Frontal deficits and atrophy in a patient with familial encephalopathy with neuroserpin inclusion bodies detected by single-case voxel-based morphometry: a case report

BACKGROUND

Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a rare genetic disorder characterized by progressive cognitive decline and myoclonic epilepsy, caused by pathogenic variants of SERPINI1. We reported a case of genetically confirmed FENIB with de novo H338R mutation in the SERPINI1, in which frontal deficits including inattention and disinhibition, and relevant atrophy in the vmPFC on brain MRI were observed in the early stage of the disease.

CASE PRESENTATION

A 23-year-old Japanese man presented with progressive inattention and disinhibition over 4 years followed by myoclonic epilepsy. The whole-genome sequencing and filtering analysis showed de novo heterozygous H338R mutation in the SERPINI1, confirming the diagnosis of FENIB. Single-case voxel-based morphometry using brain magnetic resonance imaging obtained at the initial visit revealed focal gray matter volume loss in the ventromedial prefrontal cortices, which is presumed to be associated with inattention and disinhibition.

CONCLUSION

Frontal deficits including inattention and disinhibition can be the presenting symptoms of patients with FENIB. Single-case voxel-based morphometry may be useful for detecting regional atrophy of the frontal lobe in FENIB. Detecting these abnormalities in the early stage of disease may be key findings for differentiating FENIB from other causes of progressive myoclonic epilepsy.

Morphometry and network-based atrophy patterns in SCN1A-related Dravet syndrome

Mutations of the voltage-gated sodium channel SCN1A gene (MIM#182389) are among the most clinically relevant epilepsy-related genetic mutations and present variable phenotypes, from the milder genetic epilepsy with febrile seizures plus to Dravet syndrome, a severe developmental and epileptic encephalopathy. Qualitative neuroimaging studies have identified malformations of cortical development in some patients and mild atrophic changes, partially confirmed by quantitative studies. Precise correlations between MRI findings and clinical variables have not been addressed. We used morphometric methods and network-based models to detect abnormal brain structural patterns in 34 patients with SCN1A-related epilepsy, including 22 with Dravet syndrome. By measuring the morphometric characteristics of the cortical mantle and volume of subcortical structures, we found bilateral atrophic changes in the hippocampus, amygdala, and the temporo-limbic cortex (P-value < 0.05). By correlating atrophic patterns with brain connectivity profiles, we found the region of the hippocampal formation as the epicenter of the structural changes. We also observed that Dravet syndrome was associated with more severe atrophy patterns with respect to the genetic epilepsy with febrile seizures plus phenotype (r = -0.0613, P-value = 0.03), thus suggesting that both the underlying mutation and seizure severity contribute to determine atrophic changes.

Dravet syndrome with parkinsonian symptoms and intact dopaminergic neurons: A case report

INTRODUCTION

Dravet syndrome (DS) is severe myoclonic epilepsy in infancy and associated with a heterozygous mutation of the gene for the sodium channel alpha 1 subunit (SCN1A). Recently, adult patients with DS have been reported to show parkinsonism, but no corresponding neuroimaging data are available. Here, we present neuroimaging data in 2 adult patients with DS showing parkinsonian symptoms.

CASE REPORT

Case 1: A man who had intractable seizures from the age of 1 year and 2 months was diagnosed with DS at 7 with a mutation in the SCN1A gene. At 18, he had parkinsonian symptoms such as masked face and bradykinesia. At 20, he was admitted to our department. Dopamine transporter single-photon emission computed tomography (DAT SPECT) showed no decrease in striatal binding of ¹²³I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane (¹²³I-FP-CIT), and myocardial scintigraphy showed no decrease in cardiac uptake of ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG). Levodopa showed no significant improvement in his symptoms. Case 2: A woman who had febrile seizures at 4 months of age and myoclonic seizures at 1 year and 5 months was diagnosed with DS at 31. She had myoclonus, resting tremor, hypertonia, antecollis, crouch gait, and bradykinesia. DAT SPECT imaging showed no decrease in striatal FP-CIT binding, and levodopa did not improve her symptoms.

