Reexamination of 123 I-IMP-SPECT at Interictal Stages in Adult Partial Epilepsy

¹²³I-ZMP-SPECT scans at the interictal stages in 13 epileptic patients with normal X-ray CT findings were reexamined at intervals of 1.9 ± 0.8 years. Interictal scalp EEGs were recorded a few hours after each SPECT scan. All of the SPECT abnormalities indicated focal hypo fixation images of ¹²³I-IMP, i.e. zones of a decreased rCBF reflecting a functional inactivation. Among 11 patients with the SPECT abnormalities in the first SPECTs, eight cases had the complete or partial regional reproduction of the abnormalities in the second SPECTs. As changes in the SPECT findings, an alteration from the abnormal SPECT images to     

High reproducibility of regional abnormalities on interictal123I-IMP SPECT brain scans in adults with partial epilepsy

Summary The reproducibility of twoN-isopropyl-(iodine 123)p-iodoamphetamine (¹²³I-IMP single photon emission computed tomography (SPECT) scans both taken during interictal periods was studied in 13 adult patients with partial epilepsy who had normal CT scans. The frequency of the seizures and the nature of the ictal symptoms were virtually unchanged during the interval between the two SPECT scans performed in each case. In 8 (72.7%) of 11 patients who had abnormal images consisting of focal hypofixation images of¹²³I-IMP, i.e. zones of decreased regional cerebral blood flow on the first scans, complete or partial regional reproduction of the SPECT abnormalities was observed. This high reproducbility supports the usefulness of SPECT scans in the regional diagnosis of epileptic foci.     

Sequential 123I-IMP-SPECT in acute infantile hemiplegia

Sequential 123I-N-isopropyl-p-iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) was performed in 2 patients with acute infantile hemiplegia. In both patients, low uptake of IMP was detected in the targeted abnormal hemisphere. The 123I-IMP-SPECT findings indicative of a pathologic condition persisted even when the clinical findings and electroencephalographic abnormalities improved. Because of its sensitivity, noninvasiveness, and accurate reflection of the cerebral blood flow distribution, 123I-IMP-SPECT is useful in the examination of acute infantile hemiplegia and in the evaluation of prognosis.     

Two cases of adult Down's syndrome presenting parietal low uptake in 123I-IMP-SPECT]

We performed 123I-IMP-SPECT to patients with Down's syndrome who were supposed to have neuropathological findings of dementia of the Alzheimer's type. In case 1, a 52-year-old man with dementia, bilateral posterior parietal low uptake and right temporal low uptake were noted. Uptake was markedly lower in the right hemisphere. Case 2, a 38-year-old man not exhibiting clinical features of dementia, presented slightly decreased uptake in bilateral posterior parietal areas. We conclude that the patterns of abnormally decreased uptake in these cases of Down's syndrome are similar to those in dementia of Alzheimer's type, and that there is a possibility to detect the predemented stage of Down's syndrome by 123I-IMP-SPECT.     

Sleep-EEG modulation of interictal epileptiform discharges in adult partial epilepsy: a spectral analysis study.

INTRODUCTION: In order to define accurately the relationship between EEG components (spindles, delta and theta frequencies) and the occurrence of interictal epileptiform discharges (IED) during sleep in partial epilepsy, a correlation study between spike overnight distribution and EEG spectral power time series was performed. METHODS: Eighteen patients (mean age: 24.7+/-5.5 years) affected by partial epilepsy underwent continuous EEG-polysomnography. The temporal series of Slow Wave Activity (SWA), Sigma Activity (SA) and Theta Band (TB), derived from spectral analysis, were obtained from a spike-free and pathologic alteration-free derivation, contralateral to the most active lead, where the IED count was performed. Relationships between SA, SWA and TB and time series of IED were tested by means of correlation techniques after data normalization. RESULTS: Our results revealed a significantly higher correlation between IED and SWA in 12 subjects; a significantly higher correlation between IED and SA in three subjects and a significant correlation with TB in three cases. CONCLUSIONS: Data suggest that in most adult patients with partial epilepsy IED production during sleep is facilitated by the action of synchronizing mechanisms which are active during NREM sleep and lead to the appearance of EEG delta waves. Nevertheless evidence is given of two smaller groups of patients. In one of them IED are more sensitive to the promoting action of the spindle generating mechanism, active during stage 2 of NREM sleep. In the other one the promoting action of TB, characterizing EEG during stage 1 and REM sleep, is evident.     

