The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Margaret J Snowling - One of the best experts on this subject based on the ideXlab platform.
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language skills but not Frequency Discrimination predict reading skills in children at risk of dyslexia
Psychological Science, 2018Co-Authors: Margaret J Snowling, Debbie Gooch, Genevieve Mcarthur, Charles HulmeAbstract:This study evaluated the claim that auditory processing deficits are a cause of reading and language difficulties. We report a longitudinal study of 245 children at family risk of dyslexia, children with preschool language impairments, and control children. Children with language impairments had poorer Frequency-Discrimination thresholds than controls at 5.5 years, but children at family risk of dyslexia did not. A model assessing longitudinal relationships among Frequency Discrimination, reading, language, and executive function skills showed that Frequency Discrimination was predicted by executive skills but was not a longitudinal predictor of reading or language skills. Our findings contradict the hypothesis that Frequency Discrimination is causally related to dyslexia or language impairment and suggest that individuals at risk for dyslexia or who have language impairments may perform poorly on auditory processing tasks because of comorbid attentional difficulties.
Christophe Micheyl - One of the best experts on this subject based on the ideXlab platform.
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on the utility of perceptual anchors during pure tone Frequency Discrimination
Journal of the Acoustical Society of America, 2020Co-Authors: Samuel R Mathias, Christophe Micheyl, Leonard Varghese, Barbara G ShinncunninghamAbstract:Perceptual anchors are representations of stimulus features stored in long-term memory rather than short-term memory. The present study investigated whether listeners use perceptual anchors to improve pure-tone Frequency Discrimination. Ten amateur musicians performed a two-interval, two-alternative forced-choice Frequency-Discrimination experiment. In one half of the experiment, the Frequency of the first tone was fixed across trials, and in the other half, the Frequency of the first tone was roved widely across trials. The durations of the interstimulus intervals (ISIs) and the Frequency differences between the tones on each trial were also manipulated. The data were analyzed with a Bayesian model that assumed that performance was limited by sensory noise (related to the initial encoding of the stimuli), memory noise (which increased proportionally to the ISI), fluctuations in attention, and response bias. It was hypothesized that memory-noise variance increased more rapidly during roved-Frequency Discrimination than fixed-Frequency Discrimination because listeners used perceptual anchors in the latter condition. The results supported this hypothesis. The results also suggested that listeners experienced more lapses in attention during roved-Frequency Discrimination.Perceptual anchors are representations of stimulus features stored in long-term memory rather than short-term memory. The present study investigated whether listeners use perceptual anchors to improve pure-tone Frequency Discrimination. Ten amateur musicians performed a two-interval, two-alternative forced-choice Frequency-Discrimination experiment. In one half of the experiment, the Frequency of the first tone was fixed across trials, and in the other half, the Frequency of the first tone was roved widely across trials. The durations of the interstimulus intervals (ISIs) and the Frequency differences between the tones on each trial were also manipulated. The data were analyzed with a Bayesian model that assumed that performance was limited by sensory noise (related to the initial encoding of the stimuli), memory noise (which increased proportionally to the ISI), fluctuations in attention, and response bias. It was hypothesized that memory-noise variance increased more rapidly during roved-Frequency discr...
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Do normal-reading listeners use “perceptual anchors” in Frequency-Discrimination tasks?
Journal of the Acoustical Society of America, 2014Co-Authors: Samuel R Mathias, Christophe Micheyl, Barbara G. Shinn-cunninghamAbstract:A controversial hypothesis about the origins of dyslexia states that dyslexic listeners are poor at Frequency Discrimination when the standard Frequency is fixed from trial to trial because they find it difficult to use “perceptual anchors.” This hypothesis tacitly assumes that normal listeners use perceptual anchors during fixed-Frequency Discrimination, which they cannot do when the standard Frequency is random (“roved”). To test this assumption, we measured Frequency-Discrimination performance in normal listeners for tones separated by silent intervals (ISIs) of up to 10 s. Critically, in either the first or second half of the experiment (counterbalanced across listeners), the Frequency of the first tone was the same on each trial (“fixed” conditions); in the other half, the Frequency of this tone was random (“roved” conditions). The data were analyzed using a model that estimated the precision of Frequency representations. In the roved conditions, Frequency representations were less precise at longer ...
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psychometric functions for pure tone Frequency Discrimination
Journal of the Acoustical Society of America, 2011Co-Authors: Christophe MicheylAbstract:The form of the psychometric function (PF) for auditory Frequency Discrimination is of theoretical interest and practical importance. In this study, PFs for pure-tone Frequency Discrimination were measured for several standard frequencies (200–8000 Hz) and levels [35–85 dB sound pressure level (SPL)] in normal-hearing listeners. The proportion-correct data were fitted using a cumulative-Gaussian function of the sensitivity index, d′, computed as a power transformation of the Frequency difference, Δf. The exponent of the power function corresponded to the slope of the PF on log(d′)-log(Δf) coordinates. The influence of attentional lapses on PF-slope estimates was investigated. When attentional lapses were not taken into account, the estimated PF slopes on log(d′)-log(Δf) coordinates were found to be significantly lower than 1, suggesting a nonlinear relationship between d′ and Δf. However, when lapse rate was included as a free parameter in the fits, PF slopes were found not to differ significantly from 1, consistent with a linear relationship between d′ and Δf. This was the case across the wide ranges of frequencies and levels tested in this study. Therefore, spectral and temporal models of Frequency Discrimination must account for a linear relationship between d′ and Δf across a wide range of frequencies and levels.
