Browsing by Author "Mahtani, Gordhan B."

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    Altered Sagittal- and Frontal-Plane Kinematics Following High-Intensity Stepping Training Versus Conventional Interventions in Subacute Stroke
    (Oxford, 2016) Mahtani, Gordhan B.; Kinnaird, Catherine R.; Connolly, Mark; Holleran, Carey L.; Hennessy, Patrick W.; Woodward, Jane; Brazg, Gabrielle; Roth, Elliot J.; Hornby, T. George; Physical Medicine and Rehabilitation, School of Medicine
    Background Common locomotor deficits observed in people poststroke include decreased speeds and abnormal kinematics, characterized by altered symmetry, reduced sagittal-plane joint excursions, and use of compensatory frontal-plane behaviors during the swing phase of gait. Conventional interventions utilized to mitigate these deficits often incorporate low-intensity, impairment-based or functional exercises focused on normalizing kinematics, although the efficacy of these strategies is unclear. Conversely, higher-intensity training protocols that provide only stepping practice and do not focus on kinematics have demonstrated gains in walking function, although minimal attention toward gait quality may be concerning and has not been assessed. Objective The present study evaluated changes in spatiotemporal and joint kinematics following experimental, high-intensity stepping training compared with conventional interventions. Design Kinematic data were combined from a randomized controlled trial comparing experimental and conventional training and from a pilot experimental training study. Methods Individuals with gait deficits 1 to 6 months poststroke received up to 40 sessions of either high-intensity stepping training in variable contexts or conventional lower-intensity interventions. Analyses focused on kinematic changes during graded treadmill testing before and following training. Results Significant improvements in speed, symmetry, and selected sagittal-plane kinematics favored experimental training over conventional training, although increases in compensatory strategies also were observed. Changes in many kinematic patterns were correlated with speed changes, and increased compensatory behaviors were associated with both stride length gains and baseline impairments. Limitations Limitations include a small sample size and use of multiple statistical comparisons. Conclusions Improved speeds and selected kinematics were observed following high-intensity training, although such training also resulted in increased use of compensatory strategies. Future studies should explore the consequences of utilizing these compensatory strategies despite the observed functional gains.
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    Exercise-Induced Alterations in Sympathetic-Somatomotor Coupling in Incomplete Spinal Cord Injury
    (Mary Ann Liebert, Inc., publishers, 2019-09-15) Onushko, Tanya; Mahtani, Gordhan B.; Brazg, Gabrielle; Hornby, T. George; Schmit, Brian D.; Physical Medicine and Rehabilitation, School of Medicine
    The aim of this study was to understand how high- and low-intensity locomotor training (LT) affects sympathetic-somatomotor (SS) coupling in people with incomplete spinal cord injury (SCI). Proper coupling between sympathetic and somatomotor systems allows controlled regulation of cardiovascular responses to exercise. In people with SCI, altered connectivity between descending pathways and spinal segments impairs sympathetic and somatomotor coordination, which may have deleterious effects during exercise and limit rehabilitation outcomes. We postulated that high-intensity LT, which repeatedly engages SS systems, would alter SS coupling. Thirteen individuals (50 ± 7.2 years) with motor incomplete spinal cord injuries (American Spinal Injury Association Impairment Scale C or D; injury level >T6) participated in a locomotor treadmill training program. Patients were randomized into either a high-intensity (high-LT; 70–85% of maximum predicted heart rate; n = 6) group or a low-intensity (low-LT; 50–65% of maximum predicted heart rate; n = 7) group and completed up to 20 LT training sessions over 4–6 weeks, 3–5 days/week. Before and after taining, we tested SS coupling by eliciting reflexive sympathetic activity through a cold stimulation, noxious stimulation, and a mental math task while we measured tendon reflexes, blood pressure, and heart rate. Participants who completed high- versus low-LT exhibited significant decreases in reflex torques during triggered sympathetic activity (cold: −83 vs. 13%, p < 0.01; pain: −65 vs. 54%, p < 0.05; mental math: −43 vs. 41%; p < 0.05). Mean arterial pressure responses to sympathetic stimuli were slightly higher following high- versus low-LT (cold: 30 vs. −1.5%; pain: 6 vs. −12%; mental math: 5 vs. 7%), although differences were not statistically significant. These results suggest that high-LT may be advantageous to low-LT to improve SS coupling in people with incomplete SCI.
