Summary:Purpose: The exact anatomic and neurophysiologic correlates of idiopathic generalized epilepsy (IGE) in humans are still not well understood, although the thalamus has frequently been invoked as the crucial structure in the generation of primary generalized seizures. The few in vivo magnetic resonance (MR)-based studies in IGE patients suggest an altered cortical/subcortical gray matter ratio, but with no evidence of structural alterations of the thalamus. In this study, we sought to determine the volumes of the other subcortical structures.Methods: The volumes of the caudate nucleus, putamen, pallidum as well as the thalamus were each determined in both hemispheres in 11 patients with various IGE syndromes, normalized for whole-brain volumes and then compared with 15 age-matched controls.Results: No differences were noted in thalamic volumes, confirming previous reports. However, smaller subcortical volumes were noted in the IGE patients (p < 0.009), mainly due to smaller putamen bilaterally (p ≤ 0.015).Conclusions: It is speculated that the presence of discrete frontal dysfunction, as noted in neuropsychological studies in IGE patients, indirectly supports our results because the putamen projects predominantly to the frontal cortex. Larger studies with more homogeneous patient populations are needed to determine the robustness of these findings and whether they are specific for particular IGE syndromes.

Periodic lateralized epileptiform discharges (PLEDs) are a well defined electroencephalographic entity but whether PLEDs represent an ictal condition or not remains debated. Much work has been done using electroencephalography (EEG) but new approaches using cerebral perfusion imaging may give more information about this question. We aimed to evaluate if PLEDs were associated with high regional cerebral blood flow (rCBF). We studied 18 patients with PLEDs and different pathologies, and performed brain single-photon-emission computed tomography (SPECT) during and, for three cases, after the disappearance of PLEDs. Qualitative variations and locations of rCBF were compared with PLEDs. Association with seizures and type of seizures were also assessed. SPECT showed high rCBF in 18/18 patients (100%). The location of PLEDs and high rCBF matched in 17/18 cases (94%). In the three cases where SPECT was performed after PLEDs disappeared, the high rCBF had cleared (100%). Eighteen cases (100%) presented seizures before recording of PLEDs, mainly motor (partial motor or generalized tonic-clonic). Where there was a decreased rCBF (related to a lesion) there was little relationship to PLEDs and all patients with decreased rCBF had an adjacent increased rCBF. These results confirm preliminary case reports. Hyperperfusion adds further to the argument that PLEDs may be related to a form of partial status epilepticus.

Introduction: Psychiatric disorders are known to occur frequently in chronic epilepsy. The aim of this study is to investigate the prevalence of psychiatric comorbidity and its relationship to regional cerebral dysfunction in patients admitted to a tertiary epilepsy center for epilepsy surgery. Methods: 217 patients were investigated. A presurgical workup was performed and allowed precise localization of the epileptogenic focus in 156 patients. Sixty-one patients had multifocal or generalized discharges. After 1–3 psychiatric interviews, a psychiatric diagnosis was made (DSM-IV classification). Results: Psychiatric comorbidity was found in 85 patients (39%), more often in those with right or bilateral hemispheric dysfunction (74%, p = 0.04) with no difference between temporal or extratemporal foci location frequency. Additionally, patients with psychiatric disorders were less likely to undergo epilepsy surgery compared to ‘epilepsy-only’ patients (p = 0.003), despite similar good outcome in patients with and without psychiatric comorbidity. Conclusions: Right-sided or bilateral foci seem to represent a risk factor for psychiatric comorbidity in epilepsy, although we did not find any particular association between a psychiatric syndrome and focus localization. Recognition and treatment of psychiatric comorbidity is of major importance since its presence may interfere with patient’s decision making for epilepsy surgery treatment.

Summary:Purpose: To describe the behavioral and EEG topographic correlates of absences with 3-Hz generalized spikewaves and partitioned impairment of consciousness.Methods: Two adult women had so-called "phantom" absences, characterized by brief and mild impairments of consciousness that were previously inconspicuous to both patient and physician. Neuropsychological examination was performed under video-EEG monitoring during absence status. EEG topographic mapping of spike-wave discharges was obtained in the two cases.Results: Only mild attentional and executive disturbances were observed during absence status despite prolonged discharges. Spike-wave bursts were associated with selective i npairment in the initiation of response and self-generated action, whereas short-term storage of external information during discharges was fully preserved. This is consistent with a predominant involvement of frontomesial cortex demonstrated by topographic mapping of spike-wave discharges in the two cases. By contrast, in two other patients with typical absences and a complete lack of retention for information given during the discharges, topographic mapping found a more lateral frontal involvement by spike-wave activity.Conclusions: Different types of absence seizures may impair distinct components of conscious behavior. A predominant involvement of frontomesial thalamocortical circuitry may underlie an "inconspicuous" disorder of consciousness as seen in phantom absences with selective loss of initiation and goaloriented behavior, whereas involvement of more lateral frontal areas in typical absences may additionally disrupt working memory processes. Key Words: Absence seizureAbsence status-Consciousness-Cingulate cortex-Frontal lobe.Absence seizures are defined by impairment of consciousness concomitant with 3-Hz generalized spikewave on EEG (1,2). But absences do not constitute a single disorder, and consciousness is not subserved by a unitary process. Absences occur in several idiopathic epileptic syndromes during childhood or adolescence (1,2) and may occasionally persist into adulthood (3).Absence status also may occur in adults because of drug exposure or withdrawal, or as de novo status (3-5). One form recently emphasized under the term of "phantom absences" is characterized by "brief and mild impairments of consciousness that are inconspicuous to both the patient and physician and may exist for many years before diagnosis" (6,7). It remains unclear whether these cases correspond to a distinct entity (5,7) or a seizure type along a broader continuum of idiopathic epilepsies (8,s). Variable impairment of consciousness during absences (1 0,ll) or subtle cognitive changes related to interictal spikes known as "transient cognitive impairment" (1 2) have been long noted. A5 consciousness cannot be regarded as a unitary phenomenon (13,14), we studied ictal behavior in two cases with so-called phantom absences to learn whether a distinct deficit in the mechanisms of consciousness rather than a different "degree" of deficit m...

This report describes a patient with complex partial seizures arising from the right temporal lobe who developed symptomatic sinus arrest following the end of his seizure activity. A ventricular pacemaker was implanted and was documented to function appropriately, preventing development of bradycardia associated symptoms during subsequent seizures. Possibly relevant cerebral structures are briefly discussed.