DISCUSSION

The normal DAT SPECT and ¹²³I-MIBG results suggest that dopaminergic neurons projecting onto striatal neurons were not impaired in our patients, explaining the lack of response to levodopa. Thus, dopamine imaging can help to guide treatment decisions in patients with DS and parkinsonism.

EEG abnormalities in patients with chronic neuronopathic Gaucher disease: A retrospective review

The clinical phenotype of Gaucher disease type 3 (GD3), a neuronopathic lysosomal storage disorder, encompasses a wide array of neurological manifestations including neuro-ophthalmological findings, developmental delay, and seizures including progressive myoclonic epilepsy. Electroencephalography (EEG) is a widely available tool used to identify abnormalities in cerebral function, as well as epileptiform abnormalities indicating an increased risk of seizures. We characterized the EEG findings in GD3, reviewing 67 patients with 293 EEGs collected over nearly 50 years. Over 93% of patients had some form of EEG abnormality, most consisting of background slowing (90%), followed by interictal epileptiform discharges (IEDs) (54%), and photoparoxysmal responses (25%). The seven patients without background slowing were all under age 14 (mean 6.7 years). There was a history of seizures in 37% of this cohort; only 30% of these had IEDs on EEG. Conversely, only 56% of patients with IEDs had a history of seizures. These observed EEG abnormalities document an important aspect of the natural history of GD3 and could potentially assist in identifying neurological involvement in a patient with subtle clinical findings. Additionally, this comprehensive description of longitudinal EEG data provides essential baseline data for understanding central nervous system involvement in neuronopathic GD.

Elimination of amyloid precursor protein in senile plaques in the brain of a patient with Alzheimer-type dementia and Down syndrome

The average lifespan of individuals with Down syndrome has approximately doubled over the past three decades to 55-60 years. To reveal the pathogenic process of Alzheimer-type dementia in individuals with Down syndrome, we immunohistochemically examined senile plaque formation in the cerebral cortex in the autopsy brain and compared findings with our previous studies. We described a 52-year-old female with Down syndrome who developed progressively more frequent myoclonus following cognitive decline and died at the age of 59 years. Her karyotype [46XX, inv(9)(p12q13), i(21)(q10)] included triplication of the gene for amyloid precursor protein and the Down syndrome critical region. On microscopy, very few gamma-aminobutyric acid-ergic (GABAergic) neurons, in the form of small granular cells, in the cortex and Purkinje cells in the cerebellum were visible. In our previous study, amyloid precursor protein immunoreactivity was first noted in senile plaques at the age of 32 years. In this patient, even though amyloid β immunoreactivity was detected in the cores of senile plaques and diffuse plaques, amyloid precursor protein immunoreactivity was not noted in senile plaques in the frontal cortex. Amyloid precursor protein and its derivative amyloid-β play an important role in the formation of senile plaques and the time course of immunoreactive expression may be related to the pathogenic process of Alzheimer-type dementia.

Antimyoclonic Effect of Levetiracetam and Clonazepam Combined Treatment on Myoclonic Epilepsy with Ragged-Red Fiber Syndrome with m.8344A>G Mutation

BACKGROUND

Treatment of myoclonic seizures in myoclonic epilepsy with ragged-red fibers (MERRFs) has been empirical and ineffective. Guideline on this disease is not available. Additional trials must be conducted to find more suitable treatments for it. In this study, the antimyoclonic effects of monotherapies, including levetiracetam (LEV), clonazepam (CZP), valproic acid (VPA), and topiramate (TPM) compared to combination therapy group with LEV and CZP on MERRF, were evaluated to find a more advantageous approach on the treatment of myoclonic seizures.

