Circling seizures

Localization value of ictal turning prone

PURPOSE

Ictal semiology complements ictal EEG in identifying the likely epileptogenic zone. Ictal turning prone (ITP) with body turning of 90 ° or more can be seen with frontal lobe epilepsies. The aim of our study was to evaluate the localizing value of ITP in a general population of patients undergoing long term video-EEG monitoring.

METHODS

We reviewed our epilepsy monitoring unit database for adult patients with recorded habitual seizures with ITP. All 16 patients identified had continuous video-EEG monitoring using standard scalp electrodes; eight patients also had intracranial EEG monitoring. We only included focal seizures without evolution to bilateral tonic-clonic activity.

RESULTS

We identified 16 patients with ITP, mean age of 32.5 years (range 18-50). ITP was consistently seen in at least one focal impaired awareness seizure of all patients. Ictal onset zone on scalp EEG was left temporal in five, right temporal in three, left frontal convexity in two, right frontal convexity in two, probable right medial frontal in three and probable left medial frontal in one patient. Direction of ITP was uni-directional in 12 patients while 4 patients had ITP in opposite direction in different seizures. Nine patients underwent epilepsy surgery; five patients had Engel class I outcome and four patients had Engel class III outcome.

CONCLUSIONS

Ictal turning prone does not have a consistent single localizing or lateralizing value and can be seen with various epileptogenic zones including medial frontal, lateral frontal or temporal. ITP direction can vary even with a single epileptogenic zone.

Reflex epilepsy induced by playing Go-stop or Baduk games

PURPOSE

Seizures can be triggered by complex mental activities. The aim of this study was to investigate the clinical characteristics of reflex epilepsy induced by playing Go-stop or Baduk games.

METHODS

The study comprised 11 patients with this type of reflex epilepsy identified from our patient database. We collected data on clinical features, EEG, and brain MRI as well as seizure outcomes.

RESULTS

The patients had a late age of onset (range, 43-65 years, except for one patient with an age of onset of 11 years). An MRI abnormality and interictal EEG abnormalities were found in one patient respectively. The seizures exhibited diverse semiological features suggesting a focal or generalized onset. No myoclonic seizures were observed. Individualized strategies such as avoiding the precipitating game or reducing exposure to the stimulus were most effective in preventing the seizures.

CONCLUSION

The pathophysiological mechanisms underlying Go-stop- or Baduk-induced seizures may be different from other cognition-associated reflex epileptic phenomena. This type of reflex epilepsy may be a heterogeneous syndrome manifesting in a range of diverse semiological features.

Ictal/interictal EEG patterns and functional neuroimaging findings in subcortical band heterotopia: report of three cases and review of the literature

Subcortical band heterotopia (SBH) is a rare, genetic disorder of neuronal migration, which is seen almost exclusively in females. Little is known about the functionality of the band heterotopia, in terms of both physiology and pathology, in this malformation. Patients are reported to have several different types of seizures, which are usually drug resistant. Interictal EEG findings are known to correlate with the type of seizures, however less is known about the ictal EEG patterns. We present 3 female patients who were investigated at our center with video-scalp EEG monitoring, interictal single photon emission computed tomography (SPECT), functional magnetic resonance (MR) imaging (fMRI) and MR spectroscopy (MRS) besides routine MR imaging. They had several different types of seizures, and one of them reported also having circling seizures that have not been reported previously in patients with SBH. Ictal EEG recordings were remarkable for their unusual patterns of propagation. The findings in structural and functional neuroradiological investigations are discussed in light of the literature.

Daily rhythms of seizure activity and behavior in a model of atypical absence epilepsy

We studied daily rhythms of chronic seizure activity and behavior in adult rats and mice treated with the cholesterol biosynthesis inhibitor AY-9944 (AY) during early postnatal development. Chronic atypical absence seizures were verified in the AY-treated animals by the presence of spontaneous 5- to 6-Hz slow spike-wave discharges (SSWDs) in the neocortex. General behavioral activity, as measured by total movements (TM), movement time (MT), ambulatory movement time (AMT), time spent in center of arena (CT), jumps (JFP), and rotational behavior (TURNS), were continuously recorded under a 12-hour light:12-hour dark photocycle. The average SSWD duration in AY-treated rats varied daily, with two peaks occurring at approximately dark phase and light phase onset. Mice treated with AY exhibited significant increases in all behavioral measures during the light and dark phases, with the exception of light-phase CT, which did not differ from that of controls. Consequently, the daily rhythm of total behavioral activity (TM) exhibited a significantly higher mean oscillation (mesor) and amplitude without evidence of phase shift compared with the TM rhythm of controls. The occurrence of SSWD activity in the AY model appears to be subject to regulation by biological timing mechanisms and, furthermore, associated with motor hyperactivity that does not alter the timing of behavioral rhythmicity.

