Global Measures Of Disability Research Articles

An exploratory study of longitudinal trajectory of language, swallowing and cognition post endovascular clot retrieval.

Endovascular clot retrieval (ECR) is known to reduce global disability at 3 months post stroke however limited research exists regarding the trajectory of specific clinical impairments including language, swallowing and cognitive deficits between onset and 3 months. To assess language, swallowing, and cognitive performance following ECR and explore whether impairment severity is correlated with modified Thrombolysis in Cerebral Infarction score (mTICI), stroke severity or quality of life (QoL). Assessment was completed within 7 days (T1), 1 month (T2) and 3 months (T3) post-stroke. Performance was measured with the Functional Oral Intake Scale (FOIS), Repeatable Battery for Assessment of Neuropsychological Status (RBANS), Trail Making Test (TMT A and B) and Brixton Spatial Awareness Test. The Western Aphasia Battery (WAB) was used for left hemisphere stroke. QoL was measured with the Stroke and Aphasia Quality of Life Scale. Twenty-five participants (median 72 years; 64% male) were prospectively recruited following ECR. High reperfusion success (68% mTICI 3) and low stroke severity post ECR (median 24h NIHSS = 3, IQR 7-18) were noted. At T1, 10 participants presented with aphasia, eight required a modified diet and 20 had impaired cognition. At T3 all had recovered to a normal oral diet, 39% had persistent cognitive impairment and 45% of patients with left hemisphere stroke remained aphasic. Performance on the WAB, FOIS, RBANS and TMT changed significantly over time (all p<0.05). The severity score at T1 for all measures, excluding TMT B and Brixton, was significantly correlated with 24h NIHSS. WAB scores at T3 were correlated with QoL (r = 0.618; p = 0.043). This exploratory study found the longitudinal performance of language, swallowing and cognition significantly improved over time and severity in the first-week post-ECR was correlated with 24h NIHSS rather than the degree of reperfusion. What is already known on the subject Randomised control trials have demonstrated the benefit of ECR in patients with ischemic stroke using global measures of disability and function. Limited research exists regarding the trajectory of specific clinical impairments including language, swallowing and cognitive deficits. There is also a reliance on screening assessments and a lack of consideration of the influence of co-occurring impairments. What this paper adds to existing knowledge This prospective study is amongst the first to explore the longitudinal trajectory of language, swallowing and cognitive impairment using a standardised assessment battery. Twenty-four-hour NIHSS was significantly correlated with language, swallowing, global cognition and some measures of executive function. Language performance post ECR was correlated with domain-specific cognitive assessment of attention, immediate memory and delayed memory, which differed from swallowing performance post ECR that correlated with measures of executive function. What are the potential or actual clinical implications of this work? It is important for speech-language pathologists and the wider medical team to monitor language, swallowing and cognitive performance post ECR regardless of treatment success. Stroke severity at 24h post-ECR influences the severity of language, swallowing and cognitive impairments.

Validity of the modified Rankin Scale in patients with aneurysmal subarachnoid hemorrhage: a randomized study

PurposeThe modified Rankin Scale (mRS), a clinician-reported outcome measure of global disability, has never been validated in patients with aneurysmal subarachnoid hemorrhage (aSAH). The aims of this study are to assess: (1) convergent validity of the mRS; (2) responsiveness of the mRS; and (3) the distribution of mRS scores across patient-reported outcome measures (PROMs).MethodsThis is a prospective randomized multicenter study. The mRS was scored by a physician for all patients, and subsequently by structured interview for half of the patients and by self-assessment for the other half. All patients completed EuroQoL 5D-5L, RAND-36, Stroke Specific Quality of Life scale (SS-QoL) and Global Perceived Effect (GPE) questionnaires. Convergent validity and responsiveness were assessed by testing hypotheses.ResultsIn total, 149 patients with aSAH were included for analysis. The correlation of the mRS with EQ-5D-5L was r = − 0.546, while with RAND-36 physical and mental component scores the correlation was r = − 0.439and r = − 0.574 respectively, and with SS-QoL it was r = − 0.671. Three out of four hypotheses for convergent validity were met. The mRS assessed through structured interviews was more highly correlated with the mental component score than with the physical component score of RAND-36. Improvement in terms of GPE was indicated by 83% of patients; the mean change score of these patients on the mRS was − 0.08 (SD 0.915). None of the hypotheses for responsiveness were met.ConclusionThe results show that the mRS generally correlates with other instruments, as expected, but it lacks responsiveness. A structured interview of the mRS is best for detecting disabling neuropsychological complaints.RegistrationURL: https://trialsearch.who.int; Unique identifier: NL7859, Date of first administration: 08-07-2019

