Atanu Biswas

A Prospective Community-Based Study of Stroke in Kolkata, India

Background and Purpose— Information on essential stroke parameters are lacking in India. This population-based study on stroke disorder was undertaken in the city of Kolkata, India, to determine the subtypes, prevalence, incidence, and case fatality rates of stroke. Methods— This was a longitudinal descriptive study comprising 2-stage door-to-door survey of a stratified randomly selected sample of the city population, conducted twice per year for 2 successive years from March 2003 to February 2005. Results— Out of the screened population of 52 377 (27 626 men, 24 751 women), the age standardized prevalence rate of stroke to world standard population is 545.10 (95% CI, 479.86 to 617.05) per 100 000 persons. The age standardized average annual incidence rate to world standard population of first-ever-in-a-lifetime stroke is 145.30 (95% CI, 120.39 to 174.74) per 100 000 persons per year. Thirty-day case fatality rate is 41.08% (95% CI, 30.66 to 53.80). Women have higher incidence and case fatality rates. Despite divergence on socioeconomic status between the slum and nonslum dwellers, stroke parameters were not significantly different. Conclusion— The age standardized prevalence and incidence rates of stroke in this study are similar to or higher than many Western nations. The overall case fatality rate is among the highest category of stroke fatality in the world. The women have higher incidence and case fatality rates compared with men.

An epidemiologic study of mild cognitive impairment in Kolkata, India

Objectives: To estimate the prevalence of two types of mild cognitive impairment (MCI)—amnestic and multiple domain types—among nondemented and nondepressed elderly subjects aged 50 and older. Methods: The study was carried out in Kolkata, the eastern metropolis of India. A cross-sectional community screening was carried out, and 960 subjects were selected by systematic random sampling for the assessment of cognitive function with the help of a validated cognitive questionnaire battery administered through house-to-house survey. A case-control study was also undertaken to identify potential risk factors through univariate analysis. Results: Ultimately, full evaluation of cognitive function was possible in 745 of 960 subjects. An overall prevalence of MCI detected based on neuropsychological testing was 14.89% (95% CI: 12.19 to 17.95). Prevalence of the amnestic type was 6.04% (95% CI: 4.40 to 8.1) and that of the multiple domain type was 8.85% (95% CI: 6.81 to 11.32). Adjusted for age, education. and gender, the amnestic type was more common among men and the multiple domain type among women with advancement of age. Rates differed considerably with educational attainment. Hypertension and diabetes mellitus were the major risk factors for both types of MCI. Conclusion: In this first community-based study of mild cognitive impairment (MCI) from India, prevalence of the amnestic type is comparable with and that of the multiple domain type is less than the prevalence in developed countries. Variations in age, education, and gender specific prevalence of MCI of both types were encountered. The putative risk factors identified merit further study.

Altered Serum Levels of Adipokines and Insulin in Probable Alzheimer's Disease

Cerebral hypometabolism of glucose, weight loss, and decreased food intake are characteristic features of sporadic Alzheimers disease (AD). A systematic study on the serum levels of adipokines and insulin, the major hormones regulating energy metabolism, food intake, and body weight, in sporadic AD is necessary. The present study compares the serum levels of leptin, adiponectin, and insulin, measured by commercially available immuno-assay kits, between controls and sporadic AD subjects. The results show a conspicuous decrease in the level of leptin, a dramatic rise in the level of adiponectin, and also a statistically significant increase in insulin level, in the blood of AD subjects, with respect to controls. The changes in the serum levels of adiponectin and insulin in AD are positively correlated with the severity of dementia. Likewise, the serum level of leptin in AD subjects is negatively correlated with the degree of dementia. The changes in the levels of adipokines and insulin have implications in the amyloid pathology, neurodegeneration, and hypometabolism of glucose existing in the AD brain.

Reactive oxygen species, redox signaling and neuroinflammation in Alzheimer's disease: the NF-κB connection.

