Correlative study of the cognitive impairment, regional cerebral blood flow, and electroencephalogram abnormalities in children with Down's syndrome

The aim of this study was to investigate possible correlations of the cognitive impairment with abnormalities of regional cerebral blood flow and electroencephalogram in children with (Down's Syndrome) DS. Nine patients with DS were evaluated by single photon emission computed tomography (SPECT) in combination with clinical findings, electroencephalography (EEG), and magnetic resonance imaging (MRI). In cases with IQs below 40, there were one or more findings of abnormal EEG/MRI and brain perfusion SPECT. In 6 cases (66.7%) EEG findings were normal, but 3 (33.3%) had abnormal EEG findings. Perfusion abnormalities were most pronounced in the fronto-parieto-temporal region in the form of hypoperfusion (n = 5) and in the right hemisphere (n = 5) than the left hemisphere (n = 1). These findings suggest that the children with DS had varying levels of structural, perfusion, and electrophysiological abnormalities in the brain and these abnormalities were reflected by measurable alterations of the cognitive functions.     

Comparison of SPECT, EEG, CT, MRI, and pathology in partial epilepsy.

Twenty children with partial epilepsy who had surgery between the ages of 4 1/2 months and 18 years were studied preoperatively with electroencephalography (EEG), computed tomography (CT), and technetium-99m hexamethylpropyleneamineoxime 99mTc-HmPAO single photon emission computed tomography (SPECT; 20 interictal, 4 postictal). Fourteen had magnetic resonance imaging (MRI). All had an epileptiform focus (12 unilateral, 8 predominantly unilateral) on EEG. The combination of interictal and postictal regional cerebral blood flow (rCBF) abnormalities alone correlated with EEG foci in 16 of 20 patients. Interictal rCBF abnormalities correlated with EEG foci in 14 of 20. CT findings correlated with EEG foci in 14 of 20. MRI findings correlated with EEG foci in 13 of 14. Pathology demonstrated tumor in 6, cortical dysplasia in 4, mesial temporal sclerosis in 3, Sturge-Weber in 2, cavernous hemangioma in 1, Rasmussen encephalitis in 1, porencephalic cyst and gliosis in 1, and cysts found at surgery (but normal histology) in 2. Interictal and postictal SPECT, EEG foci, and CT findings each correlated with the pathology site in 17, 19, and 15 patients, respectively. MRI correlated with pathology site in 13 of 14 patients. Postictal and interictal abnormalities of rCBF correlated with EEG and pathology as frequently as CT. In 5 patients with normal CT scans and in 1 with a normal MRI, postictal and interictal rCBF correlated with EEG and pathology results; however, these 6 patients all had abnormalities on CT or MRI. SPECT, therefore, may be considered a valuable additional diagnostic procedure in the evaluation of epilepsy surgery candidates in that it adds to the evidence of abnormality at the involved site.(ABSTRACT TRUNCATED AT 250 WORDS)     

Partial seizures manifesting as apnea only in an adult

PURPOSE: Although several cases of apneic seizures have been reported in neonates, epileptic seizures presenting as apnea only in adults are very rare. We present a case report of a 19-year-old man with viral encephalitis and frequent episodes of apneic seizures. METHODS: Prolonged electroencephalograms (EEGs), respiratory monitorings, and imaging including ictal-interictal subtraction single photon emission computed tomography (SPECT) coregistered with magnetic resonance imaging (MRI) were performed. RESULTS: Ictal EEGs recorded during apneic episodes showed repetitive sharp waves or rhythmic theta activity arising from the left or right independent bitemporal region. Ictal SPECT was performed during one episode of apnea that showed ictal EEG discharges arising from the left posterior temporal area. Ictal-interictal subtraction SPECT coregistered with MRI revealed that the seizures originated from the left, posterior, midlateral temporal cortex. CONCLUSIONS: Previous studies with ictal EEG or brain stimulation suggest that apneic seizures might be mediated through the limbic and associated cortical systems. Our study reports on a very rare case of partial seizures with apnea only in an adult patient and is supported by ictal EEG and ictal-interictal subtraction SPECT coregistered with MRI.     

