Citation

Sours C, Chen H, Roys SR, Zhuo J, Varshney A, Gullapalli RP. Brain Connect. 2015; 5(7): 442-450.

Affiliation

University of Maryland School of Medicine, Diagnostic Radiology and Nuclear Medicine , 22 South Greene Street , Baltimore, Maryland, United States , 21201 ; csours001@gmail.com.

Copyright

(Copyright © 2015, Mary Ann Liebert Publishers)

DOI

10.1089/brain.2014.0333

PMID

25808612

Abstract

The aim of this study was to investigate if discrete wavelet decomposition provides additional insight into resting state processes through the analysis of functional connectivity within specific frequency ranges within the default mode network (DMN) that may be affected by mild traumatic brain injury (mTBI). Participants included 32 mTBI patients [15 with post concussive syndrome (PCS+) and 17 without (PCS-)]. mTBI patients received rs-fMRI (resting state functional magnetic resonance imaging) at acute (within 10 days of injury) and chronic (6 months post injury) time points and were compared to 31 controls (HC). The wavelet decomposition divides the time series into multiple frequency ranges based on 4 scaling factors (SF1: 0.125-0.250 Hz, SF2: 0.060-0.125 Hz, SF3: 0.030-0.060 Hz, SF4: 0.015-0.030 Hz). Within each SF, wavelet connectivity matrices for nodes of the DMN were created for each group (HC, PCS+, PCS-), and bivariate measures of strength and diversity were calculated. The results demonstrate reduced strength of connectivity in PCS+ patients compared to PCS- patients within SF1 during both the acute and chronic stages of injury, as well as recovery of connectivity within SF1 across the two time points. Furthermore, the PCS- group demonstrated greater network strength compared to controls at both time points suggesting a potential compensatory or protective mechanism in these patients. These findings stress the importance of investigating resting state connectivity within multiple frequency ranges: however, many of our findings are within SF1, which may overlap with frequencies associated with cardiac and respiratory activity.

Language: en