Clinical value of magnetoencephalographic spike propagation represented by spatiotemporal source analysis: Correlation with surgical outcome

OBJECTIVE To investigate the correlation between spike propagation represented by spatiotemporal source analysis of magnetoencephalographic (MEG) spikes and surgical outcome in patients with temporal lobe epilepsy. METHODS Thirty-seven patients were divided into mesial (n=27) and non-mesial (n=10) groups based on the presurgical evaluation. In each patient, ten ipsilateral spikes were averaged, and spatiotemporal source maps of the averaged spike were obtained by using minimum norm estimate. Regions of interest (ROIs) were created including temporoparietal, inferior frontal, mesial temporal, anterior and posterior part of the lateral temporal cortex. We extracted activation values from the source maps and the threshold was set at half of the maximum activation at the peak latency. The leading and propagated areas of the spike were defined as those ROIs with activation reaching the threshold at the earliest and at the peak latencies, respectively. Surgical outcome was assessed based on Engel's classification. Binary variables were created from leading areas (restricted to the anterior and mesial temporal ROIs or not) and from propagation areas (involving the temporoparietal ROI or not), and for surgical outcome (Class I or not). Fisher's exact test was used for significance testing. RESULTS In total and mesial group, restricted anterior/mesial temporal leading areas were correlated with Class I (p<0.05). Temporoparietal propagation was correlated with Class II-IV (p<0.05). For the non-mesial group, no significant relation was found. CONCLUSIONS Spike propagation patterns represented by spatiotemporal source analysis of MEG spikes may provide useful information for prognostic implication in presurgical evaluation of epilepsy.

[1]  C R Jack,et al.  Predictors of outcome of anterior temporal lobectomy for intractable epilepsy , 1998, Neurology.

[2]  S. Taulu,et al.  Spatiotemporal signal space separation method for rejecting nearby interference in MEG measurements , 2006, Physics in medicine and biology.

[3]  G. Ojemann,et al.  Outcome after surgery in patients with refractory temporal lobe epilepsy and normal MRI , 2000, Seizure.

[4]  Jerome Engel,et al.  Role of the Frontal Lobes in the Propagation of Mesial Temporal Lobe Seizures , 1991, Epilepsia.

[5]  Kenneth D Laxer,et al.  Magnetoencephalography source localization and surgical outcome in temporal lobe epilepsy , 2004, Clinical Neurophysiology.

[6]  A. Genow,et al.  Epilepsy surgery, resection volume and MSI localization in lesional frontal lobe epilepsy , 2004, NeuroImage.

[7]  Jerome Engel,et al.  Outcome with respect to epileptic seizures. , 1993 .

[8]  M. Hämäläinen,et al.  Realistic conductivity geometry model of the human head for interpretation of neuromagnetic data , 1989, IEEE Transactions on Biomedical Engineering.

[9]  J. Maltez,et al.  Evaluation of L1 and L2 minimum norm performances on EEG localizations , 2004, Clinical Neurophysiology.

[10]  C. N. Guy,et al.  Intracerebral propagation of interictal activity in partial epilepsy: implications for source localisation. , 1994, Journal of neurology, neurosurgery, and psychiatry.

[11]  K. Radhakrishnan,et al.  Seizure Outcome after Anterior Temporal Lobectomy and Its Predictors in Patients with Apparent Temporal Lobe Epilepsy and Normal MRI , 2004, Epilepsia.

[12]  Alon Friedman,et al.  Propagation of interictal discharges in temporal lobe epilepsy: Correlation of spatiotemporal mapping with intracranial foramen ovale electrode recordings , 2006, Clinical Neurophysiology.

[13]  R. Schulz,et al.  Prognostic factors for surgery of neocortical temporal lobe epilepsy , 2006, Seizure.

[14]  W T Blume,et al.  A randomized, controlled trial of surgery for temporal-lobe epilepsy. , 2001, The New England journal of medicine.

