Browsing by Author "Thomas, SV"

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    Acute stroke care in India
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2008) Thomas, SV
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    An expert system for the diagnosis of epilepsy: Results of a clinical trial
    (NATIONAL MEDICAL JOURNAL OF INDIA, 2001)
    Background. Artificial intelligence is an area where computer systems are used to solve real-life problems that require expert human intelligence. Expert systems serve as an effective alternative to supplement the dearth of human experts in a narrow domain of applications. We developed an expert system named SEIZ using DIAGNOS (an expert system shell for diagnostic applications) for the diagnosis and management of epilepsy.Methods. A clinical trial was done to test the reliability of SEIZ. The clinical and demographic data from the medical records of 50 patients with epilepsy who attended an epilepsy clinic were provided to the expert system. The system-generated diagnosis was compared with the clinical diagnosis.Results. The seizure types and epileptic syndromes for the 50 patients included generalized tonic-clonic seizure (14), absence (4), complex partial seizure (18), simple partial seizure (4), juvenile myoclonic epilepsy (5) and other epileptic syndromes (3). There were two cases of hysterical conversion reaction. There was concordance in the diagnosis between the expert system and clinician in 47 cases (94%). The overall sensitivity was 94% and the specificity was 100% for absence, generalized tonic-clonic seizures, simple partial seizures and juvenile myoclonic epilepsy; 94 for for complex partial seizures and 98% for hysterical conversion reaction.Conclusions This expert system could generate reliable diagnoses for patients with epilepsy. Such a system may be useful for a doctor In a remote or peripheral area where an expert on epilepsy is not available.
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    Antiepileptic drugs and intrauterine death A prospective observational study from EURAP
    (NEUROLOGY, 2015) Tomson, T; Battino, D; Bonizzoni, E; Craig, JJ; Lindhout, D; Perucca, E; Sabers, A; Thomas, SV; Vajda, F
    Objective:To compare the risk of spontaneous abortions and stillbirth associated with maternal use of different antiepileptic drugs (AEDs).Methods:The EURAP registry is an observational international cohort study primarily designed to determine the risk of major congenital malformations (MCMs) after prenatal AED exposure. Using EURAP data, we prospectively monitored pregnancies exposed to the 6 most common AED monotherapies and to polytherapy. Intrauterine death (spontaneous abortion and stillbirth combined) was the primary endpoint.Results:Of 7,055 pregnancies exposed to monotherapy with lamotrigine (n = 1,910), carbamazepine (n = 1,713), valproic acid (n = 1,171), levetiracetam (n = 324), oxcarbazepine (n = 262), or phenobarbital (n = 260), and to polytherapy (n = 1,415), 632 ended in intrauterine deaths (592 spontaneous abortions and 40 stillbirths). Rates of intrauterine death were similar across the different monotherapies (8.2%; 95% confidence interval [CI] 7.5%-8.9%), higher with polytherapy (12.1%; 95% CI 10.5%-13.9%), but showed no relationship with AED dose in monotherapy at conception. Multivariable analysis including 11 covariates in addition to the different AED exposures showed that the risk was greater with polytherapy vs monotherapy (risk ratio [RR] 1.38; 95% CI 1.14-1.66), parental history of MCMs (RR 1.92; 1.20-3.07), maternal age (RR 1.06; 1.04-1.07), and number of previous intrauterine deaths (RR 1.09; 1.00-1.19). The risk was greater with early enrollment and decreased with later gestational week at enrollment (RR 0.84; 0.82-0.86).Conclusions:The most important risk factors for intrauterine death in pregnancies of women with epilepsy include maternal exposure to AED polytherapy and the presence of MCMs in at least one of the parents.
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    Arcuate fasciculus laterality by diffusion tensor imaging correlates with language laterality by functional MRI in preadolescent children
    (NEURORADIOLOGY, 2015) Sreedharan, RM; Menon, AC; James, JS; Kesavadas, C; Thomas, SV
    Language lateralization is unique to humans. Functional MRI (fMRI) and diffusion tensor imaging (DTI) enable the study of language areas and white matter fibers involved in language, respectively. The objective of this study was to correlate arcuate fasciculus (AF) laterality by diffusion tensor imaging with that by fMRI in preadolescent children which has not yet been reported. Ten children between 8 and 12 years were subjected to fMRI and DTI imaging using Siemens 1.5 T MRI. Two language fMRI paradigms-visual verb generation and word pair task-were used. Analysis was done using SPM8 software. In DTI, the fiber volume of the arcuate fasciculus (AFV) and fractional anisotropy (FA) was measured. The fMRI Laterality Index (fMRI-LI) and DTI Laterality Index (DTI-LI) were calculated and their correlation assessed using the Pearson Correlation Index. Of ten children, mean age 10.6 years, eight showed left lateralization while bilateral language lateralization was seen in two. AFV by DTI was more on the left side in seven of the eight children who had left lateralization by fMRI. DTI could not trace the AF in one child. Of the two with bilateral language lateralization on fMRI, one showed larger AFV on the right side while the other did not show any asymmetry. There was a significant correlation (p < 0.02) between fMRI-LI and DTI-LI. Group mean of AFV by DTI was higher on the left side (2659.89 +/- 654.75 mm(3)) as compared to the right (1824.11 +/- 582.81 mm(3)) (p < 0.01). Like fMRI, DTI also reveals language laterality in children with a high degree of correlation between the two imaging modalities.
