title: Non-linearity in invasive EEG recordings from patients with temporal lobe epilepsy.
abstract: Electrographic recordings from depth and subdural electrodes, performed in two patients with seizures of mesial temporal origin, were analyzed for the presence of non-linearities in the signal. The correlation integral, a measure sensitive to a wide variety of non-linearities, was used for detection. Statistical significance was determined by comparison of the original signal to surrogate datasets. Statistically significant non-linearities were present in signals generated by the epileptogenic hippocampus and interictal spike foci in the temporal neocortex. Less prominent non-linearities were found in EEG signals generated by more normal areas of the brain. These results indicate that techniques developed for the study of non-linear systems can be used to characterize the epileptogenic regions of the brain during the interictal period and can elucidate the dynamical mechanisms of the epileptic transition.
authors.affiliation: Harrison Randall Laboratory of Physics, Department of Physics, University of Michigan, Ann Arbor, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Casdagli
authors.forename: L D
authors.initials: LD
authors.lastname: Iasemidis
authors.forename: R S
authors.initials: RS
authors.lastname: Savit
authors.forename: R L
authors.initials: RL
authors.lastname: Gilmore
authors.forename: S N
authors.initials: SN
authors.lastname: Roper
authors.forename: J C
authors.initials: JC
authors.lastname: Sackellares
mesh_terms: D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D006801:Humans