| 1. |
- Dahlström, Örjan, et al.
(författare)
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Cognitive training and effects on speech-in noise performance in normal hearing and hearing impaired individuals
- 2015
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Ingår i: CHSCOM2015. - : Linköping University Electronic Press. ; , s. 127-127
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Cognitive training might have potential to improve speech understanding under adverse listening conditions. Here, we have examined the effects of a 5-week computer-based cognitive training program on speech-in-noise-performance, in normal hearing (NH) participants and in participants with mild-to-moderate sensorineural hearing loss (HI).Two groups, matched on gender and age (45-65 years), of 20 participants each (HI and NH respectively) are recruited. Participants perform four test-sessions; inclusion (t0), five weeks (t1), ten weeks (t2) and six months (t3). Training is performed either between t0 and t1, or between t1 and t2 (using a cross-over design), using the computer-based Cogmed training program, approximately 30-40 minutes per day, five days per week, during five weeks. At each session participants are tested in three different ways: (a) cognitive testing (KIPS, SICSPAN, TRT); (b) auditory performance (pure tone-audiometry (air- and bone-conduction) and speech audiometry (HINT, Swedish SPIN-test (SNR +4dB))); (c) cortical activation (MR sessions where participants performed a speech-in-noise task using Hagerman-sentences with steady-state speech-spectrum noise (SSN) and with two competing talkers). MR imaging is performed on a Philips Achieva 1.5 Tesla scanner using a sparse imaging technique in which stimuli are presented during the silent period between successive scans. Participants listen to auditory stimuli under eight different conditions: clear speech, SSN or two competing talkers (each at 90%, 50% and 0% intelligibility), and silent rest. Pre- and post-training, hearing disability is assessed by the Speech-Spatial-Qualities-Questionnaire.The study is on-going and behavioral results as well as results from fMRI will be presented.
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| 4. |
- Davis, M.H., et al.
(författare)
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Does semantic context benefit speech understanding through top-down processes? Evidence from time-resolved sparse fMRI.
- 2011
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Ingår i: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 23:12, s. 3914-3932
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Tidskriftsartikel (refereegranskat)abstract
- When speech is degraded, word report is higher for semantically coherent sentences (e.g., her new skirt was made of denim) than for anomalous sentences (e.g., her good slope was done in carrot). Such increased intelligibility is often described as resulting from “top–down” processes, reflecting an assumption that higher-level (semantic) neural processes support lower-level (perceptual) mechanisms. We used time-resolved sparse fMRI to test for top–down neural mechanisms, measuring activity while participants heard coherent and anomalous sentences presented in speech envelope/spectrum noise at varying signal-to-noise ratios (SNR). The timing of BOLD responses to more intelligible speech provides evidence of hierarchical organization, with earlier responses in peri-auditory regions of the posterior superior temporal gyrus than in more distant temporal and frontal regions. Despite Sentence content × SNR interactions in the superior temporal gyrus, prefrontal regions respond after auditory/perceptual regions. Although we cannot rule out top–down effects, this pattern is more compatible with a purely feedforward or bottom–up account, in which the results of lower-level perceptual processing are passed to inferior frontal regions. Behavioral and neural evidence that sentence content influences perception of degraded speech does not necessarily imply “top–down” neural processes.
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| 5. |
- Heinrich, A., et al.
(författare)
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The continuity illusion does not depend on attentonal state: fMRI evidence from illusory vowels.
- 2011
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Ingår i: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 23:10, s. 2675-2689
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Tidskriftsartikel (refereegranskat)abstract
- We investigate whether the neural correlates of the continuity illusion, as measured using fMRI, are modulated by attention. As we have shown previously, when two formants of a synthetic vowel are presented in an alternating pattern, the vowel can be identified if the gaps in each formant are filled with bursts of plausible masking noise, causing the illusory percept of a continuous vowel (“Illusion” condition). When the formant-to-noise ratio is increased so that noise no longer plausibly masks the formants, the formants are heard as interrupted (“Illusion Break” condition) and vowels are not identifiable. A region of the left middle temporal gyrus (MTG) is sensitive both to intact synthetic vowels (two formants present simultaneously) and to Illusion stimuli, compared to Illusion Break stimuli. Here, we compared these conditions in the presence and absence of attention. We examined fMRI signal for different sound types under three attentional conditions: full attention to the vowels; attention to a visual distracter; or attention to an auditory distracter. Crucially, although a robust main effect of attentional state was observed in many regions, the effect of attention did not differ systematically for the illusory vowels compared to either intact vowels or to the Illusion Break stimuli in the left STG/MTG vowel-sensitive region. This result suggests that illusory continuity of vowels is an obligatory perceptual process, and operates independently of attentional state. An additional finding was that the sensitivity of primary auditory cortex to the number of sound onsets in the stimulus was modulated by attention.
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| 6. |
- Hervais-Adelman, Alexis G., et al.
(författare)
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Brain regions recruited for the effortful comprehension of noise-vocoded words
- 2012
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Ingår i: Language and cognitive processes (Print). - : Taylor & Francis. - 0169-0965 .- 1464-0732. ; 27:7-8, s. 1145-1166
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Tidskriftsartikel (refereegranskat)abstract
- We used functional magnetic resonance imaging (fMRI) to investigate the neural basis of comprehension and perceptual learning of artificially degraded [noise vocoded (NV)] speech. Fifteen participants were scanned while listening to 6-channel vocoded words, which are difficult for naïve listeners to comprehend, but can be readily learned with appropriate feedback presentations. During three test blocks, we compared responses to potentially intelligible NV words, incomprehensible distorted words and clear speech. Training sessions were interleaved with the test sessions and included paired presentation of clear then noise-vocoded words: a type of feedback that enhances perceptual learning. Listeners' comprehension of NV words improved significantly as a consequence of training. Listening to NV compared to clear speech activated left insula, and prefrontal and motor cortices. These areas, which are implicated in speech production, may play an active role in supporting the comprehension of degraded speech. Elevated activation in the precentral gyrus during paired clear-then-distorted presentations that enhance learning further suggests a role for articulatory representations of speech in perceptual learning of degraded speech.
