Patterns of cerebral glucose metabolism in patients with partial seizures

We analyzed local cerebral metabolic rates of glucose (LCMRglu) in 20 regions from 22 patients with complex partial seizures, who were taking neither phenytoin nor phenobarbital and who had normal CTs. Results were compared with data from 19 normal controls. Ten patients had left temporal, eight right temporal, and four bitemporal or generalized EEG discharges. There were no significant differences between patient and control values in any of 20 regions of interest. LCMRglu was depressed at the site of the epileptic focus: L/R ratio was 0.85 +/- 0.12 (p less than 0.003 compared with control), 0.92 +/- 0.08 (p less than 0.05), and 0.84 +/- 0.1 (p less than 0.001), respectively, in mesial, superior, and inferior temporal regions for patients with left temporal foci; 1.7 +/- 0.96 (p less than 0.04), 1.1 +/- 0.1 (NS), and 1.15 +/- 0.04 (p less than 0.001) for patients with right temporal foci. Patients with left temporal EEG foci had significantly lower values than patients with right temporal foci in left superior frontal and thalamic as well as left temporal regions, while patients with right-sided EEG foci had depressed LCMRglu (compared with patients with left temporal EEG foci) restricted to right mesial temporal lobe. The patients with left temporal foci tended to have longer seizure histories (22.7 +/- 5.4 versus 11 +/- 5.6 years; p less than 0.001). There was an inverse correlation between length of seizure history and mean LCMRglu (r = 0.38; 0.1 greater than p greater than 0.05). Our study suggests that LCMRglu is not depressed in regions beyond the epileptic focus when patients are not taking drugs known to decrease cerebral glucose metabolism.     

Complex partial seizures. Correlation of clinical and metabolic features

We compared metabolic patterns on 18F-2-deoxyglucose positron emission tomography (PET) with closed circuit television and simultaneous electroencephalographic ictal recordings of complex partial seizures in 48 patients. Closed circuit television and electroencephalographic data and PET scans were scored by "blinded" raters. Of the 48 patients, 26 had unilateral temporal; three, frontal; ten, ipsilateral frontotemporal; one, frontoparietal; and five, temporoparietal hypometabolism; and three had widespread hypometabolism affecting frontal, temporal, and parietal lobes. patients with frontal hypometabolism alone had shorter ictal and postictal durations, but involvement of multiple regions was associated with prolonged seizures. Auras were more likely to be present in patients with temporal hypometabolism alone, but an initial motionless stare did not distinguish this group. However, other metabolic patterns did not predict specific ictal clinical features. Vocalizations (formed or unformed) were not more closely associated with frontal involvement. When hypometabolism is multilobar, it may be difficult to use PET to distinguish between complex partial seizures of frontal and temporal origin.     

Cerebral activation during speech discrimination in temporal lobe epilepsy

Eight patients with uncontrolled complex partial seizures underwent positron emission tomography with 18-fluoro-2-deoxyglucose both at rest and during an auditory order discrimination task using speech syllables. Eight age-matched controls were scanned under identical conditions; an additional 18 normal subjects were scanned only at rest. No consistent task-related changes were seen in control subjects. For the 3 patients with left temporal epileptogenic foci, left inferior temporal lobe hypometabolism was more evident during the activated than during the resting scan. Activation procedures may augment the diagnostic yield of metabolic scanning in epilepsy.     

Hippocampal volume and glucose metabolism in temporal lobe epileptic foci

PURPOSE: Reports conflict on the relation of glucose metabolism to hippocampal volume in temporal lobe foci. Previous studies usually have used side-side ratios rather than regional metabolic rates. METHODS: We measured hippocampal volume and glucose metabolism in 37 patients with temporal epileptogenic zones identified by ictal video-EEG telemetry. Metabolic rates were normalized to global brain mean. RESULTS: Both 18-fluoro-2-deoxyglucose-PET and volumetric MRI lateralized the epileptic focus determined by ictal video-EEG. There were significant correlations between left-right metabolic asymmetry and hippocampal formation volume left-right ratios. Comparisons between normalized metabolism and hippocampal formation volume, ignoring the side of the epileptic focus, showed significant relations between left hippocampal volume and left inferior lateral temporal metabolism, right hippocampus and right inferior mesial temporal, and left hippocampus and left inferior mesial temporal metabolism. In contrast, when normalized metabolism was compared with hippocampal volume in the epileptic focus, no relation was found. CONCLUSIONS: Our study suggests that the relation between hippocampal volume and glucose metabolism breaks down in epileptic foci and that hypometabolism is not dependent on neuronal loss. It is consistent with data suggesting that hypometabolism is an independent predictor of surgical outcome.     

