Toronto Rehabilitation Institute

When a mixture of molecules is passed through a column of porous gel granules, the molecules may appear in the effluent in order of decreasing size. Fractionation is believed to occur when diffusion of the molecules into the gel pores is restricted but not prevented because of their size, and because they pass through the column at rates that are related inversely to the fluid volume accessible to them within the column. Lathe & Ruthven (1956) suggested that the dimensions of protein and poly- saccharide molecules might be estimated by this technique, now widely known as gel-filtration. However, evaluation of their suggestion is difficult because of uncertainty about the size and shape of macromolecules in solution (Schachman, 1960). Although molecular weight is unlikely to be a good approximation for size in comparing such dis- similar molecules as proteins and polysaccharides, the correlation between molecular weights and gelfiltration behaviour of dextrans (Granath & Flodin, 1961) indicates that, for a homogeneous series of macromolecules, size and molecular weight are closely related. Andrews (1962) obtained evidence from experiments with agar-gel columns that this was also true for a number of proteins, and showed that gel-filtration can be used as a comparative method to give useful estimates of the molecular weights of proteins.

The original Physical Activity Readiness Questionnaire (PAR-Q) offers a safe preliminary screening of candidates for exercise testing and prescription, but it screens out what seems an excessive proportion of apparently healthy older adults. To reduce unnecessary exclusions, an expert committee established by Fitness Canada has now revised the questionnaire wording. The present study compares responses to the original and the revised PAR-Q questionnaire in 399 men and women attending 40 accredited fitness testing centres across Canada. The number of subjects screened out by the revised test decreased significantly (p < .05), from 68 to 48 of the 399 subjects. The change reflects in part the inclusion of individuals who had made an erroneous positive response to the original question regarding high blood pressure. There is no simple gold standard to provide an objective evaluation of the sensitivity and specificity of either questionnaire format, but the revised wording has apparently had the intended effect of reducing positive responses, particularly to the question regarding an elevation of blood pressure.

STUDY DESIGN: Method guidelines for systematic reviews of trials of treatments for neck and back pain. OBJECTIVE: To help review authors design, conduct and report systematic reviews of trials in this field. SUMMARY OF BACKGROUND DATA: In 1997, the Cochrane Back Review Group published Method Guidelines for Systematic Reviews, which was updated in 2003. Since then, new methodologic evidence has emerged and standards have changed. Coupled with the upcoming revisions to the software and methods required by The Cochrane Collaboration, it was clear that revisions were needed to the existing guidelines. METHODS: The Cochrane Back Review Group editorial and advisory boards met in June 2006 to review the relevant new methodologic evidence and determine how it should be incorporated. Based on the discussion, the guidelines were revised and circulated for comment. As sections of the new Cochrane Handbook for Systematic Reviews of Interventions were made available, the guidelines were checked for consistency. A working draft was made available to review authors in The Cochrane Library 2008, issue 3. RESULTS: The final recommendations are divided into 7 categories: objectives, literature search, inclusion criteria, risk of bias assessment, data extraction, data analysis, and updating your review. Each recommendation is classified into minimum criteria (mandatory) and further guidance (optional). Instead of recommending Levels of Evidence, this update adopts the GRADE approach to determine the overall quality of the evidence for important patient-centered outcomes across studies and includes a new section on updating reviews. CONCLUSION: Citations of previous versions of the method guidelines in published scientific articles (1997: 254 citations; 2003: 209 citations, searched February 10, 2009) suggest that others may find these guidelines useful to plan, conduct, or evaluate systematic reviews in the field of spinal disorders.

The Canadian Association of Occupational Therapists, in collaboration with Health and Welfare Canada have developed and published a conceptual model for occupational therapy, the Occupational Performance model. This paper describes the development of an outcome measure, The Canadian Occupational Performance Measure (COPM), which is designed to be used with these guidelines for client-centred clinical practice. The COPM is an outcome measure designed for use by occupational therapists to assess client outcomes in the areas of self-care, productivity and leisure. Using a semi-structured interview, the COPM is a five step process which measures individual, client-identified problem areas in daily function. Two scores, for performance and satisfaction with performance are obtained. This paper describes the rationale and development of the COPM as well as information about its use for therapists.

In previous analyses of the occurrence of central (CSA) and obstructive sleep apnea (OSA) in patients with congestive heart failure (CHF), only men were studied and risk factors for these disorders were not well characterized. We therefore analyzed risk factors for CSA and OSA in 450 consecutive patients with CHF (382 male, 68 female) referred to our sleep laboratory. Risk factors for CSA were male gender (odds ratio [OR] 3.50; 95% confidence interval [CI], 1.39 to 8.84), atrial fibrillation (OR 4.13; 95% CI 1.53 to 11. 14), age > 60 yr (OR 2.37; 95% CI 1.35 to 4.15), and hypocapnia (PCO(2 )< 38 mm Hg during wakefulness) (OR 4.33; 95% CI 2.50 to 7. 52). Risk factors for OSA differed by gender: in men, only body mass index (BMI) was significantly associated with OSA (OR for a BMI > 35 kg/m(2), 6.10; 95% CI 2.86 to 13.00); whereas, in women, age was the only important risk factor (OR for age > 60 yr, 6.04; 95% CI 1.75 to 20.0). We conclude that historical information, supplemented by a few simple laboratory tests may enable physicians to risk stratify CHF patients for the presence of CSA or OSA, and the need for diagnostic polysomnography for such patients. Sin DD, Fitzgerald F, Parker JD, Newton G, Floras JS, Bradley TD. Risk factors for central and obstructive sleep apnea in 450 men and women with congestive heart failure.

