Interictal activity is an important contributor to abnormal intrinsic network connectivity in paediatric focal epilepsy

TY - JOUR

T1 - Interictal activity is an important contributor to abnormal intrinsic network connectivity in paediatric focal epilepsy

AU - Shamshiri, Elhum A

AU - Tierney, Tim M

AU - Centeno, Maria

AU - St Pier, Kelly

AU - Pressler, Ronit M

AU - Sharp, David J

AU - Perani, Suejen

AU - Cross, J Helen

AU - Carmichael, David W

N1 - © 2016 Wiley Periodicals, Inc.

PY - 2017/1

Y1 - 2017/1

N2 - Patients with focal epilepsy have been shown to have reduced functional connectivity in intrinsic connectivity networks (ICNs), which has been related to neurocognitive development and outcome. However, the relationship between interictal epileptiform discharges (IEDs) and changes in ICNs remains unclear, with evidence both for and against their influence. EEG-fMRI data was obtained in 27 children with focal epilepsy (mixed localisation and aetiologies) and 17 controls. A natural stimulus task (cartoon blocks verses blocks where the subject was told "please wait") was used to enhance the connectivity within networks corresponding to ICNs while reducing potential confounds of vigilance and motion. Our primary hypothesis was that the functional connectivity within visual and attention networks would be reduced in patients with epilepsy. We further hypothesized that controlling for the effects of IEDs would increase the connectivity in the patient group. The key findings were: (1) Patients with mixed epileptic foci showed a common connectivity reduction in lateral visual and attentional networks compared with controls. (2) Having controlled for the effects of IEDs there were no connectivity differences between patients and controls. (3) A comparison within patients revealed reduced connectivity between the attentional network and basal ganglia associated with interictal epileptiform discharges. We also found that the task activations were reduced in epilepsy patients but that this was unrelated to IED occurrence. Unexpectedly, connectivity changes in ICNs were strongly associated with the transient effects of interictal epileptiform discharges. Interictal epileptiform discharges were shown to have a pervasive transient influence on the brain's functional organisation. Hum Brain Mapp 38:221-236, 2017. © 2016 Wiley Periodicals, Inc.

AB - Patients with focal epilepsy have been shown to have reduced functional connectivity in intrinsic connectivity networks (ICNs), which has been related to neurocognitive development and outcome. However, the relationship between interictal epileptiform discharges (IEDs) and changes in ICNs remains unclear, with evidence both for and against their influence. EEG-fMRI data was obtained in 27 children with focal epilepsy (mixed localisation and aetiologies) and 17 controls. A natural stimulus task (cartoon blocks verses blocks where the subject was told "please wait") was used to enhance the connectivity within networks corresponding to ICNs while reducing potential confounds of vigilance and motion. Our primary hypothesis was that the functional connectivity within visual and attention networks would be reduced in patients with epilepsy. We further hypothesized that controlling for the effects of IEDs would increase the connectivity in the patient group. The key findings were: (1) Patients with mixed epileptic foci showed a common connectivity reduction in lateral visual and attentional networks compared with controls. (2) Having controlled for the effects of IEDs there were no connectivity differences between patients and controls. (3) A comparison within patients revealed reduced connectivity between the attentional network and basal ganglia associated with interictal epileptiform discharges. We also found that the task activations were reduced in epilepsy patients but that this was unrelated to IED occurrence. Unexpectedly, connectivity changes in ICNs were strongly associated with the transient effects of interictal epileptiform discharges. Interictal epileptiform discharges were shown to have a pervasive transient influence on the brain's functional organisation. Hum Brain Mapp 38:221-236, 2017. © 2016 Wiley Periodicals, Inc.

KW - Acoustic Stimulation

KW - Adolescent

KW - Brain/diagnostic imaging

KW - Brain Mapping

KW - Child

KW - Electroencephalography

KW - Epilepsies, Partial/pathology

KW - Female

KW - Humans

KW - Image Processing, Computer-Assisted

KW - Magnetic Resonance Imaging

KW - Male

KW - Models, Statistical

KW - Neural Pathways/diagnostic imaging

KW - Neuropsychological Tests

KW - Oxygen/blood

KW - Photic Stimulation

U2 - 10.1002/hbm.23356

DO - 10.1002/hbm.23356

M3 - Article

C2 - 27543883

SN - 1065-9471

VL - 38

SP - 221

EP - 236

JO - Human Brain Mapping

JF - Human Brain Mapping

IS - 1

ER -