Cortical thickness of contralesional cortices positively relates to future outcome after severe stroke.

Imaging studies have evidenced that contralesional cortices are involved in recovery after motor stroke. Cortical thickness (CT) analysis has proven its potential to capture the changes of cortical anatomy, which have been related to recovery and treatment gains under therapy. An open question is whether CT obtained in the acute phase after stroke might inform correlational models to explain outcome variability. Data of 38 severely impaired (median NIH Stroke Scale 9, interquartile range: 6-13) acute stroke patients of 2 independent cohorts were reanalyzed. Structural imaging data were processed via the FreeSurfer pipeline to quantify regional CT of the contralesional hemisphere. Ordinal logistic regression models were fit to relate CT to modified Rankin Scale as an established measure of global disability after 3-6 months, adjusted for the initial deficit, lesion volume, and age. The data show that CT of contralesional cortices, such as the precentral gyrus, the superior frontal sulcus, and temporal and cingulate cortices, positively relates to the outcome after stroke. This work shows that the baseline cortical anatomy of selected contralesional cortices can explain the outcome variability after severe stroke, which further contributes to the concept of structural brain reserve with respect to contralesional cortices to promote recovery.

Age-Related Ethnic Differences in Self-Reported Hand Function

Barriers to affordable insurance may worsen disparities among underserved populations. Immigrants with <5 years of residence are not eligible for Medicare and Medicaid and are potentially without affordable alternatives. This study aims to look at the relationship between length of residence in the U.S. and insurance coverage within U.S. Chinese older adults ages 65+.This study used data from a representative sample of 2,365 community-dwelling U.S. Chinese older adults age 65+. The association between length in the U.S. (<5, 6-10, 10+) and insurance status was analyzed using chi squared test and logistic regressions. Within this sample, 58 (2.78%) participants had coverage outside Medicare and Medicaid, with 279 participants reporting no coverage. The vast majority of participants living in the U.S. <5 years had no insurance (81.48%). In a fully adjusted model, participants who were older and female were positively associated with having insurance coverage (OR:1.11 [1.07,1.15] and OR:1.29 [0.88,1.90]). Conversely, both living in the U.S. <5 years (OR:0.009 [0.006, 0.014]),and between 5-10 years (OR:1.20 [0.13,0.30]) were negatively associated with insurance coverage. When including coverage outside of Medicaid and Medicare, residence <5 years and 5-10 years were still negatively associated with insurance coverage ((OR:0.13 [0.009,0.02]), and (OR:0.19 [0.13,0.30])). Vulnerable populations such as older immigrants may not have access to insurance outside of public options, making a 5-year waiting period an additional barrier to quality health care.

Validation of the Munich Swallowing Score (MUCSS) in patients with neurogenic dysphagia: A preliminary study.

The Munich Swallowing Score (MUCSS) is a clinician rated scale for the assessment of the functional level of swallowing saliva/secretions, food and liquids. The MUCSS consists of two eight-point subscales, MUCSS-Saliva and MUCSS-Nutrition. In a previous article, content validity and interrater reliability were described. The aim of the present study was to investigate criterion validity and sensitivity to change of the MUCSS. The research was conducted at a tertiary care academic hospital. Data were collected retrospectively in a cohort of 100 acute and subacute neurologic patients. Criterion validity was judged by comparison to the Gugging Swallowing Screen (GUSS), the Barthel Index (BI), Early Rehabilitation Barthel Index (ERI), Extended Barthel Index (EBI) and also by comparison to three physiological scales drawn from FEES videos: The Penetration - Aspiration Scale (PAS), the Yale Pharyngeal Residue Severity Rating Scale (YPR) and the Murray Secretion Scale (MSS). Changes in oral intake and saliva swallowing were followed up for three months. Between MUCSS and scores directly reflecting dysphagic symptoms (GUSS, PAS, YPR, MSS, ERI), strong to moderate correlations were found, weaker but statistically significant associations were seen with global measures of disability (BI isolated, EBI-subscale cognitive functions). MUCSS was sensitive to positive change of saliva swallowing and oral intake during the recovery period. These preliminary data suggest that the MUCCS is a valid scale and may be appropriate for documenting clinical change in swallowing abilities of patients with neurogenic dysphagia.

