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Tonic-absence seizures: an underrecognized seizure type
Tina T Shih1, Lawrence J Hirsch
1Columbia Comprehensive Epilepsy Center, Department of Neurology, Columbia University, New York Presbyterian Hospital, New York, New York 10032, USA. ts259@columbia.edu
Epilepsia
|March 5, 2003
Summary
This study identifies a new seizure type in symptomatic generalized epilepsy, called tonic-absence seizures. These seizures combine tonic activity with generalized paroxysmal fast activity and absence activity with generalized slow spike-and-wave.
Area of Science:
- Neurology
- Epileptology
- Clinical Neuroscience
Background:
- Tonic seizures with generalized paroxysmal fast activity (GPFA) and absence seizures with generalized slow spike-and-wave (GSS&W) are well-documented epilepsy patterns.
- The combined pattern of GPFA followed by GSS&W has been poorly characterized, especially with modern video-EEG correlation.
Purpose of the Study:
- To characterize a previously underrecognized seizure type combining tonic and absence features.
- To describe the electroclinical features of this seizure pattern in patients with symptomatic generalized epilepsy.
Main Methods:
- Retrospective review of eight patients with stereotyped EEG and clinical seizure patterns.
- Analysis of video-EEG data from Epilepsy Monitoring Units (EMUs) between 1993 and 2002.
- Correlation of EEG findings with clinical manifestations.
Main Results:
- Eight patients (6 female, age 6-29) with symptomatic generalized epilepsy were identified.
- Twenty-nine seizures showed a pattern of generalized paroxysmal fast activity (GPFA, 14-30 Hz) followed by generalized slow spike-and-wave (GSS&W, 1-2 Hz).
- Clinical presentation involved bilateral tonic activity followed by inattentiveness, differentiating it from typical tonic seizures.
Conclusions:
- A novel seizure type, termed tonic-absence seizures, is described in symptomatic generalized epilepsy.
- This seizure type is characterized by an electrographic and clinical sequence of tonic seizure (GPFA) followed by absence seizure (GSS&W).
- This finding expands the understanding of seizure semiology in generalized epilepsy syndromes.
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