Browsing by Author "Radhakrishnan, K"

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    A locus for juvenile myoclonic epilepsy maps to 2q33-q36
    (HUMAN GENETICS, 2010) Ratnapriya, R; Vijai, J; Kadandale, JS; Iyer, RS; Radhakrishnan, K; Anand, A
    We performed a whole genome linkage analysis in a three-generation south Indian family with multiple members affected with juvenile myoclonic epilepsy (JME). The maximum two-point LOD score obtained was 3.32 at recombination fraction (theta) = 0 for D2S2248. The highest multipoint score of 3.59 was observed for the genomic interval between D2S2322 and D2S2228 at the chromosomal region 2q33-q36. Proximal and distal boundaries of the critical genetic interval were defined by D2S116 and D2S2390, respectively. A 24-Mb haplotype was found to co-segregate with JME in the family. While any potentially causative variant in the functional candidate genes, SLC4A3, SLC23A3, SLC11A1 and KCNE4, was not detected, we propose to examine brain-expressed NRP2, MAP2, PAX3, GPR1, TNS1 and DNPEP, and other such positional candidate genes to identify the disease-causing gene for the disorder.
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    A multi-level wavelet approach for automatic detection of epileptic spikes in the electroencephalogram
    (COMPUTERS IN BIOLOGY AND MEDICINE, 2008) Indiradevi, KP; Elias, E; Sathidevi, PS; Nayak, SD; Radhakrishnan, K
    We describe a strategy to automatically identify epileptiform activity in 18-channel human electroencephalogram (EEG) based on a multi-resolution, multi-level analysis. The signal on each channel is decomposed into six sub-bands using discrete wavelet transform. Adaptive threshold is applied on sub-bands 4 and 5. The spike portion of EEG signal is then extracted from the raw data and energy of the signal for locating the exact location of epileptic foci is determined. The key points of this process are identification of a suitable wavelet for decomposition of EEG signals, recognition of a proper resolution level, and computation of an appropriate dynamic threshold. (c) 2008 Elsevier Ltd. All rights reserved.
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    A pilot study of a yoga meditation protocol for patients with medically refractory epilepsy
    (JOURNAL OF ALTERNATIVE AND COMPLEMENTARY MEDICINE, 2006)
    Objective: The objective was to assess the efficacy of a yoga meditation protocol (YMP) as an adjunctive treatment in patients with drug-resistant chronic epilepsy.Design: The design was a prospective, nonrandomized, open-label, add-on trial with a 12-week baseline period, followed by a 12-week supervised YMP administration phase. The frequency of complex partial seizures (CPS) was assessed at 3, 6, and 12 months of the treatment period.Setting: The setting was a comprehensive epilepsy care center attached to a tertiary referral medical institution situated on the southwest coast of the Indian peninsula.Subjects: The subjects were 20 patients (14 males and 6 females, age range 15 to 47 years, median 27 years) with unequivocally established diagnoses of epilepsy with at least 4 CPS (with or without secondary generalization) during the preceding 3 months.Intervention: Intervention consisted of a YMP 20 minutes twice daily (mornings and evenings) at home, and supervised sessions of a YMP every week for 3 months. Continuation of the YMP beyond 3 months was optional.Outcome measure: The outcome measure was the seizure frequency at 3, 6, and 12 months of the treatment period. The subjects with >= 50% reduction in monthly seizure rate from baseline were classified as responders, and subjects with < 50% seizure reduction as nonresponders.Results: At 3 months, a reduction in seizure frequency was noted in all except 1 patient, six of whom had >= 50% seizure reduction. Of 16 patients who continued the YMP beyond 3 months, 14 patients responded at 6 months; 6 of them were seizure-free for 3 months. All eight patients who continued the YMP beyond 6 months responded; three of them were seizure free for 6 months.Conclusions: If confirmed through randomized trials involving a larger number of patients, this YMP may become a cost-effective and adverse effect-free adjunctive treatment in patients with drug-resistant epilepsies.
