Ictal SPECT of Thalamocortical Coupling in a Patient with Frontal Absence

H. Kanemura; F. Sano; K. Sugita; M. Aihara

doi:10.1055/s-0031-1291222

Neuropediatrics, Table of Contents

Neuropediatrics 2011; 42(05): 200-203
DOI: 10.1055/s-0031-1291222

Short Communication

Ictal SPECT of Thalamocortical Coupling in a Patient with Frontal Absence

Authors

H. Kanemura

¹Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
F. Sano

¹Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
K. Sugita

¹Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan
M. Aihara

²Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan

Abstract

Petit mal absence has been reported with 3-Hz generalized spike-and-wave discharges induced by secondary bilateral synchrony. Absence seizure may be present in patients with frontal lobe epilepsy. The thalamic rhythmogenic mechanisms responsible for spike-and-wave discharges have been investigated, providing a better understanding of the underlying anatomico-physiological mechanisms. We report the thalamocortical coupling in a patient with frontal absence by performing synchronous ictal single photon emission computed tomography (SPECT) analysis. Ictal SPECT revealed thalamic hyperperfusion combined with ipsilateral frontal cortical hyperperfusion in the patient. Moreover, lateral indexes of cerebral blood flow in the frontal region and thalamus were higher than those from non-epileptic control subjects. Thalamocortical coupling was thus revealed by ictal SPECT. Frontal absences should be considered as a secondarily generalized epilepsy syndrome originating from the frontal regions. The thalamus may play a crucial role as a pacemaker of rhythmic electroencephalographic activities such as secondary bilateral synchronous discharges in patients with frontal absences.

Key words

frontal absence - secondary bilateral synchronous discharge - thalamus - thalamocortical coupling - ictal SPECT

Full Text

References

References
1 Aihara M, Hatakeyama K, Koizumi K et al. Ictal EEG and single photon emission computed tomography in a patient with cortical dysplasia presenting with atonic seizures. Epilepsia 1997; 38: 723-727
2 Blumenfeld H, Coulter DA. Thalamocortical anatomy and physiology. In: Engel JJ, Pedley TA. editors. Epilepsy: a comprehensive textbook. 2^nd ed. Philadelphia: Lippincott-Raven; 2008: 353-366
3 Holmes MD, Brown M, Tucker DM. Are “generalized” seizures truly generalized? Evidence of localized mesial frontal and frontopolar discharges in absence. Epilepsia 2004; 45: 1568-1579
4 Kanemura H, Sano F, Shimoyama H et al. Thalamic hypoperfusion on SPECT in epilepsy with bilateral synchronous discharge. J Pediatr Epilepsy in press
5 Lagae L, Pauwels J, Monte CP et al. Frontal absences in children. Eur J Pediatr Neurol 2001; 5: 243-251
6 Pellegrini A, Ermani M, Testa G. Involvement of cortical, thalamic and midbrain reticular formation neurons in spike and wave discharges: extracellular study in feline generalized penicillin epilepsy. Exp Neurol 1985; 89: 465-478
7 Prevett MC, Duncan JS, Jones T et al. Demonstration of thalamic activation during typical absence seizures using H2150 and PET. Neurology 1995; 45: 1396-1402
8 Sofue A, Okumura A, Negoro T et al. Absence seizures in patients with localization-related epilepsy. Brain Dev 2003; 25: 422-426
9 Steriade M, Contreras D. Relations between cortical and thalamic cellular events during transition from sleep patterns to paroxysmal activity. J Neurosci 1995; 15: 623-642
10 Sztriha L, Pavics L, Ambrus E. Epilepsia partialis continua: follow-up with 99mTc-HMPAO-SPECT. Neuropediatrcis 1994; 25: 250-254