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Clinical significance of periodic lateralized epileptiform discharges: relationship with status epilepticus
S M Snodgrass1, K Tsuburaya, C Ajmone-Marsan
1Department of Neurology, EEG Laboratory, University of Miami School of Medicine, Florida 33101.
Insights
Periodic lateralized epileptiform discharges (PLEDs) often correlate with cerebrovascular accidents but can occur without focal brain pathology. PLEDs may represent a component of status epilepticus, typically appearing within four days of seizure onset.
Area of Science:
- Neurology
- Clinical Neurophysiology
Background:
- Periodic lateralized epileptiform discharges (PLEDs) are an EEG pattern observed in various neurological conditions.
- Their precise relationship with acute brain injury and seizure activity requires further elucidation.
Purpose of the Study:
- To investigate the clinical, radiological, and pathological correlates of PLEDs.
- To determine the temporal relationship between PLEDs and seizure activity or neurological dysfunction.
- To explore the potential classification of PLEDs as a manifestation of status epilepticus.
Main Methods:
- Retrospective analysis of 147 patients with PLEDs.
- Correlation of EEG findings with clinical, laboratory, radiological, and pathological data.
- Assessment of the timing of EEG recordings relative to seizure onset or neurological dysfunction.
Main Results:
- A significant association was found between PLEDs and cerebrovascular accidents.
- A substantial proportion of patients with PLEDs lacked evidence of focal central nervous system pathology.
- Most PLEDs EEGs were recorded within 4 days of seizure activity or status epilepticus.
- PLEDs typically resolved within 9 days post-ictus, often replaced by focal slowing or random spikes.
Conclusions:
- PLEDs are frequently associated with cerebrovascular events but can also occur in the absence of focal brain lesions.
- The temporal occurrence of PLEDs suggests they may be an EEG component of status epilepticus.
- Understanding the PLEDs phenomenon aids in the diagnosis and management of acute neurological conditions.
Abstract:
A retrospective study was carried out in 147 patients who had been found to have periodic lateralized epileptiform discharges (PLEDs). Clinical, laboratory, radiological, and pathological correlation was performed for all patients. As in previously published works, we found a high correlation with cerebrovascular accidents in our population. A large number of patients, however, had no evidence of focal central nervous system pathology. An attempt was made to find a temporal relationship between the onset of seizure activity (or neurological dysfunction in those patients without seizure activity) and the recording of an EEG with PLEDs. We found that most of the EEGs with PLEDs were obtained within the first 4 days of seizure activity or status epilepticus condition. We postulate that the EEG phenomenon of PLEDs could be considered a part of the status epilepticus condition. Suggestive of this was the fact that the first EEG record obtained in one-third of our patients showed electrographic partial status epilepticus. In a small percentage of our patients, a transitional record showed first status epilepticus and then PLEDs. We found that PLEDs usually disappeared from the EEG tracing within 9 days post-ictus flash status. They were most frequently replaced by focal slowing or random spike activity.