Electrodiagnosis of Guillain-Barre syndrome in the International GBS Outcome Study: Differences in methods and reference values.

OBJECTIVE: To describe the heterogeneity of electrodiagnostic (EDx) studies in Guillain-Barré syndrome (GBS) patients collected as part of the International GBS Outcome Study (IGOS). METHODS: Prospectively collected clinical and EDx data were available in 957 IGOS patients from 115 centers. Only the first EDx study was included in the current analysis. RESULTS: Median timing of the EDx study was 7 days (interquartile range 4-11) from symptom onset. Methodology varied between centers, countries and regions. Reference values from the responding 103 centers were derived locally in 49%, from publications in 37% and from a combination of these in the remaining 15%. Amplitude measurement in the EDx studies (baseline-to-peak or peak-to-peak) differed from the way this was done in the reference values, in 22% of motor and 39% of sensory conduction. There was marked variability in both motor and sensory reference values, although only a few outliers accounted for this. CONCLUSIONS: Our study showed extensive variation in the clinical practice of EDx in GBS patients among IGOS centers across the regions. SIGNIFICANCE: Besides EDx variation in GBS patients participating in IGOS, this diversity is likely to be present in other neuromuscular disorders and centers. This underlines the need for standardization of EDx in future multinational GBS studies.

Intravenous immunoglobulin treatment for mild Guillain-Barré syndrome: an international observational study.

OBJECTIVE: To compare the disease course in patients with mild Guillain-Barré syndrome (GBS) who were treated with intravenous immunoglobulin (IVIg) or supportive care only. METHODS: We selected patients from the prospective observational International GBS Outcome Study (IGOS) who were able to walk independently at study entry (mild GBS), treated with one IVIg course or supportive care. The primary endpoint was the GBS disability score four weeks after study entry, assessed by multivariable ordinal regression analysis. RESULTS: Of 188 eligible patients, 148 (79%) were treated with IVIg and 40 (21%) with supportive care. The IVIg group was more disabled at baseline. IVIg treatment was not associated with lower GBS disability scores at 4 weeks (adjusted OR (aOR) 1.62, 95% CI 0.63 to 4.13). Nearly all secondary endpoints showed no benefit from IVIg, although the time to regain full muscle strength was shorter (28 vs 56 days, p=0.03) and reported pain at 26 weeks was lower (n=26/121, 22% vs n=12/30, 40%, p=0.04) in the IVIg treated patients. In the subanalysis with persistent mild GBS in the first 2 weeks, the aOR for a lower GBS disability score at 4 weeks was 2.32 (95% CI 0.76 to 7.13). At 1 year, 40% of all patients had residual symptoms. CONCLUSION: In patients with mild GBS, one course of IVIg did not improve the overall disease course. The certainty of this conclusion is limited by confounding factors, selection bias and wide confidence limits. Residual symptoms were often present after one year, indicating the need for better treatments in mild GBS.

Rasch-Transformed Total Neuropathy Score clinical version (RT-TNSc(©) ) in patients with chemotherapy-induced peripheral neuropathy.

Composite scales such as the Total Neuropathy Score clinical version (TNSc(©) ) have been widely used to measure neurological impairment in a standardized manner but they have been criticized due to their ordinal setting having no fixed unit. This study aims to improve impairment assessment in patients with chemotherapy-induced peripheral neuropathy (CIPN) by subjecting TNSc(©) records to Rasch analyses. In particular, we wanted to investigate the influence of factors affecting the use of the TNSc(©) in clinical practice. TNSc(©) has 7 domains (sensory, motor, autonomic, pin-prick, vibration, strength, and deep tendon reflexes [DTR]) each being scored 0-4. Data obtained in 281 patients with stable CIPN were subjected to Rasch analyses to determine the fit to the model. The TNSc(©) did not meet Rasch model's expectations primarily because of misfit statistics in autonomic and DTR domains. Removing these two, acceptable model fit and uni-dimensionality were obtained. However, disordered thresholds (vibration and strength) and item bias (mainly cultural) were still seen, but these findings were kept to balance the assessment range of the Rasch-Transformed TNSc(©) (RT-TNSc(©) ). Acceptable reliability findings were also obtained. A 5-domains RT-TNSc(©) may be a more proper assessment tool in patients with CIPN. Future studies are needed to examine its responsive properties.