Hippocampal Region Asymmetry Assessed by ¹H‐MRS in Rolandic Epilepsy

Abstract

Summary:Purpose: In a previous study, we reported hippocampal abnormalities on magnetic resonance imaging (MRI) in six of 18 children with rolandic epilepsy (RE). In this study, metabolic changes were analyzed in the hippocampal region with proton magnetic resonance spectroscopy ( 1 H-MRS). Methods: In 13 children with electroclinically typical RE and 15 healthy controls, 1 H-MRS results of both hippocampal regions were analyzed. The voxels, 2 × 2 × 4-cm each, were placed to include the head and body of the hippocampus. A PRESS sequence with TR 2,000 ms and TE 32 ms was used. Total N-acetylaspartate (tNAA), glutamine and glutamate (Glx), and choline compounds (tCho) were related to total creatine (tCr), and asymmetry indices (AIs) were calculated. MRI was performed in all 13 patients and in 13 controls.Results: The tNAA/tCr AI of the hippocampal region was significantly higher in children with RE than in control children (z ‫ס‬ 4.49; p < 0.001). The AIs of Glx/tCr and tCho/tCr did not show a significant difference between the groups. Lateralization of the interictal epileptiform activity corresponded with the lower tNAA/tCr ratio in 10 of 13 patients. MRI revealed a hippocampal asymmetry in four of 13 in the RE group, three of them showed concordance between the lateralization of the lower tNAA/tCr ratio and the smaller hippocampus. In the control group, a subtle asymmetry in four of 13 children was found.Conclusions: A significant asymmetry of the hippocampal regions, measured by tNAA/tCr ratios, indicates an abnormal neuronal function in children with RE.

Quantitative 1HMRS and MRI Volumetry Indicate Neuronal Damage in the Hippocampus of Children with Focal Epilepsy and Infrequent Seizures

“…Moreover, bilateral reduction in the NAA/Cr ratio as severe as that in patients with intractable TLE has been detected within the temporal lobes of patients with newly diagnosed TLE, suggesting that neuronal abnormalities may occur already before clinical manifestations of the TLE (48). The metabolite changes observed not only in patients with TLE but also in patients with extratemporal and extrahippocampal epilepsy (33), frontal lobe epilepsy (38), and even in patients with idiopathic rolandic epilepsy (49), suggest that seizure‐induced changes in the brain metabolism are widespread, although less severe outside than within the seizure focus (50). A recent multisection proton MRS imaging ( 1 HMRSI) showed the reduction in the whole‐brain NAA/(Cr+Cho) ratio in patients with TLE (51).…”

Seizure in benign epilepsy with centro‐temporal spikes

“…For 15% of patients with BECTS, patients may have abnormal findings because of static or other brain diseases unrelated to the pathophysiology of BECTS (Gelisse et al, 2003). Hippocampal abnormality has been detected in some children with BECTS by MRI and proton magnetic resonance spectroscopy (Lundberg et al, 2003). Inter-ictal EEG, as described above, is usually seen in a routine recording.…”