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Combined EEG-fMRI and tractography to visualise propagation of epileptic activity.

Hamandi K, Powell HW, Laufs H, Symms MR, Barker GJ, Parker GJ, Lemieux L, Duncan JS - J. Neurol. Neurosurg. Psychiatr. (2007)

Bottom Line: Dynamic causal modelling suggested propagation of neural activity from the temporal focus to the area of occipital activation.Tractography showed connections from the site of temporal lobe activation to the site of occipital activation.This demonstrates the principle of combining EEG-fMRI and tractography to delineate the pathways of propagation of epileptic activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, UK. hamandik@cardiff.ac.uk

ABSTRACT
In a patient with refractory temporal lobe epilepsy, EEG-fMRI showed activation in association with left anterior temporal interictal discharges, in the left temporal, parietal and occipital lobes. Dynamic causal modelling suggested propagation of neural activity from the temporal focus to the area of occipital activation. Tractography showed connections from the site of temporal lobe activation to the site of occipital activation. This demonstrates the principle of combining EEG-fMRI and tractography to delineate the pathways of propagation of epileptic activity.

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Related in: MedlinePlus

Left panel shows EEG recorded during fMRI scanning (10–20 system, upper 10 channels referential, lower 8 bipolar (OSC channel marks scanner gradient switching)) demonstrating left temporal activity in the delta/theta band with frequent intermixed spikes phase reversing at T3 (bold arrow). (A) Significant anterior temporal IED-related fMRI activations SPM{T} overlaid onto structural echo planar image (b = 0), showing left temporal and bilateral occipital fMRI activations. There were no significant deactivations. Scale represents z-score. (B) Tractography findings overlaid onto structural echo planar image, showing white matter connectivity to occipital and frontal areas. Cross hairs at left temporal fMRI maximum and the tractography seed region. The colour bar represents a measure of connection probability or connection confidence to the start point.
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JNN-79-05-0594-f01: Left panel shows EEG recorded during fMRI scanning (10–20 system, upper 10 channels referential, lower 8 bipolar (OSC channel marks scanner gradient switching)) demonstrating left temporal activity in the delta/theta band with frequent intermixed spikes phase reversing at T3 (bold arrow). (A) Significant anterior temporal IED-related fMRI activations SPM{T} overlaid onto structural echo planar image (b = 0), showing left temporal and bilateral occipital fMRI activations. There were no significant deactivations. Scale represents z-score. (B) Tractography findings overlaid onto structural echo planar image, showing white matter connectivity to occipital and frontal areas. Cross hairs at left temporal fMRI maximum and the tractography seed region. The colour bar represents a measure of connection probability or connection confidence to the start point.

Mentions: We studied a 23-year-old right-handed man with refractory complex partial seizures (onset age 7 years) lasting 1–5 minutes and occurring every other day. These comprised a brief aura of “abnormal feelings”, followed by an inability to vocalise, then unresponsiveness with right-arm posturing and subsequent bimanual automatisms. Secondarily generalised seizures occurred twice weekly, beginning with extension of the right arm, then asymmetrical clonic movements, right greater than left. Interictal EEG showed left anterior temporal excess delta activity and frequent left temporal spikes phase reversing at T3 (fig 1). Ictal video-EEG telemetry indicated seizure onset in the left temporal lobe, spreading rapidly to the right temporal lobe. MRI showed left hippocampal sclerosis. The patient declined surgical management.


Combined EEG-fMRI and tractography to visualise propagation of epileptic activity.

Hamandi K, Powell HW, Laufs H, Symms MR, Barker GJ, Parker GJ, Lemieux L, Duncan JS - J. Neurol. Neurosurg. Psychiatr. (2007)

Left panel shows EEG recorded during fMRI scanning (10–20 system, upper 10 channels referential, lower 8 bipolar (OSC channel marks scanner gradient switching)) demonstrating left temporal activity in the delta/theta band with frequent intermixed spikes phase reversing at T3 (bold arrow). (A) Significant anterior temporal IED-related fMRI activations SPM{T} overlaid onto structural echo planar image (b = 0), showing left temporal and bilateral occipital fMRI activations. There were no significant deactivations. Scale represents z-score. (B) Tractography findings overlaid onto structural echo planar image, showing white matter connectivity to occipital and frontal areas. Cross hairs at left temporal fMRI maximum and the tractography seed region. The colour bar represents a measure of connection probability or connection confidence to the start point.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2571962&req=5

JNN-79-05-0594-f01: Left panel shows EEG recorded during fMRI scanning (10–20 system, upper 10 channels referential, lower 8 bipolar (OSC channel marks scanner gradient switching)) demonstrating left temporal activity in the delta/theta band with frequent intermixed spikes phase reversing at T3 (bold arrow). (A) Significant anterior temporal IED-related fMRI activations SPM{T} overlaid onto structural echo planar image (b = 0), showing left temporal and bilateral occipital fMRI activations. There were no significant deactivations. Scale represents z-score. (B) Tractography findings overlaid onto structural echo planar image, showing white matter connectivity to occipital and frontal areas. Cross hairs at left temporal fMRI maximum and the tractography seed region. The colour bar represents a measure of connection probability or connection confidence to the start point.
Mentions: We studied a 23-year-old right-handed man with refractory complex partial seizures (onset age 7 years) lasting 1–5 minutes and occurring every other day. These comprised a brief aura of “abnormal feelings”, followed by an inability to vocalise, then unresponsiveness with right-arm posturing and subsequent bimanual automatisms. Secondarily generalised seizures occurred twice weekly, beginning with extension of the right arm, then asymmetrical clonic movements, right greater than left. Interictal EEG showed left anterior temporal excess delta activity and frequent left temporal spikes phase reversing at T3 (fig 1). Ictal video-EEG telemetry indicated seizure onset in the left temporal lobe, spreading rapidly to the right temporal lobe. MRI showed left hippocampal sclerosis. The patient declined surgical management.

Bottom Line: Dynamic causal modelling suggested propagation of neural activity from the temporal focus to the area of occipital activation.Tractography showed connections from the site of temporal lobe activation to the site of occipital activation.This demonstrates the principle of combining EEG-fMRI and tractography to delineate the pathways of propagation of epileptic activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, UK. hamandik@cardiff.ac.uk

ABSTRACT
In a patient with refractory temporal lobe epilepsy, EEG-fMRI showed activation in association with left anterior temporal interictal discharges, in the left temporal, parietal and occipital lobes. Dynamic causal modelling suggested propagation of neural activity from the temporal focus to the area of occipital activation. Tractography showed connections from the site of temporal lobe activation to the site of occipital activation. This demonstrates the principle of combining EEG-fMRI and tractography to delineate the pathways of propagation of epileptic activity.

Show MeSH
Related in: MedlinePlus