@article {13558,
	title = {Effects of Motion Related Outliers in Dynamic Functional Connectivity Using the Sliding Window Method.},
	journal = {J Neurosci Methods},
	year = {2019},
	month = {2019 Nov 12},
	pages = {108519},
	abstract = {BACKGROUND: It has been suggested that the use of window functions, other than the rectangular, in the sliding window method, may be beneficial for reducing the effects of motion-related outliers in the time-series, when assessing dynamic functional connectivity (dFC) in resting-state fMRI (rs-fMRI). METHODOLOGY: Ten window functions for a wide range of window lengths (20-150 s) combined with Pearson and Kendall correlation metrics, were investigated. One hundred high quality rs-fMRI datasets from healthy controls, were used to systematically assess the effect of varying the window function and length on dFC assessment. To this end, two approaches were implemented: a) simulated outliers were added to the experimental data and b) the experimental data were divided into low and high motion subgroups. RESULTS: The presence of experimental motion-noise tended to inflate the number of dynamic connections for longer (>=100 s) wide-shaped windows, while shorter (20-30 s) narrow-shaped windows exhibited increased sensitivity in the presence of simulated outliers. Moreover, window sizes from 60 s to 90 s were mildly affected by motion-related effects. In most cases, the number of dynamic connections increased, and gradually lower frequencies were captured, with an increasing window size. CONCLUSIONS: Subject motion considerably affects the obtained dFC patterns; thus, it is preferable to perform motion artefact removal in the pre-processing stage rather than using alternative window functions to mitigate their effects. Provided that motion-noise is not excessive, the choice of a rectangular window is adequate. Finally, low frequency oscillations in functional connectivity seem to play an important role in the context of dFC assessment.},
	issn = {1872-678X},
	doi = {10.1016/j.jneumeth.2019.108519},
	url = {https://www.sciencedirect.com/science/article/pii/S0165027019303760?via\%3Dihub},
	author = {Savva, Antonis D and Kassinopoulos, Michalis and Smyrnis, Nikolaos and Matsopoulos, George K and Mitsis, Georgios D}
}
