Authors :
Presenting Author: Naohiro Yamamoto, MD – Osaka City General Hospital
Ichiro Kuki, Dr. – Osaka City General Hospital; Takeshi Inoue, Dr. – Osaka City General Hospital; Shizuka Nagase-Oikawa, Dr. – Osaka City General Hospital; Masataka Fukuoka, Dr. – Osaka City General Hospital; Yasunori Otsuka, Dr. – Osaka City General Hospital; Atsushi Ujio, Dr. – Osaka City General Hospital; Kiyoko Amo, Dr. – Osaka City General Hospital; Masao Togawa, Dr. – Osaka City General Hospital; Tomomi Yoshino, Dr – Osaka City General Hospital; Jyunichi Ishikawa, Dr. – Osaka City General Hospital; Hiroshi Rinka, Dr. – Osaka City General Hospital; Shin Okazaki, Dr. – Osaka City General Hospital
Rationale:
In the treatment of acute encephalitis and encephalopathy, electroencephalogram (EEG) is essential for early diagnosis and treatment of seizures. Particularly, long-term continuous EEG monitoring (cEEG) is important as the management of electrographic seizures (ESz) is directly related to neurological outcomes. (Payne E, Zhao XY, Frndova H, et al. Brain. 2014; 137; 1429-38. doi: 10.1093/brain/awu042., Gilman CA, Wusthoff CJ, Guerriero RM. Children (Basel). 2022; 9; 1368. doi: 10.3390/children9091368. )
However, in Japan, cEEG is not widely accessible, and only specialized physicians and technicians can apply the international 10-20 system (full electrodes-EEG [FE-EEG]). Therefore, it is imperative to consider optimal electrode placement to ensure reliability and simplicity.
Methods:
Patients with fever and status epilepticus or fever and impaired consciousness, admitted to our hospital between January 2015 and January 2020, and those who underwent cEEG using FE-EEG during the acute stage, were included in this study. The presence of ESz was evaluated by a consensus of several pediatric neurologists based on the Salzburg criteria (Leitinger M, Beniczky S, Rohracher A, et al. Epilepsy Behav. 2015; 49; 158-63. doi: 10.1016/j.yebeh.2015.05.007.), and cases with more than 5 ESz were selected. ESz were analyzed by longitudinally coupled bipolar montage with FE-EEG and reduced electrodes-EEG (RE-EEG) recorded with eight electrodes in bilateral frontopolar/central/occipital/mid-temporal regions. The evaluation period was 12 hours from the first ESz detection, and the seizure detection rates were compared between FE-EEG and RE-EEG.
Results:
A total of 83 patients, including 42 with acute encephalitis and encephalopathy and 41 with febrile status epilepticus (FSE) were enrolled. The results demonstrated, 30/42 (71%) patients with acute encephalitis and encephalopathy had ESz, and 17/30 (57%) patients, including 10 with acute encephalopathy with biphasic seizures and late reduced diffusion, four with hemorrhagic shock encephalopathy syndrome, and three with meningoencephalitis, had ESz > five times (median 22 [10-166] times). The median time from onset to the first ESz detected was four [two to seven] days. The median concordance rate of ESz detection between FE-EEG and RE-EEG was 98% [15-100], except for two cases in which ESz frequency analysis was difficult due to the ictal-interictal continuum.
Conclusions:
More than 70% of patients with acute encephalitis and encephalopathy experienced ESz, and more than half of them had ESz more than five times. RE-EEG could guarantee a seizure detection rate of >90% except in one case. In the future, we expect that the RE-EEG montage will enable cEEG being carried out in many more cases.
Funding:
This work was supported by the Ministry of Health, Labour and Welfare Research Program through a Grant-in-Aid for Scientific Research (C), Grant number 22K09212.