either speech-spectrum noise or by two other females talkers. When both masker and target originated from the same loudspeaker, speech recognition was independent of word position for the noise masker, but improved as a function of word position for the speech masker, suggesting that informational masking prolongs the time it takes to perceptually segregate the talker from the competing speech. Spatially separating the masker from the target sentence removed this word-position effect, as did vocoding the masker, presumably because both operations permitted more rapid segregation of the target from competing speech. The older adults in this study displayed the same pattern of results as the younger adults in Ezzatian et al. when both target and masker were presented over t...

Effect of priming on age‐related differences in release from informational masking.

In a previous study, [Freyman et al. (2004)] showed that presenting listeners with all but the last word of a target nonsense sentence immediately prior to presenting the full sentence in a noisy background, produced a greater release from masking when the masker was two‐talker nonsense speech than when it was speech‐spectrum noise, thereby demonstrating that an auditory prime could produce a release from informational masking. In Experiment 1 of this study we showed that auditory priming produced an equivalent amount of release from informational masking in good‐hearing younger and older adults. To investigate the extent to which this release from informational masking was due to the semantic content of the prime, in Experiment 2 we noise‐vocoded the prime (using three bands) to remove semantic content, while retaining the prime’s amplitude envelope. This manipulation eliminated any release from informational masking. In Experiment 3, when the speech masker, but not the prime was vocoded, the performance...

The effect of masker type and word‐position on word recall and sentence understanding

Speech understanding is influenced by not only the presence, but also the specific nature of maskers. Noise maskers primarily result in energetic masking, whereas speech maskers create additional interference due to linguistic and acoustic similarities to the target. The present study examined the influence of different types of maskers and target word position on the immediate recall of words in sentences by normal‐hearing younger adults. In Experiment 1, nonsense sentences with 3 keywords (e.g., A house should dash to the bowl.) were presented against a background of speech‐spectrum noise or two‐talker nonsense speech. With the speech masker, accuracy increased with word position. With the speech‐spectrum noise masker, performance was highest for the first word and did not vary linearly with word position. In Experiment 2, when the speech‐masker was noise‐vocoded to preserve envelope information while disrupting fine structure cues and minimizing semantic content, performance was similar to that f...