How Reproducible Are Transcranial Magnetic Stimulation-Induced MEPs in Subacute Stroke?

Purpose: Motor evoked potentials (MEPs) and total motor conduction time (TMCT) induced by transcranial magnetic stimulation (TMS) are used to make assumptions about the prognosis of motor outcome after stroke. Understanding the different sources of variability is fundamental to the concept of reliability. Reliability testing of TMS-MEPs and TMCTs within and between two independent examiners in healthy and stroke subjects is still an unexplored field in the clinical neurophysiology. Assessing the reproducibility of TMS measurements requires studies to investigate the test-retest reliability of TMS-induced MEPs and TMCT. The authors set out to test the reliability of these TMS measurements. Methods: Eighteen patients with stroke and 8 healthy volunteers were tested twice within a 1-week period by 2 examiners using TMS to determine MEPs and TMCT for the abductor pollicis brevis muscle of their affected and unaffected hands. Results: The authors found moderate to perfect reliability of TMS-induced MEPs in healthy volunteers, noninfarcted hemispheres (perfect agreement), and infarcted hemispheres (Kappa's = 0.45-0.87). Reliability of TMCT was good to excellent in the volunteers (intraclass correlation coefficients = 0.77-0.97), excellent in the noninfarcted hemispheres (intraclass correlation coefficients = 0.97-1.00), and poor to excellent in the infarcted hemispheres (intraclass correlation coefficients = 0.44-0.90). Conclusions: The reliability of TMS-induced MEPs and TMCT measurements in healthy volunteers and the noninfarcted hemisphere of patients with stroke with an upper paretic limb was good to excellent. In contrast, TMS measurements in the infarcted hemisphere were less consistent. Based on the lower reproducibility of TMCT measurements in the infarcted hemisphere, we recommend to repeat the TMCT measurements to improve the reliability of tests

Steroid resistance in COPD?: Overlap and differential anti-inflammatory effects in smokers and ex-smokers

Background: Inhaled corticosteroids (ICS) reduce exacerbation rates and improve health status but can increase the risk of pneumonia in COPD. The GLUCOLD study, investigating patients with mild-to-moderate COPD, has shown that long-term (2.5-year) ICS therapy induces anti-inflammatory effects. The literature suggests that cigarette smoking causes ICS insensitivity. The aim of this study is to compare anti-inflammatory effects of ICS in persistent smokers and persistent ex-smokers in a post-hoc analysis of the GLUCOLD study. Methods: Persistent smokers (n = 41) and persistent ex-smokers (n = 31) from the GLUCOLD cohort were investigated. Effects of ICS treatment compared with placebo were estimated by analysing changes in lung function, hyperresponsiveness, and inflammatory cells in sputum and bronchial biopsies during short-term (0-6 months) and long-term (6-30 months) treatment using multiple regression analyses. Results: Bronchial mast cells were reduced by short-term and long-term ICS treatment in both smokers and ex-smokers. In contrast, CD3(+), CD4(+), and CD8(+) cells were reduced by short-term ICS treatment in smokers only. In addition, sputum neutrophils and lymphocytes, and bronchial CD8(+) cells were reduced after long-term treatment in ex-smokers only. No significant interactions existed between smoking and ICS treatment. Conclusion: Even in the presence of smoking, long-term ICS treatment may lead to anti-inflammatory effects in the lung. Some anti-inflammatory ICS effects are comparable in smokers and ex-smokers with COPD, other effects are cell-specific. The clinical relevance of these findings, however, are uncertain

How Reproducible Are Transcranial Magnetic Stimulation-Induced MEPs in Subacute Stroke?

Methods: Eighteen patients with stroke and 8 healthy volunteers were tested twice within a 1-week period by 2 examiners using TMS to determine MEPs and TMCT for the abductor pollicis brevis muscle of their affected and unaffected hands. Results: The authors found moderate to perfect reliability of TMS-induced MEPs in healthy volunteers, noninfarcted hemispheres (perfect agreement), and infarcted hemispheres (Kappa's = 0.45-0.87). Reliability of TMCT was good to excellent in the volunteers (intraclass correlation coefficients = 0.77-0.97), excellent in the noninfarcted hemispheres (intraclass correlation coefficients = 0.97-1.00), and poor to excellent in the infarcted hemispheres (intraclass correlation coefficients = 0.44-0.90). Conclusions: The reliability of TMS-induced MEPs and TMCT measurements in healthy volunteers and the noninfarcted hemisphere of patients with stroke with an upper paretic limb was good to excellent. In contrast, TMS measurements in the infarcted hemisphere were less consistent. Based on the lower reproducibility of TMCT measurements in the infarcted hemisphere, we recommend to repeat the TMCT measurements to improve the reliability of tests. Purpose: Motor evoked potentials (MEPs) and total motor conduction time (TMCT) induced by transcranial magnetic stimulation (TMS) are used to make assumptions about the prognosis of motor outcome after stroke. Understanding the different sources of variability is fundamental to the concept of reliability. Reliability testing of TMS-MEPs and TMCTs within and between two independent examiners in healthy and stroke subjects is still an unexplored field in the clinical neurophysiology. Assessing the reproducibility of TMS measurements requires studies to investigate the test-retest reliability of TMS-induced MEPs and TMCT. The authors set out to test the reliability of these TMS measurements