In the last decade, the prevalence of obesity has increased significantly in populations worldwide. A less dramatic, but equally important increase has been seen in our knowledge of its effects on health and the burden it places on healthcare systems. This systematic review aims to assess the current published literature on the direct costs associated with obesity. A computerized search of English language articles published between 1990 and June 2009 yielded 32 articles suitable for review. Based on these articles, obesity was estimated to account for between 0.7% and 2.8% of a country's total healthcare expenditures. Furthermore, obese individuals were found to have medical costs that were approximately 30% greater than their normal weight peers. Although variations in inclusion/exclusion criteria, reporting methods and included costs varied widely between the studies, a lack of examination of how and why the excess costs were being accrued appeared to be a commonality between most studies. Accordingly, future studies must better explore how costs accrue among obese populations, in order to best facilitate health and social policy interventions.

BACKGROUND: Obstructive sleep apnea subjects the failing heart to adverse hemodynamic and adrenergic loads and may thereby contribute to the progression of heart failure. We hypothesized that treatment of obstructive sleep apnea by continuous positive airway pressure in patients with heart failure would improve left ventricular systolic function. METHODS: Twenty-four patients with a depressed left ventricular ejection fraction (45 percent or less) and obstructive sleep apnea who were receiving optimal medical treatment for heart failure underwent polysomnography. On the following morning, their blood pressure and heart rate were measured by digital photoplethysmography, and left ventricular dimensions and left ventricular ejection fraction were assessed by echocardiography. The subjects were then randomly assigned to receive medical therapy either alone (12 patients) or with the addition of continuous positive airway pressure (12 patients) for one month. The assessment protocol was then repeated. RESULTS: In the control group of patients who received only medical therapy, there were no significant changes in the severity of obstructive sleep apnea, daytime blood pressure, heart rate, left ventricular end-systolic dimension, or left ventricular ejection fraction during the study. In contrast, continuous positive airway pressure markedly reduced obstructive sleep apnea, reduced the daytime systolic blood pressure from a mean (+/-SE) of 126+/-6 mm Hg to 116+/-5 mm Hg (P=0.02), reduced the heart rate from 68+/-3 to 64+/-3 beats per minute (P=0.007), reduced the left ventricular end-systolic dimension from 54.5+/-1.8 to 51.7+/-1.2 mm (P=0.009), and improved the left ventricular ejection fraction from 25.0+/-2.8 to 33.8+/-2.4 percent (P<0.001). CONCLUSION: In medically treated patients with heart failure, treatment of coexisting obstructive sleep apnea by continuous positive airway pressure reduces systolic blood pressure and improves left ventricular systolic function. Obstructive sleep apnea may thus have an adverse effect in heart failure that can be addressed by targeted therapy.

Dysphagia is estimated to affect ~8% of the world's population (~590 million people). Texture-modified foods and thickened drinks are commonly used to reduce the risks of choking and aspiration. The International Dysphagia Diet Standardisation Initiative (IDDSI) was founded with the goal of developing globally standardized terminology and definitions for texture-modified foods and liquids applicable to individuals with dysphagia of all ages, in all care settings, and all cultures. A multi-professional volunteer committee developed a dysphagia diet framework through systematic review and stakeholder consultation. First, a survey of existing national terminologies and current practice was conducted, receiving 2050 responses from 33 countries. Respondents included individuals with dysphagia; their caregivers; organizations supporting individuals with dysphagia; healthcare professionals; food service providers; researchers; and industry. The results revealed common use of 3-4 levels of food texture (54 different names) and ≥3 levels of liquid thickness (27 different names). Substantial support was expressed for international standardization. Next, a systematic review regarding the impact of food texture and liquid consistency on swallowing was completed. A meeting was then convened to review data from previous phases, and develop a draft framework. A further international stakeholder survey sought feedback to guide framework refinement; 3190 responses were received from 57 countries. The IDDSI Framework (released in November, 2015) involves a continuum of 8 levels (0-7) identified by numbers, text labels, color codes, definitions, and measurement methods. The IDDSI Framework is recommended for implementation throughout the world.

Working memory is important for online language processing during conversation. We use it to maintain relevant information, to inhibit or ignore irrelevant information, and to attend to conversation selectively. Working memory helps us to keep track of and actively participate in conversation, including taking turns and following the gist. This paper examines the Ease of Language Understanding model (i.e., the ELU model, Rönnberg, 2003; Rönnberg et al., 2008) in light of new behavioral and neural findings concerning the role of working memory capacity (WMC) in uni-modal and bimodal language processing. The new ELU model is a meaning prediction system that depends on phonological and semantic interactions in rapid implicit and slower explicit processing mechanisms that both depend on WMC albeit in different ways. It is based on findings that address the relationship between WMC and (a) early attention processes in listening to speech, (b) signal processing in hearing aids and its effects on short-term memory, (c) inhibition of speech maskers and its effect on episodic long-term memory, (d) the effects of hearing impairment on episodic and semantic long-term memory, and finally, (e) listening effort. New predictions and clinical implications are outlined. Comparisons with other WMC and speech perception models are made.

