The Experts below are selected from a list of 43830 Experts worldwide ranked by ideXlab platform
Ruth Y Litovsky - One of the best experts on this subject based on the ideXlab platform.
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spatial acuity in 2 to 3 year old children with normal acoustic hearing unilateral cochlear implants and bilateral cochlear implants
Ear and Hearing, 2012Co-Authors: Tina M Griecocalub, Ruth Y LitovskyAbstract:OBJECTIVES: : To measure spatial acuity on a Right-Left Discrimination task in 2-to-3-year-old children who use a unilateral cochlear implant (UCI) or bilateral cochlear implants (BICIs); to test the hypothesis that BICI users perform significantly better when they use two CIs than when using a single CI, and that they perform better than the children in the UCI group; to determine how well children with CIs perform compared with children who have normal acoustic hearing (NH); to determine the effect of intensity roving on spatial acuity. DESIGN: : Three groups of children between 26 and 36 months of age participated in this study: 8 children with NH (mean age: 30.9 months), 12 children who use a UCI (mean age: 31.9 months), and 27 children who use BICIs (mean age: 30.7 months). Testing was conducted in a large sound-treated booth with loudspeakers positioned in a horizontal arc with a radius of 1.2 m. The observer-based psychophysical procedure was used to measure the children's ability to identify the hemifield containing the sound source (right versus left). Two methods were used for quantifying spatial acuity, an adaptive-tracking method and a fixed-angle method. In Experiment 1 an adaptive tracking algorithm was used to vary source angle, and the minimum audible angle (MAA), the smallest angle at which Right-Left Discrimination performance is better than chance, was estimated. All three groups participated in Experiment 1. In Experiment 2 source angles were fixed at ±50 degrees, and performance was evaluated by computing the number of SDs above chance. Children in the UCI and BICI groups participated in Experiment 2. RESULTS: : In Experiment 1, when stimulus intensity was roved by 8 dB, MAA thresholds were 3.3 degrees to 30.2 degrees (mean = 14.5 degrees) and 5.7 degrees to 69.6 degrees (mean = 30.9 degrees) in the NH group and in the BICI group, respectively. When the intensity level was fixed for the BICI group, performance did not improve. Within the BICI group, 5 out of 27 children obtained MAA thresholds within one SD of their peers who have NH; all five had >12 months of bilateral listening experience. In Experiment 2, BICIs provided some advantages when the intensity level was fixed. First, the BICI group outperformed the UCI group. Second, children in the BICI group who repeated the task with their 1st CI alone had statistically significantly better performance when using both devices. In addition, when intensity roving was introduced, a larger percentage of children who had 12 or more months of BICI experience continued to perform above chance than children who had <12 months of BICI experience. Taken together, the results suggest that children with BICIs have spatial acuity that is better than when using their first CI alone and than that of their peers who use UCIs. In addition, longer durations of BICI use tend to result in better performance, although this cannot be generalized to all participants. CONCLUSION: : This report is consistent with a growing body of evidence that spatial-hearing skills can emerge in young children who use BICIs. The observation that these skills are not concomitantly emerging in age- and experience-matched children who use UCIs suggests that BICIs provide cues that are necessary for these spatial-hearing skills that UCIs do not provide.
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sound localization skills in children who use bilateral cochlear implants and in children with normal acoustic hearing
Ear and Hearing, 2010Co-Authors: Tina M Griecocalub, Ruth Y LitovskyAbstract:Objectives To measure sound source localization in children who have sequential bilateral cochlear implants (BICIs); to determine if localization accuracy correlates with performance on a Right-Left Discrimination task (i.e., spatial acuity); to determine if there is a measurable bilateral benefit on a sound source identification task (i.e., localization accuracy) by comparing performance under bilateral and unilateral listening conditions; to determine if sound source localization continues to improve with longer durations of bilateral experience.
Tina M Griecocalub - One of the best experts on this subject based on the ideXlab platform.
