Objective: The objective was to estimate unique patterns of change in fatigue in people with the Post-Covid Syndrome (PCS) over 15 months. Design/Subjects: The Quebec Action for Post-COVID (QAPC) study was a prospective study designed to provide a patient-centered understanding of symptoms, function, and quality of life in a self-identified Quebec sample. Methods: Participants were queried every 3 months about symptoms and function. Fatigue was measured with the 10-item Post-COVID Syndrome Fatigue Severity Measure with a transformed score ranging from 0 no fatigue to 100 extreme fatigue. Group Based Trajectory Analysis (GBTA) was used to identify patterns of longitudinal change. Results: 545 people had an average value of fatigue at baseline of 62.2 / 100 (SD: 21.6); 25% of the cohort had 5 visits. Six trajectories of individual change emerged: two groups with the highest fatigue showed persistence over time; a small group with high fatigue showed improvement; two groups with average fatigue showed improvement over time; and the group with low fatigue showed no emergence of this symptom, Conclusion High fatigue seems to persist over time while less severe fatigue abates. High fatigue may indicate a sub-syndrome within PCS similar to chronic fatigue syndrome. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by a grant from the Fonds de Recherche de Quebec Sante and by an unrestricted grant from ScotiaBank. Neither entity had any role in study design, analysis, writing of the paper, or the decision to publish. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: McGill University Health Center Research Ethics Board gave ethical approval for this work. Project MP-37-2022-8066 I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors

Health-related quality of life (HRQL) is an important endpoint when evaluating the effectiveness of interventions in people living with hip and knee osteoarthritis (OA). The aim of this study was to generate domains for a new OA-specific preference-based index of HRQL in people living with hip or knee OA. The proposed HRQL index was based on a formative measurement model. The study included people aged 50 years and older, who reported being diagnosed with hip or knee OA. Participants reported the most important areas of their lives affected by OA. BERTopic method was used for topic modeling as part of Natural Language Processing. Hierarchical topic modeling was applied to merge similar topics together. A total of 102 people participated from across Canada. The participants had a mean age of 64.3 ± 7.6 years, and they reported having either knee (48.0

Purpose: Fatigue is a defining feature of post-COVID syndrome (PCS), yet there is no accepted measure of this life-altering consequence. The aim here was to create a measure fit for the purposes of quantifying the severity of PCS fatigue and provide initial evidence for its relationships with measures of converging constructs. Methods: A cross-sectional analysis of the first 414 participants in the Quebec Action for Post-COVID cohort study who self-identified with PCS was undertaken. In total, 17 items were available, including items commonly used in fatigue studies and to identify post-exertional malaise (PEM). Results: Rasch analysis identified that 10 of the 17 items fit a unidimensional linear model with a theoretical range from 0 to 21 (none to highest fatigue). The PCS Fatigue Severity Measure V1 (mean: 13.8; SD: 4.7) correlated highly with criterion measures of fatigue (r ≈│0.8│). Correlations with converging constructs of pain, physical function, and health rating exceeded │0.5│. Conclusion: PCS Fatigue Severity Measure V1 was distinguished between people working versus those on sick leave (difference: 5.1 points; effect size: 1.08). Effect sizes for people with and without irritability or meeting criteria for post-traumatic distress were approximately equal to 0.5. There is sufficient evidence that this measure is fit for purpose for quantifying fatigue in this population at one point in time. Further evidence in other samples is required to verify content and performance over time.

Aims The Post-COVID-19 syndrome (PCS) represents an epidemic within the COVID-19 pandemic, with potentially serious consequences for affected individuals, the healthcare system, and society at large. Facing a new and poorly understood health condition, this study aimed to produce a patient-centered understanding of mental health symptom patterns, functional impact, and intervention priorities. Methods A cross-sectional analysis of the first 414 participants in a longitudinal study recruited over a 5- month from September 2022 to January 2023 was carried out involving people from Quebec who self-identified as having symptoms of PCS. People were asked to name areas of their mental health affected by PCS using the structure of the Patient Generated Index (PGI), an individualized measure suited to eliciting the most frequent and most bothersome symptoms. The PGI was supplemented with a set of patient-reported outcome measures across the rubrics of the Wilson- Cleary model. The text threads from the PGI were grouped into topics using BERTopic analysis. Results Twenty topics were identified from 818 text threads referring to PCS mental health symptoms nominated using the PGI format. 35% of threads were identified as relating to anxiety, discussed in terms of five topics: generalized/social anxiety, fear/worry, post-traumatic stress, panic, and nervous. 29% of threads were identified as relating to low mood, represented by five topics: depression, discouragement, emotional distress, sadness, and loneliness. A cognitive domain (22% of threads) was covered by four topics referring to concentration, memory, brain fog, and mental fatigue. Topics related to frustration, anger, irritability. and mood swings (7%) were considered as one domain and there were separate topics related to motivation, insomnia, and isolation. Conclusion This novel method of digital transformation of unstructured text data uncovered different ways in which people think about classical mental health domains. This information could be used to evaluate the extent to which existing measures cover the content identified by people with PCS or to justify the development of a new measure of the mental health impact of PCS.

