Magnetic resonance active lesions as individual-level surrogate for relapses in multiple sclerosis

6BACKGROUND: Use of quantitative magnetic resonance imaging (MRI) metrics as surrogates for clinical outcomes in multiple sclerosis (MS) trials is controversial. OBJECTIVES: We sought to validate, at the individual-patient level, the number of MRI active lesions, as a surrogate marker for relapses in MS. METHODS: Individual-patient data from two large, placebo-controlled clinical trials of subcutaneous interferon β-1a in patients with relapsing-remitting or secondary progressive (SP) MS were analysed separately and as pooled data. The four Prentice criteria were applied to assess surrogacy for the number of new T2 MRI lesions. The predictive value of short-term treatment effects on this MRI marker for longer-term clinical relapses was also assessed. RESULTS: All Prentice criteria were satisfied. The number of new T2 MRI lesions correlated with the number of relapses over the follow-up period. The proportion of treatment effect on relapses accounted for by the effect of treatment on new T2 MRI lesions over 2 years was 53% in patients with relapsing-remitting MS, 67% in patients with secondary progressive MS, and 62% in pooled data. In the pooled data, treatment effects on new lesions over 1 year mediated a good proportion (70%) of effects on relapses over the subsequent year. CONCLUSIONS: This study provides evidence that new T2 MRI lesion count is a surrogate for relapses in patients with MS treated with interferon or drugs with a similar mechanism of action. Short-term treatment effects on this MRI measure can predict longer-term effects on relapses.reservedmixedSORMANI MP; STUBINSKI B; CORNELISSE P; ROCAK S; LI D; N. DE STEFANOSormani, Mp; Stubinski, B; Cornelisse, P; Rocak, S; Li, D; DE STEFANO, Nicol

Combined MRI lesions and relapses as a surrogate for disability in multiple sclerosis

OBJECTIVE: In multiple sclerosis (MS), the aim of therapies is to prevent the accumulation of irreversible disability. This is difficult to assess given the short time course of clinical trials. MRI markers and relapses are often used as surrogate of disability in MS studies, but their validity remains controversial. We sought to validate, at the individual patient level, MRI lesions and relapses as surrogates for disability progression over the course of MS trials. METHODS: Individual patient data from a large, placebo-controlled trial of interferon β-1a in relapsing-remitting MS (RRMS) were analyzed. The Prentice criteria were applied to evaluate surrogacy of 1-year MRI active lesions and relapses for disability worsening (Expanded Disability Status Scale [EDSS]) over the 2-year follow-up. RESULTS: All Prentice criteria were satisfied. Treatment reduced by 31% the odds of having EDSS worsening over 2 years, reducing the mean number of MRI lesions by 61% and the mean number of relapses by 36% over 1 year. Both 1-year MRI lesion activity and relapses, when considered independently, accounted for more than 60% of the treatment effect on 2-year EDSS worsening. A combination of 1-year MRI lesion activity and relapses explained 100% of the treatment effect on EDSS worsening over 2 years. CONCLUSIONS: A combined measure of 1-year changes in MRI lesions and relapses after interferon therapy fully estimated the corresponding effect on 2-year EDSS worsening. This short-term combined measure appears to be a surrogate for disability progression over a longer term when evaluating the effect of interferon in RRMS

Comparison between visual scoring of cyclic alternating pattern (CAP) and computerized assessment of slow EEG oscillations in the transition from light to deep non-REM sleep.

Ten healthy volunteers (six men and four women) aged between 20 and 30 years underwent a nocturnal polygraphic recording on paper and on tape. Spectral analysis was accomplished and EEG sleep scored according to standard criteria and to the guidelines for the identification of cyclic alternating pattern (CAP). The initial 25 min of sleep, starting from the first clear-cut k-complex and ending within stage 4, was subdivided into five consecutive blocks of 5 min each. Using a zero-crossing technique, we evaluated the number of total power oscillations in each block and we tested the hypothesis of significant modifications of the number of total power oscillations and of their periodicity in the successive sessions. In addition, we measured the gap between the maximum and minimum values, respectively, of two successive half-waves making up each oscillation. The hypothesis of time-related trends of the values of the gaps was tested by means of linear regression techniques. Within the 25-min time span, the number of periodic oscillations and the number of CAP cycles showed significant increases. The amplitude gaps underwent a decreasing trend. The present data suggest that slow rhythmic oscillations expressed by CAP can be detected by means of spectral analysis. Their dynamics suggests a close relationship with the EEG synchronization processes

Comparison between visual scoring of cyclic alternating pattern (CAP) and computerized assessment of slow EEG oscillations in the transition from light to deep non-REM sleep

Ten healthy volunteers (six men and four women) aged between 20 and 30 years underwent a nocturnal polygraphic recording on paper and on tape. Spectral analysis was accomplished and EEG sleep scored according to standard criteria and to the guidelines for the identification of cyclic alternating pattern (CAP). The initial 25 min of sleep, starting from the first clear- cut k-complex and ending within stage 4, was subdivided into five consecutive blocks of 5 min each. Using a zero-crossing technique, we evaluated the number of total power oscillations in each block and we tested the hypothesis of significant modifications of the number of total power oscillations and of their periodicity in the successive sessions. In addition, we measured the gap between the maximum and minimum values, respectively, of two successive half-waves making up each oscillation. The hypothesis of time-related trends of the values of the gaps was tested by means of linear regression techniques. Within the 25-min time span, the number of periodic oscillations and the number of CAP cycles showed significant increases. The amplitude gaps underwent a decreasing trend. The present data suggest that slow rhythmic oscillations expressed by CAP can be detected by means of spectral analysis. Their dynamics suggests a close relationship with the EEG synchronization processes