METHODS

Treatments of myoclonic seizures with VPA, LEV, CZP, and TPM were reported as monotherapies in 17 MERRF patients from Qilu Hospital between 2003 and 2016, who were diagnosed through clinical data and genetic testing. After 1-4 months of follow-up (mean: 82.9 ± 28.1 days), 12 patients that exhibited poor responses to monotherapy were given a combined treatment consisting of LEV and CZP subsequently. The follow-up period was 4-144 months (mean: 66.3 ± 45.3 months), the effective rates of monotherapy group (17 patients) and combination therapy group (12 patients) were analyzed by Chi-square test.

RESULTS

The m.8344 A>G mutation was detected in all patients. There were four patients with partial response (4/17, two in the CZP group and two in the LEV group), ten patients with stable disease (10/17, six in the CZP group, three in the LEV group, and one in the TPM group), and three patients with progressive disease (3/18, two in the VPA group and one in the TPM group). Twelve of the patients with LEV combined with CZP showed a positive effect and good tolerance (12/12), eight of them demonstrated improved cognition and coordination. There was a significant difference between the monotherapy group and combination therapy group in the efficacy of antimyoclonic seizures (χ2 = 13.7, P < 0.001).

CONCLUSIONS

LEV in combination with CZP is an efficient and safe treatment for myoclonic seizures in patients with this disease exhibiting the m.8344A>G mutation.

Myoclonus epilepsy, retinitis pigmentosa, leukoencephalopathy and cerebral calcifications associated with a novel m.5513G>A mutation in the MT-TW gene

We sequenced the mitochondrial genome from a 40-year-old woman with myoclonus epilepsy, retinitis pigmentosa, leukoencephalopathy and cerebral calcifications. Histological and biochemical features of mitochondrial respiratory chain dysfunction were present. Direct sequencing showed a novel heteroplasmic mutation at nucleotide 5513 in the MT-TW gene that encodes tRNA^Trp. Restriction Fragment Length Polymorphism analysis confirmed that about 80% of muscle mtDNA harboured the mutation while it was present in minor percentages in mtDNA from other tissues. The mutation is predicted to disrupt a highly conserved base pair within the aminoacyl acceptor stem of the tRNA. This is the 17° mutation in MT-TW gene and expands the known causes of late-onset mitochondrial diseases.

[Myoclonus as a movement disorder]

Myoclonus is often a diagnostic and therapeutic challenge due to its broad phenomenological variability and limited therapeutic options. This article gives a short survey and characterizes in detail two common types of myoclonus, cortical myoclonus and reticular reflex myoclonus. Clinical testing and electrophysiological investigations provide relevant local diagnostic indications for the generating structure(s). Such indications would influence not only the strategies of neuroimaging and laboratory investigations aimed at clarifying the underlying cause but also the selection of drugs to suppress myoclonus.

CBF changes in drug naive juvenile myoclonic epilepsy patients

PURPOSE

The role of thalamus and brainstem in generalized epilepsy has been suggested in previous studies. The aim of the present study was to assess regional cerebral blood flow (rCBF) abnormality in juvenile myoclonic epilepsy (JME) patients.

METHODS

(99m)Tc-ethylcysteinate dimer brain single photon emission computed tomography (SPECT) was performed in 19 drug naive JME patients and 25 normal controls with the similar age and gender distribution. Differences of rCBF between a JME group and a normal control group were examined by the statistical parametric mapping of brain SPECT images using independent t test. The regression analyses in SPM were also performed between rCBF and the age of seizure onset or the disease duration in JME group.

RESULTS

Compared to normal controls, the JME group showed a significant rCBF reduction in bilateral thalami, red nucleus, midbrain, pons, left hippocampus, and in the cerebelli (FDR corrected p < 0.01) whereas rCBF increase in the left superior frontal gyrus (uncorrected p < 0.001 but FDR corrected p > 0.05). Disease duration was negatively correlated with rCBF in bilateral frontal cortices, caudate nuclei, brainstem and cerebellar tonsils.

CONCLUSIONS

Our results suggest that abnormal neural networks in the thalamus, hippocampus, brainstem and cerebellum are associated with JME.