抑郁症首次发病患者静息态脑功能局部一致性的研究

目的 利用功能磁共振(fMRI)和局部一致性(regional homogeneity,ReHo)探讨抑郁症首次发病(以下简称首发)患者在静息态脑功能是否存在异常及异常部位.方法 对34例符合美国精神疾病诊断与统计手册第4版诊断标准的首发抑郁症患者(抑郁症组)和34名性别、年龄、文化程度匹配的健康志愿者(对照组)进行静息态fMRI扫描.结果 抑郁症组静息态脑血氧水平依赖信号的ReHo高于对照组的脑区有左侧额叶眶回、顶下小叶、颞上回,右侧额内侧回、顶下小叶、小脑后叶;低于对照组的脑区有左颞下回、右颞上同和胼胝体、双侧后扣带回(P＜0.005,K≥10).结论首发抑郁症患者在静息态存在多个腩区功能活动的异常,并可能和抑郁症的病理机制有关.     

Low incidence of abnormal (18)FDG-PET in children with new-onset partial epilepsy: a prospective study

OBJECTIVE: Patients with refractory partial epilepsy often exhibit regional hypometabolism. It is unknown whether the metabolic abnormalities are present at seizure onset or develop over time. METHODS: The authors studied 40 children within 1 year of their third unprovoked partial seizure with EEG, MRI, and [(18)F]-fluorodeoxyglucose ((18)FDG)-PET (mean age at seizure onset = 5.8 years, range 0.9 to 11.9 years; mean epilepsy duration = 1.1 years, range 0.3 to 2.3 years; mean number of seizures = 30, range 3 to 200). The authors excluded children with abnormal structural MRI, except four with mesial temporal sclerosis and two with subtle hippocampal dysgenesis. (18)FDG-PET was analyzed with a region of interest template. An absolute asymmetry index, [AI], greater than 0.15 was considered abnormal. RESULTS: Thirty-three children had a presumptive temporal lobe focus, five frontotemporal, and two frontal. Mean AI for all regions was not different from 10 normal young adults, even when children less likely to have a temporal focus were excluded. Eight of 40 children (20%) had focal hypometabolism, all restricted to the temporal lobe, especially inferior mesial and inferior lateral regions. Abnormalities were ipsilateral to the presumed temporal lobe ictal focus. CONCLUSIONS: Abnormalities of glucose utilization may be less common and profound in children with new-onset partial seizures than in adults with chronic partial epilepsy. Although these patients' prognosis is uncertain, resolution of epilepsy after three documented seizures is uncommon. If the subjects develop a higher incidence of hypometabolism in the future with planned follow-up studies, metabolic dysfunction may be related to persistent epilepsy rather than present at seizure onset.     

Temporo-spatial analyses define epileptogenic and functional zones in a case of Dyke–Davidoff–Masson syndrome

Dyke–Davidoff–Masson syndrome (DDMS) is a rare epilepsy syndrome that is characterized by cerebral hemiatrophy, homolateral skull hyperplasia, hyperpneumatization of the paranasal sinuses, seizures with or without mental retardation, and contralateral hemiparesis. We describe a case of DDMS in a 40-year-old female who had complex partial seizures with occasional secondary generalization since the age of 4 years. Her seizure frequency was 10–20 seizures/month even though she took four antiepileptic drugs. We applied magnetic resonance imaging (MRI), positron emission tomography (PET), functional MRI, and invasive electroencephalography (EEG) to define her epileptogenic and functional zones. Brain MRI showed prominent atrophy in the left frontal dorsal and lateral regions and mild atrophy of the left superior temporal gyrus and left parietal gyri. Interictal PET revealed decreased glucose metabolism in the atrophic regions. Functional MRI demonstrated that the inferior frontal and inferior parieto-occipital regions of the right hemisphere were activated by language testing. Invasive EEG revealed that the left lateral temporal lobe was the sole source of her seizures. Our results imply that the “metabolic border zone” rather than the atrophic region plays an important role in seizure activity, and that reorganization of functional zones occur after cerebral damage early in life.     

