Clinical and laboratory-reconfirmed myasthenia gravis: a population-based study.

The aim of this study was to compare the clinically based prevalence of myasthenia gravis (MG) with the prevalence of laboratory-confirmed cases. All patients with a diagnosis of MG living in Estonia as on 1 January 1997 were asked to participate in re-examination. The criteria for laboratory-supported MG were weakness and rapid fatigue and a positive outcome of at least one of three laboratory tests: (i) blinded acetylcholinesterase inhibitor test; (ii) determination of antibodies to acetylcholine receptor and (iii) neurophysiological examination using repetitive nerve stimulation and single-fibre EMG. Eighty-nine patients were re-examined and 70 patients (79%) fulfilled the criteria of laboratory-supported MG. The corrected prevalence ratio was 78 per million. In the non-confirmed MG group, there was more women (92%) than men (43%) whose diagnosis was established within 1 year from onset of symptoms (P = 0.016). In all women with non-confirmed MG the diagnosis was established within 1 year from referral to the physician, whereas 68% of women with confirmed MG was diagnosed within 1 year (P < 0.0001). Thus, we conclude that, in Estonia the prevalence of MG based on medical records seems overestimated by 21% and women are at higher risk of obtaining an uncertain diagnosis of MG.

A population based epidemiological study on myasthenia gravis in Estonia.

OBJECTIVE: To describe the occurrence of myasthenia gravis in the Baltic area. METHODS: Data were obtained from hospital files recorded during the period 1942 to 1996 from neurologists and the patient organisation. Survival data were checked with the Estonian Citizenship and Migration Board. Prevalence was determined on 1 January 1997. A questionnaire on the course of myasthenia gravis was sent to all the prevalent patients. RESULTS: The size of the population surveyed was 1 462 130. The average annual incidence from 1970 to 1996 was 4.0 per million (women, 5.2; men, 2.6). The point prevalence was 99 per million (women, 133; men 59). The incidence in the younger age group (<50 years) was 3.4 per million (women, 4.8; men, 1.9) and in the older age group (>or=50 years), 5.5 (women, 5.9; men, 4.9). The prevalence ratio was twofold higher in the older age group (p<0.0001)-for men (p = 0.034) as well as for women (p<0.001). CONCLUSIONS: Prevalence and incidence values of myasthenia gravis from Estonia are similar to those reported in most studies from Europe and north America. However, there seems to be a higher frequency in the elderly (>or=50 years) in Estonia.

Epilepsy in Estonia: a quality-of-life study.

PURPOSE: To study the impact of epilepsy and its treatment on people with epilepsy in Estonia and to analyze how it is affected by the characteristics of epilepsy. METHODS: Clinical and demographic data about patients were obtained from medical notes and mailed self-completed questionnaires (including the RAND 36-Items Health Survey 1.0 (RAND-36)). RESULTS: Information was collected from 203 patients aged 20-74 years, who all had active epilepsy. A third of the respondents had been seizure free during the last year. Eighty-four percent were receiving monotherapy. More than half of respondents felt stigmatized by epilepsy, 24.7% of them highly so. A third were working full-time, 31.9% were underemployed workers, and 11%, unemployed. Sixty-two percent of these same unemployed or underemployed workers considered their epilepsy to be a significant reason for this situation. Overall, 44% believed they had been treated unfairly at work or when trying to get a job. Study respondents scored lower in all domains on the RAND-36 than did persons from the control group. The biggest differences were found in five domains: Social functioning, Role limitations-physical, Role limitations-emotional, General health, and Vitality. CONCLUSIONS: The clinical characteristics of this study were similar to those of most other series of prevalence cases of epilepsy. The level of employment among persons with epilepsy was not lower than that in the general population. The percentage of stigmatization was high. There were significant differences in the way respondents scored on the stigma scale and on the RAND-36 domains when measuring their health status, depending above all on seizure frequency and type.

Survival of patients with primary CNS tumours in Estonia.