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    High intensity variable stepping training in persons with motor incomplete spinal cord injury: a case series
    (Lippincott, Williams & Wilkins, 2020-04-05) Holleran, Carey L.; Hennessey, Patrick W.; Leddy, Abigail L.; Mahtani, Gordhan B.; Brazg, Gabrielle; Schmit, Brian D.; Hornby, T. George; Physical Medicine and Rehabilitation, School of Medicine
    Background and Purpose: Previous data suggest that large amounts of high intensity stepping training in variable contexts (tasks and environments) may improve locomotor function, aerobic capacity and treadmill gait kinematics in individuals post-stroke. Whether similar training strategies are tolerated and efficacious for patients with other acute-onset neurological diagnoses, such as motor incomplete spinal cord injury (iSCI) is unknown, particularly with potentially greater, bilateral impairments. This case series evaluated the feasibility and preliminary short and long-term efficacy of high intensity variable stepping practice in ambulatory participants >1 year post-iSCI. Case Series Description: Four participants with iSCI (neurological levels C5-T3) completed up to 40 1-hr sessions over 3–4 months. Stepping training in variable contexts was performed at up to 85% maximum predicted heart rate, with feasibility measures of patient tolerance, total steps/session, and intensity of training. Clinical measures of locomotor function, balance, peak metabolic capacity and gait kinematics during graded treadmill assessments were performed at baseline and post-training, with >1 year follow-up. Outcomes: Participants completed 24–40 sessions over 8–15 weeks, averaging 2222±653 steps/session, with primary adverse events of fatigue and muscle soreness. Modest improvements in locomotor capacity where observed at post-training, with variable changes in lower extremity kinematics during treadmill walking. Discussion: High intensity, variable stepping training was feasible and tolerated by participants with iSCI although only modest gains in gait function or quality were observed. The utility of this intervention in patients with more profound impairments may be limited.
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    Kinematic and Neuromuscular Adaptations in Incomplete Spinal Cord Injury after High- versus Low-Intensity Locomotor Training
    (Mary Ann Liebert, 2019-05-28) Ardestani, Marzieh M.; Henderson, Christopher E.; Salehi, Seyed H.; Mahtani, Gordhan B.; Schmit, Brian D.; Hornby, T. George; Physical Medicine and Rehabilitation, School of Medicine
    Recent data demonstrate improved locomotion with high-intensity locomotor training (LT) in individuals with incomplete spinal cord injury (iSCI), although concerns remain regarding reinforcement of abnormal motor strategies. The present study evaluated the effects of LT intensity on kinematic and neuromuscular coordination in individuals with iSCI. Using a randomized, crossover design, participants with iSCI received up to 20 sessions of high-intensity LT, with attempts to achieve 70–85% of age-predicted maximum heart rate (HRmax), or low-intensity LT (50–65% HRmax), following which the other intervention was performed. Specific measures included spatiotemporal variables, sagittal-plane gait kinematics, and neuromuscular synergies from electromyographic (EMG) recordings. Correlation analyses were conducted to evaluate associations between variables. Significant improvements in sagittal-plane joint excursions and intralimb hip-knee coordination were observed following high- but not low-intensity LT when comparing peak treadmill (TM) speed before and after LT. Neuromuscular complexity (i.e., number of synergies to explain >90% of EMG variance) was also increased following high- but not low-intensity LT. Comparison of speed-matched trials confirmed significant improvements in the knee excursion of the less impaired limb and intralimb hip-knee coordination, as well as improvements in neuromuscular complexity following high-intensity LT. These findings suggest greater neuromuscular complexity may be due to LT and not necessarily differences in speeds. Only selected kinematic changes (i.e., weak hip excursion) was correlated to improvements in treadmill speed. In conclusion, LT intensity can facilitate gains in kinematic variables and neuromuscular synergies in individuals with iSCI.