[15]  Takashi Yoshimoto,et al.  Surgical Implications of Neuromagnetic Spike Localization in Temporal Lobe Epilepsy , 2002, Epilepsia.

[16]  Gabriela Scheler,et al.  Utilization of magnetoencephalography results to obtain favourable outcomes in epilepsy surgery. , 2004, Brain : a journal of neurology.

[17]  B. Fritsch,et al.  Predictive value of electrocorticography in epilepsy patients with unilateral hippocampal sclerosis undergoing selective amygdalohippocampectomy , 2006, Neurosurgical Review.

[18]  L. Soufflet,et al.  Linear Inverse Solutions: Simulations from a Realistic Head Model in MEG , 2005, Brain Topography.

[19]  C. H. Lücking,et al.  Cortical current density reconstruction of interictal epileptiform activity in temporal lobe epilepsy , 2001, Clinical Neurophysiology.

[20]  B. Bourgeois,et al.  Dynamic statistical parametric mapping for analyzing ictal magnetoencephalographic spikes in patients with intractable frontal lobe epilepsy , 2009, Epilepsy Research.

[21]  Patrick Van Bogaert,et al.  Cluster-based spike detection algorithm adapts to interpatient and intrapatient variation in spike morphology , 2012, Journal of Neuroscience Methods.

[22]  François Dubeau,et al.  Patients with Temporoparietal Ictal Symptoms and Inferomesial EEG Do Not Benefit from Anterior Temporal Resection , 2004, Epilepsia.

[23]  A. Dale,et al.  Cortical Surface-Based Analysis II: Inflation, Flattening, and a Surface-Based Coordinate System , 1999, NeuroImage.

[24]  S. Taulu,et al.  Suppression of Interference and Artifacts by the Signal Space Separation Method , 2003, Brain Topography.

[25]  C. Elger,et al.  Clinical Relevance of Quantified Intracranial Interictal Spike Activity in Presurgical Evaluation of Epilepsy , 2000, Epilepsia.

[26]  R. Ilmoniemi,et al.  Interpreting magnetic fields of the brain: minimum norm estimates , 2006, Medical and Biological Engineering and Computing.

[27]  Seppo P. Ahlfors,et al.  Propagation of epileptic spikes reconstructed from spatiotemporal magnetoencephalographic and electroencephalographic source analysis , 2010, NeuroImage.

[28]  S. Spencer.  Neural Networks in Human Epilepsy: Evidence of and Implications for Treatment , 2002, Epilepsia.

[29]  E. Halgren,et al.  Application of Magnetoencephalography in Epilepsy Patients with Widespread Spike or Slow‐wave Activity , 2005, Epilepsia.

[30]  H. Stefan,et al.  Monofocal MEG in lesional TLE: Does video EEG monitoring add crucial information? , 2010, Epilepsy Research.

[31]  B. Steinhoff,et al.  Source Reconstruction of Mesial‐Temporal Epileptiform Activity: Comparison of Inverse Techniques , 2000, Epilepsia.

[32]  H. Lüders,et al.  Interictal EEG and Ictal Scalp EEG Propagation Are Highly Predictive of Surgical Outcome in Mesial Temporal Lobe Epilepsy , 2000, Epilepsia.

[33]  Anders M. Dale,et al.  Cortical Surface-Based Analysis I. Segmentation and Surface Reconstruction , 1999, NeuroImage.

[34]  B. Bourgeois,et al.  Language Lateralization Represented by Spatiotemporal Mapping of Magnetoencephalography , 2013, American Journal of Neuroradiology.

[35]  C D Binnie,et al.  Origin and propagation of interictal discharges in the acute electrocorticogram. Implications for pathophysiology and surgical treatment of temporal lobe epilepsy. , 1997, Brain : a journal of neurology.

[36]  S Rabe-Hesketh,et al.  Predictors of outcome and pathological considerations in the surgical treatment of intractable epilepsy associated with temporal lobe lesions , 2001, Journal of neurology, neurosurgery, and psychiatry.