We studied a population-based survey that included 1417 patients with a primary central nervous system (CNS) tumour diagnosed in Estonia between 1986 and 1996. Survival rates at 1 and 5 years and median survival by histology and patient's age at diagnosis were estimated. Median survival time for all tumours was 33.2 months and 1- and 5-year survival rates were 59.3 and 46.0%, respectively. In multivariate analysis, younger age, better clinical condition (i.e. a Karnofsky Performance Status (KPS) score of 60 and more) and tumour histology were all dependent prognostic factors for better survival. Risk of death was more than 8 times greater for glioblastoma (Risk Ratio (RR) 8.31) and approximately seven times greater for anaplastic astrocytoma (RR 7.22) and other gliomas (RR 5.74) compared with meningiomas. Comparing the first (1986-1989) and the third (1994-1996) time periods, statistically significant improvements in survival occurred for all tumours and astrocytomas. Declines in survival during the second period (1990-1993) were statistically significant for all the tumour groups, but the most striking decrease took place in patients with glioblastoma. Age-specific rates showed that the increase in survival was more evident for patients aged between 45 and 64 years.

Seizure disorders in patients with brain tumors.

The aim of this study was to analyze the clinical data of patients with epileptic seizures and diagnosed brain tumors. Analysis included 711 patients with primary and secondary brain tumors. 165 (23%) patients had experienced at least one seizure before tumor diagnosis. The mean time from the first epileptic seizure to tumor diagnosis was 16 months. The patient's age, location and pathology of tumor were associated with occurrence of seizures. Seizures were more common in patients aged 30-50 years. Tumors involving the frontal, frontoparietal, temporal and frontotemporal lobes were associated with occurrence of seizures. According to the histological diagnosis, patients with mixed gliomas (62%), oligodendrogliomas (53%) and astrocytomas (42%) experienced seizures most frequently.

Epidemiology of primary central nervous system tumors in Estonia.

During the period from 1986 to 1996, 1,665 cases of primary central nervous system (CNS) tumors were identified in the resident population of Estonia. Histological verification was available in 81% of the cases. Gliomas were more common in men, while meningiomas and neurinomas were more common in women. No significant difference was observed between the sexes for all primary CNS tumors. The age-specific incidence increased from the age of 30, reached a maximum in the age range of 50-69 years and declined in the elderly which may reflect under-diagnosis. The age-adjusted incidence rate for CNS tumors was 8.5/100,000 population. A comparison of our results with those of a previous study carried out in Estonia revealed a significant histology-specific increase in incidence in all age groups.

Felt stigma and impact of epilepsy on employment status among Estonian people: exploratory study.

This article examines the impact of epilepsy and its treatment on employment status and the extent of stigma among patients with epilepsy. Clinical and demographic data concerning patients examined during a recent epidemiological survey were obtained from medical notes and postal self-completed questionnaires. Information was collected from 90 patients aged 16-70 years. A third of the respondents had been seizure-free during the last year. Thirty-nine percent were working full-time, 24% were working part-time and 11% were unemployed. Sixty-three percent from those working part-time or unemployed considered their epilepsy to be a significant reason for this. Overall, 55.4% believed they had been treated unfairly at work or when trying to get a job. Fifty-one percent of respondents felt stigmatized by epilepsy, 14% of them highly so. The level of employment among epileptic people was not lower than in the general population. The percentage of stigmatization in general and the percentage of the severely stigmatized was as high or even higher than in other studies. Occurrence of stigma and its severity depended first and foremost on the type of seizures. The frequency of seizures was not clearly related to this.

Registry of first-ever stroke in Tartu, Estonia, 1991 through 1993: outcome of stroke.

OBJECTIVES: To provide information about the functional ability of the survivors of first-ever stroke in Estonia. PATIENTS AND METHODS: A population based epidemiological study 1991 through 1993 in Tartu. Herewith the data for 1991 and 1993 are presented. A total of 519 persons were registered; 82% of them were admitted (mean length 14 days), 66% were discharged home. RESULTS: During 6 months 41% of the patients died, the remaining 305 patients were interviewed about their living conditions, and functional ability using the Barthel ADL Index. Although 58% of patients responded to the questionnaire, no significant differences in several factors between the respondents and non-respondents were found. Thirty-eight percent of the patients were totally independent in ADL. CONCLUSION: The case-fatality rate at 6 months was high in Estonia and the proportion of totally independent patients 6 months after stroke is slightly lower compared to other studies. The short length of hospital treatment was possibly compensated by sufficient support by relatives after discharge.

