Diffusion tensor imaging abnormalities in photosensitive juvenile myoclonic epilepsy.
OBJECTIVE
Multiple structural white matter abnormalities have been described in patients with juvenile myoclonic epilepsy (JME). In the present study, the question of whether microstructural variations exist between the two subgroups of JME, with and without photoparoxysmal responses (PPR positive and negative), was addressed using diffusion tensor imaging.


METHODS
A selection of 18 patients (eight PPR positive) from a tertiary epilepsy center diagnosed with JME and 27 healthy controls was studied. The following regions of interest were investigated: the ascending reticular activating system, lateral geniculate nucleus, genu of the internal capsule, ventromedial thalamus and inferior cerebellar peduncle.


RESULTS
Widespread white matter microstructural abnormalities in JME and in particular in PPR positive cases were identified. PPR positive patients demonstrated increased fractional anisotropy in the ascending reticular activating system and ventromedial thalamus compared to PPR negative patients and healthy controls. Reduced fractional anisotropy of the lateral geniculate nucleus was observed in the entire JME group compared to healthy controls.


CONCLUSIONS
Several microstructural variations between PPR positive and negative JME patients have been identified. Our findings highlight the pivotal role of the thalamus in the pathophysiology of primary generalized seizures and suggest that thalamo-premotor connections are both an essential part of epileptic networks and important in the pathogenesis of photosensitivity.
Department of Neurology, Epilepsy Center, University Medicine Greifswald, Greifswald, Germany.
F
F
von Podewils
Department of Neurology, Epilepsy Center, University Medicine Greifswald, Greifswald, Germany.
U
U
Runge
Department of Neurology, Epilepsy Center, University Medicine Greifswald, Greifswald, Germany.
S
S
Krüger
Epilepsie-Zentrum Berlin-Brandenburg, Ev. Krankenhaus Königin Elisabeth Herzberge, Berlin, Germany.
J
J
Geithner
Epilepsy Center, Neurological Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
Z I
ZI
Wang
Department of Neurology, Epilepsy Center, University Medicine Greifswald, Greifswald, Germany.|Department of Clinical Neurosciences, Schulich School of Medicine and Dentistry, London Health Sciences Centre, University of Western Ontario, London, ON, Canada.
A V
AV
Khaw
Department of Neurology, Epilepsy Center, University Medicine Greifswald, Greifswald, Germany.
A
A
Angermaier
Department of Neurology, Epilepsy Center, University Medicine Greifswald, Greifswald, Germany.
B
B
Gaida
Center for Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Greifswald, Germany.
M
M
Domin
Department of Neurology, Epilepsy Center, University Medicine Greifswald, Greifswald, Germany.
C
C
Kessler
Center for Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Greifswald, Germany.
S
S
Langner
D000328:Adult; D016880:Anisotropy; D056324:Diffusion Tensor Imaging / Q000379:methods*; D020195:Epilepsy, Reflex / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D020190:Myoclonic Epilepsy, Juvenile / Q000473:pathology*; D012154:Reticular Formation / Q000473:pathology*; D013788:Thalamus / Q000473:pathology*; D055815:Young Adult
diffusion tensor imaging; juvenile myoclonic epilepsy; microstructural abnormalities; photosensitivity