TY - JOUR
T1 - Postoperative seizure freedom does not normalize altered connectivity in temporal lobe epilepsy
AU - Maccotta, Luigi
AU - Lopez, Mayra A.
AU - Adeyemo, Babatunde
AU - Ances, Beau M.
AU - Day, Brian K.
AU - Eisenman, Lawrence N.
AU - Dowling, Joshua L.
AU - Leuthardt, Eric C.
AU - Schlaggar, Bradley L.
AU - Hogan, Robert Edward
N1 - Publisher Copyright:
Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.
PY - 2017/11
Y1 - 2017/11
N2 - Objectives: Specific changes in the functional connectivity of brain networks occur in patients with epilepsy. Yet whether such changes reflect a stable disease effect or one that is a function of active seizure burden remains unclear. Here, we longitudinally assessed the connectivity of canonical cognitive functional networks in patients with intractable temporal lobe epilepsy (TLE), both before and after patients underwent epilepsy surgery and achieved seizure freedom. Methods: Seventeen patients with intractable TLE who underwent epilepsy surgery with Engel class I outcome and 17 matched healthy controls took part in the study. The functional connectivity of a set of cognitive functional networks derived from typical cognitive tasks was assessed in patients, preoperatively and postoperatively, as well as in controls, using stringent methods of artifact reduction. Results: Preoperatively, functional networks in TLE patients differed significantly from healthy controls, with differences that largely, but not exclusively, involved the default mode and temporal/auditory subnetworks. However, undergoing epilepsy surgery and achieving seizure freedom did not lead to significant changes in network connectivity, with postoperative functional network abnormalities closely mirroring the preoperative state. Significance: This result argues for a stable chronic effect of the disease on brain connectivity, with changes that are largely “burned in” by the time a patient with intractable TLE undergoes epilepsy surgery, which typically occurs years after the initial diagnosis. The result has potential implications for the treatment of intractable epilepsy, suggesting that delaying surgical intervention that may achieve seizure freedom may lead to functional network changes that are no longer reversible by the time of epilepsy surgery.
AB - Objectives: Specific changes in the functional connectivity of brain networks occur in patients with epilepsy. Yet whether such changes reflect a stable disease effect or one that is a function of active seizure burden remains unclear. Here, we longitudinally assessed the connectivity of canonical cognitive functional networks in patients with intractable temporal lobe epilepsy (TLE), both before and after patients underwent epilepsy surgery and achieved seizure freedom. Methods: Seventeen patients with intractable TLE who underwent epilepsy surgery with Engel class I outcome and 17 matched healthy controls took part in the study. The functional connectivity of a set of cognitive functional networks derived from typical cognitive tasks was assessed in patients, preoperatively and postoperatively, as well as in controls, using stringent methods of artifact reduction. Results: Preoperatively, functional networks in TLE patients differed significantly from healthy controls, with differences that largely, but not exclusively, involved the default mode and temporal/auditory subnetworks. However, undergoing epilepsy surgery and achieving seizure freedom did not lead to significant changes in network connectivity, with postoperative functional network abnormalities closely mirroring the preoperative state. Significance: This result argues for a stable chronic effect of the disease on brain connectivity, with changes that are largely “burned in” by the time a patient with intractable TLE undergoes epilepsy surgery, which typically occurs years after the initial diagnosis. The result has potential implications for the treatment of intractable epilepsy, suggesting that delaying surgical intervention that may achieve seizure freedom may lead to functional network changes that are no longer reversible by the time of epilepsy surgery.
KW - Epilepsy surgery
KW - Functional network
KW - Longitudinal
KW - TLE
KW - fcMRI
UR - http://www.scopus.com/inward/record.url?scp=85026774801&partnerID=8YFLogxK
U2 - 10.1111/epi.13867
DO - 10.1111/epi.13867
M3 - Article
C2 - 28776646
AN - SCOPUS:85026774801
SN - 0013-9580
VL - 58
SP - 1842
EP - 1851
JO - Epilepsia
JF - Epilepsia
IS - 11
ER -