Abstract P233: Descriptions of the Meaning of Modified Rankin Scale Outcomes in Acute Stroke Clinical Trials: Meta-Analysis and Call to Corrective Action

Background: The modified Rankin scale, a 7-level, clinician-reported, measure of global disability, is the most widely employed outcome scale in acute stroke trials. As the meaning of technical mRS scores (e.g. mRS 1, mRS 4) is not well-known among general clinicians, patients, and policy-makers, trialists sometimes apply valence (e.g. “excellent”, “good”) and health-state (e.g. “disabled”, “dependent”) terms to convey the clinical meaning of trial findings. The terms employed have not been well-delineated. Methods: Systematic meta-analysis assessing mRS descriptive terms across all large (n ≥ 100) RCTs for acute ischemic or hemorrhagic stroke reported 2000 - 2020, following PRISMA guidelines. Results: Among the 60 RCTs meeting study entry criteria, patient populations were acute ischemic stroke (AIS) in 88%, intracerebral hemorrhage in 8%, both in 3%. Among the 55 AIS trials, tested agents included: antiplatelet - 28%, endovascular thrombectomy - 20%, IV lytics - 20%, neuroprotective - 11%. The mRS was a major endpoint measure in 82% of trials (primary in 60%, secondary in 22%). Table 1 shows frequency of different valence terms (1A) and health state terms (1B) for 9 types of mRS analysis. Trials often used mutually contradictory terms for particular mRS outcomes. e.g. “good outcome” was applied to outcomes mRS 0-1 (2 trials), mRS 0-2 (2 trials), mRS 0-3 (1 trial), and ordinal mRS (3 trials); “favorable” was applied to mRS 0-1 (5 trials), mRS 0-2 (6 trials), and ordinal mRS (6 trials). Also many trials provided no meaningful descriptor (no valence descriptor in 82%, no health state descriptor in 58%). Conclusion: Across major acute stroke trials of the past 20 years, the valence and health state terms for different mRS outcomes have been often mutually contradictory or not provided at all. A standardized nomenclature for mRS outcome description would improve clinician and policy-maker understanding of trial results

Nine Hole Peg Test asymmetry in refining upper limb assessment in multiple sclerosis

BackgroundThe Expanded Disability Status Scale (EDSS) is the most frequently used scale to measure neurologic impairment and quantify the level of disability in Multiple Sclerosis (MS) even though the scale focuses on ambulation and undervalues upper limb (UL) impairment.The 9-Hole Peg Test (9-HPT) is the gold standard for UL assessment in MS, calculating a mean score from right and left arms, even though subjects with MS often show a lateralization of neurological deficit. ObjectiveThe study aimed to determine whether an interaction exists between mean right-left 9-HPT scores or 9HPT score asymmetry (difference between right and left side) in predicting EDSS in MS subjects. MethodsDemographic and disease variables and 9-HPT scores were obtained from medical records of individuals with MS collected in an ad-hoc database. Subjects with 9-HPT score ≤180 s for each arm were included. An asymmetry score was represented as the absolute value of the difference between 9-HPT scores for both arms. Results549 subjects were included: 67.8% female, mean age 45±13.14 years, mean EDSS 3.98±2.12, 356 relapsing-remitting, 68 primary and 125 secondary progressive, mean 9-HPT scores: right arm 30.20 ± 19.99 s, left arm 31.80 ± 20.35 s. Mean asymmetry was 9.35±18.20 s. Correlation between mean right-left 9-HPT scores and EDSS was 0.58 (p<.001). Significant interaction between mean right-left 9-HPT scores and 9-HPT asymmetry in predicting EDSS scores was found. Regression slope of EDSS on mean right-left 9-HPT score decreases as asymmetry value increases (non-significance area values ≥ 40.93 s). ConclusionsFindings suggest interaction exists between mean right-left 9-HPT scores and asymmetry in predicting EDSS. A consequence of this is that, by disregarding information about asymmetry, studies exploring the association between mean right-left 9-HPT scores and global measures of disability may provide biased results. The bias tends to increase as asymmetry increases, and to be most prevalent among patients with EDSS scores > 6.