Localization of extratemporal epileptic foci during ictal single photon emission computed tomography.

We obtained single photon emission computed tomography (SPECT) scans with technetium-99M-hexamethyl-propylene-amine-oxime in 11 patients during 12 extratemporal partial seizures (9 simple partial, 3 complex partial). Ten ictal SPECT studies in 9 patients showed a focal region of hyperperfusion, which agreed with electrical seizure onset in 5 and with clinical seizure localization in 4 in whom ictal electroencephalography was not localized. Contralateral cerebellar and ipsilateral basal ganglia hyperperfusion was seen in 3 patients with a frontal lobe seizure focus. Ictal hyperperfusion was well circumscribed, unlike the diffuse hyperperfusion changes reported during temporal lobe seizures. This observation may indicate a different degree of seizure spread in temporal as opposed to extratemporal epilepsy. Because electroencephalographic localization is often elusive in extratemporal seizures, ictal SPECT may be very helpful for the localization of extratemporal foci.     

Calcification of the pineal gland: relationship to laterality of the epileptic foci in patients with complex partial seizures.

The right and left temporal lobes differ from each other with respect to the rate of intrauterine growth, the timing of maturation, rate of aging, anatomical organization, neurochemistry, metabolic rate, electroencephalographic measures, and function. These functional differences between the temporal lobes underlies the different patterns of psychopathology and endocrine reproductive disturbances noted in patients with temporolimbic epilepsy. The right hemisphere has greater limbic and reticular connections than the left. Since the pineal gland receives direct innervation from the limbic system and the secretion of melatonin is influenced by an input from the reticular system, I propose that lesions in the right temporal lobe have a greater impact on pineal melatonin functions as opposed to those in the left dominant temporal lobe. Consequently, since calcification of the pineal gland is thought to reflect past secretory activity of the gland, I predicted a higher prevalence of pineal calcification (PC) in epileptic patients with right temporal lobe as opposed to those with left temporal lobe foci. To investigate this hypothesis, the prevalence of PC on CT scan was studied in a sample of 70 patients (43 men, 27 women, mean age: 29.2 years, range 9-58; SD = 10.1) with complex partial seizures, of whom 49 (70.0%) had a right temporal lobe focus. PC was present in 51 patients (72.8%) and was unrelated to any of the historical and demographic data surveyed. In the patients with a focus in the right temporal lobe, PC was present in 46 cases (93.8%) as compared to 5 of 21 patients (23.8%) with left temporal lobe foci.(ABSTRACT TRUNCATED AT 250 WORDS)     

Selective hypometabolism in the inferior frontal lobe in depressed patients with Parkinson's disease

Depression is a frequent finding in patients with Parkinson's disease (PD). Regional cerebral glucose metabolism was measured in depressed and nondepressed patients with PD and in age-comparable normal control subjects using 2-[18F]-fluoro-2-deoxy-D-glucose and positron emission tomography (PET). Relative metabolic activity in the caudate and orbital-inferior region of the frontal lobe was significantly lower in the depressed patients with PD as compared to both nondepressed patients and control subjects. There was a significant inverse correlation between relative glucose metabolism in the orbital-inferior area of the frontal lobe and depression scores. This study suggests that depression in PD is associated with dysfunction in the caudate and orbital-inferior area of the frontal lobe. This metabolic pattern is unlike that seen in patients with PD who have other behavioral deficits such as dementia, and suggests that disruption of basal ganglia circuits involving the inferior region of the frontal lobe may affect the regulation of mood.     