CORRELATIVE STUDY OF THE COGNITIVE IMPAIRMENT,REGIONAL CEREBRAL BLOOD FLOW,AND ELECTROENCEPHALOGRAM ABNORMALITIES IN CHILDREN WITH DOWN’S SYNDROME

The aim of this study was to investigate possible correlations of the cognitive impairment with abnormalities of regional cerebral blood flow and electroencephalogram in children with (Down's Syndrome) DS. Nine patients with DS were evaluated by single photon emission computed tomography (SPECT) in combination with clinical findings, electroencephalography (EEG), and magnetic resonance imaging (MRI). In cases with IQs below 40, there were one or more findings of abnormal EEG/MRI and brain perfusion SPECT. In 6 cases (66.7%) EEG findings were normal, but 3 (33.3%) had abnormal EEG findings. Perfusion abnormalities were most pronounced in the fronto-parieto-temporal region in the form of hypoperfusion (n = 5) and in the right hemisphere (n = 5) than the left hemisphere (n = 1). These findings suggest that the children with DS had varying levels of structural, perfusion, and electrophysiological abnormalities in the brain and these abnormalities were reflected by measurable alterations of the cognitive functions.     

SPECT, CT, and MRI in head injury: acute abnormalities followed up at six months.

Neuroimaging with single photon emission computed tomography (SPECT) using the cerebral blood flow tracer 99Tc(m)-HMPAO has been used to study acute functional alterations after head injury and residual abnormalities at six month follow up in 32 patients. Comparison has been made with anatomical abnormalities defined acutely with CT and on follow up with MRI. SPECT showed slightly more abnormalities than CT in the acute phase (49 regions of abnormally low tracer uptake on SPECT and 45 lesions on CT). Twenty two of the acute SPECT abnormalities were in normal regions on CT. At follow up MRI showed more abnormalities than SPECT (30 on SPECT and 48 on MRI). Ten of the SPECT deficits were in regions with normal MRI. Comparison of the intensity of late and early SPECT deficits showed that only four early deficits deteriorated whereas 28 improved. Only five of 27 lesions seen on both acute SPECT and CT resolved compared with 16 of 22 lesions seen on SPECT but not on CT. Regions of abnormally high tracer uptake were detected in the acute stage in five of the patients. No high focal uptake was evident on follow up. Ten patients with a residual SPECT abnormality and eight with residual MRI lesions were graded clinically in the upper band of good recovery.     

A case of transient global amnesia (TGA) showing bilateral hippocampal hypoperfusion by a new SPECT analyzing system, eZIS]

We here reported a case of typical transient global amnesia (TGA). A 64-year-old right-handed man was suddenly unable to keep his recent memory without any event. There were no neurological deficits except for recent memory disturbances. He showed no causative findings of the attack on examinations of laboratory data, EEG and MRI. Examination of single photon emission CT (SPECT), using 99mTc-ECD, was performed in acute and chronic stages. We were able to detect bilateral hippocampal hypoperfusion in the acute stage using a new analyzing system, easy Z-score Imaging System (eZIS). It showed extensive hypoperfusion also in the vertebrobasilar artery territory. Twenty-seven days later, these findings disappeared. Using this system, we are able to evaluate cerebral blood flow objective with anatomical information by SPECT. Therefore, we concluded that this analyzing system would be helpful to reveal the pathophysiological mechanism of TGA.     

Periodic lateralized epileptiform discharges in multiple sclerosis: a case report.

The occurrence of epileptiform abnormalities on the EEG in patients with multiple sclerosis (MS) is rare. The following case correlates the clinical, EEG, MRI, and single photon emission computed tomographic (SPECT) findings in a patient with a long history of MS and acute onset of focal motor seizures and confusion. Two routine EEGs, brain MRI, and brain SPECT were performed. The patient was a 44-year-old woman with a long history of clinically definite MS of the relapsing-remitting and secondary progressive form with three events of focal motor seizures followed by generalized tonic-clonic seizures and postictal confusion. The first EEG done during admission showed periodic lateralized epileptiform discharges in the right temporal region. Brain MRI done several weeks later showed scattered T2 hyperintensities in several locations, including the periventricular and subcortical white matter bilaterally. Brain SPECT using Tc99-Neurolite demonstrated decreased perfusion on the right parietal and temporal lobes. This case suggests that focal motor seizures and a transient state of altered consciousness can be the result of an exacerbation of MS. The neurophysiologic expression of these clinical manifestations may present as periodic lateralized epileptiform discharges on the EEG and decreased regional perfusion on brain SPECT.     