Background Rehabilitation is the mainstay of management for people with disabilities of neurological origin to maximize function and reduce disability. Access to in-patient rehabilitation is usually reserved for people after crises or those who are discharged from acute care such as in stroke or trauma. Access to people with Multiple Sclerosis (MS) differs across countries and unknown for Canada. With the progression of MS, quality of life (QOL) becomes more closely coupled with independence and hence timely access to rehabilitation is important. The objectives of this paper are (i) to characterize the disability profiles of people with MS admitted to in-patient rehabilitation in Canada; and (ii) to estimate the extent to which disability profiles differ from admission to discharge. Methods A longitudinal study of a rehabilitation admission-to-discharge cohort of 3500 people with MS was conducting using latent class analysis on the five Functional Independence Measure (FIM) subscales for Self-care, Transfers, Locomotion, Bladder/Bowel, and Cognition. The extent to which age, sex, and calendar time was associated with latent class membership, at both admission and discharge, was estimated using ordinal logistic regression, and proportional odds model was calculated for each age and sex. Results A five-class model fit the data at admission and a four-class model fit the data at discharge determined using likelihood ratio G 2 , Akaike’s Information Criterion, and Bayesian Information Criterion. Conclusion At admission, the disability profiles showed a hierarchical progression across the FIM subscales. The least disabled profile was characterized by locomotion dependency only; the most disabled profile was characterized by dependencies in all subscales except cognition. At discharge, the least disabled class, representing 28% of discharges, was characterized by no dependencies; the most disabled class remained with dependencies (23%) in all areas. The study highlights the importance of reserving scarce rehabilitation services to those with more disability.

Purpose Strongly framed research questions are clear as to the population (P), the exposures or interventions (E/I), comparison groups (C), outcomes (O), time when relevant (T), and what the investigator wants to know. A solid framework sets up the measurement model, analysis, and anticipated results. The purpose of this study was to estimate the extent to which research questions in journals that focused on patient-reported outcome measures (PROM) and quality of life (QOL) are clear. Methods All 440 research articles published in four PROM journals in 2020. excluding reviews, psychometric, and qualitative papers, were reviewed. Research questions were classified as: (i) adequately framed (ii) poorly framed; or (iii) unframed based on clarity criteria. Examples from each journal were presented and reframed to match results in the article. Results Of 440 articles, 195 (44.3%) were classified as adequately framed; 230 (52.2%) as poorly framed; and 15 (3.4%) as unframed. There was heterogeneity across journals (Chi-square: 20.8; 6 df; p = 0.002). Only 29% were framed according to what the investigators wanted to know; 72% were framed like a “to do” list; and 6% were framed as a research agenda. Conclusion Almost half of the questions were poorly framed or unframed a practice that could contribute to research wastage. Even “adequately framed” questions rarely stated what they wanted to know a priori, increasing the risk of biased reporting. Researchers, reviewers, and editors should encourage the use established frameworks for research questions.

