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Last updated: 06 June 2024

Bilateral Synchrony

The term “bilateral synchrony” was introduced by Wilder Penfield. According to Penfield and Jasper “An epileptogenic lesion of the mesial or inferior aspect of a frontal lobe, although it is one-sided, may produce bifrontal synchronous discharges”. The mechanisms by which seizures that become secondarily generalised are not yet known fully.

The wave and spike of petit mal is a primary bilateral synchronous discharge . . . ; it appears not to be related to a unilateral cortical focus, but may be of subcortical origin …. On the other hand, a bilateral synchronous discharge which can be shown to arise from a unilateral cortical focus we shall call secondary bilateral synchrony - Tükel and Jasper[1]

  • it is important to differentiate between primary and secondary bilateral synchrony when bilaterally synchronous spike and wave discharges are seen on EEG
  • 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[2].
References
1. Tukel K, Jasper H. The electroencephalogram in parasagittal lesions. Electroencephalogr Clin Neurophysiol. 1952 Nov;4(4):481-94. doi: 10.1016/0013-4694(52)90079-5.
 2Kobayashi K, Ohtsuka Y, Oka E, Ohtahara S. Primary and secondary bilateral synchrony in epilepsy: differentiation by estimation of interhemispheric small time differences during short spike-wave activity. Electroencephalogr Clin Neurophysiol. 1992 Aug;83(2):93-103. doi: 10.1016/0013-4694(92)90022-a.

Also see A reappraisal of secondary bilateral synchrony


Cite this: Cite this: ICNApedia contributors.Bilateral Synchrony. ICNApedia, The Child Neurology Knowledge Environment. 30 June 2024. Available at: https://icnapedia.org/knowledgebase/articles/bilateral-synchrony Accessed  30 June 2024. 

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