Value of HM-PAO SPECT in selective temporal lobe surgery for epilepsy

The purpose of this study was to assess the value of interictal ^99mTc-hexamethyl-propylenamine oxime (HM-PAO) single-photon emission computed tomography (SPECT) in the preoperative evaluation of epileptic patients with medically refractory seizures of temporal lobe (TL) origin. For this study, we selected 31 patients, who were preoperatively evaluated according to the Zürich presurgical protocol. All patients underwent selective amygdalohippocampectomy. Their surgery was based on ictal and interictal EEG recordings, using scalp and foramen ovale electrodes simultaneously. Postoperatively, 27 patients (87%) were seizure-free or had more than a 90% seizure reduction. All patients had preoperative interictal SPECT and magnetic resonance imaging (MRI) performed. Postoperative SPECT was performed in 18 patients. Preoperative MRI showed structural lesions in 20 cases, and 23 patients had abnormal histopathological findings. Preoperative SPECT determined correctly the primary epileptogenic area in 15 cases (48%), showing a zone of hypoperfusion restricted either to the TL (n = 9; 29%) or exceeding the TL structures (n = 6; 19%). In two patients (6%), the SPECT findings were located contralateral to the affected TL, and in one (3%) there was reduced regional cerebral blood flow in the ipsilateral basal ganglia. Thirteen patients (42%) had normal SPECT. No significant correlations were found among preoperative SPECT findings, MRI and histopathological results, and the postoperative clinical outcome. Based on the results of this study, we regard HM-PAO SPECT to be a useful confirmatory diagnostic tool in presurgical evaluation of epileptic patients. Given the present technological level, it cannot, however, replace the semi-invasive EEG methods.     

MRI-SPECT and PET-EEG findings on brain dysfunction in schizophrenia.

1. In this article the author reviews a series of investigations on brain dysfunction in untreated schizophrenics using manumotor and music listening tasks as activation paradigms. Methods involved were EEG mapping, Single Photon Emission Computerized Tomography (SPECT; Xenon-133 inhalation method), Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET; 11-2-Deoxyglucose as tracer). 2. Major signs of brain dysfunction yielded a "nonreactivity" on both motor and music stimulation in patients displaying marked negative symptomatology, as shown consistently by EEG Mapping, SPECT and PET. In contrast, first-break patients with predominant "positive" and without underlying negative symptoms showed signs of "normal" to "diffuse hyperactivation" on such stimulations, as demonstrated by EEG and SPECT imaging methods. 3. Interestingly, MRI planimetry of the size of the corpus callosum (CC) corroborated the above findings, showing a significantly larger CC in "positive" than "negative" patients. 4. Together with functional imaging findings of other working groups and recent neuropathological theories we finally raise some speculative neurophysiological hypotheses on brain dysfunction in subgroups of schizophrenics, which might have direct implications for treatment and follow-up of these patients.     