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    A questionnaire survey about doctor-patient communication, compliance and locus of control among South Indian people with epilepsy
    (EPILEPSY RESEARCH, 2000)
    To date, very few studies have investigated patients' views on the information they receive from the doctor concerning epilepsy and its management. Little information is available about the influence of doctor-patient communication and locus of control on the compliance of persons with epilepsy. We investigated, through a questionnaire-interview design, among patients attending the epilepsy clinic of a tertiary referral center in South India, their views about the provision of information by the doctor, and their compliance and locus of control. We also determined the interrelation between doctor-patient communication, compliance and locus of control. Our subjects comprised 200 adult persons with epilepsy, 113 males and 87 females, mean age 30.5 (range 18-67) years. Over one-third of the subjects received from the doctor insufficient information about epilepsy and its treatment. There was a significant positive correlation between effective doctor-patient communication and compliance. A majority of our patients had an external locus of control, which negatively influenced the compliance. Even in a comprehensive epilepsy clinic of a model tertiary referral center in a developing country, a significant proportion of patients do not receive optimal information about epilepsy from the doctor. Knowledge about their disease will encourage people with epilepsy to make informed choices, and achieve better compliance and personal control of their problems. Educating primary and secondary care physicians about the importance of doctor-patient communication in the management of epilepsy and educating the public about the positive aspects of life in epilepsy cannot be overemphasized. (C) 2000 Published by Elsevier Science B.V. All rights reserved.
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    A survey of epilepsy surgery in India
    (SEIZURE-EUROPEAN JOURNAL OF EPILEPSY, 2015) Menon, RN; Radhakrishnan, K
    Purpose: Epilepsy surgery (ES) not only remains one of the most underutilized of all accepted medical interventions, but there has also been a decrease in referrals for ES in recent years in high-income countries. We undertook this study to determine the temporal trends of ES and its current state in India. Methods: We asked the directors of epilepsy centers across India to complete an online questionnaire about the number and type of ES procedures carried out from 1995 or commencement of the program till December 2012. Results: During the 18-year period, a total of 4252 ES have been undertaken. On an average, 420 ES were being carried out each year in India. Three-fourths of resective surgeries involved the temporal lobe. Although majority of patients were selected for ES by noninvasive strategies, 13 centers had performed long-term invasive EEG monitoring to select complex cases. In between 1995-2000 and 2007-2012, the number of ES carried out in India registered an increase by three-fold. Conclusions: A steadily increasing number of eligible patients with drug-resistant epilepsy in India are undergoing ES in recent years. This temporal trend of ES in India is in contrast to the recent experience of high-income countries. (C) 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.
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    Absence of GABRA1 Ala322Asp mutation in juvenile myoclonic epilepsy families from India
    (JOURNAL OF GENETICS, 2003) Kapoor, A; Vijai, J; Ravishankar, HM; Satishchandra, P; Radhakrishnan, K; Anand, A
    An Ala322Asp mutation in the GABRA1 gene was recently reported to be responsible for causing the autosomal dominant (AD) form of juvenile myoclonic epilepsy (JME) in a French-Canadian family. To study if WE families from India exhibiting the AD mode of inheritance carry the Ala322Asp mutation, we examined 35 unrelated JME-affected individuals from such families for the Ala322Asp mutation in GABRA1. Ala322Asp mutation was not observed in any of these JME-affected individuals, suggesting that this mutation is unlikely to be a predominant mutation involved in causation of epilepsy. To evaluate the possibility of other mutation(s) in and around GABRA1 that may predispose to JME, we compared the allele frequencies at two marker loci, D5S2118 and D5S422, flanking GABRA1, in probands and 100 matched population controls. One of the allele frequencies at D5S422 shows a significant difference between the cases and controls (chi(2) = 11.44, d.f. = 1, P = 0.0007), suggesting genetic association between WE and genes located in the proximity of the DNA marker.
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    An overview of pre-surgical evaluation
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2014) Radhakrishnan, K
    The success of an epilepsy surgery program depends upon the early identification of potential surgical candidates and selecting from them, ideal candidates for surgery, who are destined to have a post-operative seizure-free outcome without any unacceptable neurological deficits. Since epilepsy surgery centers in resource-poor countries will lack the full range of state-of-the-art technologies usually available in resource-rich countries to perform pre-surgical evaluation, cost-effectively utilization of the locally available investigative facilities to select the surgical candidates becomes challenging. In the present era of rapid electronic communications and telemedicine, it has become possible for epilepsy surgery centers to pool their technological and human resources and to partner with centers nationally and internationally in implementing pre-surgical evaluation strategies.