Autosomal recessive microcephaly with neonatal myoclonic seizures: clinical and MRI findings

We describe an infant who was born to a consanguineous couple of Palestinian origin. The patient had severe microcephaly, myoclonic seizures, hypsarrythmia, spasticity, hypertonicity, and profound mental retardation. A similar case was reported in another unrelated Palestinian family, suggesting that this condition may be endemic. The condition resembles early onset myoclonic seizures and spasticity described by Tolmie et al.: Am J Med Genet 27:583-594 [1987]. To the best of our knowledge, only four pairs of sibs have been described with this syndrome; however, to date no magnetic resonance imaging (MRI) findings were reported for this condition. We present the clinical and radiological findings in the patients, including the first report of MRI findings.

Comparison of EEG, MRI and PET in reading epilepsy: a case report

The pathophysiological and neuroanatomical bases of reading epilepsy (RE) are unclear. We performed video-EEG, high quality MRI and [11C]diprenorphine PET in a patient with RE to detect structural and functional abnormalities. EEG showed multifocal seizure onset bilaterally in temporal and fronto-central regions. MRI was normal, whereas [11C]diprenorphine PET revealed peri-ictal opioid binding decreases in both temporal lobes and the left frontal lobe. These findings confirm that RE is due to abnormal activity in the network subserving reading.

Utility of high doses of melatonin as adjunctive anticonvulsant therapy in a child with severe myoclonic epilepsy: two years' experience

Recent data indicate that melatonin inhibits brain glutamate receptors and nitric oxide production, thus suggesting that it may exert a neuroprotective and antiexcitotoxic effect. Melatonin has been seen to prevent seizures in several animal models and to decrease epileptic manifestations in humans. The lack of response to conventional anticonvulsants in an epileptic child led us to use melatonin in this case. A female child who began to have convulsive seizures at the age of 1.5 months and was diagnosed as having severe myoclonic epilepsy was unsuccessfully treated with different combinations of anticonvulsants, including valproic acid, phenobarbital, clonazepam, vigabatrin, lamotrigin, and clobazam. Melatonin was thus added to the treatment. Imaging studies (CT, SPECT, and MNR), EEG recordings, blood biochemical, and hematological analyses, including measures of the circadian rhythm of melatonin, were made. The child was initially treated with various anticonvulsants. Severe neurological and psychomotor deterioration combined with increased seizure activity showed a lack of response to the treatment. At the age of 29 mon the patient was in a pre-comatose stage at which time melatonin was added to treatment. After 1 month of melatonin plus phenobarbital therapy and for a year thereafter, the child's seizures were under control. On reducing the melatonin dose after this time, however, seizures resumed and the patient's condition was re-stabilized after restoring melatonin. Prior to our attempts to reduce melatonin, all analyses, including EEG recordings and SPECT, were normal. As far as the results of neurological examination are concerned, only mild hypotony without focalization remained. Changes in the therapeutic schedules during the second year of melatonin treatment, including the withdrawal of phenobarbital, did not result in the same degree of seizure control, although progressively the child became satisfactorily controlled. At the present moment the child continues to have mild hypotony and shows attention disorder and irritability. Melatonin has proven to be useful as adjunctive therapy in the clinical control of this case of severe infantile myoclonic epilepsy. The results suggest that melatonin may have a useful role in mechanisms of neuroprotection and also indicate its use in other cases of untreatable epilepsy. Further studies using more patients and placebo-treatment would be beneficial in understanding the potential use of melatonin as a co-therapy in some cases of seizures.

Recurrent pain attacks in a 3-year-old patient with myoclonus epilepsy associated with ragged-red fibers (MERRF): a single-photon emission computed tomographic (SPECT) and electrophysiological study

We reported a 3-year-old girl with myoclonus epilepsy associated with ragged-red fibers (MERRF) who was afflicted with recurrent pain attacks and allodynia on the right side of the body. Although magnetic resonance imaging showed normal intensity in the thalamus, single-photon emission computed tomography (SPECT) revealed hypoperfusion in the thalamus. Somatosensory evoked potentials showed delayed early cortical responses, particularly on right median nerve stimulation. The parenteral administration of cytochrome c with flavin mononucleotide and thiamine diphosphate abolished the intolerable pain. This clinical improvement was objectively supported by the results of SPECT and neurophysiological findings. These observations suggested that a dysfunction of the thalamus was responsible for her pain and that cytochrome c therapy was of benefit for this symptom.

