SPECT in a patient with postictal PLEDs: is hyperperfusion evidence of electrical seizure?

The pathophysiological relation between periodic lateralized epileptiform discharges (PLEDs) and epileptic seizures is not known and the exact causative mechanism of PLEDs still remains unclear. In this report, the authors present a case in which the EEG displayed PLEDs after a complex partial seizure. This patient, with a long history of complex partial seizures, had previously undergone right standard anterior temporal lobectomy with hippocampectomy, with a diagnosis of mesial temporal sclerosis. She had one complex partial seizure 72 days after operation and was admitted to hospital. Her brain MRI revealed changes due to temporal lobectomy and small residual posterior hippocampic anomalies. PLEDs over the right temporal lobe were seen in postictal EEGs and persisted for 4 days despite the patient's normal mental status and normal neurologic examination. Brain perfusion scintigraphy with Tc-99m-HMPAO during PLEDs was performed on the second day after the seizure, and right temporal hyperperfusion was detected. EEGs and scintigraphic imaging were repeated after cessation of PLEDs. The repeated brain scan displayed right temporal hypoperfusion. PLEDs during the postictal period may actually be an ictal pattern, and if hyperperfusion in the brain SPECT studies during PLEDs is seen, further aggressive antiepileptic drug therapy may be necessary in some cases.     

Periodic lateralized epileptiform discharges in neurosyphilis

We report two patients of neurosyphilis with periodic lateralized epileptiform discharges (PLEDs) in the EEG. Patient 1, a 32-yr-old man manifested with rapidly progressive cognitive decline and abnormal behavior and recurrent generalized tonic-clonic seizures. EEG revealed periodic epileptiform discharges arising from the anterior temporal and frontal region, predominantly from the right. Diffusion weighted MRI of brain did not show any focal restricted diffusion. Patient 2, a 33-yr-old woman presented with 2-year history of behavioral abnormalities, generalized tonic-clonic seizures and unconcerned urinary incontinence. EEG revealed PLEDS arising from the left anterior temporal region. Her CT scan showed gross cerebral atrophy. Both the patients improved partially with treatment and PLEDs resolved completely. PLEDs may be recorded in EEG of patients with neurosyphilis without imageological evidence of focal cerebral lesion.     

Correlation of SPECT, EEG and CT in patients with epilepsy. A preliminary report

Single photon emission computed tomography (SPECT) were performed in 14 patients with epilepsy. Among 6 patients with GTC, five had no focal abnormalities in EEG and CT scan, SPECT also showed no changes of regional cerebral perfusion. In another one patient EEG was normal, CT scan showed hypodensity in right frontal area, SPECT showed decreased regional cerebral perfusion in right frontotemporal area. AVM in frontal lobe was found at operation. In 3 patients with complex partial seizures and 5 patients with complex partial seizures and GTC, SPECT showed regional cerebral perfusion coincided with the area of focal epileptic form discharges in EEG. In one patient with complex partial seizures and GTC EEG showed right antero-temporal focal sharp wave discharges, discrete calcification in superior suprasella cisterna on CT, SPECT showed decreased regional perfusion in right temporal area, pathological examination revealed hematoma in right temporal lobe. SPECT is useful for localizing epileptogenic foci in epileptics.     

Periodic EEG patterns observed in two cases with partial seizures.

Two cases with partial seizure and periodic EEG pattern were reported. Case 1. A 74-year-old woman reveal typical periodic lateralized epileptiform discharges (PLED's) on the right hemisphere. The patient was semicomatous with mild jaundice and epilepsia partialis continua in the left lower limb. Postmortem examination revealed a main metastatic carcinoma of pancreas head origin in the right parietooccipital region. In the right hemisphere, the cortical structures were relatively preserved, but the white matter including the frontal lobe was swollen and its demyelinating changes were observed diffusely. The PLED's might result from an anatomical or functional severance of the cerebral cortex from normal connections with deeper structures. Case 2. A 61-year-old woman, with idiopathic hypoparathyroidism showed partial complex seizure. The EEG revealed an anterior temporal spike focus and slowing in the right hemisphere, corresponding with repetitive seizures of about one minute duration and with several minutes interval. An interictal periodic EEG pattern appeared in the right anterior and mid-temporal region. No cerebral abnormalities were found with other neurological examinations including brain scanning, carotisangiogram, and echoencephalogram. The periodic pattern was assumed as subclinical focal seizure discharges from the right anterior temporal deep structures.     