Innovations in Stroke: The Use of PROMIS and NeuroQoL Scales in Clinical Stroke Trials.

There are significant limitations with the use of modified Rankin Scale (mRS) score as the primary outcome in clinical stroke trials. We propose the exploration of the Patient-Reported Outcome Measure Information System (PROMIS) and Quality of Life in Neurological Disorders (NeuroQoL) tools as outcome measures in clinical trials and provide preliminary data on the distribution of these measures in a cohort of patients with ischemic stroke. The mRS, a clinician-reported measure of global disability,1 is a commonly used primary outcome in clinical stroke trials. It is a 1-item measure ranging from grades 0 to 5 with 0 representing no symptoms and 5 representing severe disability. A score of 6 is often used to represent death. Although its beneficial attributes include simplicity and various modes of administration and demonstrated construct and convergent validity,2 there are also limitations when using mRS. There can be substantial interobserver variability in scoring, especially between scores 1 and 4,3 which is of key importance for stroke trials that dichotomize outcomes. In addition, the mRS is heavily weighted towards mobility4 and does not specifically delineate several other important domains of health that are frequently affected by stroke, such as cognition, fatigue, or ability to participate in social roles. The traditional approach to analyzing mRS in clinical trials is to dichotomize the score, which reduces the sensitivity to detect change. Shift analysis has the potential to increase power to detect differences compared with dichotomization. However, to allow adjustment for covariates and estimate an effect size, shift analyses must be done using ordinal regression, which requires that the data meet proportionality assumption.5 Importantly, because the mRS has only 6 levels, the ability to detect meaningful change and differences in outcomes among treatment groups is limited, even with the use of shift analysis. The use …

Measurement Invariance of the WHODAS 2.0 in a Population-Based Sample of Youth

The World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) is a brief measure of global disability originally developed for adults, which has since been implemented among samples of children and youth. However, evidence of its validity for use among youth, particularly measurement invariance, is lacking. Investigations of measurement invariance assess the extent to which the psychometric properties of observed items in a measure are generalizable across samples. Satisfying the assumption of measurement invariance is critical for any inferences about between-group differences. The objective of this paper was to empirically assess the measurement invariance of the 12-item interview version of the WHODAS 2.0 measure in an epidemiological sample of youth (15 to 17 years) and adults (≥ 18 years) in Canada. Multiple-group confirmatory factor analysis using a categorical variable framework allowed for the sequential testing of increasingly restrictive models to evaluate measurement invariance of the WHODAS 2.0 between adults and youth. Findings provided evidence for full measurement invariance of the WHODAS 2.0 in youth aged 15 to 17 years. The final model fit the data well: χ2(159) = 769.04, p < .001; CFI = 0.950, TLI = 0.958, RMSEA (90% CI) = 0.055 [0.051, 0.059]. Results from this study build on previous work supporting the validity of the WHODAS 2.0. Findings indicate that the WHODAS 2.0 is valid for making substantive comparisons of disability among youth as young as 15 years of age.

