Recovery of cognitive and dynamic motor function following concussion
TL;DR: In order to fully examine the effects of concussion and determine the optimal time for a safe return to activity, a multi-factorial approach, including both cognitive and motor tasks, should be employed.
Abstract: Objective: Neuropsychological testing has been advocated as an important tool of proper post-concussion management. Although these measures provide information that can be used in the decision of when to return an individual to previous levels of physical activity, they provide little data on motor performance following injury. The purpose of this investigation was to examine the relationship between measures of dynamic motor performance and neuropsychological function following concussion over the course of 28 days. Methods: Participants completed two experimental protocols: gait stability and neuropsychological testing. The gait stability protocol measured whole-body centre of mass motion as subjects walked under conditions of divided and undivided attention. Neuropsychological testing consisted of a computerised battery of tests designed to assess memory, reaction time, processing speed and concussion symptoms. Correlation coefficients were computed between all neuropsychological and gait variables and comparisons of neuropsychological and gait stability post-concussion recovery curves were assessed. Results: Dynamic motor tasks, such as walking under varying conditions of attention, are complex and demanding undertakings, which require a longer recovery time following a concussion than cognitive measures. Little statistical relationship was found between the neuropsychological and gait variables, and the recovery curves of neuropsychological and gait domains were observed to be independent. Conclusions: In order to fully examine the effects of concussion and determine the optimal time for a safe return to activity, a multi-factorial approach, including both cognitive and motor tasks, should be employed.
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TL;DR: Dual-task assessments concurrently evaluating gait and cognitive performance may allow for the detection of persistent deficits beyond those detected by computerized neurocognitive deficits alone.
39 citations
TL;DR: Overall, the findings reveal that intercollegiate football players with concussions have difficulty controlling temporal characteristics of gait, which cause dynamic instability to persist even at RTP.
38 citations
Cites result from "Recovery of cognitive and dynamic m..."
...Since participants were instructed to take two steps prior to initiating the turn, the task allowed proactive control of balance and therefore, these results are not attributed to a slowed reaction time following a concussion [27]....
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TL;DR: For high school athletes, RTP within the first 2 days after concussion was unlikely, and the probability of return rose substantially after 1 week, so prognostic time-to-event probabilities allow clinicians to provide coaches, parents, and athletes with a prediction of the likelihood of RTPWithin certain timeframes after a concussion.
Abstract: Context: Whereas guidelines about return-to-play (RTP) after concussion have been published, actual prognoses remain elusive. Objective: To develop probability estimates for time until RTP after sp...
34 citations
TL;DR: This narrative review looks at how the task of walking and the inseparable cognitive demands and interference of the surrounding environment are exploited in dual task walking (DTW) paradigms to expose executive dysfunction.
Abstract: Within rehabilitation, clinical assessment plays a crucial role in diagnosis, prognostication and making decisions about return to function. The ecological validity of the assessment of executive dysfunction has become a particular focus in neuropsychology and is gaining interest in mobility research and neurological rehabilitation of acquired brain injury or degenerative neurological diseases. In this narrative review, we look at how the task of walking and the inseparable cognitive demands and interference of the surrounding environment are exploited in dual task walking (DTW) paradigms to expose executive dysfunction. While quite a number of studies and reviews have recently focused on the utility of DTW for gait assessment, particularly to assess fall risk, very little consideration has been given to the level of ecological validity required. This paper directly addresses this issue with discussion of evidence and lacunas related to task, personal and technological factors that should be addressed in order to exploit fully DTW paradigms as an ecological assessment tool.
33 citations
TL;DR: Brain regions associated with contact sport participation, athletes with a history of concussion also showed greater alterations in FA and functional connectivity, indicating a potential cumulative effect of both contact exposure and concussion history on brain physiology.
Abstract: There is growing concern about how participation in contact sports may affect the brain. Retrospective evidence suggests that contact sports are associated with long-term negative health outcomes. However, much of the research to date has focused on former athletes with significant health problems. Less is known about the health of current athletes in contact and collision sports who have not reported significant medical issues. In this cross-sectional study, advanced magnetic resonance imaging (MRI) was used to evaluate multiple aspects of brain physiology in three groups of athletes, participating in non-contact sports (N=20), contact sports (N=22) and collision sports (N=23). Diffusion tensor imaging (DTI) was used to assess white matter microstructure based on measures of fractional anisotropy (FA) and mean diffusivity (MD); resting state functional MRI (fMRI) was used to evaluate global functional connectivity; single-voxel spectroscopy (SVS) was used to compare ratios of neural metabolites, including n-acetyl aspartate (NAA), creatine (Cr), choline (Cho) and myo-insositol (Ins). Multivariate analysis revealed structural, functional and metabolic measures that reliably differentiate between sport groups. Both collision and contact sport groups had significantly elevated FA and reduced MD in white matter, compared to the non-contact group. In contrast, only the collision group showed significant reductions in functional connectivity and the NAA/Cr metabolite ratio, relative to the non-contact group. For brain regions associated with contact sport participation, athletes with a history of concussion also showed greater alterations in FA and functional connectivity, indicating a potential cumulative effect of contact exposure and concussion history on brain physiology. These findings indicate persistent differences in brain physiology for athletes participating in contact and collision sports, which should be considered in future studies of concussion and subconcussive impacts.