Importance: Given the importance of apathy for stroke, we felt it was time to scrutinize the psychometric properties of the commonly used Starkstein Apathy Scale (SAS) for this purpose. Objectives: The objectives were to: (i) estimate the extent to which the SAS items fit a hierarchical continuum of the Rasch Model; and (ii) estimate the strength of the relationships between the Rasch analyzed SAS and converging constructs related to stroke outcomes. Methods: Data was from a clinical trial of a community-based intervention targeting participation. A total of 857 SAS questionnaires were completed by 238 people with stroke from up to 5 time points. SAS has 14 items, rated on a 4-point scale with higher values indicating more apathy. Psychometric properties were tested using Rasch partial-credit model, correlation, and regression. Items were rescored so higher scores are interpreted as lower apathy levels. Results: Rasch analysis indicated that the response options were disordered for 8/14 items, pointing to unreliability in the interpretation of the response options; they were consequently reduced from 4 to 3. Only 9/14 items fit the Rasch model and therefore suitable for creating a total score. The new rSAS was deemed unidimensional (residual correlations: < 0.3), reasonably reliable (person separation index: 0.74), with item-locations uniform across time, age, sex, and education. However, 30% of scores were > 2 SD above the standardized mean but only 2/9 items covered this range (construct mistargeting). Apathy (rSAS/SAS) was correlated weakly with anxiety/depression and uncorrelated with physical capacity. Regression showed that the effect of apathy on participation and health perception was similar for rSAS/SAS versions: R2 participation measures ranged from 0.11 to 0.29; R2 for health perception was ∼0.25. When placed on the same scale (0–42), rSAS value was 6.5 units lower than SAS value with minimal floor/ceiling effects. Estimated change over time was identical (0.12 units/month) which was not substantial (1.44 units/year) but greater than expected assuming no change (t: 3.6 and 2.4). Conclusion: The retained items of the rSAS targeted domains of behaviors more than beliefs and results support the rSAS as a robust measure of apathy in people with chronic stroke.

Objectives: Almost half of the patients with a bipolar disorder (BD) have anxiety disorder(s) (AD) during their lifetime, but feasible measures for all AD are few. Furthermore, cognitive impairments can compromise reliability of existing scales, since many are needed for full coverage. Thus, we investigated how reliably patients responded to anxiety scales and any symptom overlap to propose future improvements to anxiety assessments. Methods: We collected 152 observations in patients with BD with the Clinically Useful Anxiety Outcome Scale, Social Phobia Inventory, Panic Disorder Severity Measurement, and Trauma Screening Questionnaire (in total, 57 items). The scales were analyzed as a set in a Rasch model. Results: During our analyses, we found indication that BD outpatients had difficulty differentiating response options to 70% (40/57) of items which were rescored or deleted. Only one case was misfitting (-2.65 +/-.41). In total, 22 items were locally dependent and one indicated misfit. The final model included 25-items and fit the Rasch model (chi(2)=35.92, DF=50, p=.93). The model was unidimensional, without losing appropriate associations with depression (r = 0.62), suicidality (r = 0.37), and hypomania (r=-0.01). Limitations: Bolstering the size of less frequent subgroups should be accomplished in future work. Conclusion: A unidimensional rather than categorical approach to severity of anxiety might be both useful and feasible in this population. Further development of screens is necessary to enable systematic screening and measurement of anxiety in BD.

Background Recent evidence has suggested an existence of a MS prodome, indicating that symptoms of neurodegeneration were present before the first clinical event. These early signs of MS are usually not recognized as a symptom of MS and some young adults with MS are very likely to have had these symptoms in their childhood or adolescence. It is thus of interest to examine the differences in disability profiles of young people with MS. This study focused on young people with MS with severe enough disability as to need rehabilitation services. The most likely reason for this need is poor recovery from a relapse. Objectives The purpose of the study is to characterize and compare the functional profiles (as reflected by Functional Independence Measure scores) of people with MS admitted to in-patient rehabilitation in Canada across two age groups (younger than 25 and 26 to 35 years old) with specific aims to estimate the extent to which these profiles change over time; and to identify the proportions of people who made a reliable change. Methods Data from the National Rehabilitation Reporting System (NRS) in Canada was analyzed. The dataset contained information of 457 people with MS aged 16 to 35 who were admitted to inpatient rehabilitation. Scores on the Functional Independence Measure at admission and discharge were analyzed using latent class analysis. Change in FIM was estimated using reliable change index. Probability of making a reliable change across the different classes, age and sex was estimated using logistic regression. Results There were four functional classes at admission and three classes at discharge. The four functional classes at admission were: A). Minimal assistance/Supervision in walking, B). Assistance in Activities of Daily Living (ADL)/Mobility, C). Assistance/dependent in ADL/Mobility, and D). Dependent in ADL and mobility. At admission, 19.7% of patients belonged to the best class, but at discharge, 66.8% of people belonged to the best class, indicating that 45% of the patients improved. Across the two age groups, disability profiles differed at admission and discharge. People who are 25 years and younger were more likely to belong to the lower functioning profiles classes (Class C and D) compared to the older group who were more likely to belong to Class B and C, indicating that younger people were more impaired at admission. The probability of making reliable change was also different between the latent classes. People in the lowest two classes at admission, were more likely to make reliable change (OR=10.9, OR=7.2). Conclusions The results of this study suggest that younger people were admitted with a more severe disability profile when compared to a slightly older group but were more likely to make improvements during rehabilitation. The functional profiles in MS differed across sex and age, signaling a need to tailor rehabilitation interventions across the functional profiles, age and sex. Accessing existing sources of data is a useful method for filling in gaps about outcomes for populations with rare diseases.

