Epileptic network of hypothalamic hamartoma: An EEG-fMRI study.
To investigate the brain networks involved in epileptogenesis/encephalopathy associated with hypothalamic hamartoma (HH) by EEG with functional MRI (EEG-fMRI), and evaluate its efficacy in locating the HH interface in comparison with subtraction ictal SPECT coregistered to MRI (SISCOM).



Eight HH patients underwent EEG-fMRI. All had gelastic seizures (GS) and 7 developed other seizure types. Using a general linear model, spike-related activation/deactivation was analyzed individually by applying a hemodynamic response function before, at, and after spike onset (time-shift model=-8-+4s). Group analysis was also performed. The sensitivity of EEG-fMRI in identifying the HH interface was compared with SISCOM in HH patients having unilateral hypothalamic attachment.



EEG-fMRI revealed activation and/or deactivation in subcortical structures and neocortices in all patients. 6/8 patients showed activation in or around the hypothalamus with the HH interface with time-shift model before spike onset. Group analysis showed common activation in the ipsilateral hypothalamus, brainstem tegmentum, and contralateral cerebellum. Deactivation occurred in the default mode network (DMN) and bilateral hippocampi. Among 5 patients with unilateral hypothalamic attachment, activation in or around the ipsilateral hypothalamus was seen in 3 using EEG-fMRI, whereas hyperperfusion was seen in 1 by SISCOM.



Group analysis of this preliminary study may suggest that the commonly activated subcortical network is related to generation of GS and that frequent spikes lead to deactivation of the DMN and hippocampi, and eventually to a form of epileptic encephalopathy. Inter-individual variance in neocortex activation explains various seizure types among patients. EEG-fMRI enhances sensitivity in detecting the HH interface compared with SISCOM.
Department of Neurology, Kyoto University, Graduate School of Medicine, Kyoto, Japan.
Kiyohide
K
Usami
Department of Epilepsy, Movement Disorders and Physiology, Kyoto University, Graduate School of Medicine, Kyoto, Japan. Electronic address: matsumot@kuhp.kyoto-u.ac.jp.
Riki
R
Matsumoto
Department of Neurology, Kyoto University, Graduate School of Medicine, Kyoto, Japan; Human Brain Research Center, Kyoto University, Graduate School of Medicine, Kyoto, Japan.
Nobukatsu
N
Sawamoto
Department of Neurosurgery, Nishi-Niigata Chuo National Hospital, Niigata, Japan.
Hiroatsu
H
Murakami
Department of Neurology, Kyoto University, Graduate School of Medicine, Kyoto, Japan; Department of Respiratory Medicine, Kyoto University, Graduate School of Medicine, Kyoto, Japan.
Morito
M
Inouchi
Research and Educational Unit of Leaders for Integrated Medical System, Kyoto University, Kyoto, Japan.
Tomoyuki
T
Fumuro
Department of Neurology, Kyoto University, Graduate School of Medicine, Kyoto, Japan.
Akihiro
A
Shimotake
Department of Pediatrics, Kyoto University, Graduate School of Medicine, Kyoto, Japan.
Takeo
T
Kato
Human Brain Research Center, Kyoto University, Graduate School of Medicine, Kyoto, Japan.
Tatsuya
T
Mima
Department of Neurosurgery, Nishi-Niigata Chuo National Hospital, Niigata, Japan.
Hiroshi
H
Shirozu
Department of Neurosurgery, Nishi-Niigata Chuo National Hospital, Niigata, Japan.
Hiroshi
H
Masuda
Human Brain Research Center, Kyoto University, Graduate School of Medicine, Kyoto, Japan.
Hidenao
H
Fukuyama
Department of Neurology, Kyoto University, Graduate School of Medicine, Kyoto, Japan.
Ryosuke
R
Takahashi
Department of Neurosurgery, Nishi-Niigata Chuo National Hospital, Niigata, Japan.
Shigeki
S
Kameyama
Department of Epilepsy, Movement Disorders and Physiology, Kyoto University, Graduate School of Medicine, Kyoto, Japan. Electronic address: akio@kuhp.kyoto-u.ac.jp.
Akio
A
Ikeda
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004827:Epilepsy / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006222:Hamartoma / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007027:Hypothalamic Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D007223:Infant; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D064847:Multimodal Imaging; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon; D055815:Young Adult
EEG-fMRI; Epileptic encephalopathy; Gelastic seizure; Ictal SPECT; Subcortical epilepsy