Oxidative stress and inflammatory response are important elements of Alzheimers disease (AD) pathogenesis, but the role of redox signaling cascade and its cross-talk with inflammatory mediators have not been elucidated in details in this disorder. The review summarizes the facts about redox-signaling cascade in the cells operating through an array of kinases, phosphatases and transcription factors and their downstream components. The biology of NF-κB and its activation by reactive oxygen species (ROS) and proinflammatory cytokines in the pathogenesis of AD have been specially highlighted citing evidence both from post-mortem studies in AD brain and experimental research in animal or cell-based models of AD. The possibility of identifying new disease-modifying drugs for AD targeting NF-κBsignaling cascade has been discussed in the end.

Neurological disorders in children and adolescents

ObjectiveTo ascertain the prevalence of active epilepsy, febrile seizures (FS), cerebral palsy (CP) and tic disorders (TD) in aged 19 years or less.MethodsThis was a cross-sectional observational study conducted as a two-stage door-to-door survey of a stratified randomly selected population in 2003-04. Trained field workers screened the population followed by case examination by the field neurologist.ResultsA total of 16979 (male 8898, female 8081) subjects aged ≤ 19 years were surveyed. The prevalence rates per 100,000 population of active epilepsy, FS, CP and TD with 95% confidence intervals are 700.87 (580.60–838.68), 1113.14 (960.07–1283.59), 282.70 (CI 208.43–374.82) and 35.34 (12.96–76.92) respectively. Active epilepsy prevalence shows a rising trend and that of other disorders a declining trend with age. Of the epileptics who had brain CT scans, 23.4% showed single or multiple lesions suggestive of neurocysticercosis. Regarding treatment, 23.5% of the epileptics never received any antiepileptic drugs. Among those with history of FS, 9.5% developed epilepsy later on. The prevalence of FS among slum dwellers is lower than in the non-slum population. Among CP cases, 39.6% gave history of birth anoxia, 16.7% kernicterus and 31.3% epilepsy. Prevalence of CP is significantly associated with lower education status.ConclusionThe prevalence of CP and TD is lower than reported from western countries. CP prevalence is also comparatively lower than in many community studies from India. Compared to western nations, higher proportion of FS cases develops epilepsy. A third of the CP cases have seizures which is higher than in many Indian studies. Birth anoxia is a common cause of CP and educational underachievement is frequent.

Metabolic Risk Factors of Sporadic Alzheimer's Disease: Implications in the Pathology, Pathogenesis and Treatment

Alzheimers disease (AD), the major cause of dementia among the elderly world-wide, manifests in familial and sporadic forms, and the latter variety accounts for the majority of the patients affected by this disease. The etiopathogenesis of sporadic AD is complex and uncertain. The autopsy studies of AD brain have provided limited understanding of the antemortem pathogenesis of the disease. Experimental AD research with transgenic animal or various cell based models has so far failed to explain the complex and varied spectrum of AD dementia. The review, therefore, emphasizes the importance of AD related risk factors, especially those with metabolic implications, identified from various epidemiological studies, in providing clues to the pathogenesis of this complex disorder. Several metabolic risk factors of AD like hypercholesterolemia, hyperhomocysteinemia and type 2 diabetes have been studied extensively both in epidemiology and experimental research, while much less is known about the role of adipokines, pro-inflammatory cytokines and vitamin D in this context. Moreover, the results from many of these studies have shown a degree of variability which has hindered our understanding of the role of AD related risk factors in the disease progression. The review also encompasses the recent recommendations regarding clinical and neuropathological diagnosis of AD and brings out the inherent uncertainty and ambiguity in this area which may have a distinct impact on the outcome of various population-based studies on AD-related risk factors.

Gut dysfunction in Parkinson's disease.

Early involvement of gut is observed in Parkinsons disease (PD) and symptoms such as constipation may precede motor symptoms. α-Synuclein pathology is extensively evident in the gut and appears to follow a rostrocaudal gradient. The gut may act as the starting point of PD pathology with spread toward the central nervous system. This spread of the synuclein pathology raises the possibility of prion-like propagation in PD pathogenesis. Recently, the role of gut microbiota in PD pathogenesis has received attention and some phenotypic correlation has also been shown. The extensive involvement of the gut in PD even in its early stages has led to the evaluation of enteric α-synuclein as a possible biomarker of early PD. The clinical manifestations of gastrointestinal dysfunction in PD include malnutrition, oral and dental disorders, sialorrhea, dysphagia, gastroparesis, constipation, and defecatory dysfunction. These conditions are quite distressing for the patients and require relevant investigations and adequate management. Treatment usually involves both pharmacological and non-pharmacological measures. One important aspect of gut dysfunction is its contribution to the clinical fluctuations in PD. Dysphagia and gastroparesis lead to inadequate absorption of oral anti-PD medications. These lead to response fluctuations, particularly delayed-on and no-on, and there is significant relationship between levodopa pharmacokinetics and gastric emptying in patients with PD. Therefore, in such cases, alternative routes of administration or drug delivery systems may be required.

