IgM anti-MAG± peripheral neuropathy (IMAGiNe) study protocol: An international, observational, prospective registry of patients with IgM M-protein peripheral neuropathies.

BACKGROUND: International consensus on IgM ± anti-MAG ± PNP (IgM PNP) is lacking. Despite increasing interest in clinical trials, validated disease-specific measures are needed to adequately capture limitations and changes over time. The IMAGiNe (IgM ± anti-myelin associated glycoprotein [MAG] peripheral neuropathy) study surges as an international collaboration to create a standardized registry of patients with IgM ± anti-MAG PNP. The consortium, which currently consists of 11 institutions from 7 countries, presents here the IMAGiNe study design and protocol. AIMS: Functional outcome measures will be constructed at the level of impairment, as well as activity and participation. We aim to describe the natural history of the cohort, the role of anti-MAG antibodies, the presence of clinical subtypes, and potential biomarkers. METHODS: The IMAGiNe study is a prospective, observational cohort study with a 3-year follow-up. At each assessment, researchers collect clinical data and subjects complete a list of preselected outcome measures. Among these, the "Pre-Rasch-built Overall Disability Scale (Pre-RODS)" questionnaire will be submitted to Rasch analysis to assess classic and modern clinimetric requirements. RESULTS: The final measures will include the IgM-PNP-specific RODS and Ataxia Rating Scale (IgM-PNP-ARS). Descriptions of the disease course, clinical heterogeneity, treatment regimes, variations in laboratory values, and antibody titers will help reach consensus on diagnosis and follow-up strategies. CONCLUSION: The constructed interval scales will be cross-culturally valid and suitable for use in future clinical trials and daily practice. The ultimate goals are to improve functional individualized assessment, reach international consensus, and lay the foundations for successful designs in future studies.

Validation of the Serbian version of inflammatory Rasch-built overall disability scale in patients with chronic inflammatory demyelinating polyradiculoneuropathy.

Inflammatory Rasch-built overall disability scale (I-RODS) seems to be a valid activity measure for use in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Our aim was to translate and validate the I-RODS for use in CIDP patients from Serbia. Study comprised 83 patients diagnosed with CIDP. I-RODS was translated and cross-culturally validated using the standard guidelines. Following scales were also administered: Medical Research Council (MRC) sum score, Inflammatory Neuropathy Cause and Treatment (INCAT) sensory and disability scores, Krupp's Fatigue Severity Scale, Beck Depression Inventory, Visual Analogue Scale for pain, and health survey-36 (SF-36) as a quality of life measure. According to the I-RODS, significant proportion of our patients reported that "running" (51%), "dancing" (41%), and "standing for hours" (40%) were impossible tasks to perform, while "teeth brushing" (94%), "eating" (88%), and "reading a newspaper/book" (82%) were noted as the easiest items. Patients with more muscle weakness (lower MRC sum score) and more severe INCAT sensory score had lower I-RODS score (P < .01). Also, patients with fatigue, depression and pain had lower I-RODS scores (P < .01). I-RODS score correlated with the INCAT disability score (P < 0.01) was 78 ± 19 compared to 51 ± 30 in patients with INCAT >1 (P < .01). I-RODS score correlated with the total SF-36 score (rho = +0.73, P < .01), as well as with all SF-36 domain scores. Serbian version of the I-RODS seems to be a valid activity measure for use in CIDP patients. I-RODS was able to assess different levels of disability, it was in association with impairment measures, INCAT disability scale and quality of life. Further studies are needed to assess its responsiveness.

Recent advances in outcome measures in IgM-anti-MAG+ neuropathies.

PURPOSE OF REVIEW: This review aims to provide an overview of all randomized trials performed in IgM Anti-Myelin Associated Glycoprotein related peripheral neuropathy (MGUSP) with emphasis on the applied outcome measures including the rationale for their choice and possible limitations, emphasizing new advances in modern clinimetrics. RECENT FINDINGS: All clinical trials performed in patients with MGUSP have been negative, which raises many unanswered questions: were the sample sizes too small, the duration of the trials too short, the chosen medical interventions not aggressive enough, the definition of being a responder inadequate, and, last but not least, the outcome measures used improper? Only recently has attention been directed towards the possibility of using suboptimal outcome measures as a potential factor that may have contributed to the negative results in MGUSP. SUMMARY: Since there is no international consensus on how to assess and treat patients with MGUSP, the current study addresses new advances in the field of modern clinimetrics and recommendations for future outcome measure studies in MGUSP before proceeding with new interventional trials.

The Val30Met familial amyloid polyneuropathy specific Rasch-built overall disability scale (FAP-RODS(©) ).

Familial amyloid polyneuropathy (FAP) is a chronic debilitating multi-organic disorder, mainly assessed using ordinal-based impairment measures. To date, no outcome measure at the activity and participation level has been constructed in FAP. The current study aimed to design an interval activity/participation scale for FAP through Rasch methodology. A preliminary FAP Rasch-built overall disability scale (pre-FAP-RODS) containing 146 activity/participation items was assessed twice (interval: 2-4 week; test-retest reliability) in 248 patients with Val30Met FAP examined in Porto, Portugal, of which 65.7% have received liver transplantation. An ordinal-based 24-item FAP-symptoms inventory questionnaire (FAP-SIQ) was also assessed (validity purposes). The pre-FAP-RODS and FAP-SIQ data were subjected to Rasch analyses. The pre-FAP-RODS did not meet model's expectations. On the basis of requirements such as misfit statistics, differential item functioning, and local dependency, items were systematically removed until a final 34-item FAP-RODS(©) was constructed fulfilling all Rasch requirements. Acceptable reliability/validity scores were demonstrated. In conclusion, the 34-item FAP-RODS(©) is a disease-specific interval measure suitable for detecting activity and participation restrictions in patients with FAP. The use of the FAP-RODS(©) is recommended for future international clinical trials in patients with Val30Met FAP determining its responsiveness and its cross-cultural validation. Its expansion to other forms of FAP should also be focus of future clinical studies.

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© (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 (½ × 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 ≥ 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.

Grip strength comparison in immune-mediated neuropathies: Vigorimeter vs. Jamar.

The Jamar dynamometer and Vigorimeter have been used to assess grip strength in immune-mediated neuropathies, but have never been compared to each other. Therefore, we performed a comparison study between these two devices in patients with immune-mediated neuropathies. Grip strength data were collected in 102 cross-sectional stable and 163 longitudinal (new diagnoses or changing condition) patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), gammopathy-related polyneuropathy (MGUSP), and multifocal motor neuropathy (MMN). Stable patients were assessed twice (validity/reliability studies). Longitudinal patients were assessed 3-5 times during 1 year. Responsiveness comparison between the two tools was examined using combined anchor-/distribution-based minimum clinically important difference (MCID) techniques. Patients were asked to indicate their preference for the Jamar or Vigorimeter. Both tools correlated highly with each other (ρ = 0.86, p < 0.0001) and showed good intra-class correlation coefficients (Jamar [Right/Left hands]: ICC 0.997/0.96; Vigori: ICC 0.95/0.98). Meaningful changes were comparable between the two instruments, being higher in GBS compared to CIDP patients. In MGUSP/MMN poor responsiveness was seen. Significant more patients preferred the Vigorimeter. In conclusion, validity, reliability, and responsiveness aspects were comparable between the Jamar dynamometer and Vigorimeter. However, based on patients' preference, the Vigorimeter is recommended in future studies in immune-mediated neuropathies.