RATIONALE: Sleep-disordered breathing has been linked to stroke in previous studies. However, these studies either used surrogate markers of sleep-disordered breathing or could not, due to cross-sectional design, address the temporal relationship between sleep-disordered breathing and stroke. OBJECTIVES: To determine whether sleep-disordered breathing increases the risk for stroke. METHODS: We performed cross-sectional and longitudinal analyses on 1,475 and 1,189 subjects, respectively, from the general population. Sleep-disordered breathing was defined by the apnea-hypopnea index (frequency of apneas and hypopneas per hour of sleep) obtained by attended polysomnography. The protocol, including polysomnography, risk factors for stroke, and a history of physician-diagnosed stroke, was repeated at 4-yr intervals. MEASUREMENTS AND MAIN RESULTS: In the cross-sectional analysis, subjects with an apnea-hypopnea index of 20 or greater had increased odds for stroke (odds ratio, 4.33; 95% confidence interval, 1.32-14.24; p = 0.02) compared with those without sleep-disordered breathing (apnea-hypopnea index, <5) after adjustment for known confounding factors. In the prospective analysis, sleep-disordered breathing with an apnea-hypopnea index of 20 or greater was associated with an increased risk of suffering a first-ever stroke over the next 4 yr (unadjusted odds ratio, 4.31; 95% confidence interval, 1.31-14.15; p = 0.02). However, after adjustment for age, sex, and body mass index, the odds ratio was still elevated, but was no longer significant (3.08; 95% confidence interval, 0.74-12.81; p = 0.12). CONCLUSIONS: These data demonstrate a strong association between moderate to severe sleep-disordered breathing and prevalent stroke, independent of confounding factors. They also provide the first prospective evidence that sleep-disordered breathing precedes stroke and may contribute to the development of stroke.

The Canadian Society for Exercise Physiology assembled a Consensus Panel representing national organizations, content experts, methodologists, stakeholders, and end-users and followed an established guideline development procedure to create the Canadian 24-Hour Movement Guidelines for Adults aged 18–64 years and Adults aged 65 years or older: An Integration of Physical Activity, Sedentary Behaviour, and Sleep. These guidelines underscore the importance of movement behaviours across the whole 24-h day. The development process followed the strategy outlined in the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument. A large body of evidence was used to inform the guidelines including 2 de novo systematic reviews and 4 overviews of reviews examining the relationships among movement behaviours (physical activity, sedentary behaviour, sleep, and all behaviours together) and several health outcomes. Draft guideline recommendations were discussed at a 4-day in-person Consensus Panel meeting. Feedback from stakeholders was obtained by survey (n = 877) and the draft guidelines were revised accordingly. The final guidelines provide evidence-based recommendations for a healthy day (24-h), comprising a combination of sleep, sedentary behaviours, and light-intensity and moderate-to-vigorous-intensity physical activity. Dissemination and implementation efforts with corresponding evaluation plans are in place to help ensure that guideline awareness and use are optimized. Novelty First ever 24-Hour Movement Guidelines for Adults aged 18–64 years and Adults aged 65 years or older with consideration of a balanced approach to physical activity, sedentary behaviour, and sleep Finalizes the suite of 24-Hour Movement Guidelines for Canadians across the lifespan

Scoping reviews are an increasingly common approach to evidence synthesis with a growing suite of methodological guidance and resources to assist review authors with their planning, conduct and reporting. The latest guidance for scoping reviews includes the JBI methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Extension for Scoping Reviews. This paper provides readers with a brief update regarding ongoing work to enhance and improve the conduct and reporting of scoping reviews as well as information regarding the future steps in scoping review methods development. The purpose of this paper is to provide readers with a concise source of information regarding the difference between scoping reviews and other review types, the reasons for undertaking scoping reviews, and an update on methodological guidance for the conduct and reporting of scoping reviews.Despite available guidance, some publications use the term 'scoping review' without clear consideration of available reporting and methodological tools. Selection of the most appropriate review type for the stated research objectives or questions, standardised use of methodological approaches and terminology in scoping reviews, clarity and consistency of reporting and ensuring that the reporting and presentation of the results clearly addresses the review's objective(s) and question(s) are critical components for improving the rigour of scoping reviews.Rigourous, high-quality scoping reviews should clearly follow up to date methodological guidance and reporting criteria. Stakeholder engagement is one area where further work could occur to enhance integration of consultation with the results of evidence syntheses and to support effective knowledge translation. Scoping review methodology is evolving as a policy and decision-making tool. Ensuring the integrity of scoping reviews by adherence to up-to-date reporting standards is integral to supporting well-informed decision-making.

AIM: These international clinical practice recommendations (CPR) for developmental coordination disorder (DCD), initiated by the European Academy of Childhood Disability (EACD), aim to address key questions on the definition, diagnosis, assessment, intervention, and psychosocial aspects of DCD relevant for clinical practice. METHOD: Key questions in five areas were considered through literature reviews and formal expert consensus. For recommendations based on evidence, literature searches on 'mechanisms', 'assessment', and 'intervention' were updated since the last recommendations in 2012. New searches were conducted for 'psychosocial issues' and 'adolescents/adults'. Evidence was rated according to the Oxford Centre for Evidence-Based Medicine (level of evidence [LOE] 1-4) and transferred into recommendations. For recommendations based on formal consensus, two meetings of an international, multidisciplinary expert panel were conducted with a further five Delphi rounds to develop good clinical practice (GCP) recommendations. RESULTS: Thirty-five recommendations were made. Eight were based on the evidence from literature reviews (three on 'assessment', five on 'intervention'). Twenty-two were updated from the 2012 recommendations. New recommendations relate to diagnosis and assessment (two GCPs) and psychosocial issues (three GCPs). Additionally, one new recommendation (LOE) reflects active video games as adjuncts to more traditional activity-oriented and participation-oriented interventions, and two new recommendations (one GCP, one LOE) were made for adolescents and adults with DCD. INTERPRETATION: The CPR-DCD is a comprehensive overview of DCD and current understanding based on research evidence and expert consensus. It reflects the state of the art for clinicians and scientists of varied disciplines. The international CPR-DCD may serve as a basis for national guidelines. WHAT THIS PAPER ADDS: Updated international clinical practice guidelines on developmental coordination disorder (DCD). Refined and extended recommendations on clinical assessment and intervention for DCD. A critical synopsis of current research on mechanisms of DCD. A critical synopsis of psychosocial issues in DCD, with implications for clinical practice. The first international recommendations to consider adolescents and adults with DCD.