33 citations
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01 May 1990TL;DR: The Fourth Edition of Biomechanics as an Interdiscipline: A Review of the Fourth Edition focuses on biomechanical Electromyography, with a focus on the relationship between Electromyogram and Biomechinical Variables.
Abstract: Preface to the Fourth Edition. 1 Biomechanics as an Interdiscipline. 1.0 Introduction. 1.1 Measurement, Description, Analysis, and Assessment. 1.2 Biomechanics and its Relationship with Physiology and Anatomy. 1.3 Scope of the Textbook. 1.4 References. 2 Signal Processing. 2.0 Introduction. 2.1 Auto- and Cross-Correlation Analyses. 2.2 Frequency Analysis. 2.3 Ensemble Averaging of Repetitive Waveforms. 2.4 References. 3 Kinematics. 3.0 Historical Development and Complexity of Problem. 3.1 Kinematic Conventions. 3.2 Direct Measurement Techniques. 3.3 Imaging Measurement Techniques. 3.4 Processing of Raw Kinematic Data. 3.5 Calculation of Other Kinematic Variables. 3.6 Problems Based on Kinematic Data. 3.7 References. 4 Anthropometry. 4.0 Scope of Anthropometry in Movement Biomechanics. 4.1 Density, Mass, and Inertial Properties. 4.2 Direct Experimental Measures. 4.3 Muscle Anthropometry. 4.4 Problems Based on Anthropometric Data. 4.5 References. 5 Kinetics: Forces and Moments of Force. 5.0 Biomechanical Models. 5.1 Basic Link-Segment Equations-the Free-Body Diagram. 5.2 Force Transducers and Force Plates. 5.3 Bone-on-Bone Forces During Dynamic Conditions. 5.4 Problems Based on Kinetic and Kinematic Data. 5.5 References. 6 Mechanical Work, Energy, and Power. 6.0 Introduction. 6.1 Efficiency. 6.2 Forms of Energy Storage. 6.3 Calculation of Internal and External Work. 6.4 Power Balances at Joints and Within Segments. 6.5 Problems Based on Kinetic and Kinematic Data. 6.6 References. 7 Three-Dimensional Kinematics and Kinetics. 7.0 Introduction. 7.1 Axes Systems. 7.2 Marker and Anatomical Axes Systems. 7.3 Determination of Segment Angular Velocities and Accelerations. 7.4 Kinetic Analysis of Reaction Forces and Moments. 7.5 Suggested Further Reading. 7.6 References. 8 Synthesis of Human Movement-Forward Solutions. 8.0 Introduction. 8.1 Review of Forward Solution Models. 8.2 Mathematical Formulation. 8.3 System Energy. 8.4 External Forces and Torques. 8.5 Designation of Joints. 8.6 Illustrative Example. 8.7 Conclusions. 8.8 References. 9 Muscle Mechanics. 9.0 Introduction. 9.1 Force-Length Characteristics of Muscles. 9.2 Force-Velocity Characteristics. 9.3 Muscle Modeling. 9.4 References. 10 Kinesiological Electromyography. 10.0 Introduction. 10.1 Electrophysiology of Muscle Contraction. 10.2 Recording of the Electromyogram. 10.3 Processing of the Electromyogram,. 10.4 Relationship between Electromyogram and Biomechanical Variables. 10.5 References. 11 Biomechanical Movement Synergies. 11.0 Introduction. 11.1 The Support Moment Synergy. 11.2 Medial/Lateral and Anterior/Posterior Balance in Standing. 11.3 Dynamic Balance during Walking. 11.4 References. APPENDICES. A. Kinematic, Kinetic, and Energy Data. Figure A.1 Walking Trial-Marker Locations and Mass and Frame Rate Information. Table A.1 Raw Coordinate Data (cm). Table A.2( a ) Filtered Marker Kinematics-Rib Cage and Greater Trochanter (Hip). Table A.2( b ) Filtered Marker Kinematics-Femoral Lateral Epicondyle (Knee) and Head of Fibula. Table A.2( c ) Filtered Marker Kinematics-Lateral Malleolus (Ankle) and Heel. Table A.2( d ) Filtered Marker Kinematics-Fifth Metatarsal and Toe. Table A.3( a ) Linear and Angular Kinematics-Foot. Table A.3( b ) Linear and Angular Kinematics-Leg. Table A.3( c ) Linear and Angular Kinematics-Thigh. Table A.3( d ) Linear and Angular Kinematics-1/2 HAT. Table A.4 Relative Joint Angular Kinematics-Ankle, Knee, and Hip. Table A.5( a ) Reaction Forces and Moments of Force-Ankle and Knee. Table A.5( b ) Reaction Forces and Moments of Force-Hip. Table A.6 Segment Potential, Kinetic, and Total Energies-Foot, Leg, Thigh, and1/2 HAT. Table A.7 Power Generation/Absorption and Transfer-Ankle, Knee, and Hip. B. Units and Definitions Related to Biomechanical and Electromyographical Measurements. Table B.1 Base SI Units. Table B.2 Derived SI Units. Index.
