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  • Addiction, Drugs
  • Information from Lay-Language Summaries is Embargoed Until the Conclusion of the Scientific Presentation

    550—Mutisensory: Cross-Modal Processing in Humans

    Tuesday, November 12, 2013, 8:00 am - 12:00 noon

    550.08: Somatosensory-to-auditory cross-modal plasticity in deaf children with cochlear implants

    Location: Halls B-H

    ">*G. J. CARDON, A. SHARMA;
    Speech, Language, and Hearing Sci., Univ. of Colorado At Boulder, Boulder, CO

    Abstract Body: Objective: Mounting evidence suggests that the maturation and plasticity of the cerebral cortex may play a significant role in predicting functional performance. For instance, it appears that a deficient sensory system has the tendency to re-organize through the recruitment of deprived sensory areas by intact modalities (i.e., cross-modal re-organization), and that recruited sensory modalities seem to suffer functional deficits. Deafness is a naturally occurring instance of sensory deprivation. Due to technology, such as cochlear implants (CI), sensory stimulation can be restored to deprived systems. However, not all CI recipients exhibit favorable functional performance. Somatosensory-to-auditory (SS-A) cross-modal re-organization has been demonstrated in deafness, though never in CI children. However, because the SS and A systems are responsive to virtually the same physical phenomena (i.e., mechanical pressure in the form of oscillations), and due to the highly plastic state of the developing brain, it is plausible that SS-A cross-modal re-organization could occur in deafness and be related to functional outcome in CI children. Thus, we aimed to investigate SS-A cross-modal re-organization in CI children, and whether the degree of SS-A cross-modal re-organization was related to variability in functional abilities.
    Methods: Two groups of children were recruited: 1) children with normal hearing; 2) cochlear-implanted children. Each participant underwent high-density EEG testing in response to both auditory and somatosensory stimulation. Assessment of both cortical auditory and somatosensory evoked potential (CAEP; CSEP) waveform components was performed. Current density reconstruction was also carried out to ascertain the sources of cortical activity in response to each type of stimulation.
    Results: Results from both evoked potential analysis and current density reconstruction suggest that CI children, but not those with normal hearing, showed SS-A cross-modal re-organization. Additionally, CI children with poor speech perception performance presented with a greater degree of SS-A cross-modal re-organization than those with more favorable functional abilities.
    Conclusions: Our findings indicate that SS-A cross-modal re-organization can occur in deaf children who use CIs. The degree of this cortical re-organization also appears to be related to functional outcome. These findings contribute to our understanding of experience-dependent compensatory cortical plasticity in humans. Furthermore, understanding, and being able to harness, cortical plasticity could lead to advancements in clinical management of CI users.

    Lay Language Summary: Cochlear implants are one of the most successful biomedical interventions. These surgically implanted devices electrically stimulate the cochlea allowing many deaf children to hear and develop oral speech and language. However, not all deaf children benefit to the maximum extent with cochlear implants, with some showing poor performance. This variability in real-world performance has baffled researchers that have tried to explain it through demographic means. Thus, in the current clinical landscape, while cochlear implantation is often very successful, there is no guarantee that a given patient will benefit from this procedure.
    Our preliminary findings, using high-density electroencephalography (EEG) brain imaging, show that in many deaf children with cochlear implants the somatosensory (i.e., sense of touch) system of the cerebral cortex encroaches on areas that are typically reserved for the processing of auditory information. It also appears that when this type of re-organization occurs, the auditory portions of the neocortex that are recruited by the somatosensory system may become unavailable for auditory processing, which, in turn, may affect children’s performance on clinically relevant indices of speech perception. Thus, deaf children who use cochlear implants are at risk of experiencing the effects of cross-modal cortical re-organization, which may compromise their ability to acquire oral speech and language. A better understanding of this type of brain plasticity would be useful for improving clinical management of pediatric cochlear implant patients. We are currently collecting data from cochlear-implanted children to better understand the extent to which somatosensory-to-auditory cross-modal reorganization influences clinical outcomes for cochlear-implanted children.
    Supported by the National Institutes of Health.