The risk of motor neurone disease and multiple sclerosis is different in Estonians and Russians. Data from South Estonia.

Epidemiological studies were performed in South Estonia to establish the prevalence rate of multiple sclerosis (MS) and motor neurone disease (MND). The case finding method included information from the hospital records of the central hospital in the region-the University Hospital (for MS from 1942 to 1989), from all neurologists in the region, from the Estonian MS Society and Association of Muscular Disorders, and from nursing homes in the region. The prevalence day was 31 December 1989. MND incidence was established for the period of 1986-1995. The results demonstrated high prevalence rates of MS among native Estonians (55.3 per 100 000), somewhat lower prevalence among native-born representatives of other nationalities (43.6 per 100 000) and the lowest prevalence rate of MS among non-Estonian immigrants (26.6 per 100 000). The differences were not statistically significant. The results for MND demonstrated the opposite pattern. The mean annual incidence rate of MND for 10 years was statistically significantly higher among people of other nationalities (2.5 per 100 000) and Russians (2.6 per 100 000), and lower in native-born Estonians (1.1 per 100 000). No differences in health care or clinical picture were established. The reasons for the demonstrated differences in MND incidence remain unclear.

Motor neurone disease in South Estonia. Diagnosis and incidence rate.

The current study evaluated the diagnostic standards of MND and epidemiological markers of MND in Estonia. A total of 108 patients were referred to the University Hospital from 1986 to 1995 with the first suggested diagnosis or final diagnosis of amyotrophic syndrome, amyotrophic lateral sclerosis (ALS), progressive bulbar paralysis (PBP) or progressive muscular atrophy (PMA). In addition neurologists of the region and the National Society of Neuromuscular disorders were contacted. Some 94 patients satisfied the diagnostic criteria. The annual incidence rate in South Estonia and in the city of Tartu ranged from 0.5 to 2.8 per 100,000. The mean annual incidence rate in Tartu is 1.98 and in South Estonia in general 1.3. The highest incidence rate was 8.3 for men in the age group 60 to 64 years and 7.49 in the age group 70-74; among female patients the highest incidence rate -4.6 was in the age group from 65 to 69.

Changes of sympatho-adrenal and hypothalamo-pituitary-adrenocortical system in patients with head injury.

To determine the role of the sympatho-adrenal (SAS) and hypothalamo-pituitary-adrenocortical system (HPAS) after head injury, the relationship between venous blood epinephrine (E), norepinephrine (NE), adrenocorticotropic hormone (ACTH), cortisol levels, and clinical condition was examined in 55 patients. These observations suggest that head injury causes mainly activation of the above-mentioned systems depending on the severity of trauma. An inverse correlation between the levels of E, NE and Glasgow Coma Scale score, indicating the severity of head injury was revealed. ACTH and cortisol were similarly related to the clinical condition, although the observed correlation was less expressed. The changes in hormonal levels were present during the whole research period (1 week), although a certain shift to normalization was observed. However, catecholamines and ACTH levels in plasma were relatively low in severely head-injured patients whose CT scans revealed serious alterations in the mesencephalic-diencephalic area. At the same time their cortisol levels obtained maximal values and their chance to survive was diminutive. The results of this study indicate that investigation of hormones of SAS and HPAS might be useful as an additional method in the complex of ordinary examinations in establishing early prognosis in patients with brain injury.

Changed incidence and case-fatality rates of first-ever stroke between 1970 and 1993 in Tartu, Estonia.