Predictors and indicators of disability and quality of life 4 years after a severe traumatic brain injury. A Structural Equation Modelling analysis from the PariS-TBI study

To assess the predictors and indicators of disability and quality of life four years after a severe traumatic brain injury (TBI), using a Structural Equation Modelling (SEM). SEM is a multivariate approach permitting to take into account the complex inter-relationships between individual predictors, in order to disentangle factors which have a direct or indirect relationship with the dependant variable. The Paris-TBI study is a longitudinal inception cohort study of 504 patients with severe TBI in the Parisian area [1] . Among 245 survivors, 147 patients were assessed four years post-injury. Two outcome measures were analysed separately using SEM: the Glasgow Outcome Scale-extended (GOS-E) [2] , which is a global measure of disability after TBI, and the QOLIBRI, a disease-specific measure of quality of life after TBI [3] . Four groups of variable were entered in the model: demographics; injury severity; psychological and cognitive impairments; somatic impairments. The GOS-E was directly significantly related to all four groups of variables (age, gender, severity of injury, psycho-cognitive and somatic impairments). Education duration had an indirect effect, mediated by psycho-cognitive impairments. In contrast, the QOLIBRI was only directly predicted by psycho-cognitive impairments. Age and somatic impairments had an indirect influence on the QOLIBRI, via psycho-cognitive impairments. Disability and quality of life were directly influenced by different factors. While disability appeared to result from an interaction of a wide range of factors, including demographics, injury severity, psycho-cognitive and somatic deficiencies, quality of life was solely directly related to psycho-cognitive factors. Other factors, such as age and somatic impairments only had an indirect effect.

Functional Outcomes: One Year after a Cardiac Arrest.

Objective. The study aim was to characterize the time-course of recovery in impairments, activity limitations, participation restrictions, disability, and quality of life during the first year after cardiac arrest. Secondarily, the study described the associations between the instruments used to measure each of these domains. Methods. Measures of global disability (Cerebral Performance Category, CPC, Modified Rankin Scale, mRS), quality of life, activity limitations, participation restrictions, and affective and cognitive impairments were administered to 29 participants 1, 6, and 12 months after cardiac arrest. Results. Global measures of disability indicated recovery between one month and one year after cardiac arrest (mean CPC: 2.1 versus 1.69, P < 0.05; mean mRS: 2.55 versus 1.83, P < 0.05). While global measures of disability were moderately associated with participation, they were poorly associated with other measures. The cohort endorsed depressive symptomatology throughout the year but did not have detectable cognitive impairment. Conclusions. Recovery from cardiac arrest is multifaceted and recovery continues for months depending upon the measures being used. Measures of global disability, reintegration into the community, and quality of life yield different information. Future clinical trials should include a combination of measures to yield the most complete representation of recovery after cardiac arrest.

Item response theory-based measure of global disability in multiple sclerosis derived from the Performance Scales and related items.

BackgroundThe eight Performance Scales and three assimilated scales (PS) used in North American Research Committee on Multiple Sclerosis (NARCOMS) registry surveys cover a broad range of neurologic domains commonly affected by multiple sclerosis (mobility, hand function, vision, fatigue, cognition, bladder/bowel, sensory, spasticity, pain, depression, and tremor/coordination). Each scale consists of a single 6-to-7-point Likert item with response categories ranging from “normal” to “total disability”. Relatively little is known about the performances of the summary index of disability derived from these scales (the Performance Scales Sum or PSS). In this study, we demonstrate the value of a combination of classical and modern methods recently proposed by the Patient-Reported Outcome Measurement Information System (PROMIS) network to evaluate the psychometric properties of the PSS and derive an improved measure of global disability from the PS.MethodsThe study sample included 7,851adults with MS who completed a NARCOMS intake questionnaire between 2003 and 2011. Factor analysis, bifactor modeling, and item response theory (IRT) analysis were used to evaluate the dimension(s) of disability underlying the PS; calibrate the 11 scales; and generate three alternative summary scores of global disability corresponding to different model assumptions and practical priorities. The construct validity of the three scores was compared by examining the magnitude of their associations with participant’s background characteristics, including unemployment.ResultsWe derived structurally valid measures of global disability from the PS through the proposed methodology that were superior to the PSS. The measure most applicable to clinical practice gives similar weight to physical and mental disability. Overall reliability of the new measure is acceptable for individual comparisons (0.87). Higher scores of global disability were significantly associated with older age at assessment, longer disease duration, male gender, Native-American ethnicity, not receiving disease modifying therapy, unemployment, and higher scores on the Patient Determined Disease Steps (PDDS).ConclusionPromising, interpretable and easily-obtainable IRT scores of global disability were generated from the PS by using a sequence of traditional and modern psychometric methods based on PROMIS recommendations. Our analyses shed new light on the construct of global disability in MS.Electronic supplementary materialThe online version of this article (doi:10.1186/s12883-014-0192-1) contains supplementary material, which is available to authorized users.