Neuronal hyperexcitability in stroke-like episodes of MELAS syndrome

BACKGROUND: The pathogenesis of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) remains unknown. METHODS: Fourteen stroke-like episodes in six patients with MELAS were studied using clinical, neuroradiologic, and electrophysiologic approaches. In two patients postmortem examination was done. RESULTS: Headache and epileptic seizure were the most common presenting symptoms. In 13 of 14 episodes the cerebral cortex was primarily involved with variable subcortical edema particularly in the temporal, occipital, and parietal cortex. Repeated MRI performed in two episodes revealed progressive spread of the cortical lesion to the surrounding cortex for a few weeks after the onset of symptoms. In 6 of 11 episodes T1-weighted hyperintense cortical signal compatible with cortical laminar necrosis was seen during subacute stage of the episode. Fat-suppression MRI confirmed intracortical gyral hemorrhage in one episode. Petechial gyral microhemorrhages were also pathologically confirmed in the autopsy of another patient. In 9 of 11 episodes focal epileptiform discharges on EEG were noted in the acute brain lesion. In seven of nine episodes focal cortical hyperperfusion was seen in SPECT studies. CONCLUSION: The stroke-like episodes in MELAS may reflect neuronal hyperexcitability, which increases energy demand and creates energy imbalance between energy requirement and adequate availability of adenosine triphosphate due to oxidative phosphorylation defect particularly in the susceptible neuronal population, causing cortical necrosis. The episodic nature of stroke-like episodes is unexplained.     

Comparative utility of technetium-99m hexamethylpropylenamine oxime single photon emission computed tomography (SPECT) with anatomic neuroimaging and electroencephalography (EEG) in childhood intractable epilepsy

Intractable epilepsies pose a therapeutic challenge. Precise localization of the epileptic focus is imperative before planning surgical intervention. Functional imaging is an important component of presurgical work-up. Positron emission tomography is unavailable in developing countries; hence, the need to evaluate the available imaging modality, single photon emission computed tomography (SPECT), was felt. We investigated 61 children with intractable epilepsy, identified by predefined criteria, by performing electroencephalography (EEG), magnetic resonance imaging (MRI), computed tomography (CT), and ictal and interictal SPECT. The localizing value of ictal and interictal SPECT imaging for epileptic foci was correlated with clinical, electrophysiologic, and anatomic neuroimaging data. An ictal SPECT was obtained in 9, and interictal SPECT was performed in all (61). Ictal SPECT was localizing in 8 of 9 (88.8%). Interictal SPECT was localizing in a significantly higher proportion of patients (47.54%) than either the scalp EEG (16.39%) (P = .0003) or CT scan (21.56%) (P = .0046). Our data demonstrated that interictal and ictal SPECT identified more focal changes in children with intractable epilepsy than interictal EEG, CT, and probably MRI. The definitive proof of the SPECT-based findings being epileptogenic foci awaits correlation with intraoperative monitoring and postoperative follow-up.     

Rhythmic fast activity on EEG in a patient with Mollaret's meningitis

Mollaret's meningitis is a rare disease of unknown etiology, characterized by repeated aseptic meningitis with transient neurological symptoms and quick recovery. The patient, a 16-year-old boy, had episodes of acute encephalitis followed by complete recovery every year from the age of 13 to 16 years. The symptoms at onset were loss of consciousness, a generalized tonic clonic seizure and pyramidal signs. He was first admitted to our hospital at the age of 15 years. EEG in the early stage showed diffuse low-voltage rhythmic fast actvity. He recovered consciousness after a week. At the age of 16 years, he was admitted again because of high fever (39 degrees C). Soon after admission, he had generalized tonic-clonic seizure and was accompanied by alternating deep coma and delirium. Cerebrospinal fluid examination during early stage revealed mild leukocytic pleocytosis, elevation of protein and a high level of IL-6. although brain CT and MRI showed no abnormal findings. EEG showed intermittent, diffuse, middle-voltage, rhythmic fast activity. After 5 days, the neurological symptoms completely disappeared with EEG normalization. To our knowledge, this is the first report of rhythmic fast activity on EEG in Mollaret's meningitis. The clinical pictures of this case suggest a transient functional disorder of brainstem or cerebrum may occur in this condition.     