9,092 citations
TL;DR: A study with 40 normal adult subjects indicates that the ANT produces reliable single subject estimates of alerting, orienting, and executive function, and further suggests that the efficiencies of these three networks are uncorrelated.
Abstract: In recent years, three attentional networks have been defined in anatomical and functional terms. These functions involve alerting, orienting, and executive attention. Reaction time measures can be used to quantify the processing efficiency within each of these three networks. The Attention Network Test (ANT) is designed to evaluate alerting, orienting, and executive attention within a single 30-min testing session that can be easily performed by children, patients, and monkeys. A study with 40 normal adult subjects indicates that the ANT produces reliable single subject estimates of alerting, orienting, and executive function, and further suggests that the efficiencies of these three networks are uncorrelated. There are, however, some interactions in which alerting and orienting can modulate the degree of interference from flankers. This procedure may prove to be convenient and useful in evaluating attentional abnormalities associated with cases of brain injury, stroke, schizophrenia, and attention-deficit disorder. The ANT may also serve as an activation task for neuroimaging studies and as a phenotype for the study of the influence of genes on attentional networks.
3,166 citations
TL;DR: In this paper, a study of 1631 football players from 15 US colleges found that players with concussions exhibited more severe symptoms (mean GSC score 20.93 [95% confidence interval {CI, 15.65-26.21] points higher than that of controls), cognitive impairments (mean SAC score 2.94 [ 95% CI, 1.41 to 2.06], cognitive functioning improved to baseline levels within 5 to 7 days (day 7 SAC mean difference, −0.33;
Abstract: ContextLack of empirical data on recovery time following sport-related concussion
hampers clinical decision making about return to play after injury.ObjectiveTo prospectively measure immediate effects and natural recovery course
relating to symptoms, cognitive functioning, and postural stability following
sport-related concussion.Design, Setting, and ParticipantsProspective cohort study of 1631 football players from 15 US colleges.
All players underwent preseason baseline testing on concussion assessment
measures in 1999, 2000, and 2001. Ninety-four players with concussion (based
on American Academy of Neurology criteria) and 56 noninjured controls underwent
assessment of symptoms, cognitive functioning, and postural stability immediately,
3 hours, and 1, 2, 3, 5, 7, and 90 days after injury.Main Outcome MeasuresScores on the Graded Symptom Checklist (GSC), Standardized Assessment
of Concussion (SAC), Balance Error Scoring System (BESS), and a neuropsychological
test battery.ResultsNo player with concussion was excluded from participation; 79 players
with concussion (84%) completed the protocol through day 90. Players with
concussion exhibited more severe symptoms (mean GSC score 20.93 [95% confidence
interval {CI}, 15.65-26.21] points higher than that of controls), cognitive
impairment (mean SAC score 2.94 [95% CI, 1.50-4.38] points lower than that
of controls), and balance problems (mean BESS score 5.81 [95% CI, –0.67
to 12.30] points higher than that of controls) immediately after concussion.
On average, symptoms gradually resolved by day 7 (GSC mean difference, 0.33;
95% CI, −1.41 to 2.06), cognitive functioning improved to baseline levels
within 5 to 7 days (day 7 SAC mean difference, −0.03; 95% CI, −1.33
to 1.26), and balance deficits dissipated within 3 to 5 days after injury
(day 5 BESS mean difference, −0.31; 95% CI, −3.02 to 2.40). Mild
impairments in cognitive processing and verbal memory evident on neuropsychological
testing 2 days after concussion resolved by day 7. There were no significant
differences in symptoms or functional impairments in the concussion and control
groups 90 days after concussion.ConclusionsCollegiate football players may require several days for recovery of
symptoms, cognitive dysfunction, and postural instability after concussion.
Further research is required to determine factors that predict variability
in recovery time after concussion. Standardized measurement of postconcussive
symptoms, cognitive functioning, and postural stability may enhance clinical
management of athletes recovering from concussion.
1,484 citations
TL;DR: The recommendations for concussion management provided here are based on the most current research and divided into sections on education and prevention, documentation and legal aspects, evaluation and return to play, and other considerations.
Abstract: Objective: To provide athletic trainers, physicians, and other health care professionals with best-practice guidelines for the management of sport-related concussions. Background: An estimated 3.8 ...
1,026 citations
TL;DR: A subroutine package is presented in which the amount of smoothing on a set of n noisy datapoints is determined from the data by means of the Generalized Cross-Validation or predicted Mean-Squared Error criteria of Wahba and her collaborators.
987 citations