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spatial acuity in 2 to 3 year old children with normal acoustic hearing unilateral cochlear implants and bilateral cochlear implants
Ear and Hearing, 2012Co-Authors: Tina M Griecocalub, Ruth Y LitovskyAbstract:OBJECTIVES: : To measure spatial acuity on a Right-Left Discrimination task in 2-to-3-year-old children who use a unilateral cochlear implant (UCI) or bilateral cochlear implants (BICIs); to test the hypothesis that BICI users perform significantly better when they use two CIs than when using a single CI, and that they perform better than the children in the UCI group; to determine how well children with CIs perform compared with children who have normal acoustic hearing (NH); to determine the effect of intensity roving on spatial acuity. DESIGN: : Three groups of children between 26 and 36 months of age participated in this study: 8 children with NH (mean age: 30.9 months), 12 children who use a UCI (mean age: 31.9 months), and 27 children who use BICIs (mean age: 30.7 months). Testing was conducted in a large sound-treated booth with loudspeakers positioned in a horizontal arc with a radius of 1.2 m. The observer-based psychophysical procedure was used to measure the children's ability to identify the hemifield containing the sound source (right versus left). Two methods were used for quantifying spatial acuity, an adaptive-tracking method and a fixed-angle method. In Experiment 1 an adaptive tracking algorithm was used to vary source angle, and the minimum audible angle (MAA), the smallest angle at which Right-Left Discrimination performance is better than chance, was estimated. All three groups participated in Experiment 1. In Experiment 2 source angles were fixed at ±50 degrees, and performance was evaluated by computing the number of SDs above chance. Children in the UCI and BICI groups participated in Experiment 2. RESULTS: : In Experiment 1, when stimulus intensity was roved by 8 dB, MAA thresholds were 3.3 degrees to 30.2 degrees (mean = 14.5 degrees) and 5.7 degrees to 69.6 degrees (mean = 30.9 degrees) in the NH group and in the BICI group, respectively. When the intensity level was fixed for the BICI group, performance did not improve. Within the BICI group, 5 out of 27 children obtained MAA thresholds within one SD of their peers who have NH; all five had >12 months of bilateral listening experience. In Experiment 2, BICIs provided some advantages when the intensity level was fixed. First, the BICI group outperformed the UCI group. Second, children in the BICI group who repeated the task with their 1st CI alone had statistically significantly better performance when using both devices. In addition, when intensity roving was introduced, a larger percentage of children who had 12 or more months of BICI experience continued to perform above chance than children who had <12 months of BICI experience. Taken together, the results suggest that children with BICIs have spatial acuity that is better than when using their first CI alone and than that of their peers who use UCIs. In addition, longer durations of BICI use tend to result in better performance, although this cannot be generalized to all participants. CONCLUSION: : This report is consistent with a growing body of evidence that spatial-hearing skills can emerge in young children who use BICIs. The observation that these skills are not concomitantly emerging in age- and experience-matched children who use UCIs suggests that BICIs provide cues that are necessary for these spatial-hearing skills that UCIs do not provide.
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sound localization skills in children who use bilateral cochlear implants and in children with normal acoustic hearing
Ear and Hearing, 2010Co-Authors: Tina M Griecocalub, Ruth Y LitovskyAbstract:Objectives To measure sound source localization in children who have sequential bilateral cochlear implants (BICIs); to determine if localization accuracy correlates with performance on a Right-Left Discrimination task (i.e., spatial acuity); to determine if there is a measurable bilateral benefit on a sound source identification task (i.e., localization accuracy) by comparing performance under bilateral and unilateral listening conditions; to determine if sound source localization continues to improve with longer durations of bilateral experience.
Alfredo Ardila - One of the best experts on this subject based on the ideXlab platform.