BACKGROUND: Clinical practice guidelines have been a popular tool for the improvement of health care through the implementation of evidence from systematic research. Yet, it is increasingly clear that knowledge alone is insufficient to change practice. The social, cultural, and material contexts within which practice occurs may invite or reject innovation, complement or inhibit the activities required for success, and sustain or alter adherence to entrenched practices. However, knowledge translation (KT) models are limited in providing insight about how and why contextual contingencies interact, the causal mechanisms linking structural aspects of context and individual agency, and how these mechanisms influence KT. Another limitation of KT models is the neglect of methods to engage potential adopters of the innovation in critical reflection about aspects of context that influence practice, the relevance and meaning of innovation in the context of practice, and the identification of strategies for bringing about meaningful change. DISCUSSION: This paper presents a KT model, the Critical Realism and the Arts Research Utilization Model (CRARUM), that combines critical realism and arts-based methodologies. Critical realism facilitates understanding of clinical settings by providing insight into the interrelationship between its structures and potentials, and individual action. The arts nurture empathy, and can foster reflection on the ways in which contextual factors influence and shape clinical practice, and how they may facilitate or impede change. The combination of critical realism and the arts within the CRARUM model promotes the successful embedding of interventions, and greater impact and sustainability. CONCLUSION: CRARUM has the potential to strengthen the science of implementation research by addressing the complexities of practice settings, and engaging potential adopters to critically reflect on existing and proposed practices and strategies for sustaining change.

BACKGROUND: Although memory impairment is the main symptom of Alzheimer's disease (AD), language impairment can be an important marker. Relatively few studies of language in AD quantify the impairments in connected speech using computational techniques. OBJECTIVE: We aim to demonstrate state-of-the-art accuracy in automatically identifying Alzheimer's disease from short narrative samples elicited with a picture description task, and to uncover the salient linguistic factors with a statistical factor analysis. METHODS: Data are derived from the DementiaBank corpus, from which 167 patients diagnosed with "possible" or "probable" AD provide 240 narrative samples, and 97 controls provide an additional 233. We compute a number of linguistic variables from the transcripts, and acoustic variables from the associated audio files, and use these variables to train a machine learning classifier to distinguish between participants with AD and healthy controls. To examine the degree of heterogeneity of linguistic impairments in AD, we follow an exploratory factor analysis on these measures of speech and language with an oblique promax rotation, and provide interpretation for the resulting factors. RESULTS: We obtain state-of-the-art classification accuracies of over 81% in distinguishing individuals with AD from those without based on short samples of their language on a picture description task. Four clear factors emerge: semantic impairment, acoustic abnormality, syntactic impairment, and information impairment. CONCLUSION: Modern machine learning and linguistic analysis will be increasingly useful in assessment and clustering of suspected AD.

BACKGROUND AND PURPOSE: Hemiparesis resulting in functional limitation of an upper extremity is common among stroke survivors. Although existing evidence suggests that increasing intensity of stroke rehabilitation therapy results in better motor recovery, limited evidence is available on the efficacy of virtual reality for stroke rehabilitation. METHODS: In this pilot, randomized, single-blinded clinical trial with 2 parallel groups involving stroke patients within 2 months, we compared the feasibility, safety, and efficacy of virtual reality using the Nintendo Wii gaming system (VRWii) versus recreational therapy (playing cards, bingo, or "Jenga") among those receiving standard rehabilitation to evaluate arm motor improvement. The primary feasibility outcome was the total time receiving the intervention. The primary safety outcome was the proportion of patients experiencing intervention-related adverse events during the study period. Efficacy, a secondary outcome measure, was evaluated with the Wolf Motor Function Test, Box and Block Test, and Stroke Impact Scale at 4 weeks after intervention. RESULTS: Overall, 22 of 110 (20%) of screened patients were randomized. The mean age (range) was 61.3 (41 to 83) years. Two participants dropped out after a training session. The interventions were successfully delivered in 9 of 10 participants in the VRWii and 8 of 10 in the recreational therapy arm. The mean total session time was 388 minutes in the recreational therapy group compared with 364 minutes in the VRWii group (P=0.75). There were no serious adverse events in any group. Relative to the recreational therapy group, participants in the VRWii arm had a significant improvement in mean motor function of 7 seconds (Wolf Motor Function Test, 7.4 seconds; 95% CI, -14.5, -0.2) after adjustment for age, baseline functional status (Wolf Motor Function Test), and stroke severity. CONCLUSIONS: VRWii gaming technology represents a safe, feasible, and potentially effective alternative to facilitate rehabilitation therapy and promote motor recovery after stroke.

