Investigation of Magnetic Resonance Spectroscopy Findings in Patients with Absence Status Epilepticus

Zeynep Aydın Özemir; Betül Baykan; Ebru Nur Vanlı Yavuz; Serra Sencer

doi:10.4274/tnd.25633

Zeynep Aydın Özemir¹, Betül Baykan¹, Ebru Nur Vanlı Yavuz¹, Serra Sencer²

¹İstanbul University İstanbul Faculty of Medicine, Department of Neurology, Division of Clinical Neurophysiology, İstanbul, Turkey
²İstanbul University İstanbul Faculty of Medicine, Department of Radiology, İstanbul, Turkey

Keywords: Absance, status epilepticus, magnetic resonance spectroscopy

Abstract

INTRODUCTION: Absence status epilepticus (ASE) has been well recognized for many years, but its pathophysiology has not yet been illuminated and there are speculations about GABAergic mechanisms. We aimed to study the etiopathogenesis of ASE by using magnetic resonance-spectroscopy (MRS), which gives in vivo information about neuronal loss and/or dysfunction by correlating the results with age- and sex-matched normal healthy controls (HC).

METHODS: Four patients with genetic generalized epilepsy (GGE), which was diagnosed in accordance with the International League Against Epilepsy criteria, with recurrent ASE were investigated. The control groups consisted of ten age- and sex-matched patients with HC and ten patients with GGE. MRS measurements of N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine (Cr) were performed in the frontal lobes and thalamus bilaterally with a voxel size of 20x20x20 mm, the values of the patients were compared with those of the controls using appropriate statistical tests.

RESULTS: In patients with ASE, NAA/Cr levels were decreased when compared with those with HC and GGE in the frontal lobes and thalamus. Moreover, frontal lobe Cho values and Cho/Cr ratios were elevated in all patients with GGE, and more pronounced in patients with ASE comparison with those with HC. There was a positive correlation of ASE with the frontal Cho/Cr ratio and a negative correlation with NAA/Cr ratios in patients with GGE (p=0.002, z=-0.745). The presence of absence seizures related negatively to the thalamic NAA/Cr ratio and NAA levels. Prognosis showed a negative correlation with thalamic NAA levels (p=0.026, z=-0.591) and the NAA/Cr ratio (p=0.013, z=-0.645).

DISCUSSION AND CONCLUSION: Although our sample size was small due to the rarity of the condition, this first MRS study in patients with ASE showed that neuronal dysfunction in frontal lobes and thalamus was more pronounced when compared with those with GGE and related to poor prognosis. Our study suggested that the dysfunction in thalamocortical circuits might underlie ASE attacks.