Abstract 214: The Field Administration of Stroke Therapy - Magnesium (FAST-MAG) Phase 3 Trial: Primary Results

BACKGROUND: Magnesium is neuroprotective in preclinical models of stroke and has been safe and shown signals of potential efficacy when delivered early after onset of human cerebral ischemia. Delayed initiation of neuroprotective agents has hindered past neuroprotective agent trials. We performed a multicenter, randomized, double-blind, placebo-controlled phase 3, trial to test whether paramedic initiation of intravenous magnesium sulfate within 2 hours of symptom onset improves the longterm functional outcome of hyperacute stroke patients. METHODS: Inclusion criteria were: 1) likely stroke as identified by the Los Angeles Prehospital Stroke Screen (LAPSS), 2) age 40-95, 3) symptom onset within 2 hours of treatment initiation, 4) deficit present ≥ 15 minutes. Trial sites included 315 ambulances, 40 EMS agencies, and 60 receiving hospitals throughout Los Angeles and Orange Counties, with 2988 paramedics trained in study procedures. From Jan 2005 - Dec 2012, paramedics in the field administered a loading dose (4 grams over 15 minutes) of magnesium sulfate (Mg) or matched saline placebo. Upon arrival in an ED, a maintenance infusion followed: 16 grams Mg or matched placebo over 24 hours. The primary endpoint was the modified Rankin Scale measure of global disability at 90 days. RESULTS: Among the 1700 enrolled patients, mean age was 69 (SD 13.6), 42.7% were female, median pretreatment stroke severity on the Los Angeles Motor Scale (LAMS) was 4.0, and median early post-treatment NIHSS stroke severity on ED arrival was 9.0. Final diagnosis of the presenting event was acute cerebral ischemia in 73.0%, acute hemorrhagic stroke in 23.2%, and stroke-mimicking condition in 3.8%. The median time from last known well to start of study infusion was 48 minutes (IQR 37 - 68). The proportion of patients receiving study infusion within the first hour after last known well was 74.1%. CONCLUSION: Prehospital initiation of neuroprotective agents can be performed in a large phase 3 acute stroke trial, permitting rapid drug start, with treatment in the first, “golden” hour in three-quarters of patients. The study blind will be broken in late fall and the first public presentation of trial efficacy results presented at the ISC meeting.

Methodology of the Field Administration of Stroke Therapy – Magnesium (FAST-MAG) Phase 3 Trial: Part 1 – Rationale and General Methods

Prehospital initiation by paramedics may enable delivery of neuroprotective therapies to stroke patients in the hyperacute period when they are most effective in preclinical studies. Magnesium is neuroprotective in experimental stroke models and has been shown to be safe with signals of potential efficacy when started early after onset of human cerebral ischemia. (a) To demonstrate that paramedic initiation of the neuroprotective agent magnesium sulfate in the field is an efficacious and safe treatment for acute stroke; (b) To demonstrate that field enrollment of acute stroke patients is a practical and feasible strategy for phase 3 stroke trials, permitting enrollment of greater numbers of patients in hyperacute time windows. Multicenter, randomized, double-blinded, placebo-controlled, pivotal clinical trial. The study is enrolling 1700 patients (850 in each arm) with likely acute stroke, including both cerebral infarction and intracerebral hemorrhage patients. Inclusion criteria are: (a) likely stroke as identified by the modified Los Angeles Prehospital Stroke Screen (mLAPSS), (b) age 40-95, (c) symptom onset within 2 h of treatment initiation, and (d) deficit present ≥15 min. Paramedics administer a loading dose of magnesium sulfate (Mg) or matched placebo in the field, 4 grams over 15 min. In the Emergency Department, a maintenance infusion follows, 16 grams Mg or matched placebo over 24 h. The primary endpoint is the modified Rankin Scale measure of global disability, assessed using the Rankin Focused Assessment, 90 days after treatment. Secondary efficacy endpoints include the NIHSS (neurologic deficit), Barthel Index (activities of daily living), and the Stroke Impact Scale (quality of life).