A case of early myoclonic encephalopathy with the congenital nephrotic syndrome

We describe a male infant with early myoclonic encephalopathy (EME) associated with the congenital nephrotic syndrome, microcephaly, multiple minor anomalies, and cerebellar hypoplasia. He had erratic and massive myoclonus, and partial seizures from the neonatal period. Electroencephalography showed the so-called suppression-burst pattern. He died of disseminated intravascular coagulation caused by the congenital nephrotic syndrome at the age of two months. Our patients is the first reported case with EME associated with the congenital nephrotic syndrome.

Focal abnormalities detected by 18FDG PET in epileptic encephalopathies

A prospective study of 32 children with epileptic encephalopathies 12 years or younger revealed a high incidence of focal cortical metabolic defects on 18-fluorodeoxyglucose positron emission tomography (PET) not suspected from clinical, EEG, or magnetic resonance imaging findings. PET scans were normal in all five children with typical de novo Lennox-Gastaut syndrome but showed cortical metabolic abnormalities in three out of four with atypical de novo Lennox-Gastaut syndrome, five out of six with Lennox-Gastaut syndrome following infantile spasms, six out of eight with severe myoclonic epilepsy in infancy, one out of two with epilepsy with myoclonic-astatic seizures, and four out of six with an unclassified epileptic encephalopathy. This suggests that some children with epileptic encephalopathies previously thought to have primary generalised seizures or seizures due to multifocal pathology may have unifocal cortical origin for their seizures. Such an origin may be amenable to surgery.

A Croatian case of the Schinzel-Giedion syndrome

The Schinzel-Giedion syndrome is an infrequently described malformation syndrome, mainly characterized by a profound mental deficiency, a typical face including a midface hypoplasia, urogenital abnormalities, and minor radiographic features. Death prior to two year of age is the rule. A boy with typical features of the syndrome is described. He died at the age of 21 months. This is the first case of this syndrome reported from Croatia. The recurrence in only one of the 20 families, does not firmly sustain an autosomal recessive pattern of inheritance, although this still remains possible.

[Single photon emission tomography (SPECT) in severe infantile myoclonic epilepsy (EMS)]

Ten children, three boys and seven girls, with an average age of 7.5 years diagnosed as having severe myoclonic epilepsy (SME) underwent single photon emission computerised tomography (SPECT) with HMPAO. All had CT, nuclear MR and various EEG studies, these findings made at the same time as SPECT. CT and nuclear MR produced no relevant data. EEG, although without paroxystic abnormalities in two cases, showed generalised discharge in the remaining eight, predominantly in the right hemisphere in five. SPECT was normal in two cases (of 20 and 30 months) and showed areas of hypoperfusion localised in one hemisphere in five cases, three in the left and two in the right, and in both hemispheres in three cases. Areas of hypoperfusion were located in frontal and/or temporal and/or parietal regions. In two cases there was concordance with the prevalence of EEG paroxystic activity and in two other cases there was discordance. Our findings, with SPECT abnormalities after two years of age, suggest SME could be considered as a multifocal epilepsy brought on by secondary structural irregularities.