Importance: Although wait times for hip fracture surgery have been linked to mortality and are being used as quality-of-care indicators worldwide, controversy exists about the duration of the wait that leads to complications. Objective: To use population-based wait-time data to identify the optimal time window in which to conduct hip fracture surgery before the risk of complications increases. Design, Setting, and Participants: Population-based, retrospective cohort study of adults undergoing hip fracture surgery between April 1, 2009, and March 31, 2014, at 72 hospitals in Ontario, Canada. Risk-adjusted restricted cubic splines modeled the probability of each complication according to wait time. The inflection point (in hours) when complications began to increase was used to define early and delayed surgery. To evaluate the robustness of this definition, outcomes among propensity-score matched early and delayed surgical patients were compared using percent absolute risk differences (RDs, with 95% CIs). Exposure: Time elapsed from hospital arrival to surgery (in hours). Main Outcomes and Measures: Mortality within 30 days. Secondary outcomes included a composite of mortality or other medical complications (myocardial infarction, deep vein thrombosis, pulmonary embolism, and pneumonia). Results: Among 42 230 patients with hip fracture (mean [SD] age, 80.1 years [10.7], 70.5% women) who met study entry criteria, overall mortality at 30 days was 7.0%. The risk of complications increased when wait times were greater than 24 hours, irrespective of the complication considered. Compared with 13 731 propensity-score matched patients who received surgery earlier, 13 731 patients who received surgery after 24 hours had a significantly higher risk of 30-day mortality (898 [6.5%] vs 790 [5.8%]; % absolute RD, 0.79; 95% CI, 0.23-1.35) and the composite outcome (1680 [12.2%]) vs 1383 [10.1%]; % absolute RD, 2.16; 95% CI, 1.43-2.89). Conclusions and Relevance: Among adults undergoing hip fracture surgery, increased wait time was associated with a greater risk of 30-day mortality and other complications. A wait time of 24 hours may represent a threshold defining higher risk.

As a greater proportion of patients survive their initial cardiac insult, medical systems worldwide are being faced with an ever-growing need to understand the mechanisms behind the pathogenesis of chronic heart failure (HF). There is a wealth of information about the role of inflammatory cells and pathways during acute injury and the reparative processes that are subsequently activated. We discuss the different causes that lead to chronic HF development and how the sum of initial inflammatory and reparative responses only sets the trajectory for disease progression. Unfortunately, comparatively little is known about the contribution of the immune system once the trajectory has been set, and chronic HF has been established-which clinically represents the majority of patients. It is known that chronic HF is associated with circulating inflammatory cytokines that can predict clinical outcomes, yet the causative role inflammation plays in disease progression is not well defined, and the majority of clinical trials that target aspects of inflammation in patients with chronic HF have largely been negative. This review will present what is currently known about inflammation in chronic HF in both humans and animal models as a means to highlight the gap in our knowledge base that requires further examination.