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    Autoimmune encephalitis: Clinical diagnosis versus antibody confirmation
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2015) Cyril, AC; Nair, SS; Mathai, A; Kannoth, S; Thomas, SV
    Context: Autoimmune encephalitis is a heterogeneous disorder which is being diagnosed with increasing frequency. The diagnosis of these disorders is based on the detection of autoantibodies and characteristic clinical profiles. Aims: We aimed to study the antibody profile in encephalitis patients with suspected autoimmune etiology presenting to a tertiary care center. Settings and Design: The subjects were selected by screening all patients with clinical profile suggesting autoimmune encephalitis admitted in the neuromedical intensive care unit (ICU) of a tertiary care center in South India. Materials and Methods: Patients who fulfilled modified Zuliani et al.'s, criteria for autoimmune encephalitis were identified during the period December 2009-June 2013. Blood samples from these subjects were screened for six neuronal antibodies. Statistical analysis used: Chi-square test was applied to compare the antibody positive and negative patients. Results: Out of 1,227 patients screened, 39 subjects (14 males: 25 females) were identified with a mean age of 15.95 years and 19 cases were assessed in the acute and 20 in the convalescent phase of the illness. Seizure (87.8 %) was the most common presenting symptom; status epilepticus occurred in 23 (60.5%) patients during the course of the illness. Fourteen (35.9%) patients were N-methyl-D-aspartate receptor (NMDAR) antibody-positive and all were negative for the other antibodies tested. Conclusions: One-third of patients presenting with acute noninfective encephalitis would be positive for NMDAR antibodies with the remaining two-thirds with clinically suspected autoimmune encephalitis being antibody-negative. There are few markers in the clinical and investigative profiles to distinguish antibody-positive and -negative patients.
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    Cardiac malformations are increased among infants of mothers with epilepsy
    (EPILEPSIA, 2005) Ajaykumar, B; Thomas, SV; Sindhu, K; Sarma, PS; Francis, E; Namboodiri, KKN; Tharakan, JA
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    Cardiac malformations are increased in infants of mothers with epilepsy
    (PEDIATRIC CARDIOLOGY, 2008)
    We aimed to ascertain the prevalence of cardiac malformation (CM) and its association with antenatal exposure to an antiepileptic drug (AED) in infants of mothers with epilepsy (IMEs). Women with epilepsy (WWE) are enrolled in Kerala Registry of Epilepsy and Pregnancy (KREP) in the prepregnancy or early pregnancy period and are followed up with a standard protocol until the IMEs are 6 years old. At 3 months postpartum, a cardiologist, blinded to the AED exposure, carried out a clinical examination and echocardiography on all live-born babies. Patent foramen ovale (PFO) and interatrial septal defects of < 5 mm in size were excluded from CM. Details of maternal epilepsy, folate usage, AED exposure in the first trimester, and newborn characteristics were abstracted from the records of the KREP. We examined 462 babies. Maternal epilepsy was generalized in 201 (43.50%) or localization related in 241 (52.2%). The AED exposure was monotherapy in 262 (56.7%)-carbamazepine (112), valproate (71), phenobarbitone (43), phenytoin (31), and clonazepam (2)-and polytherapy in 126 (27.3%). Seventy-four infants (16.01%) had no AED exposure. There were 36 infants with CM (7.8%; 95% confidence interval: 5.5-10.6). CMs included atrial septal defect (26; 72.2%), tetrology of Fallot (3; 8.3%), patent ductus arteriosus and pulmonic stenosis (2 each; 5.6%), and ventricular septal defect, tricuspid regurgitation, transposition of great arteries (1 each; 2.8%). CMs were significantly more for IMEs with premature birth (p < .003). There was no association between CM and maternal age, epilepsy syndrome, seizure frequency during pregnancy, and folate use. CMs were more frequent with polytherapy (13; 10.3%) compared to monotherapy (17; 6.5%). Those with valproate exposure had a trend (not statistically significant) toward higher frequency of CM compared to IMEs on other AEDs as monotherapy.
