Publications (40) View all
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Article: School-age children's environmental object identification in natural auditory scenes: Effects of masking and contextual congruence.
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ABSTRACT: This study investigated the development of children's skills in identifying ecologically relevant sound objects within naturalistic listening environments, using a non-linguistic analogue of the classic 'cocktail-party' situation. Children aged 7 to 12.5 years completed a closed-set identification task in which brief, commonly encountered environmental sounds were presented at varying signal-to-noise ratios. To simulate the complexity of real-world acoustic environments, target sounds were embedded in either a single, stereophonically presented scene, or in one of two different scenes, with each scene presented to a single ear. Each target sound was either congruent or incongruent with the auditory context. Identification accuracy improved with increasing age, particularly in trials with low signal-to-noise ratios. Performance was most accurate when target sounds were incongruent with the background scene, and when sounds were presented in a single background scene. The presence of two backgrounds disproportionately disrupted children's performance relative to that of previously tested adults, and reduced children's sensitivity to contextual cues. Successful identification of familiar sounds in complex auditory contexts is the outcome of a protracted learning process, with children reaching adult levels of performance after a decade or more of experience.Hearing research 03/2013; · 2.18 Impact Factor -
Article: Consonant Accuracy after Severe Pediatric Traumatic Brain Injury: A Prospective Cohort Study.
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ABSTRACT: PURPOSE: To describe longitudinal changes in Percentage of Consonants Correct-Revised (PCC-R) after severe pediatric traumatic brain injury (TBI); to compare the odds of normal-range PCC-R in children injured at older and younger ages; and to correlate predictor variables and PCC-R outcomes. METHOD: In 56 children injured between age 1 mo and 11 yr, PCC-R was calculated over 12 monthly sessions beginning when the child produced >10 words. At each session, odds of normal-range PCC-R were compared in children injured at younger (< 60 mo) and older (> 60 mo) ages. Correlations were calculated between final PCC-R and age at injury, injury mechanism, gender, maternal education, residence, treatment, Glasgow Coma Score, and intact brain volume. RESULTS: PCC-Rs varied within and between children. Odds of normal-range PCC-R were significantly higher for the older than for the younger group at all sessions but the first; odds of normal-range PCC-R were 9-33 times higher in the older group in sessions 3-12. Age at injury was significantly correlated with final PCC-R. CONCLUSION: Over a 12-month period, severe TBI had more adverse effects for children whose ages placed them in the most intensive phase of PCC-R development than for children injured later.Journal of Speech Language and Hearing Research 12/2012; · 1.88 Impact Factor -
Article: Differential face-network adaptation in children, adolescents and adults.
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ABSTRACT: Faces are complex social stimuli, which can be processed both at the categorical and the individual level. Behavioural studies have shown that children take more than a decade of exposure and training to become proficient at processing faces at the individual level. The neurodevelopmental trajectories for different aspects of face-processing are still poorly understood. In this study, we used an fMR-adaptation design to investigate differential processing of three face aspects (identity, expression and gaze) in children, adolescents and adults. We found that, while all three tasks showed some overlap in activation patterns, there was a significant age effect in the occipital and temporal lobes and the inferior frontal gyrus. More importantly, the degree of adaptation differed across the three age groups in the inferior occipital gyrus, a core face processing area that has been shown in previous studies to be both integral and necessary for individual-level face processing. In the younger children, adaptation in this region seemed to suggest the use of a predominantly featural processing strategy, whereas adaptation effects in the adults exhibited a more strategic pattern that depended on the task. Interestingly, our sample of adolescents did not exhibit any differential adaptation effects; possibly reflecting increased heterogeneity in processing strategies in this age group. Our results support the notion that, in line with improving behavioural face-processing abilities, core face-responsive regions develop throughout the first two decades of life.NeuroImage 12/2012; · 5.89 Impact Factor -
Article: In Vivo Functional and Myeloarchitectonic Mapping of Human Primary Auditory Areas.
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ABSTRACT: In contrast to vision, where retinotopic mapping alone can define areal borders, primary auditory areas such as A1 are best delineated by combining in vivo tonotopic mapping with postmortem cyto- or myeloarchitectonics from the same individual. We combined high-resolution (800 μm) quantitative T(1) mapping with phase-encoded tonotopic methods to map primary auditory areas (A1 and R) within the "auditory core" of human volunteers. We first quantitatively characterize the highly myelinated auditory core in terms of shape, area, cortical depth profile, and position, with our data showing considerable correspondence to postmortem myeloarchitectonic studies, both in cross-participant averages and in individuals. The core region contains two "mirror-image" tonotopic maps oriented along the same axis as observed in macaque and owl monkey. We suggest that these two maps within the core are the human analogs of primate auditory areas A1 and R. The core occupies a much smaller portion of tonotopically organized cortex on the superior temporal plane and gyrus than is generally supposed. The multimodal approach to defining the auditory core will facilitate investigations of structure-function relationships, comparative neuroanatomical studies, and promises new biomarkers for diagnosis and clinical studies.Journal of Neuroscience 11/2012; 32(46):16095-16105. · 7.11 Impact Factor -
Article: Mapping the Human Cortical Surface by Combining Quantitative T1 with Retinotopy.
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ABSTRACT: We combined quantitative relaxation rate (R(1)= 1/T(1)) mapping-to measure local myelination-with fMRI-based retinotopy. Gray-white and pial surfaces were reconstructed and used to sample R(1) at different cortical depths. Like myelination, R(1) decreased from deeper to superficial layers. R(1) decreased passing from V1 and MT, to immediately surrounding areas, then to the angular gyrus. High R(1) was correlated across the cortex with convex local curvature so the data was first "de-curved". By overlaying R(1) and retinotopic maps, we found that many visual area borders were associated with significant R(1) increases including V1, V3A, MT, V6, V6A, V8/VO1, FST, and VIP. Surprisingly, retinotopic MT occupied only the posterior portion of an oval-shaped lateral occipital R(1) maximum. R(1) maps were reproducible within individuals and comparable between subjects without intensity normalization, enabling multi-center studies of development, aging, and disease progression, and structure/function mapping in other modalities.Cerebral Cortex 07/2012; · 6.54 Impact Factor