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| 7. |
- Hervais-Adelman, Alexis G., et al.
(författare)
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Generalization of perceptual learning of vocoded speech
- 2011
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Ingår i: Journal of Experimental Psychology. - : American Psychological Association (APA). - 0096-1523 .- 1939-1277. ; 37:1, s. 283-295
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Tidskriftsartikel (refereegranskat)abstract
- Recent work demonstrates that learning to understand noise-vocoded (NV) speech alters sublexical perceptual processes but is enhanced by the simultaneous provision of higher-level, phonological, but not lexical content (Hervais-Adelman, Davis, Johnsrude, & Carlyon, 2008), consistent with top-down learning (Davis, Johnsrude, Hervais-Adelman, Taylor, & McGettigan, 2005; Hervais-Adelman et al., 2008). Here, we investigate whether training listeners with specific types of NV speech improves intelligibility of vocoded speech with different acoustic characteristics. Transfer of perceptual learning would provide evidence for abstraction from variable properties of the speech input. In Experiment 1, we demonstrate that learning of NV speech in one frequency region generalizes to an untrained frequency region. In Experiment 2, we assessed generalization among three carrier signals used to create NV speech: noise bands, pulse trains, and sine waves. Stimuli created using these three carriers possess the same slow, time-varying amplitude information and are equated for naïve intelligibility but differ in their temporal fine structure. Perceptual learning generalized partially, but not completely, among different carrier signals. These results delimit the functional and neural locus of perceptual learning of vocoded speech. Generalization across frequency regions suggests that learning occurs at a stage of processing at which some abstraction from the physical signal has occurred, while incomplete transfer across carriers indicates that learning occurs at a stage of processing that is sensitive to acoustic features critical for speech perception (e.g., noise, periodicity).
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| 8. |
- Huyck, Julia, J., et al.
(författare)
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Rapid perceptual learning of noise-vocoded speech requires attention
- 2012
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Ingår i: Journal of the Acoustical society of America - Express Letters. - : Acoustical Society of America (ASA). - 0001-4966. ; 131:3, s. 236-242
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Tidskriftsartikel (refereegranskat)abstract
- Humans are able to adapt to unfamiliar forms of speech (such as accented, time-compressed, or noise-vocoded speech) quite rapidly. Can such perceptual learning occur when attention is directed away from the speech signal? Here, participants were simultaneously exposed to noise-vocoded sentences, auditory distractors, and visual distractors. One group attended to the speech, listening to each sentence and reporting what they heard. Two other groups attended to either the auditory or visual distractors, performing a target-detection task. Only the attend-speech group benefited from the exposure when subsequently reporting noise-vocoded sentences. Thus, attention to noise-vocoded speech appears necessary for learning.
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| 9. |
- Johnsrude, Ingrid S., et al.
(författare)
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Swinging at a Cocktail Party : Voice Familiarity Aids Speech Perception in the Presence of a Competing Voice
- 2013
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Ingår i: Psychological Science. - : Sage Publications. - 0956-7976 .- 1467-9280. ; 24:10, s. 1995-2004
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Tidskriftsartikel (refereegranskat)abstract
- People often have to listen to someone speak in the presence of competing voices. Much is known about the acoustic cues used to overcome this challenge, but almost nothing is known about the utility of cues derived from experience with particular voicescues that may be particularly important for older people and others with impaired hearing. Here, we use a version of the coordinate-response-measure procedure to show that people can exploit knowledge of a highly familiar voice (their spouses) not only to track it better in the presence of an interfering strangers voice, but also, crucially, to ignore it so as to comprehend a strangers voice more effectively. Although performance declines with increasing age when the target voice is novel, there is no decline when the target voice belongs to the listeners spouse. This finding indicates that older listeners can exploit their familiarity with a speakers voice to mitigate the effects of sensory and cognitive decline.
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| 10. |
- Kitada, Ryo, et al.
(författare)
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Brain networks involved in haptic and visual identification of facial expressions of emotion : An fMRI study
- 2010
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 49:2, s. 1677-1689
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Tidskriftsartikel (refereegranskat)abstract
- Previous neurophysiological and neuroimaging studies have shown that a cortical network involving the inferior frontal gyrus (IFG), inferior parietal lobe (IPL) and cortical areas in and around the posterior superior temporal sulcus (pSTS) region is employed in action understanding by vision and audition. However, the brain regions that are involved in action understanding by touch are unknown. Lederman et al. (2007) recently demonstrated that humans can haptically recognize facial expressions of emotion (FEE) surprisingly well. Here, we report a functional magnetic resonance imaging (fMRI) study in which we test the hypothesis that the IFG, IPL and pSTS regions are involved in haptic, as well as visual, FEE identification. Twenty subjects haptically or visually identified facemasks with three different FEEs (disgust, neutral and happiness) and casts of shoes (shoes) of three different types. The left posterior middle temporal gyrus, IPL, IFG and bilateral precentral gyrus were activated by FEE identification relative to that of shoes, regardless of sensory modality. By contrast, an inferomedial part of the left superior parietal lobule was activated by haptic, but not visual, FEE identification. Other brain regions, including the lingual gyrus and superior frontal gyrus, were activated by visual identification of FEEs, relative to haptic identification of FEEs. These results suggest that haptic and visual FEE identification rely on distinct but overlapping neural substrates including the IFG, IPL and pSTS region.
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