P126. Functional connectivity of resting state EEG in MS patients: Follow-up over two years. Issue 8 (August 2015)

• Record Type: Journal Article
• Authors: Hardmeier, M.; Hatz, F.; Penner, I.K.; Naegelin, Y.; Bousleiman, H.; Schindler, C.; Kappos, L.; Fuhr, P.
• Is Part Of: Clinical neurophysiology. Volume 126:Issue 8(2015:Aug.)
• Page Start: e153
• Publication Date: 2015-08
• Subjects: Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2015.04.253
• Languages: English
• ISSNs: 1388-2457

Abstract

<abstract xml:lang="en" abstract-type="author" id="ab005"> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title id="st005">Background</title> <p id="sp005">Functional connectivity is a promising tool to characterize and analyze alterations of oscillating brain activity. In MS the significance of such alterations is not well known.</p> </sec> <sec> <title id="st010">Objective</title> <p id="sp010">To explore the dynamics of functional connectivity in MS over time.</p> </sec> <sec> <title id="st015">Methods</title> <p id="sp015">57 RRMS-patients (76% female; median age: 38.4 yrs, interquartile range (IQR): 33.2–44.5 yrs; median EDSS: 2.0; IQR: 1.5–3.0) and 35 normal controls (80% female; median age: 38.4 yrs, IQR: 30.4–43.2 yrs) received a 256 channel EEG at baseline and at years 1 and 2, and were assessed by the EDSS, the symbol digit modalities test (SDMT) and the fatigue scale for motor and cognitive functions (FSMC, Penner et al., 2009). Functional connectivity between 22 regions was determined by the phase lag index (PLI, Stam et al., 2007) using TAPEEG (Hatz et al., 2014). The connectomes and the average connectivity of each region were calculated in four frequency bands (theta, lower and upper alpha, beta) and compared between groups and over time by permutation <italic>t</italic>-tests and ANOVA.</p> </sec> <sec> <title id="st020">Result</title> <p id="sp020">Compared with normal controls, patients had reduced cognitive processing speed (SDMT: 56.2 vs. 63.8, p0.1). Connectivity in the beta-band was reduced in MS patients, most significantly over left temporo-parieto-occipital regions (p).</p> </sec> <sec> <title id="st025">Conclusions</title> <p id="sp025">Reduced connectivity over the left temporo-parieto-occipital regions in the beta-band discriminates between groups of MS patients and healthy controls, but does not change over time, whereas connectivity over the right centro-parietal regions in the upper alpha band may be a more dynamic marker. However, on average, patients neither experience a change in clinical status, cognitive function nor fatigue during the observation period. Thus it remains unclear whether reduced beta-connectivity represents a marker of state or of trait.</p> </sec> <sec> <title id="st030">Disclosure</title> <p id="sp030">The study has been financially supported by grants of the Swiss National Science Foundation (grants # 33CM30-124115/1; # 33CM30–140338; # 326030–128775/1) and the Swiss Multiple Sclerosis Society.</p> </sec> </abstract>