Andrea Cripps

A Comparison of Both Motorized and Nonmotorized Treadmill Gait Kinematics to Overground Locomotion

CONTEXT Motorized treadmills (MTs) present an altered motor task compared to overground (OG) locomotion in that MT belt surfaces are motor-driven, whereas individuals walking/running OG must propel themselves. A possible solution may lie with novel nonmotorized treadmill (NMT) devices as the belt surface is propelled by the user. OBJECTIVE The purpose of this study was to compare gait performance during both MT and NMT locomotion to OG. DESIGN Crossover study. SETTING A university research laboratory. PATIENTS A total of 20 healthy adults (10 women) participated in the study. INTERVENTION Each participant performed self-selected walking and running OG, and on both an MT and NMT. MAIN OUTCOME MEASURE Shoulder, trunk, and lower-extremity kinematics were analyzed for each treadmill condition and compared to OG. RESULTS The analyses demonstrated that there were no differences between MT and OG gait kinematics during either walking or running. However, NMT gait showed increased hip, knee, and ankle flexions in late swing and early stance compared to OG during both walking and running. For example, during walking, the NMT elicited hip-, knee-, and ankle-flexion/extension angles of 34.7°, 8.0°, and 3.6° at foot strike compared to 24.8°, -3.1°, and -5.8° in the OG condition (P < .05). There was also a significant reduction in trunk-flexion/extension range of motion during running compared to OG (7.7° in NMT vs 9.8° in OG). CONCLUSIONS These differences may have implications for both training and rehabilitation on an NMT. Future studies should consider the influence of NMT familiarization on gait performance and should emphasize the assessment of neuromuscular performance.

Visual perturbation impacts upright postural stability in athletes with an acute concussion

ABSTRACT Objective: The impact that visual perturbation has on upright postural stability in an athlete with a concussion has not been established. The present study aimed to characterize the influence that visual perturbation stimuli have on upright balance among athletes with acute concussions. Design: A 2X2X2 repeated measure designed was used. Method: The present study examined the influence visual perturbation has on individuals suffering from an acute concussion. Fourteen participants (7 with a concussion and 7 matched controls) underwent various balance assessments with and without visual perturbation. Results: Overall, athletes with acute concussions demonstrated impairments in balance 24–48 hours following a concussion. However, when assessed using a visual perturbation task, athletes with acute concussions demonstrated improved balance, while control subjects did not show any significant changes during the same visual perturbation task. Conclusion: An athlete’s ability to disregard visual perturbation stimuli is imperative for successful participation in sports. Due to the observed alterations in balance when given a visual perturbation task, it is suggested that athletes with acute concussions place more attention on the balance task and may disregard other less meaningful tasks.

Differentiating Concussion From Intracranial Pathology in Athletes

Clinical Scenario: A cerebral concussion is a traumatically induced transient disturbance of brain function characterized by a complex pathophysiologic process and is classified as a subset of mild traumatic brain injury. The occurrence of intracranial lesions after sport-related head injury is relatively uncommon, but the possibility of serious intracranial injury (ICI) should be included in the differential diagnosis. ICIs are potentially life threatening and necessitate urgent medical management; therefore, prompt recognition and evaluation are critical to proper medical management. One of the primary objectives of the initial evaluation is to determine if the concussed athlete has an acute traumatic ICI. Athletic trainers must be able promptly recognize clinical signs and symptoms that will enable them to accurately differentiate between a concussion (ie, a closed head injury not associated with significant ICI) and an ICI. The identification of predictors of intracranial lesions is, however, relatively broad. Focused Clinical Question: Which clinical examination findings (ie, clinical signs and symptoms) indicate possible intracranial pathology in individuals with acute closed head injuries?

Visuo-Motor Processing Impairments Following Concussion in Athletes

Visuo-Motor Processing Impairments Following Concussion in Athletes Objective: Conduct a pilot study to determine if visuo-motor processing is altered in athletes following sports-related concussion. Research design: A longitudinal matched cohort was used to assess 7 concussed and 7 matched control subjects. Interventions: All subjects completed a simple visuo-motor processing task (SVMP). Each subject completed 120 randomized trials. Subjects were asked to identify which direction the motion occurred in (left/right). Repeated testing was conducted 10 days following initial testing. Main outcome measures: Reaction time (overall, each grouping of 20 trials, ambiguous and unambiguous trials right/left), number of correct responses, and number of incorrect responses. A repeated measures ANOVA was conducted to determine differences between groups (concussed/control) and sessions (10 days apart). Results: Concussed athletes has significantly delayed visuo-motor reaction time compared to control subjects and between days of testing. Conclusions: Visuo-motor processing is impaired during the initial 10 days following a sports-related concussion. Concussed athletes demonstrate functional differences in SVMP task performance between testing days. An athlete may be placed at greater risk of injury if returned to sports participation with an impaired ability to quickly make decisions regarding direction of movement. Visuomotor processing should be a routine component of concussion assessment and RTP decision making.

Visual Cortices and their Impact on Sport-Related Concussion: A Review

Visual Cortices and their Impact on Sport-Related Concussion: A Review The human visual cortex is a complex anatomical system which involves inputs and outputs from multiple areas of the brain including both the ventral and dorsal visual pathways. These visual areas and pathways may be altered following a concussion (a subtype of mild traumatic brain injury or TBI) as a result of topdown processing in the brain. Theoretical models for changes occurring in the visual pathways derived from primate research can be applied to the visual cortex in humans following concussions. The purposes of this review article are to: (1) provide an overview of the two anatomical pathways of the human visual system, (2) describe the implications for the differential effects of brain injury in the dorsal and ventral visual pathways of individuals who have sustained a mild TBI, and (3) explain how frontal cortex function or dysfunction modulates both perception and action which take place in posterior parts of the brain.