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    Central nervous system tuberculosis
    (AFRICAN HEALTH SCIENCES, 2011) Cherian, A; Thomas, SV
    Central nervous system (CNS) involvement, one of the most devastating clinical manifestations of tuberculosis (TB) is noted in 5 to 10% of extrapulmonary TB cases, and accounts for approximately 1% of all TB cases. Definitive diagnosis of tuberculous meningitis (TBM) depends upon the detection of the tubercle bacilli in the CSF. Every patient with TBM should preferably be evaluated by imaging with contrast enhanced CT either before or within the first 48 hours of treatment. An extra-neural focus of tuberculosis should be sought clinically and radiologically in all patients with CNS TB as it may indicate safer and more accessible sites for diagnostic samplings. A minimum of 10 months treatment is warranted, prompted by the uncertain influences of disease severity, CNS drug penetration, undetected drug resistance and patient compliance. All patients with TB meningitis may receive adjunctive corticosteroids at presentation regardless of disease severity even for those with HIV infection. Drug resistance is strongly associated with previous treatment. The key principle of managing drug-resistant TB is never to add a single drug to a failing regimen. Early ventriculo-peritoneal shunting should be considered in those with hydrocephalus failing medical management. The single most important determinant of outcome is the stage of tuberculous meningitis at which treatment has been started.
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    Cerebrospinal fluid hypovolemia syndrome with benign course
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2010) Ramesha, KN; Chandrashekaran, K; Thomas, SV
    Background: The cerebrospinal fluid hypovolemia syndrome (CHS) is an under recognized cause of headache. This study was designed to highlight the clinico-radiological and cerebrospinal fluid (CSF) picture of CHS and their long-term outcome from a tertiary referral center. Materials and Methods: The CHS was diagnosed on the basis of the criteria proposed by Chung et al. Cases with CSF rhinorrhoea or other CSF leak or head trauma were excluded from the study. Results: The study included eight consecutive cases of CHS diagnosed over the past 7 years from 2001. The mean age at diagnosis was 40.7 years (range, 34-56 years) and male-to-female ratio was 1:3. All patients presented with orthostatic headache of subacute onset and normal neurological examination. Magnetic resonance imaging studies of all patients showed hyperintensity of pachymeninges in T2W sequences, venous distension sign, and diffuse pachymeningeal gadolinium enhancement. The descent of the brainstem and subdural effusion were noted in two each (25%). CSF study (n = 5) showed low opening pressure in three (60%), and mild pleocytosis with elevated protein in two each (40%). The mean time to complete recovery with conservative treatment alone was 25.6 days. All radiological signs disappeared with clinical improvement in three patients where follow-up imaging was done. On mean follow-up period of 3.6 years, all were asymptomatic without any recurrence of CHS. Conclusion: CHS can resolve completely with conservative management and intervention with subdural blood patch or surgical repair would be required only if symptoms persist for more than 1 month.
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    Child rearing issues for mothers with epilepsy: A case control study
    (Annals of Indian Academy of Neurology, 2014) Saramma, PP; Thomas, SV; Sarma, PS
    Background: Epilepsy can cause additional problems in child rearing to mothers with epilepsy (MWE). We aimed to ascertain the knowledge and practice of child rearing in MWE with a pretested questionnaire and compare it with that of mothers without epilepsy (MWoE).Materials and Methods: A standard questionnaire on knowledge (20 questions) and practice (10 questions) of child rearing was prepared through literature review, consultation with subject experts and interview with patients. The questionnaire was administered to 20 MWE with infants less than one-year age and 20 MWoE (matched for age, parity and education). Results: The knowledge on safety needs of infants was significantly ( P <0.01) lower for MWE than for MWoE but the over all knowledge on child rearing was comparable for both groups (12.45 ± 2.95 for MWE and 13.1 ± 3.13 for MWoE). The mean score on child rearing practice (CRP) was significantly lower ( P <0.05) for MWE (27 ± 2.51) than for MWoE (28 ± 1.6). There were three instances of accidentally dropping the baby for the epilepsy group. There was a trend towards better CRP as the knowledge on CR increased.