This paper is a revision and update of the recommendations developed following the 1st (Vienna) and 2nd (Prague) International Symposia on Concussion in Sport.1,2 The Zurich Consensus statement is designed to build on the principles outlined in the original Vienna and Prague documents and to develop further conceptual understanding of this problem using a formal consensus-based approach. A detailed description of the consensus process is outlined at the end of this document under the background section (see Section 11). This document is developed for use by physicians, therapists, certified athletic trainers, health professionals, coaches, and other people involved in the care of injured athletes, whether at the recreational, elite, or professional level.While agreement exists pertaining to principal messages conveyed within this document, the authors acknowledge that the science of concussion is evolving and, therefore, management and return-to-play (RTP) decisions remain in the realm of clinical judgment on an individualized basis. Readers are encouraged to copy and distribute freely the Zurich Consensus document and the Sports Concussion Assessment Tool (SCAT2) card, and neither is subject to any copyright restriction. The authors request, however, that the document and the SCAT2 card be distributed in their full and complete format.The following focus questions formed the foundation for the Zurich concussion consensus statement:Acute Simple ConcussionRTP IssuesComplex Concussion and Long-Term IssuesPediatric ConcussionFuture DirectionsThe Zurich document additionally examines the management issues raised in the previous Prague and Vienna documents and applies the consensus questions to these areas.Panel discussion regarding the definition of concussion and its separation from mild traumatic brain injury (mTBI) was held. Although there was acknowledgment that the terms refer to different injury constructs and should not be used interchangeably, it was not felt that the panel would define mTBI for the purpose of this document. There was unanimous agreement, however, that concussion is defined as follows:There was unanimous agreement to abandon the "simple" versus "complex" terminology that had been proposed in the Prague agreement statement, as the panel felt that the terminology itself did not fully describe the entities. The panel, however, unanimously retained the concept that the majority (80%–90%) of concussions resolve in a short (7- to 10-day) period, although the recovery time frame may be longer in children and adolescents.2The panel agreed that the diagnosis of acute concussion usually involves the assessment of a range of domains, including clinical symptoms, physical signs, behaviour, balance, sleep, and cognition. Furthermore, a detailed concussion history is an important part of the evaluation, both in the injured athlete and when conducting a preparticipation examination. The detailed clinical assessment of concussion is outlined in the SCAT2 form, which is an appendix to this document.The suspected diagnosis of concussion can include one or more of the following clinical domains:If any one or more of these components is present, a concussion should be suspected and the appropriate management strategy instituted.When a player shows ANY features of a concussionIt was unanimously agreed that sufficient time for assessment and adequate facilities should be provided for the appropriate medical assessment, both on and off the field, for all injured athletes. In some sports, this may require rule change to allow an off-field medical assessment to occur without affecting the flow of the game or unduly penalizing the injured player's team.Sideline evaluation of cognitive function is an essential component in the assessment of this injury. Brief neuropsychological test batteries that assess attention and memory function have been shown to be practical and effective. Such tests include the Maddocks questions3,4 and the Standardized Assessment of Concussion (SAC).5–7 It is worth noting that standard orientation questions (eg, time, place, person) have been shown to be unreliable in the sporting situation when compared with memory assessment.4,8 It is recognized, however, that abbreviated testing paradigms are designed for rapid concussion screening on the sidelines and are not meant to replace comprehensive neuropsychological testing, which is sensitive to detecting subtle deficits that may exist beyond the acute episode, nor should they be used as a stand-alone tool for the ongoing management of sports concussions.It should also be recognized that the appearance of symptoms might be delayed several hours following a concussive episode.An athlete with concussion may be evaluated in the emergency room or doctor's office as a point of first contact following injury or may have been referred from another care provider. In addition to the points outlined above, the key features of this exam should encompassIn large part, the points above are included in the SCAT2 assessment, which is included in the Zurich consensus statement.A range of additional investigations may be utilized to assist in the diagnosis and/or exclusion of injury. These include the following.It was recognized by the panelists that conventional structural neuroimaging is normal in concussive injury. Given that caveat, the following suggestions are made: Brain computed tomography (CT) (or, where available, MR brain scan) contributes little to concussion evaluation but should be employed whenever suspicion of an intracerebral structural lesion exists. Examples of such situations may include prolonged disturbance of conscious state, focal neurologic deficit, or worsening symptoms.Newer structural MR imaging modalities, including gradient echo, perfusion, and diffusion imaging, have greater sensitivity for structural abnormalities. However, the lack of published studies as well as absent preinjury neuroimaging data limits the usefulness of this approach in clinical management at the present time. In addition, the predictive value of various MR abnormalities that may be incidentally discovered is not established at the present time.Other imaging modalities such as functional magnetic resonance imaging (fMRI) demonstrate activation patterns that correlate with symptom severity and recovery in concussion.9–13 While not part of routine assessment at the present time, they nevertheless provide additional insight to pathophysiologic mechanisms. Alternative imaging technologies (eg, positron emission tomography, diffusion tensor imaging, magnetic resonance spectroscopy, functional connectivity), while demonstrating some compelling findings, are still at early stages of development and cannot be recommended other than in a research setting.Published studies using both sophisticated force plate technology as well as those using less sophisticated clinical balance tests (eg, Balance Error Scoring System [BESS]) have identified postural stability deficits lasting approximately 72 hours following sport-related concussion. It appears that postural stability testing provides a useful tool for objectively assessing the motor domain of neurologic functioning and should be considered a reliable and valid addition to the assessment of athletes suffering from concussion, particularly when symptoms or signs indicate a balance component.14–20The application of neuropsychological (NP) testing in concussion has been shown to be of clinical value and continues to contribute significant information in concussion evaluation.21–26 Although in most cases cognitive recovery largely overlaps with the time course of symptom recovery, it has been demonstrated that cognitive recovery may occasionally precede or more commonly follow clinical symptom resolution, suggesting that the assessment of cognitive function should be an important component in any RTP protocol.27,28 It must be emphasized, however, that NP assessment should not be the sole basis of management decisions; rather, it should be seen as an aid to the clinical decision-making process in conjunction with a range of clinical domains and investigational results.Neuropsychologists are in the best position to interpret NP tests by virtue of their background and training. However, there may be situations where neuropsychologists are not available and other medical professionals may perform or interpret NP screening tests. The ultimate RTP decision should remain a medical one, in which a multidisciplinary approach, when possible, has been taken. In the absence of NP and other (eg, formal balance assessment) testing, a more conservative return-to-play approach may be appropriate.In the majority of cases, NP testing will be used to assist RTP decisions and will not be done until the