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Gerstmann Syndrome
Current Neurology and Neuroscience Reports, 2020Co-Authors: Alfredo ArdilaAbstract:Purpose of Review Gerstmann (left angular gyrus) syndrome includes the tetrad of finger agnosia (inability to distinguish, name, and recognize the fingers), agraphia (acquired disturbance in the ability to write), acalculia (loss of the ability to perform arithmetical operations and use numerical concepts), and Right-Left disorientation (Right-Left Discrimination defect when using language). There is some disagreement regarding its exact localization, but it most likely involves the left angular gyrus with a probable subcortical extension. This article reviews recent research on the clinical aspects of this syndrome. Recent Findings During the last years, just some few new reports of Gerstmann syndrome are found in neurological and neuropsychological literature. Most of the reports are single-case reports. An association between Gerstmann syndrome and the so-called semantic aphasia has been pointed out. Two different explanations to this unusual syndrome have been recently proposed: (1) the pathological process is located in the left parietal white matter disconnecting separate cortical networks and (2) it represents a disturbance in the ability to verbally mediate some spatial knowledge. Summary Although Gerstmann syndrome continues as a controversial syndrome, and most of the reports are single case reports, recently two different explanations have been advance the understanding of this polemic but fascinating syndrome.
Martina Piefke - One of the best experts on this subject based on the ideXlab platform.
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The Bergen left–right Discrimination test: practice effects, reliable change indices, and strategic performance in the standard and alternate form with inverted stimuli
Cognitive Processing, 2014Co-Authors: Philip Grewe, Hanno A. Ohmann, Hans J. Markowitsch, Martina PiefkeAbstract:Several authors pointed out that left–right Discrimination (LRD) tasks may be entangled with differential demands on mental rotation (MR). However, studies considering this interrelationship are rare. To differentially assess LRD of stimuli with varying additional demands on MR, we constructed and evaluated an extended version of the Bergen right–left Discrimination (BRLD) test including additional subtests with inverted stickmen stimuli in 174 healthy participants (50♂, 124♀) and measured subjective reports on participants’ strategies to accomplish the task. Moreover, we analyzed practice effects and reliable change indices (RCIs) on BRLD performance, as well as gender differences. Performance significantly differed between subtests with high and low demands on MR with best scores on subtests with low demands on MR. Participants’ subjective strategies corroborate these results: MR was most frequently reported for subtests with highest MR demands (and lowest test performance). Pronounced practice effects were observed for all subtests. Sex differences were not observed. We conclude that our extended version of the BRLD allows for the differentiation between LRD with high and low demands on MR abilities. The type of stimulus materials is likely to be critical for the differential assessment of MR and LRD. Moreover, RCIs provide a basis for the clinical application of the BRLD.
Philip Grewe - One of the best experts on this subject based on the ideXlab platform.
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The Bergen left–right Discrimination test: practice effects, reliable change indices, and strategic performance in the standard and alternate form with inverted stimuli
Cognitive Processing, 2014Co-Authors: Philip Grewe, Hanno A. Ohmann, Hans J. Markowitsch, Martina PiefkeAbstract:Several authors pointed out that left–right Discrimination (LRD) tasks may be entangled with differential demands on mental rotation (MR). However, studies considering this interrelationship are rare. To differentially assess LRD of stimuli with varying additional demands on MR, we constructed and evaluated an extended version of the Bergen right–left Discrimination (BRLD) test including additional subtests with inverted stickmen stimuli in 174 healthy participants (50♂, 124♀) and measured subjective reports on participants’ strategies to accomplish the task. Moreover, we analyzed practice effects and reliable change indices (RCIs) on BRLD performance, as well as gender differences. Performance significantly differed between subtests with high and low demands on MR with best scores on subtests with low demands on MR. Participants’ subjective strategies corroborate these results: MR was most frequently reported for subtests with highest MR demands (and lowest test performance). Pronounced practice effects were observed for all subtests. Sex differences were not observed. We conclude that our extended version of the BRLD allows for the differentiation between LRD with high and low demands on MR abilities. The type of stimulus materials is likely to be critical for the differential assessment of MR and LRD. Moreover, RCIs provide a basis for the clinical application of the BRLD.
