Clinical Neuroscience

[Positron emission tomography in presurgical localization of epileptic foci]

JUHÁSZ Csaba

AUGUST 20, 2003

Clinical Neuroscience - 2003;56(07-08)

[The success of cortical resection for intractable epilepsy of neocortical origin is highly dependent on the accurate presurgical delineation of the regions responsible for generating seizures. In addition to EEG and structural imaging studies, functional neuroimaging such as positron emission tomography (PET) can assist lateralization and localization of epileptogenic cortical areas. In the presented studies, objectively delineated focal PET abnormalities have been analyzed in patients (mostly children) with intractable epilepsy, using two different tracers: 2-deoxy-2-[18F]fluoro-D-glucose (FDG), that measures regional brain glucose metabolism, and [11C]flumazenil (FMZ), that binds to GABAA receptors. The PET abnormalities were correlated with scalp and intracranial EEG findings, structural brain abnormalities, as well as surgical outcome data. In patients with extratemporal foci and no lesion on MRI, FMZ PET was more sensitive than FDG PET for identification of the seizure onset zone defined by intracranial EEG monitoring. In contrast, seizures commonly originated from the border of hypometabolic cortex detected by FDG PET suggesting that such areas are most likely epileptogenic, and should be addressed if subdural EEG is applied to delineate epileptic cortex. In patients with cortical lesions, perilesional cortex with decreased FMZ binding was significantly smaller than corresponding areas of glucose hypometabolism, and correlated well with spiking cortex. Extent of perilesional hypometabolism, on the other hand, showed a correlation with the life-time number of seizures suggesting a seizurerelated progression of brain dysfunction. FMZ PET proved to be also very sensitive for detection of dual pathology (coexistence of an epileptogenic cortical lesion and hippocampal sclerosis). This has a major clinical importance since resection of both the cortical lesion and the atrophic hippocampus is required to achieve optimal surgical results. Finally, the author demonstrated that in patients with neocortical epilepsy, FDG PET abnormalities correctly regionalize the epileptogenic area, but their size is not related to the extent of epileptogenic tissue to be removed. In contrast, complete resection of cortex with decreased FMZ binding predicts good surgical outcome suggesting that application of FMZ PET can improve surgical results in selected patients with intractable epilepsy of neocortical origin.]

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[Imaging of dopamine transporter with 99mTc-TRODAT-SPECT in movement disorders]

KANYÓ Balázs, ÁRGYELÁN Miklós, DIBÓ György, SZAKONYI Zsolt, VÉCSEI László, FÜLÖP Ferenc, LÁNCZ Adrienn, FORGÁCS Péter, PÁVICS László

[99mTc-TRODAT-1 is a new, technetium based radiopharmaceutical that selectively binds to the dopamine transporters. The aim of the study was to evaluate the dopamine transporter status in movement disorders. Methods - In eight healthy volunteers (age range 22-58 years), 28 patients with Parkinson’s disease (age range 42-80 years), 10 patients with Parkinsonian syndrome (age range 51-79 years) and 13 patients with essential tremor (age range 43-71 years) were 99mTc-TRODAT-SPECT tests performed. The results were evaluated visually and semiquantitatively. Results - The visual assessments were concordant with those of the semiquantitative in each case. The 99mTc- TRODAT uptake of the striatum was referenced to the cerebellum, the frontal and occipital cortex. The best deviation was found in aspect of the occipital cortex. The striatum/occipital ratio was the following: healthy volunteers: 2.12±0.27; Parkinson’s disease: 1.52±0.27; Parkinsonian syndrome: 1.57±0.26; essential tremor: 2.06±0.69. The striatal dopamine transporter availability was significantly lower in subjects with Parkinson's disease or Parkinsonian syndrome compared to the control subjects. There was no difference between healthy volunteers and patients with essential tremor. Using discriminant analysis, the discriminant function had significantly different values in the group of Parkinson’s disease than in Parkinsonian syndrome: f= -3.675×caud/occipit+6.293×put/occipit -2.548. Conclusion - 99mTc-TRODAT-SPECT is able to visualise the presynaptic dopaminergic degeneration. This method itself can be useful in differential diagnosis in some type of movement disorders.]