Regional Cerebral Perfusion in PLEDs: A Case Report

[123I]N,N,N'-trimethyl-N'-(2 hydroxy-3-methyl-5-123I-iodobenzyl)- 1,3-propane-diamine 2HCl single-photon-emission computed tomography (HIPDM-SPECT) brain imaging in one patient with periodic lateralized epileptiform discharges (PLEDs) on the EEG demonstrated increased regional cerebral perfusion in the PLEDs focus suggesting that PLEDs are the manifestation of abnormally enhanced neuronal activities. This may explain the frequent association of mental confusion, focal neurologic signs, and occurrence of seizures in association with PLEDs.     

Ictal paralysis with tonic eye gazing mimicking a pontine infarction

PURPOSE: Concomitant positive and negative motor phenomena in a single seizure have not been reported before. METHOD: We used an extensive history review, neurological examination, EEG, MRI and SPECT study to demonstrate a rare combination of motor presentations as an ictal phenomenon. RESULT: A 64-year-old male was brought to the emergency room with dizziness, progressive drowsiness and left hemiparesis. A spontaneous eye deviation to the left side with nystagmus was observed. A right pontine lesion was tentatively diagnosed. However, a focal motor seizure of the patient's left face and limbs occurred 3.5h later. A brain MRI revealed a high signal in the right amygdala, hippocampus and thalamus, instead of the pons. An EEG showed periodic epileptic discharges in the right posterior temporal parietal region. Regional hyperperfusion was found by brain SPECT. The level of consciousness improved dramatically after adequate phenytoin treatment. CONCLUSION: A posterior temporal-parietal seizure can present with a prolonged ictal paralysis, a positive ocular nystagmoid deviation and an altered level of consciousness. The EEG is essential for a correct diagnosis, especially with a negative or an unexplainable MRI study. The SPECT has an additional role for the differential diagnosis.     

Periodic EEG Patterns Observed in Two Cases With Partial Seizures

Two cases with partial seizure and periodic EEG pattern were reported. Case 1. A 74-year–old woman revealed typical periodic lateralized epileptiform discharges (PLED'S) on the right hemisphere. The patient was semicomatous with mild jaundice and epilepsia partialis continua in the left lower limb. Postmortem examination revealed a main metastatic carcinoma of pancreas head origin in the right parieto–occipital region. In the right hemisphere, the cortical structures were relatively preserved, but the white matter including the frontal lobe was swollen and its demyelinat–ing changes were observed diffusely. The PLEDs might result from an anatomical or functional severance of the cerebral cortex from normal connections with deeper structures. Case 2. A 61-year-old woman, with idiopathic hypoparathyroidism showed partial complex seizure. The EEG revealed an anterior temporal spike focus and slowing in the right hemisphere, corresponding with repetitive seizures of about one minute duration and with several minutes interval. An interictal periodic EEG pattern appeared in the right anterior and mid-temporal region. No cerebral abnormalities were found with other neurological examinations including brain scanning, carotisangiogram, and echoencephalogram. The periodic pattern was assumed as subclinical focal seizure discharges from the right anterior temporal deep structures.     

EEG of partial seizures.

