Strategies to augment volitional and reflex function may improve locomotor capacity following incomplete spinal cord injury

Many studies highlight the remarkable plasticity demonstrated by spinal circuits following an incomplete spinal cord injury (SCI). Such plasticity can contribute to improvements in volitional motor recovery, such as walking function, although similar mechanisms underlying this recovery may also contribute to the manifestation of exaggerated responses to afferent input, or spastic behaviors. Rehabilitation interventions directed toward augmenting spinal excitability have shown some initial success in improving locomotor function. However, the potential effects of these strategies on involuntary motor behaviors may be of concern. In this article, we provide a brief review of the mechanisms underlying recovery of volitional function and exaggerated reflexes, and the potential overlap between these changes. We then highlight findings from studies that explore changes in spinal excitability during volitional movement in controlled conditions, as well as altered kinematic and behavioral performance during functional tasks. The initial focus will be directed toward recovery of reflex and volitional behaviors following incomplete SCI, followed by recent work elucidating neurophysiological mechanisms underlying patterns of static and dynamic muscle activation following chronic incomplete SCI during primarily single-joint movements. We will then transition to studies of locomotor function and the role of altered spinal integration following incomplete SCI, including enhanced excitability of specific spinal circuits with physical and pharmacological interventions that can modulate locomotor output. The effects of previous and newly developed strategies will need to focus on changes in both volitional function and involuntary spastic reflexes for the successful translation of effective therapies to the clinical setting

Intensive Goal-Directed Treatments in Enriched Environments Augments Patient Outcomes Post-Stroke

Objective: Previous research indicates that patients post-stroke, average 400-800 steps within physical therapy sessions and demonstrate heart rate values of 24-35% of HR Max. This dosage and intensity is inadequate to promote neuroplastic changes and maximize recovery. The goal of this study was to quantify and examine the amount of high-intensity stepping practice that was delivered within an Acute Inpatient Rehabilitation (AIR) setting for individuals with sub-acute stroke. Methods: 14 patients with a diagnosis of sub-acute stroke were admitted to AIR. Standardized outcomes included the 6-Minute Walk Test (6MWT), 10-Meter Walk Test (10MWT), the Berg Balance Scale (BBS) and the Postural Assessment Scale for Stroke Patients (PASS). A step activity monitor with an internal accelerometer was applied on the non-paretic extremity from the hours of 7 am to 5 pm. During therapy sessions, subjects were exposed to a plan of care that involved high-intensity, high-frequency stepping practice through Body Weight Supported Treadmill Training (BWSTT), over-ground stepping, stair climbing, obstacle navigation, dynamic standing balance activities and error augmentation tasks. All individuals were continuously monitored with heart rate monitors, and perceived intensity was recorded within 5-minute intervals and after modification of activity with the Borg Rate of Perceived Exertion (RPE) Scale. Target intensity was defined with heart rate values of 70-85% of HR Max and RPE values of 14-20 (hard to maximal exertion). Time spent in target intensity ranges was collected. Each subject was scheduled for 1-2 hours of physical therapy per day. Results: During the 2-month collection period, subjects demonstrated ability to tolerate a high-intensity, high-frequency stepping gait training program within the intensities defined. Stepping data indicated that subjects received an average daily stepping dosage of 2000-8000 steps per day, well above previously reported values. Conclusion: It is possible to implement a high-intensity, high-frequency stepping gait training program within an acute inpatient rehabilitation setting for the stroke population. However, future research concerning therapy intensity and frequency of stepping should be designed with a larger sample size