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[Two cases of frontotemporal dementia]

SZABÓ Erzsébet, SZABÓ Mihály

[Frontotemporal dementias represent the third most common cause of primer degenerative dementias next to Alzheimer’s disease and Lewy body disease. Frontotemporal dementia constitutes 10-20% of all praesenilis dementias. The authors present the results of the 10 years' clinical, neuropsychological, neuropathological examinations and brain imaging with the examples of two cases. At the early stage of frontotemporal dementia changes of personality and social conduct are prominent, whereas cognitive functions are relativelly well preserved. The usual dementia tests are not sufficiently sensitive to disclose noncognitive symptoms. Clinical diagnosis as well as differentiation from functional psychiatric disorders can be difficult. Brain imaging present the frontal and the anterior temporal lobe atrophy and selective hypometabolism in these areas. The typical onset is between at the age 50 and 65 years. It is very rare under the age of 30. The symptoms of two patients started at the age of 42-44. The first diagnosis was post traumatic stress disorder. Later stereotyped behaviour, mental rigidity, hyperorality, irritability, progressive reduction of speech and vegetative dysfunctions appeared. Besides the affecting of the irresistibly worsening symptoms and the medical care requiring strength and inventiveness, the authentic informing of the relatives is also a challenge. The caregivers have special relationship with the patients and their relatives.]

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Many systemic problems arise due to the side effects of antiepileptic drugs (AEDs) used in epilepsy patients. Among these adverse effects are low bone mineral density and increased fracture risk due to long-term AED use. Although various studies have supported this association with increased risk in recent years, the length of this process has not been precisely defined and there is no clear consensus on bone density scanning, intervals of screening, and the subject of calcium and vitamin D supplementation. In this study, in accordance with the most current recommendations, our applications and data, including the detection of possible bone mineralization disorders, treatment methods, and recommendations to prevent bone mineralization disorders, were evaluated in epilepsy patients who were followed up at our outpatient clinic. It was aimed to draw attention to the significance of management of bone metabolism carried out with appropriate protocols. Epilepsy patients were followed up at the Antalya Training and Research Hospital Department of Neurology, Epilepsy Outpatient Clinic who were at high risk for osteoporosis (use of valproic acid [VPA] and enzyme-inducing drugs, using any AED for over 5 years, and postmenopausal women) and were evaluated using a screening protocol. According to this protocol, a total of 190 patients suspected of osteoporosis risk were retrospectively evaluated. Four patients were excluded from the study due to secondary osteoporosis. Of the 186 patients who were included in the study, 97 (52.2%) were women and 89 (47.8%) were men. Prevalence of low bone mineral density (BMD) was 42%, in which osteoporosis was detected in 11.8% and osteopenia in 30.6% of the patients. Osteoporosis rate was higher at the young age group (18-45) and this difference was statistically significant (p=0.018). There was no significant difference between male and female sexes according to osteoporosis and osteopenia rates. Patients receiving polytherapy had higher osteoporosis rate and lower BMD compared to patients receiving monotherapy. Comparison of separate drug groups according to osteoporosis rate revealed that osteoporosis rate was highest in patient groups using VPA+ carbamazepine (CBZ) (29.4%) and VPA polytherapy (19.4%). Total of osteopenia and osteoporosis, or low BMD, was highest in VPA polytherapy (VPA+ non-enzyme-inducing AED [NEID]) and CBZ polytherapy (CBZ+NEID) groups, with rates of 58.3% and 55.1%, respectively. In addition, there was no significant difference between drug groups according to bone metabolism markers, vitamin D levels, and osteopenia-osteoporosis rates. Assuming bone health will be affected at an early age in epilepsy patients, providing lifestyle and diet recommendations, avoiding polytherapy including VPA and CBZ when possible, and evaluating bone metabolism at regular intervals are actions that should be applied in routine practice.

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Clinical Neuroscience

[The role of zonisamide in the treatment of women with epilepsy]

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[The antiepileptic drugs can effect fertility, development of gynecological diseases and occurence of sexual problems. They can cause a number of “cosmetic” problem and also influence the selection of safe contraceptive method. Many antiepileptic drugs can cause congenital malformations or affect the new-born child’s psychomotor and cognitive development, therefore during pregnancy should be treated with extreme caution in women with epilepsy. Most types of epilepsies accompany the patient through their whole life. Women spend almost the third of their lives after menopause and - due to the formation of associated diseases as well - this period is also special. According to the 2013 recommendation of International League Epilepsy (ILAE), zonisamide is one of the first-line antiepileptic drugs in focal epilepsy. In my review I discuss women’s epilepsy in the viewpoint of the application of zonisamid. ]