The lifetime prevalence of anxiety disorders (AD) in individuals with a bipolar disorder (BD) is approximately 45 percent. Comorbid AD and BD is associated with an increased risk of suicide, substance abuse, and worse outcomes. To advance implementation of a transdiagnostic approach in clinical practice, we aimed to reveal psychometric evidence of cross-cutting symptoms in AD. Our study n=89 individuals with a bipolar disorder (type I, type II) involved the administration of a survey. The survey contained four scales that were developed according to the 5th edition of the Diagnostic and Statistical Manual and/or were well-validated. We then fit these scales; the Clinically Useful Anxiety Outcomes scale, Social Phobia Inventory, Panic Disorder Measurement, and Trauma Screening Questionnaire, to a Rasch model in RUMM2030. Across repeat-testing sessions (approximately 22 and 370 day intervals), we collected 152 responses. The model was fit to responses from the scales’ 57 items. Misfit, local dependence, or differential item functioning eliminated 22 items. A principal components analysis of the residuals revealed the set was unidimensional; no subscales existed. The final set of 25 items is optimized for brief, informative assessment of AD. A validation study in an independent sample will soon be conducted.

Research in rehabilitation has grown from a rare phenomenon to a mature science and clinical trials are now common. The purpose of this study is to estimate the extent to which questions posed and methods applied in clinical trials published in Clinical Rehabilitation have evolved over three decades with respect to accepted standards of scientific rigour. Studies were identified by journal, database, and hand searching for the years 1986 to 2016. A total of 390 articles whose titles suggested a clinical trial of an intervention, with or without randomization to form groups, were reviewed. Questions often still focused on methods to be used (57%) rather than what knowledge was to be gained. Less than half (43%) of the studies delineated between primary and secondary outcomes; multiple outcomes were common; and sample sizes were relatively small (mean 83, range 5 to 3312). Blinding of assessors was common (72%); blinding of study subjects was rare (19%). In less than one-third of studies was intention-to-treat analysis done correctly; power was reported in 43%. There is evidence of publication bias as 83% of studies reported either a between-group or a within-group effect. Over time, there was an increase in the use of parameter estimation rather than hypothesis testing and there was evidence that methodological rigour improved. Rehabilitation trialists are answering important questions about their interventions. Outcomes need to be more patient-centred and a measurement framework needs to be explicit. More advanced statistical methods are needed as interventions are complex. Suggestions for moving forward over the next decades are given.

Background: Heterogeneity in disease course exists within multiple sclerosis (MS) subtypes. Objective: The objective was to estimate disease course heterogeneity over three distinct onset periods (pre-1995, 1995–2004, and 2005–present) for men and women. Methods: Group-based trajectory model (GBTM) was used to estimate clusters of patients following stable or unstable disease progression trajectories based on the Expanded Disability Status Scale (EDSS). Inception cohorts were generated from the Montreal Neurological Institute MS Clinic registry. Stable trajectories were defined as an EDSS ⩽3.0 and change ⩽1 point over the study period. Annualized relapse rate (ARR) based on the first 5 years of disease was an explanatory variable. Results: Proportion of women classified as stable was 0% for pre-1995, 69.0% for 1995–2004, and 83.9% post-2005; for men, these proportions were 18.4%, 41.4%, and 53.8%, respectively. Men had lower percentage of stable disease than women in both post-1995 cohorts (chi-square p < 0.0001). ARR was associated with higher disability trajectories in both post-1995 cohort (odds ratios >1.0) but not in the pre-1995 cohort. Conclusion: Large proportions of patients remain stable at their initial disability level for at least 15 years. Higher ARR increases the odds of patients being in a higher disability trajectory in the latter cohorts.