SPECT in periodic lateralized epileptiform discharges (PLEDs): A case report on PLEDs

Abstract

Periodic lateralized epileptiform discharges (PLEDs), which are known as unusual electroencephalogram (EEG) patterns, are described in a patient who had stroke and seizures. This patient underwent Tc-99m HMPAO (hexamethyl propylene amine oxime) brain single photon emission computed tomography (SPECT) imaging both during PLEDs on EEG and after the cessation of PLEDs. The initial SPECT study revealed increased CBF in the left frontal and parietal cortex extending through the left temporal region and in the left basal ganglium. After the PLEDs disappeared, the second SPECT study showed decreased perfusion on the left frontal and parietal region in the brain. Brain SPECT findings supported the contention that PLEDs may be an ictal phenomenon. Here we also present a review on PLEDs and contributions of brain SPECT as a functional imaging modality to investigate the underlying mechanism of this interesting EEG pattern.

Prognostic Implications of Periodic Epileptiform Discharges

“…16 Whether PEDs are an interictal or ictal activity remains unclear, despite reports of regional increases in cerebral blood flow, oxygen use, or hypermetabolism associated with PLEDs. 23,24 In agreement with the literature, our patients with PLEDs showed mainly focal neurological deficits reflecting focal disease, while our patients with BIPLED or GPED patterns showed a higher incidence of coma, reflecting a more diffuse disease. 8,11 Neuroimaging studies indicate that PEDs may arise from a variety of structural substrates, including chronic and subcortical lesions.…”

Periodic epileptiform discharges in mesial temporal lobe epilepsy with hippocampal sclerosis

“…7,20 Whether PEDs are an interictal or ictal activity remains unclear, despite reports of regional increases in cerebral blood flow, oxygen use, or hypermetabolism associated with PLEDs. [33][34][35] In contrast to previous studies, patients in the current study who had interictal SPECT studies showed mesial temporal hypometabolism, which was similar to a case that described a patient with chronic BIPLEDs with a benign prognosis who had bilateral hypoperfusion in the mesial temporal structures during the BIPLEDs recordings. 33 A possible explanation for the discrepancies among studies could be related to the stage of the underlying neurological condition.…”

Acute CT perfusion changes in seizure patients presenting to the emergency department with stroke-like symptoms: correlation with clinical and electroencephalography findings

“…11 In vivo PET and SPECT studies have also suggested that neuronal activation during a seizure may be associated with a relative increase in perfusion; however, approximately 50% of patients with epilepsy have interictal hypoperfusion in the epileptogenic region, which corresponds to the site of structural anomalies. 12 SPECT imaging during the peri-ictal period has also demonstrated spatial concordance between areas of electroencephalography (EEG) ictal discharges and perfusion abnormalities. 13 Retrospective quantitative analysis of early CTP changes in a cohort of seizure patients who presented with an acute motor or speech deficit that simulated ischaemic stroke has not been previously reported.…”