Vertebral arch nonfusion and juvenile myoclonic epilepsy

Neural tube defects (NTD) are known to occur at a higher rate in pregnancies of women with epilepsy. Antiepileptic drugs (AEDs), notably valproate (VPA) and carbamazepine (CBZ), have been identified as risk factors, but a familial aggregation of this condition also occurs in the absence of pharmacologic teratogens. Spina bifida occulta, defined as a nonsymptomatic nonfusion of vertebral arches, has been suggested to be genetically determined, with an increased prevalence in patients with primary generalized epilepsy, and that the presence of this trait in fetal development can be enhanced pharmacologically to produce NTD such as meningomyelocele. In this study, plain abdominal radiographs were obtained from 56 patients with juvenile myoclonic epilepsy (JME) and 56 age- and sex-matched controls. The radiographs were presented in a random order to an unbiased radiologist. No difference in prevalence of vertebral arch nonfusion (VAN) was noted between the two groups. Even if it has no increased frequency in patients with epilepsy, however, VAN is a common radiologic finding, and its relation to symptomatic neural tube defects should be clarified in future studies.

[Nightly myoclonus syndrome (NMS) and restless legs syndrome (RLS)--review and case report]

The paper gives a brief review of the existing literature concerning the nocturnal myoclonus syndrome (NMS). The clinical symptomatology, criteria for differential diagnosis and the relation to the restless legs syndrome (RLS) are discussed. Recently we investigated central dopamine receptor density with 123I-labeled 3'-iodo-6-methoxybenzamide (IBZM) (a highly selective CNS D2 dopamine receptor ligand) and single photon emission tomography (SPECT) in patients with NMS and found a reduced density of dopamine D2-receptors in the striatal structures, indicating a dopaminergic dysfunction in NMS and RLS. We present a report concerning a 58-year old female with NMS-associated insomnia and present IBZM SPECTs and hypnograms before and after a 3-month treatment with L-dopa and discuss the results with regard to pathophysiological theories.

Computed tomography in patients with recurrent seizures

Eighty patients had Computed Tomography (CT) performed for evaluation of epileptic seizures. Abnormal scans were found in 37 of the 80 patients (46.3%). Focal CT abnormalities were seen in 26 of the 80 patients (32.5%). Tumors were present in four and arteriovenous malformation (AVM) in three. Simple partial motor seizures were most strongly correlated with abnormal scans (five, 45.4%). Nineteen out of 21 patients with focal electro-encephalographic (EEG) abnormalities had focal CT abnormality compared to one out of 15 of those with generalised abnormality. 88.9% of patients with hemiplegia had abnormal scans. Whilst focal EEG abnormalities and abnormal neurologic signs pointed to a higher likelihood of CT abnormality, two subjects who were shown to have vascular malformations had normal EEG and neurologic exams. Routine CT scanning for evaluation of patients with recurrent seizures is advocated.

A case of early infantile epileptic encephalopathy (EIEE) with anatomical cerebral asymmetry and myoclonus

The authors report a case of early encephalopathy with myoclonus, tonic spasms and a suppression-burst pattern on electroencephalography (EEG) associated with unilateral cerebral hypertrophy following hemiatrophy. This patient showed frequent myoclonus in relation to a suppression-burst pattern resembling that in early myoclonic encephalopathy (EME). Moreover, the case also showed tonic spasms, from the age of 13 days, in series, as seen in Ohtahara syndrome. On the other hand, there was a previously undescribed peculiar CT scan finding, which showed hypertrophy of the right cerebral hemisphere at birth, following hemiatrophy. Neuropathological examination revealed cerebral atrophy associated with heterotopia and an ependymal hyperplasia in the right hemisphere, suggesting hemimegalencephaly. This case should be classified as Ohtahara syndrome accompanied by myoclonus, because of the spasms in series interrupting the suppression-burst pattern, and the etiological factor of brain malformation. The nosological aspects of this epileptic encephalopathy are discussed.