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Learning in Discrimination of Frequency or modulation rate: generalization to fundamental Frequency Discrimination.
Hearing Research, 2003Co-Authors: Nicolas Grimault, Robert P. Carlyon, Sid P. Bacon, Christophe Micheyl, Lionel ColletAbstract:Fifteen initially inexperienced subjects were trained for 4 weeks (12 2-h sessions) in Frequency Discrimination with pure tones around 88, 250, or 1605 Hz, or amplitude modulation rate Discrimination of noise bands, using modulation rates around 88 or 250 Hz. Before, in the middle of, and after this training period, pure-tone Frequency Discrimination thresholds (DLFs), harmonic complex tone fundamental Frequency Discrimination thresholds (DLF0s), and amplitude modulation rate Discrimination thresholds (DLFMs) were measured in several conditions including the trained one. Training in pure-tone Frequency Discrimination resulted in significantly larger improvements in DLF0s when the test complexes contained resolved harmonics than when they were composed of unresolved harmonics. This result supports the hypothesis that the Discrimination of the F0 of resolved harmonics shares common underlying mechanisms with the Frequency Discrimination of pure tones. Training in rate Discrimination did not result in larger DLF0 improvements for unresolved than for resolved harmonics.
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Perceptual learning in Frequency Discrimination and amplitude‐modulation rate Discrimination, and generalization to fundamental Frequency Discrimination
Journal of the Acoustical Society of America, 2003Co-Authors: Nicolas Grimault, Robert P. Carlyon, Sid P. Bacon, Christophe Micheyl, Lionel ColletAbstract:Fifteen subjects were trained during twelve 2‐h sessions in either Frequency Discrimination with pure tones, or amplitude‐modulation rate Discrimination of noise bands. Thresholds for the Discrimination of pure‐tone Frequency, harmonic complex tone fundamental Frequency, and amplitude‐modulation rate were measured before, during, and after training. Comparison of pre‐ and post‐training thresholds revealed significant improvements in all conditions in both subjects trained in Frequency Discrimination and subjects trained in modulation rate Discrimination. Training in Frequency Discrimination resulted in larger improvements in fundamental Frequency Discrimination when the test complexes contained resolved harmonics than when they were composed of unresolved harmonics. Training in modulation rate Discrimination did not result in larger fundamental Frequency Discrimination improvements for unresolved than for resolved harmonics. The implications for models of pitch perception are discussed.
Florent Haiss - One of the best experts on this subject based on the ideXlab platform.
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tactile Frequency Discrimination is enhanced by circumventing neocortical adaptation
Nature Neuroscience, 2014Co-Authors: Simon Musall, Wolfger Von Der Behrens, Johannes M Mayrhofer, Bruno Weber, Fritjof Helmchen, Florent HaissAbstract:During adaptation, neocortical responses change as a result of repeated sensory stimulation, but it's unclear how this affects perception. Here the authors use optogenetics to mimic sensory evoked cortical responses with or without adaptation. They find adaptation impairs Frequency Discrimination but enhances change detection during whisker stimulation.
Charles Hulme - One of the best experts on this subject based on the ideXlab platform.
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language skills but not Frequency Discrimination predict reading skills in children at risk of dyslexia
Psychological Science, 2018Co-Authors: Margaret J Snowling, Debbie Gooch, Genevieve Mcarthur, Charles HulmeAbstract:This study evaluated the claim that auditory processing deficits are a cause of reading and language difficulties. We report a longitudinal study of 245 children at family risk of dyslexia, children with preschool language impairments, and control children. Children with language impairments had poorer Frequency-Discrimination thresholds than controls at 5.5 years, but children at family risk of dyslexia did not. A model assessing longitudinal relationships among Frequency Discrimination, reading, language, and executive function skills showed that Frequency Discrimination was predicted by executive skills but was not a longitudinal predictor of reading or language skills. Our findings contradict the hypothesis that Frequency Discrimination is causally related to dyslexia or language impairment and suggest that individuals at risk for dyslexia or who have language impairments may perform poorly on auditory processing tasks because of comorbid attentional difficulties.
Robert W Mccarley - One of the best experts on this subject based on the ideXlab platform.
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spatial Frequency Discrimination in schizophrenia
Journal of Abnormal Psychology, 2002Co-Authors: Brian F Odonnell, Geoffrey F Potts, Paul G Nestor, Kiriaki C Stylianopoulos, Martha E Shenton, Robert W MccarleyAbstract:Pathways within the visual system can be distinguished on the basis of selectivity for low or high spatial frequencies. Spatial Frequency Discrimination was evaluated in 17 medicated male patients with schizophrenia and 19 male control subjects. Subjects were required to discriminate whether pairs of high contrast, sinusoidally modulated gratings were the same or different in spatial Frequency. Accuracy performance was compared at high, medium, and low spatial frequencies on tasks matched for control performance. Patients showed a greater performance decrement of 12% on low as compared with 4% on high spatial frequencies. These findings suggest a disturbance of right hemisphere mechanisms involved in spatial perception and attention in schizophrenia.