Functional connectivity in temporal lobe epilepsy and the relationship with disease parameters
Abstract number :
542
Submission category :
5. Neuro Imaging / 5B. Functional Imaging
Year :
2020
Submission ID :
2422883
Source :
www.aesnet.org
Presentation date :
12/6/2020 5:16:48 PM
Published date :
Nov 21, 2020, 02:24 AM
Authors :
Sarah Buck, UCL Queen Square Institute of Neurology; Luke Allen - UCL Queen Square Institute of Neurology; John Duncan - University College London, London, United Kingdom; Chalfont Centre for Epilepsy, Chalfont St Peter, United Kingdom; Meneka Sidhu - UCL
Rationale:
Temporal lobe epilepsy (TLE) affects a network that extends beyond the temporal lobes. Memory impairment is a common complaint in TLE, and is associated with disruption in these brain networks. The disruption of memory-related functional connectivity and how disease parameters influence such disruption is poorly understood. We examined functional connectivity during a memory task, and its relationship with disease parameters.
Method:
Twenty patients with left TLE and 29 patients with right RTLE were administered a memory-encoding fMRI paradigm of faces and words. We used graph theory to provide measures of node strength for a total of 222 regions across the brain. Seizure frequency and disease duration were then correlated with the node strength of each brain region.
Results:
Longer disease duration and higher seizure frequency were associated with both increased and decreased node strength during word and face encoding. In patients with both left and right TLE, increased node strength was shown in bilateral fusiform gyri, parahippocampal gyri, right thalamus and right amygdala. Decreased node strength was shown in bilateral middle and superior frontal gyri.
Conclusion:
In TLE widespread structural changes beyond the epileptogenic temporal lobe has been shown using techniques such as voxel-based morphometry. Correspondingly, we showed widespread changes in memory-related functional connectivity, with more profound changes associated with a longer duration of epilepsy and higher seizure frequency. This suggests that these changes may be a consequence of the epilepsy, and support early intervention. Increased node strength in mesial temporal lobe regions may reflect compensatory reorganisation to support memory. Decreased node strength in frontal regions suggest a functional decoupling of the frontal lobes. The visualisation of altered memory networks illuminates the functional anatomy of memory impairments in TLE and are an effective biomarker for longitudinal and intervention studies.
Funding:
:National Institute for Health Research University College London Hospitals Biomedical Research Center (grant number 229811)
Neuro Imaging