Raised Serum Proinflammatory Cytokines in Alzheimer’s Disease with Depression

The purpose of the present study was to identify the changes in the levels of proinflammatory cytokines like IL-1β, IL-6 and TNF-α in peripheral circulation in Alzheimers disease (AD) subjects and to correlate these with associated depression and cognitive deficit. Fifty five AD subjects and thirty seven age and sex matched controls were included in the study. The AD patients were grouped as AD with depression (n= 31) and AD without depression (n= 24). The serum levels of IL-1β, IL-6 and TNF-α were determined by immunoassay by commercially available kits. The serum levels of IL-6 and TNF-α were elevated in AD patients with depression compared to control (p<0.001) or AD without depression (p<0.001). The serum level of IL-1β was higher in AD patients with or without depression as compared to controls. Furthermore, a strong inverse correlation was observed between the MMSE scores and serum levels of IL-6 or TNF-α in AD subjects with depression. The study highlights the important role of peripheral IL-6 and TNF-α in AD associated depression and cognitive deficits.

Community survey of primary dystonia in the city of Kolkata, India

An epidemiological study on dystonia has not been reported from India. As part of a major study to find out the prevalence of major neurological disorders in the large urban city of Kolkata, Eastern India, we planned to determine the prevalence of primary dystonia. The study design was a cross‐sectional study of a sample population obtained through stratified random selection and conducted in a two‐stage procedure of screening by a nonprofessional team followed by confirmation of screened positive cases by the study neurologist. A total population of 52,377 was screened, and 29 subjects with dystonia were diagnosed. Out of them 23 subjects had primary dystonias [crude prevalence rate (CPR), 43.91/100,000; 95% confidence interval (CI), 28.41–64.81; age‐standardized rates to world standard population, 49.06 (95% CI,31.74–72.41)] and all cases were focal type and predominantly of limb dystonia variety. Mean onset of dystonias were earlier in women (43.5 years) as compared to men (46.6 years). Thus our study on primary dystonia shows higher prevalence when compared with that of many studies globally, predominantly of focal type, earlier onset among women, and more cases of limb dystonias when compared with more prominent blepharospasm and cervical dystonias in western reports.

Neuropsychiatric profiles in patients with Alzheimer's disease and vascular dementia

Background/Aims: The aim of the following study is to compare the behavioral and psychological symptoms of dementia (BPSD) in patients of Alzheimer disease (AD) and vascular dementia (VaD). Materials and Methods: We used National Institute of Neurological and Communicative Disorders and Stroke-Alzheimers Disease and Related Disorders Association criteria for diagnosing AD and National Institute of Neurological Disorders and Stroke-Association International pour la Recherche et l’Enseignement en Neurosciences Criteria for diagnosing VaD. VaD cohort was further subcategorized into small vessel and large vessel disease. The severity of cognitive impairment and the BPSD were studied by means of the Clinical Dementia Rating Scale (CDR) and the Neuropsychiatric Inventory respectively. Results: We studied 50 AD and 50 VaD patients of whom 38 were small vessels and 12 were large vessels VaD. The severity of dementia was comparable in both groups. The agitation/aggression, depression/dysphoria, anxiety, apathy/indifference, irritability, aberrant motor behavior, appetite and eating behavior and night-time behaviors occurred significantly more frequently in patients with VaD than AD. We found a weak positive correlation between the CDR score and the number of neuropsychiatric symptoms per patient in both cohorts. Elation/euphoria, agitation/aggression was significantly more frequent in patients with large vessel in comparison to small vessel VaD. Conclusions: BPSD are common in both types of dementia and they are more severe in VaD than AD when the groups have similar levels of cognitive impairment.