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    Antiepileptic pharmacotherapy: Prevalence of polytherapy and its implications
    (NEUROLOGY INDIA, 1998) Radhakrishnan, K; Nayak, SD
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    BEYOND THE LEARNING CURVE IN EPILEPSY SURGERY: THE INSTITUTIONAL AND INDIVIDUAL PERSPECTIVE
    (EPILEPSIA, 2011) Vilanilam, GC; Abraham, M; Menon, G; Rao, RM; Nair, S; Radhakrishnan, K
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    Blindness, ophthalmoplegia and extensive radiculopathy: An unusual clinical syndrome in intracranial sino-venous thrombosis
    (NEUROLOGY INDIA, 2004)
    Isolated intracranial hypertension is a common manifestation of intracranial sino-venous thrombosis (ISVT). Markedly elevated intracranial tension presents with unusual features including cranial neuropathies and radiculopathy. We report two cases with ISVT, which presented with headache, papilledema, progressive visual loss, complete ophthalmoplegia and flaccid areflexic quadriparesis along with a normal sensorium. Magnetic resonance imaging (MRI) of the brain and cervical spinal cord showed no lesions that could account for the neurological deficits. Markedly elevated lumbar CSF pressure was noted in both cases. Nerve conduction study favored radiculopathy in one case and was normal in the other. Raised intracranial pressure was found to be the sole cause for the clinical manifestations. Visual impairment persisted in one patient despite lumbo-peritoneal shunting while the other died of septicemia. To our knowledge there are no previous reports of a syndrome comprising blindness, ophthalmoplegia and flaccid quadriplegia due to intracranial hypertension in ISVT.
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    Brainstem abscess complicating tetralogy of fallot successfully treated with antibiotics alone
    (NEUROLOGY INDIA, 2000)
    Medically treated brainstem abscess in a 11 year old boy with tetralogy of Fallot is reported. There was a complete resolution of the lesion without any neurologic sequelae during parenteral antibiotic therapy with crystalline penicillin, chloramphenicol and metronidazole. The pathogenesis and management of cardiogenic brain abscesses in general and brainstem abscess in particular has been reviewed.
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    Calcified neurocysticercosis lesions and antiepileptic drug-resistant epilepsy: A surgically remediable syndrome?
    (EPILEPSIA, 2013) Rathore, C; Thomas, B; Kesavadas, C; Abraham, M; Radhakrishnan, K
    PurposeIn contrast to the well-recognized association between acute symptomatic seizures and neurocysticercosis, the association between antiepileptic drug (AED)-resistant epilepsy and calcified neurocysticercosis lesions (CNLs) is poorly understood. We studied the association between AED-resistant epilepsy and CNLs, including the feasibility and outcome of resective surgery. MethodsFrom the prospective database maintained at our epilepsy center, we reviewed the data of all patients with AED-resistant epilepsy who underwent presurgical evaluation from January 2001 to July 2010 and had CNL on imaging. We used clinical, neuroimaging, and interictal, ictal, and intracranial electroencephalography (EEG) findings to determine the association between CNL and epilepsy. Suitable candidates underwent resective surgery. Key FindingsForty-five patients fulfilled the inclusion criteria. In 17 patients, CNL was proven to be the causative lesion for AED-resistant epilepsy (group 1); in 18 patients, CNL was associated with unilateral hippocampal sclerosis (HS; group 2); and in 10 patients, CNLs were considered as incidental lesions (group 3). In group 1 patients, CNLs were more common in frontal lobes (12/17), whereas in group 2 patients, CNLs were more commonly located in temporal lobes (11/18; p=0.002). Group 2 patients were of a younger age at epilepsy onset than those in group 1 (8.97.3 vs. 12.6 +/- 6.8years, p=0.003). Perilesional gliosis was more common among patients in group 1 when compared to group 3 patients (12/17 vs. 1/10; p=0.006). Fifteen patients underwent resective surgery. Among group 1 patients, four of five became seizure-free following lesionectomy alone. In group 2, four patients underwent anterior temporal lobectomy (ATL) alone, of whom one became seizure-free; five underwent ATL combined with removal of CNL (two of them after intracranial EEG and all of them became seizure-free, whereas one patient underwent lesionectomy alone and did not become seizure-free. SignificanceIn endemic regions, although rare, CNLs are potential cause for AED-resistant and surgically remediable epilepsy, as well as dual pathology. Presence of perilesional gliosis contributes to epileptogenicity of these lesions. For those patients with CNL and HS, resection of both lesions favors better chance of seizure-free outcome.