patient is symptom free.29,30 There may be persons (eg, child and adolescent athletes) in whom testing may be performed early while the patient is still symptomatic to assist in determining management. This will normally be best determined in consultation with a trained neuropsychologist.31,32The significance of apolipoprotein (Apo) E4, ApoE promotor gene, tau polymerase, and other genetic markers in the management of sports concussion risk or injury outcome is unclear at this time.33,34 Evidence from human and animal studies in more severe traumatic brain injury demonstrates induction of a variety of genetic and cytokine factors, such as insulin-like growth factor-1 (IGF-1), IGF binding protein-2, fibroblast growth factor, Cu-Zn superoxide dismutase, superoxide dismutase-1 (SOD-1), nerve growth factor, glial fibrillary acidic protein (GFAP), and S-100. Whether such factors are affected in sport concussion is not known at this stage.35–42Different electrophysiologic recording techniques (eg, evoked response potential [ERP], cortical magnetic stimulation, and electroencephalography) have demonstrated reproducible abnormalities in the postconcussive state. However, not all studies reliably differentiated concussed athletes from controls.43–49 The clinical significance of these changes remains to be established.In addition, biochemical serum and cerebrospinal fluid markers of brain injury (including S-100, neuron specific enolase [NSE], myelin basic protein [MBP], GFAP, tau, etc) have been proposed as means by which cellular damage may be detected if present.50–56 There is currently insufficient evidence, however, to justify the routine use of these biomarkers clinically.The cornerstone of concussion management is physical and cognitive rest until symptoms resolve and then a graded program of exertion prior to medical clearance and RTP. The recovery and outcome of this injury may be modified by a number of factors that may require more sophisticated management strategies. These are outlined in the section on modifiers below.As described above, the majority of patients will recover spontaneously over several days. In these situations, it is expected that an athlete will proceed progressively through a stepwise RTP strategy.57 During this period of recovery while symptomatic following an injury, it is important to emphasize to the athlete that physical AND cognitive rest is required. Activities that require concentration and attention (eg, scholastic work, video games, text messaging, etc) may exacerbate symptoms and possibly delay recovery. In such cases, apart from limiting relevant physical and cognitive activities (and other risk-taking opportunities for reinjury) while symptomatic, no further intervention is required during the period of recovery, and the athlete typically resumes sport without further problem.Return-to-play protocol following a concussion follows a stepwise process as outlined in Table 1.With this stepwise progression, the athlete should continue to proceed to the next level if asymptomatic at the current level. Generally each step should take 24 hours, so that an athlete would take approximately 1 week to proceed through the full rehabilitation protocol once asymptomatic at rest and with provocative exercise. If any postconcussion symptoms occur while in the stepwise program, then the patient should drop back to the previous asymptomatic level and try to progress again after a further 24-hour period of rest has passed.With adult athletes, in some settings, where there are team physicians experienced in concussion management and sufficient resources (eg, access to neuropsychologists, consultants, neuroimaging, etc) as well as access to immediate (ie, sideline) neurocognitive assessment, RTP management may be more rapid. The RTP strategy must still follow the same basic management principles: namely, full clinical and cognitive recovery before consideration of RTP. This approach is supported by published guidelines, such as those from the American Academy of Neurology, US Team Physician Consensus Statement, and US National Athletic Trainers' Association position statement.58–60 This issue was extensively discussed by the consensus panelists, and it was acknowledged that there is evidence that some professional American football players are able to RTP more quickly, with even same-day RTP supported by National Football League studies without a risk of recurrence or sequelae.61 There are data, however, demonstrating that at the collegiate and high school levels, athletes allowed to RTP on the same day may demonstrate NP deficits postinjury that may not be evident on the sidelines and are more likely to have delayed onset of symptoms.62–68 Yet it should be emphasized that the young (less than 18 years old) elite athlete should be treated more conservatively, even though the resources may be the same as for an older professional athlete (see section 6.1).In addition, psychological approaches may have potential application in this injury, particularly with the modifiers listed below.69,70 Caregivers are also encouraged to evaluate the concussed athlete for affective symptoms, such as depression, as these symptoms may be common in concussed athletes.57Pharmacologic therapy in sports concussion may be applied in 2 distinct situations. The first of these situations is the management of specific, prolonged symptoms (eg, sleep disturbance, anxiety, etc). The second situation is where drug therapy is used to modify the underlying pathophysiology of the condition with the aim of shortening the duration of the concussion symptoms.71 In broad terms, this approach to management should only be considered by clinicians experienced in concussion management.An important consideration in RTP is that concussed athletes should not only be symptom free but also should not be taking any pharmacologic agents or medications that may mask or modify the symptoms of concussion. Where antidepressant therapy may be commenced during the management of a concussion, the decision to RTP while still on such medication must be considered carefully by the treating clinician.Recognizing the importance of a concussion history and appreciating the fact that many athletes will not recognize all the concussions they may have suffered in the past, a detailed concussion history is of value.72–75 Such a history may identify early those athletes who fit into a high-risk category and provides an opportunity for the health care provider to educate the athlete in regard to the significance of concussive injury. A structured concussion history should include specific questions as to previous symptoms of a concussion, not just the perceived number of past concussions. It is also worth noting that dependence upon the recall of concussive injuries by teammates or coaches has been demonstrated to be unreliable.72 The clinical history should also include information about all previous head, face, and cervical spine injuries, as these may also have clinical relevance. It is worth emphasizing that in the setting of maxillofacial and cervical spine injuries, coexistent concussive injuries may be missed unless specifically assessed. Questions pertaining to disproportionate impact versus symptom severity may alert the clinician to a progressively increasing vulnerability to injury. As part of the clinical history, it is advised that details regarding protective equipment employed at time of injury be sought, both for recent and remote injuries. A comprehensive preparticipation concussion evaluation allows for modification and optimization of protective behaviour and an opportunity for education.The consensus panel agreed that a range of "modifying" factors may influence the investigation and management of concussion and, in some cases, may predict the potential for prolonged or persistent symptoms. These modifiers would also be important to consider in a detailed concussion history and are outlined in Table 2.In this setting, there may be additional management considerations beyond simple RTP advice. There may be a more important role for additional investigations including formal NP testing, balance assessment, and neuroimaging. It is envisioned that athletes with such modifying features would be managed in a multidisciplinary manner coordinated by a physician with specific expertise in the management of concussive injury.The role of female gender as a possible modifier in the management of concussion was discussed at length by the panel. There was not unanimous agreement that the current published research evidence is conclusive that this should be included as a modifying factor, although it was accepted that sex may be a risk factor for injury and/or influence injury severity.76–78In the overall management of moderate