Regional myelin alterations linked to post-ictal generalised EEG suppression
Abstract number :
532
Submission category :
5. Neuro Imaging / 5A. Structural Imaging
Year :
2020
Submission ID :
2422874
Source :
www.aesnet.org
Presentation date :
12/6/2020 5:16:48 PM
Published date :
Nov 21, 2020, 02:24 AM
Authors :
Luke Allen, UCL Institute of Neurology; Jaison Hampson - University of Texas Health Sciences Center at Houston; Ashwani Jha - UCL Institute of Neurology; Benjamin Whatley - UCL Institute of Neurology; Ronald Harper - David Geffen School of Medicine at Uni
Rationale:
Postictal generalized EEG suppression (PGES) has been linked to peri-focal to bilateral tonic-clonic (FBTCS) seizure respiratory dysfunction, post-FBTCS autonomic and respiratory dysregulation, and increased risk of sudden unexpected death in epilepsy (SUDEP). Whether PGES is associated with injury to critical brain structures mediating autonomic and breathing control, which are damaged in cases of SUDEP, remains unknown. We set out to identify and characterise the presence and extent of brain microstructural alterations accompanying PGES, particularly among sub-cortical brain areas, using T1/T2 ratio mapping and diffusion magnetic resonance imaging (dMRI).
Method:
127 subjects were recruited from 2 centers (60 males, mean age 37.7±12.5), 46 with GTCS during video EEG and respiratory monitoring: 19 exhibited PGES after GTCS (PGES+) and 27 did not (PGES-). 3D-T1, T2, and diffusion MR images were acquired on a 3T GE MR750 (site 1, 85 subjects) and a 3T Siemens Trio (site 2, 45 subjects). T1 images were segmented to outline regions of interest. Group-wise comparisons of diffusion tensor imaging metrics (fractional anisotropy, FA; mean diffusivity, MD) and myelin estimates (T1/T2 ratio) were performed, and linear regression models were built to explore associations between PGES duration and regional MRI measurements. Prospectively-acquired SpO2 data collected during long-term seizure monitoring were available in a subset of 18 FBTCS subjects.
Results:
T1/T2 ratios were lower in the right insula white matter in PGES+ compared to PGES- (p=0.03), and those without GTCS (p=0.001). FA was reduced in the bilateral ventral diencephalon in PGES+ compared to PGES- and those without GTCS (p< 0.05). Linear regression models showed inverse associations between PGES durations and T1/T2 ratios in the bilateral thalamus (p< 0.005) and bilateral cingulate white matter (p< 0.05). PGES duration correlated positively with hypoxia duration (r = 0.58, p = 0.04), and extent of oxygen desaturation was greater in PGES+ compared to PGES- (t = 3, p = 0.03).
Neuro Imaging