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Yao J.,Northwestern University | Chen A.,Northwestern University | Kuiken T.,Northwestern University | Kuiken T.,Rehabilitation Institute of ChicagoIL | And 2 more authors.
NeuroImage: Clinical | Year: 2015

This case study demonstrates the change of sensory cortical representations of the residual parts of the arm in an individual who underwent a trans-humeral amputation and subsequent targeted reinnervation (TR). As a relatively new surgical technique, TR restores a direct neural connection from amputated sensorimotor nerves to specific target muscles. This method has been successfully applied to upper-limb and lower-limb amputees, and has shown effectiveness in regaining control signals via the newly re-innervated muscles. Correspondingly, recent study results have shown that motor representations for the missing limb move closer to their original locations following TR. Besides regaining motor control signals, TR also restores the sensation in the re-innervated skin areas. We therefore hypothesize that TR causes analogous cortical sensory remapping that may return closer to their original locations. In order to test this hypothesis, cortical activity in response to sensory-level electrical stimulation in different parts of the arm was studied longitudinally in one amputated individual before and up to 2 years after TR. Our results showed that 1) before TR, the cortical response to sensory electrical stimulation in the residual limb showed a diffuse bilateral pattern without a clear focus in either the time or spatial domain; and 2) 2 years after TR, the sensory map of the reinnervated median nerve reorganized, showing predominant activity over the contralateral S1 hand area as well as moderate activity over the ipsilateral S1. Therefore, this work provides new evidence for long-term sensory cortical plasticity in the human brain after TR. ©2015 The Authors. Published by Elsevier Inc. Source


Simon N.G.,University of New South Wales | Franz C.K.,Northwestern University | Franz C.K.,Rehabilitation Institute of ChicagoIL | Gupta N.,University of California at San Francisco | And 3 more authors.
World Neurosurgery | Year: 2016

Brachial plexus trauma (BPT) often affects young patients and may result in lasting functional deficits. Standard care following BPT involves monitoring for clinical and electrophysiological evidence of muscle reinnervation, with surgical treatment decisions based on the presence or absence of spontaneous recovery. Data are emerging to suggest that central and peripheral adaptation may play a role in recovery following BPT. The present review highlights adaptive and maladaptive mechanisms of central and peripheral nervous system changes following BPT that may contribute to functional outcomes. Rehabilitation and other treatment strategies that harness or modulate these intrinsic adaptive mechanisms may improve functional outcomes following BPT. © 2016 Elsevier Inc. All rights reserved. Source


Chau A.,Rehabilitation Institute of ChicagoIL | Salazar A.M.,Oncovir, Inc. | Krueger F.,George Mason University | Cristofori I.,Rehabilitation Institute of ChicagoIL | And 3 more authors.
Consciousness and Cognition | Year: 2015

Crick and Koch proposed that the claustrum plays a crucial role in consciousness. Their proposal was based on the structure and connectivity of the claustrum that suggested it had a role in coordinating a set of diverse brain functions. Given the few human studies investigating this claim, we decided to study the effects of claustrum lesions on consciousness in 171 combat veterans with penetrating traumatic brain injuries. Additionally, we studied the effects of claustrum lesions and loss of consciousness on long-term cognitive abilities. Claustrum damage was associated with the duration, but not frequency, of loss of consciousness, indicating that the claustrum may have an important role in regaining, but not maintaining, consciousness. Total brain volume loss, but not claustrum lesions, was associated with long-term recovery of neurobehavioral functions. Our findings constrain the current understanding of the neurobehavioral functions of the claustrum and its role in maintaining and regaining consciousness. © 2015 Elsevier Inc. Source


Joshi A.B.,Duke University | McCormick Z.L.,Rehabilitation Institute of ChicagoIL | Sully K.,University of Pennsylvania | Garvan C.,University of Florida | Plastaras C.T.,University of Pennsylvania
Journal of Occupational and Environmental Medicine | Year: 2016

Objective: The aim of this study is to report satisfaction rates and identify factors predicting satisfaction in the Pennsylvania Workers' Compensation (WC) system. Methods: Cross-sectional survey data on satisfaction and care experience of injured workers were collected annually for 14 years with 27,712 injured workers responding. Results: The overall response rate was 19.44%. The overall proportion of satisfied workers was 83.97% with a range of 80.43% to 88.13%. Obtaining a correct initial diagnosis [odds ratio (OR)=4.26], explanation of WC rights (OR=2.58), and physician explanation of treatment options (OR=1.83) most strongly predicted satisfaction. Conclusions: Injured worker satisfaction with their medical care exceeded 80% in all years surveyed. Patient perception of a correct initial diagnosis, explanation of WC rights, and explanation of treatment options were the strongest predictors of satisfaction during the 14-year study period. Copyright © 2015 American College of Occupational and Environmental Medicine. Source


Zhao H.,Rehabilitation Institute of ChicagoIL | Zhao H.,Northwestern University | Zhao H.,Mayo Medical School | Ren Y.,Rehabilitation Institute of ChicagoIL | And 7 more authors.
Journal of Applied Physiology | Year: 2015

Calf muscles and Achilles tendon play important roles in functional activities. However, it is not clear how biomechanical properties of the uniarticular soleus (SOL) and biarticular gastrocnemius muscle and Achilles tendon, including the fascicle length, pennation angle, and stiffness, change concurrently post stroke. Biomechanical properties of the medial gastrocnemius (GM) and soleus muscles were evaluated bilaterally in 10 hemiparetic stroke survivors using combined ultra-sonography-biomechanical measurements. Biomechanical properties of the Achilles tendon including the length, cross-sectional area (CSA), stiffness, and Young's modulus were evaluated, together with calf muscle biomechanical properties. Gastrocnemius and SOL contributions were separated using flexed and extended knee positions. The impaired side showed decreased fascicle length (GM: 6%, P = 0.002 and SOL: 9%, P = 0.03, at full knee extension and 0° ankle dorsiflexion) and increased fascicular stiffness (GM: 64%, P = 0.005 and SOL: 19%, P = 0.012, at a common 50 N force level). In contrast, Achilles tendon on the impaired side showed changes in the opposite direction as the muscle fascicles with increased tendon length (5%, P < 0.001), decreased tendon CSA (5%, P < 0.04), decreased tendon stiffness (42%, P < 0.001) and Young's modulus (30%, P < 0.001) compared with the unimpaired side. The fascicle and tendon stiffness changes were correlated negatively to the corresponding fascicle and tendon length changes, and decrease in Achilles tendon stiffness was correlated to the increases of SOL and GM fascicular stiffness (P < 0.05). Characterizations of calf muscle fascicles and Achilles tendon biomechanical properties help us better understand concurrent changes of fascicles and tendon as part of the calf muscle-tendon unit and facilitate development of more effective treatments. Copyright © 2015 the American Physiological Society. Source

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