Interictal brain SPECT in patients with medically refractory temporal lobe epilepsy

The objective of this study was to evaluate the utility of interictal brain SPECT in localizing the epileptogenic focus in a population of patients of Epilepsy Clinic of Hospital Universitário Clementino Fraga Filho (HUCFF/UFRJ), with medically refractory temporal lobe epilepsy (TLE) and normal computed tomography (CT) scans, studying the correlation between SPECT, electroencephalogram (EEG) and, in 11 cases, brain magnetic resonance imaging (MRI), and to compare the results to the other six literature series. Twelve (52.2%) patients presented abnormal SPECT. Among these, five (41.6% of abnormal SPECTs) presented unilateral SPECT changes at the same side of EEG (hypoperfusion in four and hyperperfusion in one), three (25% of abnormal SPECTs) presented bilateral hypoperfusion and bilateral EEG changes too, and four (33.3%) presented unilateral hypoperfusion and bilateral EEG changes. The statistical analysis was based on fuzzy logic. The correlation index among SPECT X EEG, SPECT X MRI and SPECT X EEG X MRI were highly significant, with significance levels at 0.01, p < 0.0005 and trust interval at 99% in all correlations. The correlation studies between the series presented similar results.     

Is streamlined evaluation of children for epilepsy surgery possible?

Background: The presurgical evaluation of children with intractable epilepsy includes evaluation by an experienced clinician, MRI, video EEG, and functional imaging techniques to localize seizure onset. However, the contributions of each investigation to surgical decision making has not been systematically assessed.
Method: Data used for decision on eligibility for surgery on 353 children was discussed at a presurgical multidisciplinary meeting and systematically recorded. The relationships between MRI, EEG, SPECT findings, and the probability of being offered epilepsy surgery were investigated retrospectively using a quick unbiased statistical tree (QUEST).
Results: Sixteen children were offered nonresective surgery. Of the remaining, 236 (70%) were offered resective surgery. The proportion of children with a localized lesion on MRI offered resective surgery was 92%[95% CI: 88 to 95%], and EEG telemetry did not modify decision making in this group (p < 0.001). In children with bilateral MRI changes or normal scan the probability of being offered resective surgery was 78% in those with localized ictal onset on EEG compared to 9% with nonlocalized EEG (p < 0.001). SPECT did not appear to systematically influence decision making in any group.
Conclusion: Children with medically intractable epilepsy and localized lesions on MRI may not necessarily need ictal EEG recordings or SPECT prior to offering resective surgery. More targeted use of EEG telemetry could allow more children with less obvious surgical targets to be investigated without increasing resources.     

A case of subacute sclerosing panencephalitis showing various cerebral perfusion on 99mTc-ECD SPECT

We reported serial neuroradiological findings of a 20-year-old male with subacute sclerosing panencephalitis, who deteriorated from Jabbour stage 2 to stage 4 rapidly in spite of oral administration of inosine pranobex. At the stage 2, brain magnetic resonance imaging (MRI), computed tomography (CT) and [99mTc]-L, L-ethyl cysteinate dimer (99mTc-ECD) single photon emission computed tomography(SPECT) findings were normal. As the disease progressed, brain MRI and CT revealed diffuse cerebral white matter lesions as well as cerebral atrophy. 99mTc-ECD SPECT showed serially various perfusion of cerebrum. These findings in 99mTc-ECD SPECT may reflect the acute inflammatory process and consequent destruction of brain tissue.     

Functional and morphological abnormalities in temporal lobe epilepsy: a comparison of interictal and ictal EEG,CT, MRI,SPECT and PET

Summary Ten patients suffering from drug-resistant complex partial seizures, with EEG abnormalities in the temporal region, were studied by means of non-invasive electrophysiological techniques (video-monitored, 16-channel, prolonged surface and sphenoidal EEG) as well as by imaging techniques (CT, MRI, SPECT and PET). Analysis of interictal and ictal EEG indicated the localization of epileptic activity in one side in eight cases. CT demonstrated focal abnormalities in three, SPECT in five unequivocally (in another four questionably, with the same lateralization as indicated by PET), MRI in eight, and PET in all cases. While only EEG provided specific diagnostic information, the focus definition was consistently good on PET images, poor on CT scans, and generally good but less consistent on MRI.     