Bifactor structure of clinical disability in relapsing multiple sclerosis

BackgroundMultiple sclerosis (MS) can affect virtually every neurological function which complicates the conceptualization and assessment of disability. Similar challenges are encountered in other medical fields including child cognitive development and psychiatry, for instance. In these disciplines progress in diagnosis and outcome measurement has been recently achieved by capitalizing on the concept of bifactor model. ObjectiveTo present in accessible terms an application of bifactor confirmatory factor analysis to study the clinical disability outcomes in MS. MethodsData included 480 assessments on 301 patients with relapsing–remitting MS who participated in the North American interferon beta-1a clinical trial (Avonex). Measures consisted of the Expanded Disability Status Scale (EDSS), the three components of the Multiple Sclerosis Functional Composite (MSFC), and five other clinical measures of neurological functions. We determined which of three confirmatory factor analysis models (unidimensional, multidimensional, and bifactor) best described the structure of the data. ResultsEDSS scores ranged from 0 to 8 (94% between 0 and 4). The final bifactor model fitted the data well, explained 59.4% of total variance, and provided the most useful representation of the data. In this model, the nine measures defined a scoring dimension of global neurological function (63.1% of total composite score variance) and two auxiliary dimensions of extra variability in leg and cognitive function (17.1% and 9% of total composite score variance). ConclusionBifactor modeling is a promising approach to further understanding of the structure of disability in MS and for refining composite measures of global disability.

Letter by Stinear and Byblow Regarding Article, “Patient-Reported Measures Provide Unique Insights Into Motor Function After Stroke”

To the Editor: We read with interest the recent article by Stewart and Cramer1 that illustrated the importance of measuring motor function, not just impairment and disability, after stroke. These authors report results from 43 people who had experienced stroke between 5 days and 9.4 years before assessment. Global measures of disability (modified Rankin Scale) and impairment (National Institutes of Health Stroke Scale) were made, as well as measures of impairment specific to the upper limb (Fugl-Meyer [FM] scale and Purdue pegboard test). Patient-reported measures of upper limb function were also made: the difficulty of hand use (hand domain of the Stroke Impact Scale [SIS]) and amount of affected arm use (Motor Activity Log [MAL]). Nearly two-thirds of patients with minimal or no disability or impairment measured with the modified Rankin Scale, National Institutes of Health Stroke Scale, or FM scale reported difficulty with hand movements or reduced arm use. This is an important reminder that …

Design and Rationale of the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE) Trial

Multimodal imaging has the potential to identify acute ischaemic stroke patients most likely to benefit from late recanalization therapies. The general aim of the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy Trial is to investigate whether multimodal imaging can identify patients who will benefit substantially from mechanical embolectomy for the treatment of acute ischaemic stroke up to eight-hours from symptom onset. Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy is a randomized, controlled, blinded-outcome clinical trial. Acute ischaemic stroke patients with large vessel intracranial internal carotid artery or middle cerebral artery M1 or M2 occlusion enrolled within eight-hours of symptom onset are eligible. The study sample size is 120 patients. Patients are randomized to endovascular embolectomy employing the Merci Retriever (Concentric Medical, Mountain View, CA) or the Penumbra System (Penumbra, Alameda, CA) vs. standard medical care, with randomization stratified by penumbral pattern. The primary aim of the trial is to test the hypothesis that the presence of substantial ischaemic penumbral tissue visualized on multimodal imaging (magnetic resonance imaging or computed tomography) predicts patients most likely to respond to mechanical embolectomy for treatment of acute ischaemic stroke due to a large vessel, intracranial occlusion up to eight-hours from symptom onset. This hypothesis will be tested by analysing whether pretreatment imaging pattern has a significant interaction with treatment as a determinant of functional outcome based on the distribution of scores on the modified Rankin Scale measure of global disability assessed 90 days post-stroke. Nested hypotheses test for (1) treatment efficacy in patients with a penumbral pattern pretreatment, and (2) absence of treatment benefit (equivalency) in patients without a penumbral pattern pretreatment. An additional aim will only be tested if the primary hypothesis of an interaction is negative: that patients treated with mechanical embolectomy have improved functional outcome vs. standard medical management.