to severe traumatic brain injury, duration of loss of consciousness (LOC) is an acknowledged predictor of outcome.79 While published findings in concussion describe LOC associated with specific early cognitive deficits, it has not been noted as a measure of injury severity.80,81 Consensus discussion determined that prolonged (greater than 1 minute in duration) LOC would be considered as a factor that may modify management.There is renewed interest in the role of posttraumatic amnesia and its role as a surrogate measure of injury severity.67,82,83 Published evidence suggests that the nature, burden, and duration of the clinical postconcussive symptoms may be more important than the presence or duration of amnesia alone.80,84,85 Further, it must be noted that retrograde amnesia varies with the time of measurement postinjury and, hence, is poorly reflective of injury severity.86,87A variety of immediate motor phenomena (eg, tonic posturing) or convulsive movements may accompany a concussion. Although dramatic, these clinical features are generally benign and require no specific management beyond the standard treatment of the underlying concussive injury.88,89Mental health issues (such as depression) have been reported as a long-term consequences of traumatic brain injury, including sports-related concussion. Neuroimaging studies using fMRI suggest that a depressed mood following concussion may reflect an underlying pathophysiologic abnormality consistent with a limbic-frontal model of depression.52,90–100There was unanimous agreement by the panel that the evaluation and management recommendations contained herein could be applied to children and adolescents down to the age of 10 years. Below that age, children report different concussion symptoms from adults and would require age-appropriate symptom checklists as a component of assessment. An additional consideration in assessing the child or adolescent athlete with a concussion is that in the clinical evaluation by the health care professional, there may be the need to include both patient and parental input, as well as teacher and school input, when appropriate.101–107The decision to use NP testing is the same as in the adult assessment However, of testing may in to assist in school and management (and may be performed while the patient is still If cognitive testing is then it must be sensitive until the to the ongoing cognitive that during this period, in the of to the or to In this age it is more important to consider the use of trained neuropsychologists to interpret assessment data, particularly in children with and/or attention who may need more sophisticated assessment panel the that children should not be to or until symptom which may require a longer time frame than for In addition, the concept of was with to a need to exertion with activities of and to scholastic and other cognitive (eg, text messaging, video games, etc) while and activities may also need to be modified to of of the different response and longer recovery after concussion and specific (eg, to impact during and a more conservative RTP approach is It is appropriate to the of time of asymptomatic rest and/or the length of the graded exertion in children and It is not appropriate for a child or adolescent athlete with concussion to RTP on the same day as the injury, of the level of athletic Concussion modifiers even more to this than to adults and may more RTP panel unanimously agreed that all athletes, of level of should be managed using the same treatment and RTP A more useful was agreed the available resources and expertise in concussion evaluation of more importance in determining management than a separation elite and athlete management. Although formal NP screening may be beyond the resources of many sports or it is recommended that in all high-risk sports, consideration be to this cognitive evaluation, of the age or level of studies have an sports concussions during a and cognitive have noted cases in which evidence of traumatic was in football discussion was and no consensus was on the significance of such at this need to be of the potential for long-term in the management of all is no clinical evidence that currently available protective equipment will concussion, although have a role in and injury. studies have shown a in impact to the brain with the use of and but these findings have not been to a in concussion and there are a number of studies to suggest that provide and injury and, hence, should be recommended for in In specific sports such as and sports, protective may other of injury (eg, that are to on and these may be an important injury issue for those of rule changes to the injury or severity may be appropriate where a is in a An of this is in football in which research studies demonstrated that contact in for approximately of As noted rule changes also may be in some sports to allow an off-field medical assessment to occur without the affecting the flow of the or unduly penalizing the player's It is important to that rule may be a of modifying injury risk in these settings, and an important role in this important consideration in the use of protective equipment is the concept of risk This is where the use of protective equipment in such as the of more which can in a in injury This may be a in child and adolescent athletes, in whom injury are than in adult of sport that it to and should not be However, sporting should be encouraged to that may concussion and should be supported as key of the to or the of concussive injury after the is of athletes, and the is a of progress in this coaches, and health care must be regarding the of concussion, its clinical assessment and principles of RTP. to including and are important in the In addition, concussion the and of sport such as Football Association International International and International who this have value and must be and for are that should be encouraged in all sports and sporting coaches, and an important part in these are on the of consensus panelists recognize that research is a range of in to some research The key for research identified consensus document the current of and will need to be modified to the development of It provides an of issues that may be of importance to health care involved in the management of sports-related concussion. It is not as a standard of care and should not be as This document is only a and is of a nature, consistent with the of a health care treatment will on the and specific to each is that this document will be and prior to the 1st International on Concussion in was in This was by the in with and the of the As part of the for the the need for and was The 2nd International on Concussion in was by the same with the additional of the and was in in The original of the to provide recommendations for the of and health of athletes who concussive injuries in football and other this a range of to both to specific issues of basic and clinical injury cognitive assessment, research protective and long-term International on Concussion in was in on and was designed as a formal consensus following the by the US National of of the consensus can be The basic principles the of a consensus development are panel did not identify with any The was for the consensus and the from clinical and research in the of sports-related concussion. not but for their and understanding of this

This article considers the scientific process whereby new and better clinical tests of executive function might be developed, and what form they might take. We argue that many of the traditional tests of executive function most commonly in use (e.g., the Wisconsin Card Sorting Test; Stroop) are adaptations of procedures that emerged almost coincidentally from conceptual and experimental frameworks far removed from those currently in favour, and that the prolongation of their use has been encouraged by a sustained period of concentration on "construct-driven" experimentation in neuropsychology. This resulted from the special theoretical demands made by the field of executive function, but was not a necessary consequence, and may not even have been a useful one. Whilst useful, these tests may not therefore be optimal for their purpose. We consider as an alternative approach a function-led development programme which in principle could yield tasks better suited to the concerns of the clinician because of the transparency afforded by increased "representativeness" and "generalisability." We further argue that the requirement of such a programme to represent the interaction between the individual and situational context might also provide useful constraints for purely experimental investigations. We provide an example of such a programme with reference to the Multiple Errands and Six Element tests.