Different localizations underlying cortical gelastic epilepsy: Case series and review of literature

BackgroundGelastic seizures (GS) are classically observed with hypothalamic hamartomas but they can also be associated with cortical epileptogenic foci.ObjectiveTo study the different cortical localizations associated with GS.MethodsWe reviewed the data from all patients with cortical GS investigated in our epilepsy unit from 1974 to 2012 and in the literature from 1956 to 2013.ResultsSixteen cases were identified in our database and 77 in the literature. Investigations provided confident focus localization in 9 and 18, respectively. In our series, the identified foci were located in the mesial temporal structures (2 left, 1 right), lateral temporal cortex (1 right), superior frontal gyrus (1 left), and operculoinsular region [3 right (orbitofrontal or frontal operculum extending into the anterior insula) and 1 left (frontal operculum extending into the anterior insula)]. In the literature, the identified foci (13 right/5 left) were located in the temporal lobe of 4 (1 right inferior, 1 right medial and inferior, 1 right posterior middle, inferior extending posteriorly to the lingual gyrus, and 1 left middle, inferior, and medial), in the frontal lobe of 12 [10 (6 right/4 left) medial (i.e., superior, medial frontal, and/or anterior cingulate gyri), 1 lateral (right anterior inferior frontal gyrus), and 1 right medioposterior orbitofrontal cortex] and in the parietal lobe of 2 (1 left superior parietal lobule and 1 right parietal operculum) patients.ConclusionIctal laughter is a poorly lateralizing and localizing feature as it may be encountered in patients with a focus in the left or right frontal, temporal, parietal, or insular lobe.     

老年抑郁症患者的脑正电子发射体层摄影术显像分析

目的 探讨老年抑郁症患者脑^18氟-脱氧葡萄糖（18^F-FDG）正电子发射体层摄影术（PET）显像的特点。方法 分别对6例老年抑郁症患者（GD组）及10名健康体检者（对照组）进行脑^18 F-FDGPET显像，按年龄、简易智力状态检查量表总分和性别构成配对，用统计参数图第2版软件比较两组间脑局部葡萄糖代谢的差别。结果 GD组较对照组在双侧尾状核、额下回、颞上回、额中回，右侧核外、额上回、舌回和左侧扣带回、中央前回等脑区局部葡萄糖代谢减低（均P〈0．005）。GD组无局部脑葡萄糖代谢增加的脑区。结论 老年抑郁症患者存在基底节区、前额叶、颞叶和边缘系统的局部葡萄糖代谢下降。     

Alzheimer's disease: focal cortical changes shown by positron emission tomography

Local rates of cortical glucose metabolism were estimated by positron emission tomography in 13 right-handed patients with Alzheimer's disease. Individuals with disproportionate failure of language function had markedly diminished metabolism in the left frontal, temporal, and parietal regions. Patients with predominant visuo-constructive dysfunction evidenced a hypometabolic focus in the right parietal cortex. Patients with memory failure as the most apparent feature had no significant metabolic asymmetry in cortical regions. In all subjects, verbal competency generally correlated with metabolic activity in the left frontal and temporal areas, while visuo-constructive test performance was linked to glucose utilization in the right parietal lobe.     

Diurnal variation in regional brain glucose metabolism in depression.

BACKGROUND: This study compared diurnal variation in mood and regional cerebral metabolic rate of glucose (rCMRglc) in depressed and healthy subjects. METHODS: Depressed and healthy subjects were investigated using [18F]-fluoro-deoxyglucose positron emission tomography scans during morning and evening wakefulness. All subjects completed subjective mood ratings at both times of day. Statistical parametric mapping was used to compare rCMRglc between the two groups across time of day. RESULTS: Depressed patients showed evening mood improvements compared with healthy subjects. Compared with healthy subjects, depressed patients showed smaller increases in rCMRglc during evening relative to morning wakefulness in lingual and fusiform cortices, midbrain reticular formation, and locus coeruleus and greater increases in rCMRglc in parietal and temporal cortices. Depressed patients had hypermetabolism in limbic-paralimbic regions and hypometabolism in frontal and parietal cortex at both times of day compared with healthy subjects. CONCLUSIONS: Variation in rCMRglc differs across times of day in depressed and healthy subjects. In depressed patients, evening mood improvements were associated with increased metabolic activity in ventral limbic-paralimbic, parietal, temporal, and frontal regions and in the cerebellum. This increased metabolic pattern during evening wakefulness may reflect partial normalization of primary and compensatory neural systems involved in affect production and regulation.     