EEG remains the primary technique in the diagnosis, characterization, and localization of partial seizures. This review examines the significance and character of interictal epileptiform abnormalities, periodic lateralized epileptiform discharges, and ictal patterns in patients with partial epilepsy. Interictal epileptiform discharges are common and assist in the diagnosis and localization of partial seizures. Fortunately, true "false positive" EEGs with focal epileptiform abnormalities are distinctly rare. Periodic lateralized discharges have characteristics of both interictal and ictal activity and are an area of controversy as to their clinical significance. Ictal patterns in partial seizures are variable, with the most distinctive features seen in seizures from a mesial temporal lobe origin. The unifying EEG feature of a partial seizure is in its evolution. A partial seizure begins with a clear delineation of the onset of activity that is distinct from the preceding background, followed by an evolution of this activity in both frequency and amplitude and terminating with an identifiable cessation of the rhythmic pattern that merges again into the background activity.     

Subacute encephalopathy with epileptic seizures in an alcoholic patient

We introduce a case of a 66 year-old male with chronic alcoholism who suffered from confusion, Wernicke-aphasia and epileptic seizures. Several EEG revealed periodic lateralized epileptiform discharges. The patient's case resembles the symptoms of a subacute encephalopathy with epileptic seizures which can occur in alcoholics.     

A pathophysiologic approach for subacute encephalopathy with seizures in alcoholics (SESA) syndrome

Subacute encephalopathy with seizures in alcoholics (SESA) syndrome is a unique disease entity characterized by typical clinical and electroencephalographic (EEG) features in the setting of chronic alcoholism. We present two patients with distinctive serial MRI and EEG findings which suggest a clue to the underlying pathophysiologic mechanisms of SESA syndrome. Two patients with chronic alcoholism and alcoholic liver cirrhosis presented with generalized seizures and confused mental status. Brain MRI demonstrated restricted diffusion, increased T2-weighted signal intensity, and hyperperfusion in the presumed seizure focus and nearby posterior regions of the cerebral hemispheres. EEG showed periodic lateralized epileptiform discharges which were prominent in the posterior regions of the cerebral hemispheres ipsilateral to the side of brain MRI abnormalities. Even after patients clinically improved, these brain abnormalities persisted with progressive atrophic changes on follow-up brain MRI. These patients had not only the distinguishing clinical and EEG features of SESA syndrome, but also showed novel brain MRI abnormalities. These changes on MRI displayed characteristics of seizure-related changes. The posterior dominance of abnormalities on MRI and EEG suggests that the pathophysiologic mechanisms of SESA syndrome may share those of posterior reversible encephalopathy syndrome.     

Subacute encephalopathy with seizures in alcoholism.

Generalised seizures are a common manifestation of acute alcohol intoxication. Alcohol is known to precipitate generalised seizures in patients with focal brain pathology. A rare case of secondarily generalised seizures precipitated by alcohol in a patient without an underlying focal brain lesion is reported. Electroencephalopgraphy (EEG) showed periodic lateralised epileptiform discharges (PLEDs) on the side contralateral to the focal motor fits.     

Tooth-brushing epilepsy with ictal orgasms.

We report a 41-year-old woman with complex reflex epilepsy in which seizures were induced exclusively by the act of tooth brushing. All the attacks occurred with a specific sensation of sexual arousal and orgasm-like euphoria that were followed by a period of impairment of consciousness. Ictal EEG demonstrated two events of epileptic seizure that were provoked after tooth brushing for 38 and 14 seconds, respectively. The interictal EEG showed epileptiform discharges over the right anterior temporal region and interictal single photon emission computed tomography (SPECT) scan showed relative hypoperfusion in the uncus of right temporal lobe. Brain magnetic resonance imaging (MRI) revealed right hippocampal atrophy. We suggest that tooth-brushing epilepsy, especially with sexual ictal manifestations, may provide insight into the cerebral pathophysiology at the right temporolimbic structure.     