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    CALCIFIED NEUROCYSTICERCUS LESIONS (CNL) AND DRUG RESISTANT EPILEPSY: SURGICALLY REMEDIABLE SYNDROME?
    (EPILEPSIA, 2013) Rathore, C; Thomas, B; Kesavadas, C; Abraham, M; Radhakrishnan, K
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    Calcified Neurocysticercus Lesions and Hippocampal Sclerosis: Potential Dual Pathology?
    (NEUROLOGY, 2012) Radhakrishnan, K; Rathore, C; Thomas, B; Kesavadas, C
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    CAN SPIKE VOLTAGE TOPOGRAPHY PREDICT THE ICTAL PATTERNS IN TEMPORAL LOBE EPILEPSY?
    (EPILEPSIA, 2011) Parameswaran, S; Radhakrishnan, A; Radhakrishnan, K
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    Clinical and electroencephalographic correlates of breach activity
    (AMERICAN JOURNAL OF ELECTRONEURODIAGNOSTIC TECHNOLOGY, 1999) Radhakrishnan, K; Chandy, D; Menon, G; Sarma, S
    In order to define the EEG spectrum and the prevalence of breach activity, as well as the factors contributing to its genesis, we studied 50 patients with surgically induced skull defects. We observed breach activity in 32 (64%) patients. Focally enhanced alpha, beta, and mu rhythms with or without decreased amplitude of eye movement artifacts were the EEG findings encountered in our patients. The amplitude asymmetry never exceeded a factor of 3 or more. Of the variables compared between patients with and without breach activity, only the time between surgery and the EEG recording correlated positively with the development of breach activity. The delay in the development of breach activity may indicate that breach activity is not due solely to the discontinuity of bone. The development of meningocortical adhesions and gliosis could contribute to the pathogenesis of breach activity.
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    Clinical characteristics of a South Indian cohort of juvenile myoclonic epilepsy probands
    (SEIZURE-EUROPEAN JOURNAL OF EPILEPSY, 2003)
    Despite the distinctive clinical and electroencephalographic features known for five decades, even today, juvenile myoclonic epilepsy (JME) is frequently unrecognised and misdiagnosed in both developed and developing countries. Utilising 183 JME probands belonging to the South Indian state of Kerala, assembled through a tertiary referral centre for molecular genetic studies, we explored the phenotypic peculiarities, clinical genetics, and problems and pitfalls in the diagnosis of JME. At referral, only six (3.3%) patients carried the diagnostic label of JME, default in diagnosis resulted from failure to elicit the history of myoclonic jerks by the referring physicians. During the mean delay of 8.6 +/- 7.0 years in diagnosing JME, seizure control in the majority was poor due to inappropriate antiepileptic drug (AED) therapy. A history of epileptic seizures was obtained in 6.2% of the first-degree and 2.2% of the second-degree relatives of the probands; 37.7 and 11.1% of them, respectively, were diagnosed as JME. Although most of the clinical features of our cohort were in accordance with the literature, two notable differences we observed were the relatively increased occurrence of absence seizures and low frequency of photoparoxysmal responses. Although the variability in the clinical characteristics of JME may be apparent due to differences in the ascertainment of the data, they may well be an expression of a true clinical heterogeneity, and are in accordance with the complex and variable mode of inheritance and conflicting linkage studies reported for this syndrome from different ethnic groups. (C) 2003 BEA Trading Ltd. Published by Elsevier Science Ltd. All rights reserved.
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    Complications in acute stroke in India (CAST-1): A multicenter study.
    (J Stroke Cerebrovasc Dis, 2012-12) Pandian, JD; Kaur, A; Jyotsna, R; Sylaja, PN; Vijaya, P; Padma, MV; Venkateswarlu, K; Sukumaran, S; Mathew, R; Kaur, P; Singh, YP; Radhakrishnan, K
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    Complications in acute stroke in India (CAST-1): A multicenter study.
    (J Stroke Cerebrovasc Dis, 2012-12) Pandian, JD; Kaur, A; Jyotsna, R; Sylaja, P N; Vijaya, P; Padma, MV; Venkateswarlu, K; Sukumaran, S; Mathew, R; Kaur, P; Singh, YP; Radhakrishnan, K