Comparison of the effects of frontal and temporal lobe partial seizures on prolactin levels.

The acute effects of partial (focal) epileptic seizures on serum prolactin levels were studied in two groups of patients: (1) 10 with temporal lobe seizures and (2) 11 with seizures that arose from the frontal lobes, recorded on cable video-electroencephalographic telemetry. Six of the eight complex partial seizures of temporal lobe origin were associated with a marked rise in prolactin levels at 10 minutes after onset (rise in levels, from a mean of 279 to 534 mU/L), compared with a rise in only one of the eight frontal lobe complex partial seizures. None of the five simple partial seizures (two of temporal and three of frontal lobe origin) was associated with a marked rise in prolactin levels. This difference in prolactin response following complex partial seizures of frontal and temporal lobe origin may help in the clinical differentiation of these seizures. A failure of prolactin levels to rise does not, however, exclude a diagnosis of complex partial seizures; thus, this measurement will not help in the clinical differentiation of frontal lobe complex partial seizures from psychogenic attacks.     

Role of the frontal lobes in the propagation of mesial temporal lobe seizures.

The depth ictal electroencephalographic (EEG) propagation sequence accompanying 78 complex partial seizures of mesial temporal origin was reviewed in 24 patients (15 from the University of Pittsburgh Epilepsy Center and 9 from UCLA). All patients were monitored with bilateral mesial frontal and mesial temporal depth electrodes and later received anterior temporal lobectomy. Ictal EEG records were categorized according to sequence of spread from the temporal focus to the other regions. Although propagation patterns varied both within and between patients, certain features were notable: (a) It was very common for seizure activity to spread initially to the ipsilateral frontal lobe (observed in 22 of 24 patients). (b) The most common mode of spread (15 of 24 patients) was initiating temporal lobe----ipsilateral frontal lobe----contralateral frontal lobe----contralateral temporal lobe. (c) Occasionally, seizure discharges invaded the frontal lobes but failed to invade the contralateral temporal lobe (2 of 24 patients). (d) Seizure activity occasionally invaded the contralateral temporal lobe prior to invading the frontal lobes (2 of 24 patients). Other notable features included (i) a clear tendency for mesial temporal seizure discharges initially to invade orbitofrontal (as opposed to anterior cingulate) cortex and (ii) the emergence of a period of clear asymmetry in the frontal lobes during which high-amplitude, rapid discharges were present on the side ipsilateral to the initiating temporal lobe. These results suggest that the prefrontal region, especially the orbitofrontal cortex, is strongly influenced by mesial temporal ictal activity. This region appears to be frequently involved in the propagation of seizures initiated in the mesial temporal lobe and may play a role in the interhemispheric propagation of mesial temporal seizures.     

Ictal nausea with vomiting as the major symptom of simple partial seizures: electroencephalographic and magnetoencephalographic analysis

Autonomic symptoms and signs rarely occur as isolated phenomena without impaired consciousness. Ictal nausea with vomiting is a rare clinical manifestation of seizures. Ictal vomiting is considered a localizing sign in patients with partial seizures of temporal origin. We encountered two patients with simple partial seizures that produced nausea with vomiting as the sole symptom, and we describe the interictal electroencephalographic and magnetoencephalographic findings. The episodes were paroxysmal and stereotypical in nature, and patients showed symptomatic response to a trial of antiepilepsy medication. In both patients, the diagnosis was simple partial seizures with autonomic symptomatology. Although interictal electroencephalography did not reveal focal spikes and focal slowing, estimated magnetoencephalographic dipoles were clustered in the parietal lobe. Interictal magnetoencephalographic foci may serve only as subsidiary evidence for the parietal origin of the episodes. However, our findings provide evidence of additional involvement of the parietal lobe in ictal vomiting.     

