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

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.

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.

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?

The value of balance-assessment measurements in identifying and monitoring acute postural instability among concussed athletes.

CLINICAL SCENARIO: Sport-related concussions are a significant health issue due to the high incidence of concussions sustained each sports season. Current approaches to the evaluation of acutely concussed athletes include the use of balance assessments to identify and monitor underlying postural instability arising from concussion. Balance assessment has been recommended as a primary measurement tool for monitoring recovery and for making return-to-play decisions. Balance impairments have been shown to occur in the initial postconcussion period (ie, 1-10 d). Numerous clinical and laboratory measures have been used in the assessment of balance immediately after concussion, and clinicians are faced with deciding which measures to use. FOCUSED CLINICAL QUESTION: How do clinical or field-based balance-assessment tools compare to laboratory-based balance measures in identifying deficits in postural stability among acutely concussed athletes?