TY - JOUR
T1 - Primary and secondary bilateral synchrony in epilepsy
T2 - differentiation by estimation of interhemispheric small time differences during short spike-wave activity
AU - Kobayashi, K.
AU - Ohtsuka, Y.
AU - Oka, E.
AU - Ohtahara, S.
PY - 1992/8
Y1 - 1992/8
N2 - Estimation of interhemispheric small time differences (TDs) during spike-wave bursts in the EEG by coherence and phase analysis is useful for differentiation between primary bilateral synchrony (PBS) and secondary bilateral synchrony (SBS) in epilepsy. Because the previous method via Fast Fourier Transform needed long bursts for reliable analysis, a method using a 2-dimensional autoregressive model was newly developed to enable estimation of TDs even in 1.2 sec bursts, and applied to 19 epileptic patients with apparently bilaterally synchronous spike-wave bursts. At the onsets of bursts, estimated maximal TDs were 5.8 msec or less and inconsistent in leading hemispheres in 10 patients with a clinical diagnosis of idiopathic, cryptogenic or symptomatic generalized epilepsy indicating PBS, while the maximal TDs were 9.3-41.5 msec and consistent in leading in 7 patients with clinically symptomatic partial epilepsy and also in two with idiopathic and symptomatic generalized epilepsy suggesting SBS. Among 8 patients with bursts which suggested SBS and long enough for evaluation of intra-burst TD variation, TDs tended to disappear in the middle to end parts of the bursts in 5 cases, but not in the other 3, suggesting 2 different pathophysiological mechanisms in SBS.
AB - Estimation of interhemispheric small time differences (TDs) during spike-wave bursts in the EEG by coherence and phase analysis is useful for differentiation between primary bilateral synchrony (PBS) and secondary bilateral synchrony (SBS) in epilepsy. Because the previous method via Fast Fourier Transform needed long bursts for reliable analysis, a method using a 2-dimensional autoregressive model was newly developed to enable estimation of TDs even in 1.2 sec bursts, and applied to 19 epileptic patients with apparently bilaterally synchronous spike-wave bursts. At the onsets of bursts, estimated maximal TDs were 5.8 msec or less and inconsistent in leading hemispheres in 10 patients with a clinical diagnosis of idiopathic, cryptogenic or symptomatic generalized epilepsy indicating PBS, while the maximal TDs were 9.3-41.5 msec and consistent in leading in 7 patients with clinically symptomatic partial epilepsy and also in two with idiopathic and symptomatic generalized epilepsy suggesting SBS. Among 8 patients with bursts which suggested SBS and long enough for evaluation of intra-burst TD variation, TDs tended to disappear in the middle to end parts of the bursts in 5 cases, but not in the other 3, suggesting 2 different pathophysiological mechanisms in SBS.
KW - Autoregressive model
KW - Coherence and phase analysis
KW - EEG
KW - Epilepsy
KW - Secondary bilateral synchrony
KW - Spike-waves
UR - http://www.scopus.com/inward/record.url?scp=0026669259&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026669259&partnerID=8YFLogxK
U2 - 10.1016/0013-4694(92)90022-A
DO - 10.1016/0013-4694(92)90022-A
M3 - Article
C2 - 1378385
AN - SCOPUS:0026669259
VL - 83
SP - 93
EP - 103
JO - Electroencephalography and Clinical Neurophysiology
JF - Electroencephalography and Clinical Neurophysiology
SN - 0013-4694
IS - 2
ER -