Full-Length Original Research
Tonic seizures of Lennox-Gastaut syndrome: Periictal single-photon emission computed tomography suggests a corticopontine network
Article first published online: 10 OCT 2013
Wiley Periodicals, Inc. © 2013 International League Against Epilepsy
Volume 54, Issue 12, pages 2151–2157, December 2013
How to Cite
Epilepsia, 54(12):2151–2157, 2013
- Issue published online: 4 DEC 2013
- Article first published online: 10 OCT 2013
- Manuscript Accepted: 30 AUG 2013
- National Health and Medical Research Council of Australia. Grant Number: 628725
- State Government of Victoria, Australia
- Lennox-Gastaut syndrome;
- Tonic seizure;
- Single-photon emission computed tomography
Lennox-Gastaut syndrome (LGS) is a severe epileptic disorder with characteristic electroclinical features but diverse etiologies. The shared electroclinical characteristics suggest that common cerebral networks are involved in generating seizures. We sought to reveal these networks by comparing ictal and interictal single-photon emission computed tomography (SPECT).
We identified 10 ictal–interictal SPECT pairs from seven patients with LGS (median age 11 years; range 1–38) who were studied during video electroencephalography (EEG)–confirmed tonic seizures. We performed a voxel-wise comparison of ictal and interictal SPECT studies across the group. The evolution of blood flow changes was explored by examining early and late injection groups.
Median duration of tonic seizures was 10 s (range 6–29 s), and injection latency from seizure offset was −8 to 48 s. In the early injection group (<10 s; three studies), there was hyperperfusion over pons and cerebellar hemispheres (p < 0.05 cluster corrected family wise error), and hypoperfusion bilaterally over the pericentral region, with a trend toward hyperperfusion over bilateral superior and middle frontal gyri, and lateral parietal cortex. In the late injection group, there was hyperperfusion over midline and lateral cerebellar regions, with hypoperfusion widely over bilateral frontal regions.
This study suggests that the tonic seizures of LGS result from activity in a network, containing bilateral frontal and parietal association areas and the pons. We postulate that tonic seizures recruit the corticoreticular system, which connects frontal attentional areas to the pontine reticular formation, and is normally responsible for postural tone and orienting behavior.