BACKGROUND AND PURPOSE: The incidence of stroke has stabilized or increased in several developed countries recently, but few data about the trends are available from Eastern Europe. The study was designed to evaluate the possible changes of stroke incidence in Estonia. METHODS: A population-based stroke registry was conducted in Tartu during 1991 through 1993 (mean population, 110,631) to compare it with the study of 1970 through 1973 (population, 90,459). The majority of stroke patients were recorded prospectively, and most were hospitalized and evaluated by a neurologist. All available medical records were reviewed. Only first-ever stroke cases were registered. RESULTS: A total of 667 patients in 1970 through 1973 and 829 patients in 1991 through 1993 were recorded. The total annual incidence per 100,000 rose from 221 to 250 (P = .0173). The total rate for men increased nonsignificantly from 183 to 209 and for women from 258 to 284. Significant increases were observed for men aged 50 to 59 years and for women aged 50 to 69 years; for persons over 70 years, the rates slightly declined. The case-fatality rate at 1 month declined significantly, from 49% to 30%. CONCLUSIONS: A remarkable increase in the incidence and decline in the case-fatality rate of first-ever stroke was observed in Tartu, Estonia. The increase of incidence for those younger than 70 years could be due to the increased prevalence of risk factors. The decline in case fatality could theoretically be related to better management of secondary complications.

Changes of local cerebral blood flow concomitant to lead-exposure in adult rabbits.

Lead is considered a pathogenic factor of atherosclerosis and arterial hypertension, which are main risk factors of cerebrovascular disease. The brain microvasculature preferentially accumulates lead and its function is sensitive to its toxic effect. Influence of inorganic lead-exposure (20 mg/kg-I group, 40 mg/kg II group) for 10 days on local cerebral blood flow (lCBF) in hypothalamus (HYP) and cerebral cortex (CTX) of rabbits was studied by means of the hydrogen clearance method. Corresponding results were compared to sham operated group (III group). During lead-exposure lCBF was reduced in both investigated regions. The reduction of lCBF in HYP was reduced in both investigated regions. The reduction of lCBF in HYP was 12.9% (P < 0.05) in I and 19.9% (P < 0.001) in II group; corresponding changes in CTX were -16.9% (statistically non-significant -N) in I and 1.4% (NS) in II group. Present finding suggest that inorganic lead induces cerebral microvascular dysfunction with following changes in lCBF. These alteration have a biphasic character Although these disturbances reveal a tendency towards normalization, it is possible to presume that higher concentrations of ingested lead cause more severe injury to endothelium of brain microvasculature.

[The dependence of the function of the sympathetic-adrenal and hypothalamo-hypophyseal-adrenal cortical systems on the severity of the traumatic brain lesion]. / Zavisimost' sostoianiia simpatiko-adrenalovoi i gipotalamo-gipofizarno-adrenokortikal'noi sistem ot tiazhesti travmaticheskogo porazheniaia golovnogo mozga.

A total of 43 males with craniocerebral injury of varying severity were studied for the venous blood plasma levels of adrenaline, noradrenaline, adrenocorticotrophic hormone, and hydrocortisone in dynamics. Their computed tomograms were quantitatively analysed to identify the site of contusion foci in the cerebral hemispheres, especially the lesion signs of mesodiencephalic and truncal regions of the brain. The results of the studies and non-linear regression analysis have shown that brain injury leads to a substantial activation of the body's sympathoadrenal system, extremely severe injury causes its partial reduced performance. In severe and critical cerebrocranial injury, the central link of the hypothalamus-pituitary-adrenocortical system is exhausted and hydrocortisone release occurs without its control. The above changes depend on the size of hepatoma and edema of the cerebral hemispheres and on secondary lesion of the brain mesodiencephalic and truncal regions. The activity of the sympathoadrenal and hypothalamus-pituitary-adrenocortical system, which was observed over a week, tended to its gradual decrease.

Prevalence of MS in south Estonia. Evidence of a new border of the Fennoscandian focus.

A population-based study of MS was carried out in South Estonia in 1988-1989. Cases were identified from the Tartu University Hospital archives where all MS cases in South Estonia are diagnosed, from all neurologists and nursing homes of the region, and from the local Multiple Sclerosis Society. The prevalence in South Estonia is 51 per 100,000, for native Estonians 55, for Russians 29, for other nationalities 42 per 100,000. The prevalence rate in different counties was demonstrated as low as 31 per 100,000 in the County of Tartu, to 72 per 100,000 in Pôlva County; 55% of patients have retired because of their handicap and only 2 patients (1%) were living in nursing homes.