Reexamination of interictal psychoses based on DSM IV psychosis classification and international epilepsy classification

We sought to examine interictal psychoses based on the international epilepsy classification and DSM IV criteria, with special attention paid to epilepsy types as well as to subcategories of psychoses. One hundred thirty-two outpatients were studied, each with definite evidence of both epilepsy and interictal psychosis clearly demarcated from postictal psychosis. We compared them with 2,773 other epilepsy outpatients as a control. Risk factors for psychosis were examined within the temporal lobe epilepsy (TLE) group and the more extended group of symptomatic localization-related epilepsy. Further, nuclear schizophrenia and other nonschizophrenic psychotic disorders were compared. We confirmed a close correlation between TLE and interictal psychoses. Within the TLE group, only early epilepsy onset and a history of prolonged febrile convulsions were revealed to be significantly associated with interictal psychosis. Within the symptomatic localization-related epilepsy group, such parameters as complex partial seizures, autonomic aura, and temporal EEG foci were closely associated with psychoses. There was also a significant difference between groups as to ictal fear and secondary generalization. Whereas patients with early psychosis onset and a low intelligence quotient were overrepresented in the nuclear schizophrenia group, drug-induced psychosis and alternative psychosis were underrepresented. TLE proved to be preferentially associated with interictal psychoses. Within the TLE group, medial TLE in particular was found to be more closely associated with psychosis. Our data support the original postulation of Landolt, stating that alternative or drug-induced psychoses constitute a definite subgroup of interictal psychoses, which are different from chronic epileptic psychoses that simulate schizophrenia.     

Relationship of interictal epileptiform discharges to sleep depth in partial epilepsy

Non-rapid eye movement (NREM) sleep activates interictal epileptiform discharges (spikes) in many epileptic syndromes. To define this phenomenon more precisely, we studied the relationship of spikes to absolute log delta power (LDP), a continuous measure of sleep depth, in 8 patients with partial epilepsy. LDP differed significantly across visually scored sleep stages. Logistic regression analyses of spike occurrence in relation to LDP were carried out on the central-occipital channel contralateral to the dominant spike focus (C4-O2 for left and C3-O1 for right temporal focus). Within NREM sleep, spikes were more likely to occur: (1) at higher levels of LDP, (2) on the ascending limb of LDP, and (3) with more rapid rises in LDP. Spike frequency per minute was 4.6 times higher in NREM than in rapid-eye movement (REM) sleep and diminished with time from sleep onset. When the effect of LDP was controlled for in the analysis, however, there was no significant effect of REM sleep stage or time on spike occurrence. Only 1% of spikes occurred within 10 s of an arousal. These findings suggest that processes underlying the deepening of NREM sleep may contribute to spike activation in partial epilepsy.     

EEG-fMRI study of the interictal epileptic activity in patients with partial epilepsy

PURPOSE: To investigate Blood Oxygen Level Dependent (BOLD) responses to interictal epileptic discharges (IEDs) during EEG-correlated functional MRI (EEG-fMRI) in patients with partial epilepsy. METHODS: We studied eight patients who had a diagnosis of partial epilepsy and active spiking on routine scalp EEG recording. Sessions of continuous EEG-fMRI were recorded, and spikes (identified after online artifact removal) were used as events in the fMRI analysis. Regions of BOLD signal change in response to interictal epileptic discharge were assessed and epileptogenic zone localization was electroclinically identified. RESULTS: Eight patients with partial epilepsy were recruited (6 males, 2 females, mean age 18.5, mean onset age range 0.5-29). Two who underwent EEG-fMRI were excluded from further analysis: one due to absence of epileptic discharges, the other due to excessive head motion. Eight sessions of EEG-fMRI scanning in 6 patients were obtained: 6 with activation and deactivation, one with activation only, and one with deactivation only. Focal activations corresponding to electroclinical localization occurred in 7 sessions, 5 of which were maximal. CONCLUSIONS: Maximally activated areas detected by EEG-fMRI in patients with partial epilepsy appear to be concordant with epileptogenic areas as defined by electroclinical localization data. In most patients with focal epilepsy, positive BOLD responses seem to be mainly in epileptogenic zones and the corresponding contralateral areas. Responses to deactivation seem less associated with IEDs. So EEG-fMRI is a useful tool to study the pathophysiological mechanisms of epilepsy and may assist in presurgical evaluation of epilepsy.     

Intracerebral propagation of interictal activity in partial epilepsy: implications for source localisation.

