Chronic Focal Cortical Epileptogenic Lesion and Behavior Comparison of Behavioral Performance in Monkeys with either Epileptogenic or Ablative Unilateral Lesion

Seino, Masakazu; Wada, Juhn A.

doi:10.1111/j.1528-1157.1964.tb03339.x

Cited by 10 publications

(2 citation statements)

References 22 publications

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“…Because kindling is a general neurobiologic principle in the mammalian brain, its failure at the mirror EEG focus site within a sagittal fissure represents a powerful and lasting secondary antiepileptogenesis. Under this circumstance, mirror focus formation implies evolution of profound bilateral dysfunction: chronic seizure‐generating epileptogenesis on one side coupled with enduring antiepileptogenesis at the homotopic contralateral mirror focus site, both of which are attained at the expense of physiologic function (55,56). The mesial hemispheric area where lasting secondary antiepileptogenesis develops is known to be involved in cognition, conation, and emotion.…”

Section: Secondary Antiepileptogenesismentioning

confidence: 99%

Callosal Bisection and Transcallosal Secondary Antiepileptogenesis

Wada

2005

Epilepsia

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Summary:More than 28,000 neuroscientists and 3,000 epileptologists gathered at their respective 2001 meetings of the Society for Neuroscience and the American Epilepsy Society. Yet only six articles, one directly and five indirectly, discussed the corpus callosum (CC). Is not this in itself a remarkable finding? Are there no mysteries left? The reality is that considerable uncertainties exist regarding the rationale for callosal bisection (CCB) that causes contrasting effects (i.e., amelioration of generalized seizure, at times leading to freedom from seizure, and intensification of postoperatively fragmented seizure, at times leading to status epilepticus). Similarly, the clinical relevance of EEG mirror focus formation, an experimentally well-established transcallosal consequence of partial cortical epileptogenesis, continues to be debated. This presentation revisits these unresolved issues (a) to gain insight into the dynamic role played by the CC in medically refractory epilepsy, and (b) to promote the development of antiepileptogenic tools that are currently unavailable. Key Words:Corpus callosum-Anterior callosal bisectionSecondary anti-epileptogenesis.This presentation entertains two issues related to the corpus callosum (CC): (a) the rational for CC bisection in medically refractory epilepsy, and (b) secondary antiepileptogenesis as a lasting transcallosal consequence of repeated partial seizures. ROLE OF THE CORPUS CALLOSUM IN MEDICALLY REFRACTORY GENERALIZED EPILEPSYSixty-three years ago, two independent but complementary reports on the role of the CC in experimental partialonset seizures becoming secondarily generalized and an attempt to lateralize such ictal evolution in humans by commissural bisection, appeared in the same journal (1,2). Despite reasonable rationale and surgical feasibility, they did not arouse much interest, possibly in part because of the then prevailing "centrencephalic theory" for generalized epilepsy and conscious awareness (3). The theory was invalidated eventually, and the reported absence of postoperative deconnection syndrome when the splenium was spared suggested a therapeutic utility of anterior CC Address correspondence and reprint requests to Dr. J. A. Wada at Department of Neurosciences and Neurology, University of British Columbia Hospital, 2255 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2B5. E-mail: jwada@interchange.ubc.ca bisection (CCB) (4). On experimental validation of the latter, anterior CCB was adopted at the University of British Columbia (UBC) in 1977 as a diagnostic localization option for refractory generalized epilepsy suspected of having partial-onset secondarily generalized seizure (5,6). In the meantime, the effectiveness of CCB alone instead of commissural bisection also was reported (7). Consequently, the surgical target changed from commissures to the CC. However, the rationale of a dividing pathway for partial seizure becoming secondarily generalized remains unchanged despite early recognition of CCB effectiveness for generalized rathe...

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Section: Secondary Antiepileptogenesismentioning

confidence: 99%

Callosal Bisection and Transcallosal Secondary Antiepileptogenesis

Wada

2005

Epilepsia

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“…Each interictal discharge can have widespread consequences, even for aggregates of neurons at areas distant from the area of focal abnormality [26,27]. This may explain why closely spaced interictal events may produce behavior or motor disturbances [28,29]. Another cause is related to seizure spread, where a distant area sustains the seizure discharges after they have subsided in the original focusa prolonged recovery in the distant region may occur.…”

Section: Postictal Changesmentioning

confidence: 99%

Changing Presentation of Seizures with Aging: Clinical and Etiological Factors

DeToledo

1999

Gerontology

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Background: The historically higher incidence of seizures in children has changed, the elderly now have a higher incidence than any age-group, 2–3 times of that found in children. Classical teachings on etiologies, clinical presentation and progression of seizures are based on observations of a younger population and need to be revised in view of features unique to this age-group. The findings of two large VA cooperative studies show that even in sophisticated medical environments, up to 30% of patients 60 years and older with recurrent partial seizures go undiagnosed for more than 1 year of seizure onset. Objective: (a) To characterize the manifestations of auras, seizures and postictal states in the elderly and the relevance of various etiologies to these presentations. (b) To identify and discuss factors that contribute to the difficulties in the diagnosis of seizures in this population. Methods: A review of our experience in treating a large population of elderly patients in a university epilepsy center and a review of the literature relating to the problem. Conclusions: Seizures in the elderly are both overdiagnosed and underdiagnosed: either situation can have serious adverse consequences. Diversity of etiologies and atypical presentations make recognition of seizures difficult. Histories are frequently inadequate: complaints of multiple physical symptoms confuse the picture, unwillingness of elderly patients to admit to problems they believe are physiological in nature by the fear others may think they are ‘losing their mind’ and high staff turnover result in erratic identification of problems. The significant morbidity and mortality associated with poorly controlled seizures in this population are in large part preventable since excellent response to treatment can be achieved in more than 80% of individuals. The correct diagnosis of seizures is more likely if both physician and patients are familiar with the nuances of epilepsy in the elderly.

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