Infant-onset progressive myoclonus epilepsy

We report the clinical, electroencephalographic, neurophysiologic, and neuroimaging findings in eight children with infant-onset progressive myoclonus epilepsy, all of whom had muscle biopsies performed as as part of the diagnostic evaluation. Each child had myoclonic seizures, generalized tonic-clonic seizures, and neurologic regression or marked developmental delay. Four children died before 3 years of age. Electroencephalograms in seven children showed an abnormally slow background with bilateral multifocal paroxysmal discharges but no burst suppression pattern or photoparoxysmal response. Muscle biopsy specimens were submitted for histopathology and respiratory-chain enzyme studies. Nonspecific abnormalities on light microscopy or electron microscopy were found in seven samples, including increased subsarcolemmal deposits of mitochondria or morphologic mitochondrial changes, but no ragged-red fibers were seen. Respiratory-chain enzyme studies were performed on five samples and in three children (all of whom had a history of elevated lactate in serum or cerebrospinal fluid), there were low levels of rotenone-sensitive reduced nicotinamide adenine dinucleotide (NADH) cytochrome c reductase characteristic of a defect in the complex I part of the respiratory-chain pathway. This study has shown that infant-onset progressive myoclonus epilepsy can be distinguished from other myoclonic epilepsy syndromes of infancy by clinical and electrographic features. Furthermore, respiratory-chain enzyme defects are a relatively common cause of infant-onset progressive myoclonus epilepsy. The absence of ragged-red fibers on muscle histopathology does not preclude a mitochondrial enzyme abnormality.

Extracranial vertebral artery dissection following tonic clonic seizure

A 34 year old woman developed cerebral infarction, following a tonic-clonic seizure. A vertebral artery dissection was demonstrated and may have been caused by arterial trauma during the seizure. This cause of morbidity following convulsive seizures may have been overlooked in the past and needs to be recognised in view of the potential benefits of anticoagulation.

Myoclonic epilepsy in an HIV positive patient: neurophysiological findings

An HIV-positive patient is described who presented with action myoclonus. Unusually, focal sinusoidal EEG burst complexes with a frequency of 40 and 55 Hz could be recorded over the sensorimotor cortex. Activity having a similar frequency was evoked in this area by posterior tibial nerve stimulation in the affected leg, and jerk-locked averaging showed that myoclonic jerks were preceded by similar cortical sinusoidal waves.

Positron emission tomography in epilepsy: correlative study

Positron emission tomography (PET) was performed with the 18F-fluoro-deoxy-glucose method on 29 patients with epilepsy (generalized epilepsy, 4; partial epilepsy, 24; undetermined type, 1). The subjects were restricted to patients with epilepsy without focal abnormality on X-CT. All the patients with generalized epilepsy showed a normal pattern on PET. Fourteen out of the 24 patients with partial epilepsy and the 1 with epilepsy of undetermined type showed focal hypometabolism on PET. The hypometabolic zone was localized in areas including the temporal cortex in 11 patients, frontal in 2 and thalamus in 1. The location of hypometabolic zone and that of interictal paroxysmal activity on EEG were well correlated in most patients. The patients with poorly-controlled seizure showed a higher incidence of PET abnormality (12 out of 13) than those with well-controlled seizures (2 out of 11). The incidence of abnormality on PET and MRI and the location of both abnormality were not necessarily coincident. These results indicated that the PET examination in epilepsy provides valuable information about the location of epileptic focus, and that the findings on PET in patients with partial epilepsy may be one of the good indicators about the intractability of partial epilepsy, and that PET and MRI provide complementary information in the diagnosis of epilepsy.

Epilepsia partialis continua. Epileptogenic focus in motor cortex and its participation in transcortical reflexes

We performed electrophysiologic and neuroradiologic studies on a patient who had epilepsia partialis continua (EPC) to elucidate the pathophysiologic mechanism of repeated myoclonic jerks confined to the right toes. A computed tomographic scan revealed a small cortical lesion in the left parasagittal rolandic area corresponding to the sensorimotor cortex of the right toes. A pretrigger EEG analysis with a jerk-locked averaging technique revealed a positive spike 32 ms before the jerks. A similar positive spike was evoked at a latency of 48 ms after an electrical stimulation of the right posterior tibial nerve; it was followed by a myoclonic jerk with a 32-ms latency. We suppose that in our patient, an epileptogenic focus in the motor cortex and transcortical long-loop reflexes played an important role in generating EPC.