The hypothesis that focal scalp EEG and MEG interictal epileptiform activity can be modelled by single dipoles or by a limited number of dipoles was examined. The time course and spatial distribution of interictal activity recorded simultaneously by surface electrodes and by electrodes next to mesial temporal structures in 12 patients being assessed for epilepsy surgery have been studied to estimate the degree of confinement of neural activity present during interictal paroxysms, and the degree to which volume conduction and neural propagation take part in the diffusion of interictal activity. Also, intrapatient topographical correlations of ictal onset zone and deep interictal activity have been studied. Correlations between the amplitudes of deep and surface recordings, together with previous reports on the amplitude of scalp signals produced by artificially implanted dipoles suggest that the ratio of deep to surface activity recorded during interictal epileptiform activity on the scalp is around 1:2000. This implies that most such activity recorded on the scalp does not arise from volume conduction from deep structures but is generated in the underlying neocortex. Also, time delays of up to 220 ms recorded between interictal paroxysms at different recording sites show that interictal epileptiform activity can propagate neuronally within several milliseconds to relatively remote cortex. Large areas of archicortex and neocortex can then be simultaneously or sequentially active via three possible mechanisms: (1) by fast association fibres directly, (2) by fast association fibres that trigger local phenomena which in turn give rise to sharp/slow waves or spikes, and (3) propagation along the neocortex. The low ratio of deep-to-surface signal on the scalp and the simultaneous activation of large neocortical areas can yield spurious equivalent dipoles localised in deeper structures. Frequent interictal spike activities can also take place independently in areas other than the ictal onset zone and their interictal propagation to the surface is independent of their capacity to trigger seizures. It is concluded that: (1) the deep-to-surface ratios of electromagnetic fields from deep sources are extremely low on the scalp; (2) single dipoles or a limited number of dipoles are not adequate for surgical assessment; (3) the correct localisation of the onset of interictal activity does not necessarily imply the onset of seizures in the region or in the same hemisphere. It is suggested that, until volume conduction and neurophysiological propagation can be distinguished, semiempirical correlations between symptomatology, surgical outcome, and detailed presurgical modeling of the neocortical projection patterns by combined MEG, EEG, and MRI could be more fruitful than source localization with unrealistic source models.     

Clinical stages of progressive myoclonus epilepsy in adult patients

Nineteen hospitalized adult patients with progressive myoclonus epilepsy were studied. According to their clinical status they were divided into three groups of severity. The ages and durations of the disease did not differ significantly between the groups. The groups showed significant differences in ability of daily living, amount of spontaneous myoclonus, IQ and psychomotor reaction time. In EEG the groups differed in respect to the dominant occipital rhythm and amount of myoclonic spikes but not in respect to universal paroxysms. Myoclonic spikes and paroxysms in EEG were only loosely related. The results yield a conclusion that the deterioration caused by the disease is individual and the progression may even cease. In this respect progressive myoclonus epilepsy differs clearly from many hereditary neurometabolic and storage diseases.     

Paroxysmal nocturnal activity in partial epilepsy in the adult

Thirty-four adults with partial epilepsy underwent polysomnographic sessions. Three sub-groups of patients were determined by timing their EEG paroxysmal activities (PA) according to the possible increase in PA related to their sleeping or awake state. Twenty-seven had an increase in PA when sleeping, 5 when awake and no significant difference was found in two other patients. Patients who suffered from nocturnal or partial elementary epileptic seizures were those who showed a PA increase when in a sleep state. These patients had a lower PA density during a waking state than the patients with a PA increase when awake. The more synchronized (stages 3 + 4) and desynchronized (waking) cortical states influence the PA densities in such a way that there is a significant difference between both sub-groups. The PA density modulation found with the slow-wave sleep stages adds to that induced by sleep and waking states.     

Regional relationships between focal hypofixation images in 123I-IMP single photon emission computed tomography and epileptic EEG foci in interictal periods in patients with partial epilepsy.

Single photon emission computed tomographic (SPECT) brain scans with N-isopropyl-(iodine-123)-p-iodoamphetamine were performed in interictal periods in 40 patients with partial epilepsies and normal X-ray CT findings, and the regional relationships between the SPECT abnormalities and interictal epileptic EEG foci were studied. Twenty-six patients (65%) had abnormal SPECT images consisting of one or more focal hypofixation images, i.e., zones of decreased regional cerebral blood flow, while the remaining 14 patients showed normal images. Nineteen (73%) of the 26 patients showed complete or partial regional agreement between the abnormal SPECT findings and the interictal epileptic EEG foci determined from EEGs recorded repeatedly during their clinical course, while the regional relationships with the EEG foci determined from the single EEG recorded just after the SPECT scans or a short interval after the scans showed a lower rate of agreement (13 of 21 patients, 61.9%). These results confirm the utility of SPECT scans in the regional diagnosis of epileptic foci.     