A case of herpes simplex encephalitis with periodic lateralized epileptiform discharges

A case of a 50-year-old male with herpes simplex encephalitis was reported. An EEG examination revealed periodic lateralized epileptiform discharges (PLEDs) on the right hemisphere on April 17, 1990. Another EEG performed on April 26 showed PLEDs on the left hemisphere, dominantly on the temporal lobe. On and after May 2, PLEDs have not been detected. SPECT showed hyperperfusion in the right temporal and occipital lobe son April 26. T1 weighted MRI examined on April 18 showed low signal intensity and T2 and proton weighted imagings revealed high signal intensity in the greater part of the right temporal lobe and a similar abnormality in a part of the left temporal lobe. Although the origin of PLEDs is still controversial, these findings suggest that, at least in the case of herpes simplex encephalitis, PLEDs appear in the early progressive stage of the inflammatory lesion.     

Clinical significance of focal periodic discharges in neonates

Of 1,114 EEG recordings obtained for 592 neonates, focal periodic discharges were noted on 57 (5%) of recordings for 34 neonates (26 preterm and eight term). Periodic lateralized epileptiform discharges (PLEDs) were noted on four of these recordings. Sixteen patients (47%) with focal periodic discharges also had electrographic seizures on the same or a subsequent record. Stroke was the most common brain lesion (53%) in this neonatal population. Preterm neonates had discharges that were less than 60 seconds in duration and located in the parasagittal regions, while discharges in term neonates were longer in duration and were located in the temporal regions. Of the 34 neonates, 15 (44%) died, and 58% (11/19) of the survivors were abnormal with respect to neurological development. Focal periodic discharges in neonates, including PLEDs, have the same clinical significance as PLEDs recorded on EEGs in older children and adults.     

Prolonged deficits after focal inhibitory seizures

Introduction: Seizures are most commonly associated with positive phenomena such as tonic, clonic or myoclonic movements, automatisms, paresthesias and hallucinations. Negative phenomena, however, are not an uncommon manifestation of seizure activity. Examples of negative seizure phenomena include speech arrest, aphasia, amaurosis, amnesia, numbness, deafness, neglect and atonic seizures. Less commonly described in the literature are focal inhibitory motor seizures. Methods and Results: Two patients presenting with rapidly progressive, prolonged hemiparesis, sensory neglect and hemi-visual field obscuration are described. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain did not reveal progression of known structural lesions or new lesions. The superficial cortex of the hemisphere contralateral to the hemiparesis and sensory neglect enhanced diffusely with gadolinium on T1-weighted MRI images. Electroencephalography demonstrated periodic lateralized epileptiform discharges (PLEDs) in one patient and lateralized suppression and slowing in the other patient. Single photon emission computed tomography (SPECT) revealed hyperperfusion in the hemisphere contralateral to the hemiparesis and sensory neglect. The changes seen on MRI and SPECT resolved with resolution of the symptoms. Conclusion: Taken together with the clinical history, the results from these investigations suggest focal inhibitory seizure as the underlying etiology. A review of the literature and investigations helpful in making this difficult diagnosis are provided.     

Periodic lateralized epileptiform discharges (PLEDs) as early indicator of stroke in full-term newborns

We report on periodic lateralized epileptiform discharges (PLEDs) on EEG in two infants with neonatal convulsions. In both neonates, the EEG abnormalities were seen soon after the onset of seizures, at a time when cranial ultrasound scans were thought to be normal. Subsequent Magnetic Resonance Imaging scans demonstrated cerebral infarction in both patients. In one case, the localisation of the lesion on MRI was concordant with that of the EEG abnormalities, as usually observed in adults with focal lesions. The other infant showed similar EEG abnormalities, but her MRI showed a localised lesion in the basal ganglia, which has also been reported to be involved in the genesis of these abnormalities.     