    Information from Lay-Language Summaries is Embargoed Until the Conclusion of the Scientific Presentation

    550—Mutisensory: Cross-Modal Processing in Humans

    Tuesday, November 12, 2013, 8:00 am - 12:00 noon

    550.08: Somatosensory-to-auditory cross-modal plasticity in deaf children with cochlear implants

    Location: Halls B-H

    ">*G. J. CARDON, A. SHARMA;
    Speech, Language, and Hearing Sci., Univ. of Colorado At Boulder, Boulder, CO

    Abstract Body: Objective: Mounting evidence suggests that the maturation and plasticity of the cerebral cortex may play a significant role in predicting functional performance. For instance, it appears that a deficient sensory system has the tendency to re-organize through the recruitment of deprived sensory areas by intact modalities (i.e., cross-modal re-organization), and that recruited sensory modalities seem to suffer functional deficits. Deafness is a naturally occurring instance of sensory deprivation. Due to technology, such as cochlear implants (CI), sensory stimulation can be restored to deprived systems. However, not all CI recipients exhibit favorable functional performance. Somatosensory-to-auditory (SS-A) cross-modal re-organization has been demonstrated in deafness, though never in CI children. However, because the SS and A systems are responsive to virtually the same physical phenomena (i.e., mechanical pressure in the form of oscillations), and due to the highly plastic state of the developing brain, it is plausible that SS-A cross-modal re-organization could occur in deafness and be related to functional outcome in CI children. Thus, we aimed to investigate SS-A cross-modal re-organization in CI children, and whether the degree of SS-A cross-modal re-organization was related to variability in functional abilities.
    Methods: Two groups of children were recruited: 1) children with normal hearing; 2) cochlear-implanted children. Each participant underwent high-density EEG testing in response to both auditory and somatosensory stimulation. Assessment of both cortical auditory and somatosensory evoked potential (CAEP; CSEP) waveform components was performed. Current density reconstruction was also carried out to ascertain the sources of cortical activity in response to each type of stimulation.
    Results: Results from both evoked potential analysis and current density reconstruction suggest that CI children, but not those with normal hearing, showed SS-A cross-modal re-organization. Additionally, CI children with poor speech perception performance presented with a greater degree of SS-A cross-modal re-organization than those with more favorable functional abilities.
    Conclusions: Our findings indicate that SS-A cross-modal re-organization can occur in deaf children who use CIs. The degree of this cortical re-organization also appears to be related to functional outcome. These findings contribute to our understanding of experience-dependent compensatory cortical plasticity in humans. Furthermore, understanding, and being able to harness, cortical plasticity could lead to advancements in clinical management of CI users.

    Lay Language Summary: Cochlear implants are one of the most successful biomedical interventions. These surgically implanted devices electrically stimulate the cochlea allowing many deaf children to hear and develop oral speech and language. However, not all deaf children benefit to the maximum extent with cochlear implants, with some showing poor performance. This variability in real-world performance has baffled researchers that have tried to explain it through demographic means. Thus, in the current clinical landscape, while cochlear implantation is often very successful, there is no guarantee that a given patient will benefit from this procedure.
    Our preliminary findings, using high-density electroencephalography (EEG) brain imaging, show that in many deaf children with cochlear implants the somatosensory (i.e., sense of touch) system of the cerebral cortex encroaches on areas that are typically reserved for the processing of auditory information. It also appears that when this type of re-organization occurs, the auditory portions of the neocortex that are recruited by the somatosensory system may become unavailable for auditory processing, which, in turn, may affect children’s performance on clinically relevant indices of speech perception. Thus, deaf children who use cochlear implants are at risk of experiencing the effects of cross-modal cortical re-organization, which may compromise their ability to acquire oral speech and language. A better understanding of this type of brain plasticity would be useful for improving clinical management of pediatric cochlear implant patients. We are currently collecting data from cochlear-implanted children to better understand the extent to which somatosensory-to-auditory cross-modal reorganization influences clinical outcomes for cochlear-implanted children.
    Supported by the National Institutes of Health.