Validity and Reliability of the Perceived Deficit Questionnaire to Assess Cognitive Symptoms in People With Chronic Whiplash-Associated Disorders

Takasaki H, Chien C-W, Johnston V, Treleaven J, Jull G. Validity and reliability of the Perceived Deficit Questionnaire to assess cognitive symptoms in people with chronic whiplash-associated disorders. ObjectiveTo investigate the validity and reliability of the Perceived Deficit Questionnaire (PDQ) for use in people with chronic whiplash-associated disorders. DesignCross-sectional. SettingTertiary institution. ParticipantsPatients (N=105) with chronic whiplash-associated disorders and asymptomatic controls (n=50). InterventionsNot applicable. Main Outcome MeasuresThe 20-item PDQ inclusive of 4 sections (attention/concentration, retrospective memory, prospective memory, and organization/planning) rated on a 5-point scale. ResultsInternal construct validity of the PDQ was examined by Rasch analysis, confirming the appropriateness of its 5-point scale and the unidimensionality of each section after modification by eliminating 1 item each from the attention/concentration and retrospective memory sections. Preliminary evidence was also gained for external construct validity (convergent validity) of the modified PDQ by demonstrating significant (P<.05) correlations of all sections with a global measure of disability due to neck pain (the Neck Disability Index). The whiplash group demonstrated significantly (P<.05) higher scores in each section of the modified PDQ than did the control group, indicating evidence for discriminant validity. In addition, the modified PDQ demonstrated good internal consistency (Rasch-generated reliability >.8) and acceptable test-retest reliability with 1-month interval (intraclass correlation coefficients >.8). ConclusionsThe modified PDQ appears to be a valid and reliable questionnaire and could be used quickly in clinical practice to gain a basic understanding of perceived cognitive symptoms in people with chronic whiplash-associated disorders.

Validation of the Charcot–Marie–Tooth disease pediatric scale as an outcome measure of disability

Charcot-Marie-Tooth disease (CMT) is a common heritable peripheral neuropathy. There is no treatment for any form of CMT, although clinical trials are increasingly occurring. Patients usually develop symptoms during the first 2 decades of life, but there are no established outcome measures of disease severity or response to treatment. We identified a set of items that represent a range of impairment levels and conducted a series of validation studies to build a patient-centered multi-item rating scale of disability for children with CMT. As part of the Inherited Neuropathies Consortium, patients aged 3 to 20 years with a variety of CMT types were recruited from the USA, United Kingdom, Italy, and Australia. Initial development stages involved definition of the construct, item pool generation, peer review, and pilot testing. Based on data from 172 patients, a series of validation studies were conducted, including item and factor analysis, reliability testing, Rasch modeling, and sensitivity analysis. Seven areas for measurement were identified (strength, dexterity, sensation, gait, balance, power, endurance), and a psychometrically robust 11-item scale was constructed (CMT Pediatric Scale [CMTPedS]). Rasch analysis supported the viability of the CMTPedS as a unidimensional measure of disability in children with CMT. It showed good overall model fit, no evidence of misfitting items, and no person misfit, and it was well targeted for children with CMT. The CMTPedS is a well-tolerated outcome measure that can be completed in 25 minutes. It is a reliable, valid, and sensitive global measure of disability for children with CMT from the age of 3 years.

Long-term Angiographic and Clinical Outcomes in Completely Versus Incompletely Coiled Ruptured Intracranial Aneurysms

Long-term Angiographic and Clinical Outcomes in Completely Versus Incompletely Coiled Ruptured Intracranial Aneurysms