[The use of nimodipine in the acute period of a cerebral infarct]. / O primenenii nimodipina v ostrom periode infarkta mozga.

Before and after intravenous administration of 1-1.5 mg nimotop 18 patients with acute brain infarction underwent EEG, integral body rheography, computed tomography and measurement of regional volumetric cerebral circulation (RVCC). Nimotop appeared to increase RVCC in the infarction zone, especially in low initial RVCC levels. The drug induced a shift to EEG normalization and a hypotensive effect, cerebral hemodynamics remaining without changes. Nimodipine-type calcium antagonists favourably affect brain perfusion and bioelectric activity which is promising for application in acute cerebral infarction.

[The prognosis of multiple sclerosis: computed tomographic comparisons]. / Prognoz rasseiannogo skleroza: nekotorye komp'iuterno-tomograficheskie sopostavleniia.

The authors analyze the data obtained at clinical and computed tomography (CT) examinations of 56 patients suffering from multiple sclerosis. The diagnosis was established by G. Schumacher's clinical criteria. Neurologic status of the patients was assessed according to J. E. Kurtzke. A clinical and CT evaluation demonstrates significant correlations between cerebral atrophy and motor insufficiency. Two variants of the disease course are recognized: 1) malignant with emergence of brain atrophy seen at CT as early as the disease year 1; 2) benign with appearance of CT evidence of cerebral atrophy later than the disease year 5. Working ability in variant 2 is recorded for longer periods.

[Cerebral creatine kinase isoenzyme in the cerebrospinal fluid: importance of its measuring for prognosis of the disease outcome in cerebral ischemic disorders]. / Mozgovoi izoénzim kreatinkinazy v spinnomozgovoi zhidkosti: vazhnost' opredeleniia soderzhaniia dlia prognozirovaniia iskhoda bolezni pri ishemicheskikh narusheniiakh golovnogo mozga.

The concentration of cerebral isoenzyme of creatine kinase was measured repeatedly in the cerebrospinal fluid (CSF) in 84 patients with ischemic disorders of brain circulation. Of these, 14 patients presented with transitory ischemic attacks, 20 patients with regressing deficit, and 50 with brain infarction. The patients' health status and functional capacities were estimated on discharge from the hospital. It was discovered that in each patient, the maximum level of cerebral isoenzyme in the CSF was in a good agreement with the clinical course of the disease and neurological status in the survived patients. It may be concluded that measurements of the concentration of the enzyme in the CSF makes it possible to draw more valid prognostic conclusions in patients with ischemic disorders of brain circulation.

Local blood flow in the thalamus and frontal cortex in alert and narcotized dogs.

The magnitude of the local blood flow in the thalamus and cerebral cortex is studied on 22 sexually mature nonpedigree dogs. Mean values of local blood flow are obtained in alert animals, and the effect of narcosis (nitrous oxide) on the local cerebral blood flow is studied. The mean local blood flow in alert dogs is found to be 84.8 +/- 2.9 ml/100 g/min in the cerebral cortex and 68.7 +/- 1.6 ml/100 g/min in the thalamus. Insignificant fluctuations are found during a dynamic recording of the local blood flow during 7 days. Under narcosis (70% nitrous oxide) the local blood flow decreases 3-12%. According to the findings, nitrous oxide narcosis does not significantly affect the brain circulation, so that it is suitable for an experimental study of the latter.

[Late results of ventrolateral thalamotomy in parkinsonism and their mathematical prognosis]. / Otdalennye rezul'taty ventrolateral'noi talamotomii pri parkinsonizme i ikh matematicheskoe prognozirovanie.

Among 63 patients with idiopathic parkinsonism treated by ventrolateral thalamotomy 29 had a long survival period (over 8 years) 34 patients died. The mean postoperative survival period was 4.4 years, the mean survival period from time of the manifestation of the first symptoms was 9.6 years. In 10 of 29 patients the disease did not advance (in 8 with the tremor-rigid and in 2 with the rigid form of parkinsonism). From the late-term postoperative results the authors created a model of prognosis of the duration of the effect of the operation on basis of the patients' preoperative condition and the immediate and early results of the operation.