Reversible focal MRI abnormalities due to status epilepticus. An EEG,single photon emission computed tomography,transcranial Doppler follow-up study

We demonstrate clinical data and findings of MRI, transcranial Doppler (TCD), single photon emission computed tomography (SPECT) and electroencephalography (EEG) in an 8 month follow-up study of a 15 year old girl who developed focal status epilepticus with sensory and visual illusions. EEG showed right temporal and occipital seizure activity and attenuation of the alpha activity with right predominance. MRI showed a right temporo-parietal hyper signal on the T2 weighted images involving the cortex with sulcal effacement. MRI-angiography suggested insufficient flow in the right transverse sinus. TCD detected an elevated flow velocity in the ipsilateral middle cerebral artery during status epilepticus, corresponding to an increased perfusion of the epileptic area revealed by SPECT. After normalization of the TCD finding, the MRI detected persistent cortical abnormality beyond the 70th day after admission. MRI normalized on the 103rd day of follow-up. Serial EEG frequency analysis demonstrated the recovery of alpha peak frequency on the left side, but the attenuation of rhythmic signals remained persistent on the right. In our case, the restitution of postictal EEG lag behind the consolidation of MRI signal abnormality.     

Postictal mania associated with frontal lobe epilepsy

A 38-year-old man, possibly with frontal lobe epilepsy, developed postictal mania. The changes in psychiatric symptoms and laboratory examinations over time were investigated in two episodes of postictal mania, using long-term electroencephalography with closed circuit television (EEG/CCTV) monitoring, magnetoencephalography (MEG), and single-photon emission computed tomography (SPECT) to elucidate the underlying mechanism of postictal mania. According to the clinical symptoms, the postictal manic episodes of this case had four phases: a lucid interval, manic phase, hypomanic phase, and recovery phase. EEG showed forced normalization during the florid manic phase. The serial findings of EEG, MEG, and SPECT during the postictal manic episodes suggest that functional changes in bilateral frontal lobes, especially the right frontal lobe, right temporal lobe, and right paralimbic area, are crucial in the development of postictal mania, and that these functional changes are dynamic.     

Neuronal migrational disorders in children with epilepsy: MRI,interictal SPECT and EEG comparisons

Single-photon emission computed tomography (SPECT) is being increasingly used in the investigation of children with epilepsy and may provide insights into congenital malformations. We analyzed the interictal⁹⁹Tc-HMPAOSPECT in a series of seven children with developmental disorders of the neocortex, each of them representing a prototype of cerebral dysgenesis, such as lissencephaly, pachygyria, opercular dysplasia, polymicrogyria, nodular heterotopia and band heterotopia. The patients studied were selected among 22 epileptic children with neuronal migrational disorders (NMDs). Interictal SPECT hypoperfusion was observed in the area homologous to MRI findings in all the examined children. In three patients low perfusion was also present in the opposite hemisphere, probably due to functional involvement or related to an underlying microdysgenesis, not revealed by structural imaging. EEG features were in agreement with low perfusion areas, both anatomically and functionally, in all children. In one patient hypoperfusion area differed from that revealed by MRI and EEG. Ictal SPECT has been considered a useful tool for accurately locating the epileptic focus. Nevertheless, interictal brain perfusion studies, together with proton magnetic resonance spectroscopy, may play an important role in detecting anatomic substrate in developmental disorders of the neocortex.     

Brain SPECT, CT and EEG in 45 cases of epilepsy during the intermission

The regional cerebral blood flows (rCBF) in 45 cases of epilepsy during the interictal period were determined with brain SPECT. The results were compared those obtained with CT scans and EEG. 48.89% of the SPECT were found to be abnormal while 8.98% were suspected to be abnormal; the 35.71% of the CT scans were found to be abnormal; 16 cases (39.02%) were found to show focal abnormalities in the EEG while 9 cases (21.95%) had epileptic form discharge. SPECT seemed to show more significance in discovering the abnormalities in the epileptics during the interictal period than CT or EEG. However, the combined use of these three methods of examinations would be of greater help for identifying the focal abnormalities in epilepsy. Two of the 22 cases with abnormal SPECT had increased rCBF, whereas the other 20 cases had decreased rCBF. Among the 22 cases of abnormal SPECT and 4 cases of suspected abnormalities, the locations of the lesions as indicated with SPECT in 3 cases were not consistent with those as with CT. There were 5 cases in which the SPECT findings were not consistent with those in EEG.