Predictive variables of interictal psychosis in epilepsy

OBJECTIVE: To evaluate which variables predict interictal psychosis in epilepsy. METHODS: The authors reviewed the biological backgrounds, clinical characteristics, and EEG findings in 246 patients with epilepsy and interictal psychosis and in 658 control patients with epilepsy and no psychotic history. With a logistic regression approach, the significance of each variable for the development of interictal psychosis was evaluated. RESULTS: There are significant differences in family history of psychosis, age at onset of epilepsy, type of epilepsy, lateralization of epileptiform discharges, and level of intelligence between patients with interictal psychosis and those without it. Subsequent logistic regression analysis with all variables demonstrated that family history of psychosis, age at onset of epilepsy, type of seizures, and level of intelligence significantly correlated with psychosis. CONCLUSIONS: A family history of psychosis, earlier age at onset of epilepsy, complex partial seizures or generalized tonic clonic seizures, and borderline intellectual functioning were the most important predictors for development of interictal psychosis.     

Dynamic susceptibility contrast (DSC) MRI and interictal epileptiform activity in cryptogenic partial epilepsy

PURPOSE: To study the possible correlation between interictal EEG patterns and neuroradiologic data obtained by dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) in patients with partial epilepsy. METHODS: Seventeen subjects with cryptogenic partial epilepsy underwent long-term video-EEG monitoring and DSC-MRI in the same session. Ten patients had temporal lobe epilepsy (TLE) and seven, epilepsy of extratemporal origin (ExTE). MRI data were compared with EEG findings, and the accuracy of DSC-MRI was analyzed considering spiking rate (number of interictal epileptiform abnormalities, IEA/min) and type of epilepsy. RESULTS: DSC-MRI showed a relevant asymmetry in the frontal, temporal, and occipital regions in eight (47%) of 17 patients, consisting of a relative regional cerebral blood volume (rCBV) increase in these areas. Because this region corresponded to the interictal EEG focus (IEF) or to the hemisphere involved in the genesis of epileptic discharges in most patients showing a higher spiking rate, patients were classified in two groups: patients with high spiking rate (HSR, n = 9) and with low spiking rate (LSR, n = 8); the cutoff corresponded to the median value of IEA/min. The rCBV increase corresponded to the IEF or to the hemisphere involved in the genesis of epileptic discharges in seven (77.7%) of nine HSR patients. No patients with LSR showed significant asymmetries in rCBV pattern. In five of six patients with TLE-HSR (83.3%), DSC-MRI showed a relative rCBV increase concordant with IEF or hemisphere involved in the genesis of epileptic discharges; in patients with ExTE-HSR, the concordance was 66%. CONCLUSIONS: DSC-MRI is a noninvasive procedure that may provide useful additional information to lateralize and/or localize the IEF when interictal epileptiform activity is sufficiently elevated.     

Intensive monitoring of interictal psychosis in epilepsy

Ten epileptic patients developed interictal psychosis while being treated in hospital for seizure control. They were subjected to intensive behavioral, video-electroencephalographic, and serum anticonvulsant monitoring for an average of 7.1 weeks in a specialized epilepsy unit. In 9 patients, the interictal psychosis was indistinguishable from acute schizophrenia. Only 5 of these patients had complex partial seizures; the other 4 showed evidence of generalized epilepsies. Thus a “unique” association between schizophreniform psychosis and complex partial seizures, noted by previous authors, could not be confirmed. Only 1 patient showed normalization of the electroencephalogram during psychosis and an inverse relationship between psychosis and seizure frequency. In most cases the emergence of psychosis could not be explained. Interictal psychosis in epilepsy appears to be a spectrum of disorders that may be multifactorially determined.     

部分性癫(癎)二例发作间期同步应用脑电图-功能磁共振成像定位致(癎)灶

目的 探讨部分性癫(癎)(癎)性放电相关血氧水平依赖(BOLD)信号的分布规律,为进一步研究该病的发病机制、脑功能变化奠定基础.方法 采用同步脑电图一功能磁共振成像(EEG-fMRI)技术,对2例部分性癫(癎)患者进行发作问期(癎)性放电相关BOLD变化的研究,探讨该病发作间期(癎)性放电相关BOLD信号与临床脑电图定位脑区的相互关系.结果 2例患者的临床脑电图定位脑区均出现了最大激活信号,其中1例在该区域有2处显著激活;在该区对侧相应脑区也有较弱的激活信号出现.结论 部分性癫(癎)(癎)性放电相关BOLD反应以(癎)性放电脑区为主,但其对侧同源脑区也有较弱的激活信号,fMRI激活信号与脑电活动之间有着很好的对应关系.