Impaired fear processing in right mesial temporal sclerosis: a fMRI study

Lesion and neuroimaging studies have demonstrated that the mesial temporal lobe is crucial for recognizing emotions from facial expressions. In humans, bilateral amygdala damage is followed by impaired recognition of facial expressions of fear. To evaluate the influence of unilateral mesial temporal lobe damage we examined recognition of facial expressions and functional magnetic resonance (fMRI) brain activation associated with incidental processing of fearful faces in thirteen mesial temporal lobe epilepsy (MTLE) patients (eight with right MTLE, five with left MTLE). We also examined the effect of early versus later damage, comparing subjects with hippocampal-amygdalar sclerosis (MTS) and seizures occurring before five years of age to epilepsy patients with late onset seizures. Fourteen healthy volunteers participated as controls. Neuropsychological testing demonstrated that the ability of right MTLE patients to recognize fearful facial expressions is impaired. Patients with early onset of seizures were the most severely impaired. This deficit was associated with defective activation of a neural network involved in the processing of fearful expressions, which in controls and left MTLE included the left inferior frontal cortex and several occipito-temporal structures of both hemispheres.     

Executive functioning and depressed mood before and after unilateral frontal lobe resection for intractable epilepsy

Executive dysfunction occurs in a variety of patients who have sustained damage to the frontal lobes. In individuals with frontal lobe epilepsy (FLE) or after unilateral frontal lobe resection (FLR), a unique neuropsychological profile linking executive functions (EF) with the frontal lobe has been elusive, with conflicting findings in the literature. Some studies show greater risk of executive impairment with left-sided FLE or FLR, while others report greater risk for right-sided patients. Some studies report no relationship between FLE and EF impairment, while others show EF impairment regardless of side of seizure foci or surgery. In patients with temporal lobe epilepsy, executive dysfunction is associated with depressed mood possibly reflecting disruption of cortical-limbic pathways and/or frontal–striatal circuitry. Although not previously examined, depression level may affect executive functioning in those with FLE or FLR. We hypothesized that FLE patients with poor mood state would show greater executive dysfunction than FLE patients without poor mood state. The relationship among EF, side of surgery and depressed mood before and 8 months after unilateral FLR was evaluated in 64 patients using validated measures of EF and mood state (Beck Depression Inventory-II). Results indicated that individuals with depressed mood before surgery had greater difficulty on a task of mental flexibility compared to patients without preoperative depressed mood. Further, individuals with depressed mood before surgery had significant increases in perseverative responding and completed fewer categories on a card-sorting task after surgery compared to patients without preoperative depressed mood. Regression analyses showed that among side of surgery, seizure freedom status after surgery and depression status, only pre-surgical depression status explained a significant amount of variance in executive functioning performance after surgery. Results suggest that clinically elevated depressive symptoms before surgery are a risk factor for moderate declines in EF after surgery. Results may be attributable to reduced cognitive reserve in patients with depressive symptoms, or may reflect a common cause attributable to damage to unilateral dorsal and ventral lateral frontal lobe.     

局灶性难治性颞叶癫痫全脑葡萄糖代谢特点

目的 探讨局灶性难治性颞叶癫痫全脑葡萄糖代谢特点。方法 回顾性分析2017年1~12月行发作间期18FDG-PET/CT检查的23例局灶性难治性颞叶癫痫的影像学资料。将PET图像导入MIM neuro软件,软件自动分析癫痫病人葡萄糖代谢水平与正常人群葡萄糖代谢的差异,各脑区差异结果以Z-Score值显示,分析颞叶癫痫病人全脑葡萄糖代谢特点。结果 术后病理为脑皮质发育不良22例,节细胞胶质瘤1例;病灶位于左侧颞叶16例,右侧颞叶7例。除颞叶呈葡萄糖低代谢改变外,还存在同侧海马、海马旁回、岛叶、杏仁核、颞叶岛盖以及双侧小脑半球葡萄糖代谢不同程度减低;对侧颞叶、额叶、顶叶、顶上小叶以及角回葡萄糖代谢不同程度增高。结论 颞叶癫痫具有一定葡萄糖代谢特点,其特定的葡萄糖代谢特点有助于更加精准的癫痫术前定位及其病理特征的分析。