Idiopathic generalized epilepsies imitating focal epilepsies

Classification of epileptic seizures and epilepsy syndromes as either focal or generalized is a fundamental and early part in the diagnostic process and is generally fairly easily accomplished. However, in patients with idiopathic generalized epilepsies, seizure and EEG features may suggest, particularly to the unwary, the occurrence of focal rather than generalized seizures. Misinterpretation of typical absence seizures as focal seizures, especially as temporal lobe seizures and of myoclonic seizures as focal clonic seizures, is a relatively common error and focal features during generalized tonic-clonic seizures may also be quite common. Sequences of seizures in idiopathic generalized epilepsies (such as absences or jerks followed by generalized tonic-clonic seizures) may also cause confusion. Versive and circling seizures are seizure types whose ictal semiology is clearly focal; nevertheless such seizures are described in idiopathic generalized epilepsies accompanied by generalized EEG discharges. The occurrence of focal EEG abnormalities in certain idiopathic generalized epilepsy syndromes is common. This is best known in juvenile myoclonic epilepsy.

A case of 'circling seizures' and an intratumoral abscess

We describe a case of a 38-year-old woman who presented with 'circling' seizures and was found to have an intracranial mass with features consistent with a meningioma. Three weeks prior to her presentation she underwent an uncomplicated vaginal hysterectomy. However, after discharge to home she developed a 4-day history of fever, chills and night sweats that eventually resolved. She underwent surgical removal of her intracranial mass without difficulty but intra-operative pathology showed features of acute cerebritis at the margins of the tumor. Further sectioning of the mass revealed evidence of an intratumoral abscess. Culture of the meningioma revealed heavy growth of Bacteroides fragilis. The patient was treated with intravenous antibiotics, discharged home in excellent health and has had no recurrence of seizures. In our case report we will review the historical literature on the incidence and features of intratumoral abscess. Although it is considered a rare event, our case demonstrates both common and unique features about this occurrence and highlights an unusual chain of events in the natural history of the patient's meningioma and the way in which it became clinically apparent.

Spontaneous paroxysmal circling behavior in the ci2 rat mutant: epilepsy with rotational seizures or hyperkinetic movement disorder?

Circling, turning, rotating, spinning, wheeling, and cursive hyperkinesia are all synonymous terms used to describe the active movement of an animal in a circular direction. Circling behavior can be evoked by unilateral electrical and chemical stimulation or lesions of various brain sites, but can also occur after systemic drug administration or spontaneously in normal animals or mutant rodents. In humans, stereotypic body rotation can occur as a distinctive entity of generalized and focal epilepsy, and may be due to involvement of the striatum. We have previously described a Lewis rat mutant (ci2) with a behavioral phenotype characterized by lateralized circling, hyperactivity, opisthotonus, and ataxia. In these rats, circling occurs in phases or bursts either spontaneously or in response to stress. Neurochemical data indicate that the circling behavior of the ci2 mutants is related to an abnormal asymmetry in dopaminergic activity in the striatum. Because of the similarities to rotational epilepsy, we used video and electroencephalographic recordings to study whether the rotational behavior of the ci2 mutant rat is a result of a partial or generalized epilepsy. Epileptic WAG/Rij rats were used for comparison. Video monitoring of ci2 rats in the absence of any stress or disturbance showed that circling occurs in paroxysmal bursts during active wakefulness, but not during passive wakefulness or sleep. Circling was not preceded or followed by any convulsive motor seizures and was not associated with epileptiform abnormalities in the electroencephalogram, whereas WAG/Rij rats exhibited myoclonic seizures and epileptic spike-wave discharges during passive wakefulness and sleep. As a result of the association of circling with active wakefulness, ci2 rats exhibited many more rotations during the dark (active) phase compared with the light (rest) period. Increase in active wakefulness during the light phase by transfer of the rats to a new environment induced or intensified circling behavior. Most ci2 rats showed a consistent lateral preference during circling, but some rats changed their preference from one session to another. The data indicate that spontaneous paroxysmal circling behavior in the ci2 rat is not a consequence of epilepsy but reflects a hyperkinetic movement disorder with abnormal lateralization of brain function.

Circling seizures in a case with Wilson's disease

We report a case of Wilson's disease with circling seizures. Because of the existence of other types of frontal automatism and the EEG focus on the frontal regions, circling seizures of the patient were thought to originate from the frontal lobe. Magnetic resonance imaging demonstrated large cavitary lesions on bilateral frontal lobes. The mechanisms of circling behavior are discussed in association with Wilson's disease.