Electroencephalography in herpes simplex encephalitis

The EEG in the acute stage of herpes simplex encephalitis (HSE) can show a variety of abnormalities, including uni- or bilateral periodic sharp waves or attenuation of amplitude, focal or generalized slow waves or epileptiform discharges, or electrical seizures. No specific EEG patterns are pathognomonic for HSE, but a focal or lateralized EEG abnormality in the presence of encephalitis is highly suspicious of HSE. In the acute stage, EEG appears to be more sensitive than computerized tomography or radioisotope brain scanning. The EEG findings tend to differ in the course of illness, and the periodic discharges occur only during the acute stage. The EEG findings in either the acute stage or long-term follow-up do not predict the chance of survival or severity of disability, and EEG changes appear to lag behind the clinical changes. EEG results can become normal in both adults and neonates when the acute stage is over.     

A pediatric case of intractable complex partial seizures associated with mesial temporal lobe astrocytoma: usefulness of interictal epileptiform discharges in the present case]

The patient was a 10-year-old male with normal developmental milestones. He had medically intractable complex partial seizures since the age of 7 years. At the age of 10 years, he had focal motor seizures of the right face, and a head CT scan showed a calcified lesion in the left mesial temporal region. The tumor exhibited low intensity on T 1-weighted and high intensity on T 2-weighted MR images, and was not enhanced by gadolinium-diethylenetriamine pentaacetic acid. Interictal SPECT showed hypoperfusion in the left temporal region. One-day video/EEG monitoring revealed very frequent epileptiform discharges which occurred only during sleep period exclusively in the left anterior-to-middle temporal region. The patient underwent lesionectomy with the guidance of electrocorticography. The histological study of the resected tissue showed astrocytoma. After surgery he has had no seizures for 10 months. It was concluded that very frequent interictal epileptiform discharges strictly localized to the temporal lobe at which MRI-identified tumor was present could be predictive of epileptogenic zone in the present patient in whom clinical symptoms and the results of other studies were also concordant.     

Chronic PLEDs with transitional rhythmic discharges (PLEDs-plus) in remote stroke.

Background. Periodic lateralized epileptiform discharges (PLEDs) are a rare phenomenon in electroencephalography, occurring in acute structural brain lesions. In general, PLEDs appear transiently in acute lesions, but a few reports have described persistent PLEDs in chronic lesions. Case report. An 86-year-old female was admitted, in 1999, with a left MCA stroke associated with right hand focal motor seizures. The first EEG in February of 2002 showed PLEDs over the left hemisphere associated with rhythmic discharges (PLEDs-plus). The patient was admitted on a second occasion in 2003 because of three sequential seizures and the EEG showed a similar pattern. Finally in 2006, the patient was admitted again because of sequential complex partial seizures and an EEG showed the same PLEDS-plus pattern as the EEGs of 2002 and 2003. Discussion. We report an unusual case of chronic PLEDs associated with rhythmic discharges in a patient with recurrent seizures and remote stroke.     

The interpretation of the EEG in stupor and coma

This review discusses a variety of causes of stupor and coma and associated electroencephalographic (EEG) findings. These include metabolic disturbances such as hepatic or renal dysfunction, which are often characterized by slowing of background rhythms and triphasic waves. Hypoxia and drug intoxications can produce a number of abnormal EEG patterns such as burst suppression, alpha coma, and spindle coma. Structural lesions, either supra- or infratentorial, are reviewed. EEGs in the former may show focal disturbances such as delta and theta activity, epileptiform abnormalities, and attenuation of faster frequencies. In infratentorial lesions, the EEG may appear normal, particularly with a pontine lesion. Some patients may be encephalopathic because of ongoing epileptic activity with minimal or no motor movements. This entity, nonconvulsive status epilepticus (NCSE), is difficult to diagnose in obtunded/comatose patients, and an EEG is required to verify the diagnosis and to monitor treatment. Several EEG patterns and their interpretation in suspected cases of NCSE such as periodic lateralized epileptiform discharges (PLEDs), bilateral independent periodic lateralized epileptiform discharges (BIPLEDs), generalized periodic epileptiform discharges (GPEDs), and triphasic waves are reviewed. Other entities discussed include the locked-in syndrome, neocortical death, persistent vegetative state, brainstem death, and brain death.