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    CHILDREN (10-12 YEARS AGE) OF MOTHERS WITH EPILEPSY HAVE LOWER INTELLIGENCE AND VISUAL ATTENTION
    (EPILEPSIA, 2013) Gopinath, N; Muneer, AK; Unnikrishnan, SK; Thomas, SV
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    CHILDREN (10-12 YEARS AGE) OF MOTHERS WITH EPILEPSY HAVE LOWER LANGUAGE PERFORMANCE
    (EPILEPSIA, 2013) Mohan, AC; Kumari, AMMG; Unnikrishnan, SK; Thomas, SV
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    Children (10-12 years age) of women with epilepsy have lower intelligence, attention and memory: Observations from a prospective cohort case control study
    (EPILEPSY RESEARCH, 2015) Gopinath, N; Muneer, AK; Unnikrishnan, S; Varma, RP; Thomas, SV
    Objective: To compare the cognitive outcome of children of women with epilepsy (CWE) with matched controls (CWO). Methods: CWE (10-12 years) under follow up in Kerala Registry of Epilepsy and Pregnancy (n= 190) were evaluated with WISC-IV, Trail Making Test (TMT), Rey Auditory Verbal Learning Test (RAVLT) and compared with age and sex matched children of women without epilepsy - CWO (n = 149) drawn from schools in the same region. The dosage was expressed as prescribed daily dose/daily-defined dose (PDD/DDD) ratio in order to make comparisons. Results: The Full Scale IQ of CWE (77.9 +/- 14.6) was 8.5 points lower than that of CWO (86.4 +/- 13.4), which was statistically significant (p=0.001). They performed lower on TMT Part A & B and RAVLT. The FSIQ mean +/- SD; PDD/DDD ratio and number of monotherapy exposure for different anti-epileptic drugs were phenobarbital: (74.5 +/- 14; 1.1 +/- 0.8; 22), valproate: (82.8 +/- 12.4; 0.3 +/- 0.1; 36), carbamazepine: (82.2 +/- 13.9; 0.6 +/- 0.3; 41), phenytoin: (82.6 +/- 13.5; 0.8 +/- 0.3; 11). The FSIQ for those exposed to phenobarbital was significantly (p =0.01) lower than others. The significant predictors of FSIQ differed at lower and higher ends of its spectrum. These predictors were low body mass index and low maternal education for FSIQ < 80 and low maternal education, low maternal IQ and high anti-epileptic drug dosage for FSIQ < 86. High anti-epileptic drug dosage, low maternal IQ and low paternal education were the predictors for FSIQ < 92. Significance: The IQ attention and memory were significantly lower for 10-12 year old CWE when compared to CWO. The important predictors of low FSIQ were antiepileptic drug dosage, maternal IQ and parental education. (C) 2015 Elsevier B.V. All rights reserved.
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    Complications of pregnancy and delivery in women with epilepsy
    (EPILEPSIA, 2005) Sindhu, K; Thomas, SV; Ajaykumar, B; Sylaja, PN; Sulekhadevi, PB; Jacob, S
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    Design and data analysis 1 study design
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2012) Suresh, K; Suresh, G; Thomas, SV
    This article is intended to give the reader guidance in evaluating different study designs used in medical research for better scientific quality, reliability and validity of their research. This article explains three main types of study designs with understanding examples. Care and caution with skills and experience needed to design suitable studies and appropriate design coupled with reliable sampling techniques and appropriate statistical analysis, supported by clear objectives with decent communication of the findings, are essential for good research.
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    Design and data analysis case-controlled study in clinical research
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2013) Thomas, SV; Suresh, K; Suresh, G
    Clinicians during their training period and practice are often called upon to conduct studies to explore the association between certain exposures and disease states or interventions and outcomes. More often they need to interpret the results of research data published in the medical literature. Case-control studies are one of the most frequently used study designs for these purposes. This paper explains basic features of case control studies, rationality behind applying case control design with appropriate examples and limitations of this design. Analysis of sensitivity and specificity along with template to calculate various ratios are explained with user friendly tables and calculations in this article. The interpretation of some of the laboratory results requires sound knowledge of the various risk ratios and positive or negative predictive values for correct identification for unbiased analysis. A major advantage of case-control study is that they are small and retrospective and so they are economical than cohort studies and randomized controlled trials.
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    Design, data analysis and sampling techniques for clinical research
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2011) Suresh, K; Thomas, SV; Suresh, G
    Statistical analysis is an essential technique that enables a medical research practitioner to draw meaningful inference from their data analysis. Improper application of study design and data analysis may render insufficient and improper results and conclusion. Converting a medical problem into a statistical hypothesis with appropriate methodological and logical design and then back-translating the statistical results into relevant medical knowledge is a real challenge. This article explains various sampling methods that can be appropriately used in medical research with different scenarios and challenges.
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