Does ability to walk reflect general functionality in inflammatory neuropathies?

The "ability to walk" is considered a benchmark for good clinical recovery and prognosis, particularly in patients with Guillain-Barre syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). However, it has never been determined whether being "able to walk" represents general functionality. The purpose of this study was to examine whether the ability to walk outside independently reflects general functional improvement in patients with GBS, CIDP, and gammopathy-related neuropathy (MGUSP). A total of 137 patients with newly diagnosed (or relapsing) GBS (55), CIDP (59), and MGUSP (23) were serially examined (1-year). Predefined arbitrary cut-offs (so-called patients' Functional-Acceptable-Clinical-Thresholds [FACTs]) were taken at the 50th, 75th, and 90th percentile of the Inflammatory-Rasch-built-Overall-Disability-Scale (I-RODS((c)) ). We determined the proportion of patients able to walk outside independently that reached the postulated cut-offs. A mean total of 85%, 39%, and 12% of all patients able to walk reached 50th, 75th, and 90th percentile thresholds, respectively. These findings were not neuropathy type related. Our findings show that assessing only one construct of functionality (e.g., walking ability) does not reflect the full scope of daily/social functional deficits perceived by patients. The ability to walk shows a patient is doing better, but not necessarily doing well. The I-RODS((c)) bypasses these limitations

Outcome measures in MMN revisited : Further improvement needed

The objectives of this study were to provide an overview of the outcome measures (OMs) applied in clinical trials in multifocal motor neuropathy (MMN) and to determine the responsiveness of a core set of selected OMs as part of the peripheral neuropathy outcome measures standardization (PeriNomS) study. The following OMs were serially applied in 26 patients with newly diagnosed or relapsing MMN, receiving intravenous immunoglobulin (assessments: T0/T3/T12 months): 14 muscle pairs MRC (Medical Research Council) scale, the Neuropathy Impairment Scale motor-subset, a self-evaluation scale, grip strength, and MMN-RODS\ua9 (Rasch-built overall disability scale). All data, except the grip strength, were subjected to Rasch analyses before determining responsiveness. For grip strength, responsiveness was examined using a combined anchor- (SF-36 question-2) and distribution-based ( 7 SD) minimum clinically important difference (MCID) techniques, determining the proportion of patients exceeding both the identified cut-offs. For the remaining scales, the magnitude of change for each patient on each scale was determined using the MCID related to the individual SE (responder definition: MCID-SE 65 1.96). Overall, a great assortment of measures has been used in MMN trials with different responsiveness definitions. For the selected OMs, responsiveness was poor and only seen in one fourth to one third of the patients, the grip strength being more responsive. Despite the efforts taken to standardize outcome assessment, further clinimetric responsiveness studies are needed in MMN

Modified Erasmus GBS Respiratory Insufficiency Score: a simplified clinical tool to predict the risk of mechanical ventilation in Guillain-Barre syndrome

BackgroundThis study aimed to determine the clinical and diagnostic factors associated with mechanical ventilation (MV) in Guillain-Barre syndrome (GBS) and to simplify the existing Erasmus GBS Respiratory Insufficiency Score (EGRIS) for predicting the risk of MV. MethodsData from the first 1500 patients included in the prospective International GBS Outcome Study (IGOS) were used. Patients were included across five continents. Patients Results1133 (76%) patients met the study criteria. Independent predictors of MV were a shorter time from onset of weakness until admission, the presence of bulbar palsy and weakness of neck flexion and hip flexion. The modified EGRIS (mEGRIS) was based on these factors and accurately predicts the risk of MV with an area under the curve (AUC) of 0.84 (0.80-0.88). We internally validated the model within the full IGOS cohort and within separate regional subgroups, which showed AUC values of 0.83 (0.81-0.88) and 0.85 (0.72-0.98), respectively. ConclusionsThe mEGRIS is a simple and accurate tool for predicting the risk of MV in GBS. Compared with the original model, the mEGRIS requires less information for predictions with equal accuracy, can be used to predict MV at multiple time points and is also applicable in less severely affected patients and GBS variants. Model performance was consistent across different regions.Neurological Motor Disorder

Rasch-ionale for neurologists

Outcome measures are considered the most important tools to monitor patients' outcome in both clinical and research settings. Measuring the clinical state of patients is a fundamental part of our daily clinical practice and research that sometimes is taken for granted. In peripheral neuropathies, there are many scales available, but most of these are at the ordinal level. This paper will systematically address the types of scales available (being nominal, ordinal, interval, or ratio data-based) in terms of their strengths and weaknesses. The differences between classical test theory-based and modern test method-based outcome measures will be addressed with emphasis on Rasch methodology. Various steps will be highlighted as part of the evaluation and construction of outcome measures using the Rasch method, with the aim to increase the knowledge and utility of this technique. We argue that Rasch-built outcome measures should be used for future studies in neuromuscular disorders and their method of construction could be easily extrapolated to other neurological illnesses

Rasch-built Overall Disability Scale for Multifocal motor neuropathy (MMN-RODS©)

Clinical trials in multifocal motor neuropathy (MMN) have often used ordinal-based measures that may not accurately capture changes. We aimed to construct a disability interval outcome measure specifically for MMN using the Rasch model and to examine its clinimetric properties. A total of 146 preliminary activity and participation items were assessed twice (reliability studies) in 96 clinically stable MMN patients. These patients also assessed the ordinal-based overall disability sum score (construct, sample-dependent validity). The final Rasch-built overall disability scale for MMN (MMN-RODS\ua9) was serially applied in 26 patients with newly diagnosed or relapsing MMN, treated with intravenous immunoglobulin (IVIg) (1-year follow-up; responsiveness study). The magnitude of change for each patient was calculated using the minimum clinically important difference technique related to the individually obtained standard errors. A total of 121 items not fulfilling Rasch requirements were removed. The final 25-item MMN-RODS\ua9fulfilled all Rasch model's expectations and showed acceptable reliability and validity including good discriminatory capacity. Most serially examined patients improved, but its magnitude was low, reflecting poor responsiveness. The constructed MMN-RODS\uc2\ua9is a disease-specific, interval measure to detect activity limitations in patients with MMN and overcomes the shortcomings of ordinal scales. However, future clinimetric studies are needed to improve the MMN-RODS\uc2\ua9's responsiveness by longer observations and/or more rigorous treatment regimens