Browsing by Author "Menon, RN"

Now showing 1 - 10 of 10
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    A hospital-based registry of Creutzfeldt-Jakob disease: Can neuroimaging serve as a surrogate biomarker?
    (NEUROLOGY INDIA, 2016) Divya, KP; Menon, RN; Thomas, B; Nair, M
    Aim: This study addresses the role of neuroimaging in addition to the available clinical criteria for Creutzfeldt-Jakob disease (CJD) and its impact on its diagnosis in the absence of cerebrospinal fluid (CSF) biomarkers and tissue-based approaches. Methods: From a tertiary referral center in the city of Trivandrum, Kerala, South India, patients with rapidly progressive dementia (RPD) who fulfilled the World Health Organization (WHO) 1998 diagnostic criteria for CJD were included in this study. Their electrophysiological-clinical-radiological data were retrospectively studied and the results were analyzed. The other biomarkers of CJD were not assessed in the study. Results: Of the 96 patients with RPD, 41 patients were diagnosed as having a 'probable' and 'possible' CJD using the WHO 1998 diagnostic criteria between 2000 and 2013. While 92% patients satisfied the University of California, San Francisco (UCSF) 2007 and European magnetic resonance imaging (MRI)-CJD consortium criteria (2009), only 73% satisfied the MRI components of these criteria in addition to the more stringent, proposed UCSF MRI criteria (2011). The latter required the presence of diffusion weighted imaging abnormalities more than fluid attenuation inversion recovery abnormalities in the cortical and subcortical regions for the establishment of diagnosis on MRI of 'definite' (53.7%) and 'probable' CJD (19.5%). Conclusions: Significant heterogeneity exists in the presentation of CJD with only 48.8% patients simultaneously satisfying the MRI and electrophysiological criteria, suggesting that the diagnosis is impacted by these components in any of the currently prevalent criteria. With 27% of the cohort not meeting the radiological criteria, CSF and molecular biomarker assays may be reserved for MRI negative patients with suspected CJD and in atypical presentations.
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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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    A critical evaluation of the lateralizing significance of material-specific memory deficits in patients with mesial temporal lobe epilepsy with hippocampal sclerosis
    (Epilepsy Behav, 2013-08) Jeyaraj, MK; Menon, RN; Justus, S; Alexander, A; Sarma, PS; Radhakrishnan, K
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    Does F-18 FDG-PET substantially alter the surgical decision-making in drug-resistant partial epilepsy?
    (EPILEPSY & BEHAVIOR, 2015) Menon, RN; Radhakrishnan, A; Parameswaran, R; Thomas, B; Kesayadas, C; Abraham, M; Vilanilam, G; Sarma, SP
    Objective: There is a dearth of information on the critical utility of positron emission tomography (PET) in choosing candidates for epilepsy surgery especially in resource-poor countries where it is not freely available. This study aimed to critically analyze the utility of FDG-PET in the presurgical evaluation and surgical selection of patients with DRE based on the results obtained through its use in our comprehensive epilepsy program. Methods: From 2008 to 2012, 117 patients with drug-resistant epilepsy underwent F-18 fluoro-deoxy-glucose (FDG) PET in our center. We utilized their data to audit the utility of PET in choosing/deferring patients for surgery. Results: Of the 117 patients (age: 5-42 years) who underwent F-18 FDG-PET, 64 had normal MRI, and 53 had lesions. Electroclinical data favored temporal ictal onset in 48 (41%), extratemporal in 60 (51.3%), and uncertain lobar localization in 9 (7.7%). The topography of PET hypometabolism was localizing in 53 (45.3%), lateralizing in 12 (10.3%), and 52 (44.4%) had either normal or discordant results. In the nonlesional group, focal hypometabolism was concordant to the area of ictal onset in 27 (41.5%) versus 38 (58.5%) in the lesional group (p = 0.002). Greater concordance was noted in temporal lobe epilepsy (TLE) (78.0%) as compared to extratemporal epilepsy (ETPE) (28.6%) (p < 0.001). Positron emission tomography was more concordant in patients with mesial temporal sclerosis than in those with other lesions (82.8% versus 50%) (p = 0.033). Positron emission tomography helped in surgical decision-making in 68.8% of TLE and 23.3% of ETPE cases. Overall, 37 patients (31.6%) were directly selected for resective surgery based on PET results. Conclusions: Positron emission tomography, when utilized judiciously, remained an ancillary tool in the surgical selection of one-third of patients with drug-resistant partial epilepsy, although its utility as an independent tool is not very promising. (C) 2015 Elsevier Inc. All rights reserved.
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    Epilepsy with myoclonic absences: Electroclinical characteristics in a distinctive pediatric epilepsy phenotype
    (EPILEPSY & BEHAVIOR, 2016) Zanzmera, P; Menon, RN; Karkare, K; Soni, H; Jagtap, S; Radhakrishnan, A
    Purpose: The purpose of this article was to study the electroclinical characteristics and seizure outcome of children with epilepsy with myoclonic absences (EMA). Method: In this descriptive cohort study, we reviewed clinical records of patients who met the criteria for EMA. Each patient's demographic data, birth/developmental history, seizure semiology/pattern, antiepileptic drugs (AED), clinical examination, video-electroencephalography (VEEG), and neuroimaging data were reviewed. Response to AED and change in seizure frequency/pattern on follow-up were noted. Responders were defined by seizure freedom/>50%.reduction.in seizure frequency on follow-up. Result: Twelve children were diagnosed with EMA between 2008 and 2013 [50% male; mean age of onset: 3.5 years]. Main seizure types were the characteristic myoclonic absences (100%) and generalized tonic-clonic seizures (42%). Ictal correlate on VEEG was 3- to 3.5-Hz spike-and-wave discharges (82%) and fast recruiting bifrontal rhythm (25%). One patient had specific MRI abnormalities. Mean duration of follow-up was 23.9 months. Seizure frequency had significantly improved on follow-up (p = 0.005), and at last follow-up, nine patients were in the responder group: four seizure-free for at least 1 year, two with >90%, and three with >50% reduction in seizure frequency. The number of AED reduced significantly between initial visit and last follow-up among responders. Two patients on follow-up developed different seizure patterns, with generalized tonic and complex partial seizures. One responder expired because of unprovoked generalized convulsive status epilepticus. Conclusion: This cohort, the largest from the Indian subcontinent on the rare syndrome of EMA, suggests mild heterogeneity in a seemingly homogenous electroclinical phenotype. Clinical semiology while unique may demonstrate focality and variable ictal patterns. Most patients respond to either valproate monotherapy or valproate-lamotrigine combination; however, the prognosis remains guarded. The seizures of a minority of patients remain drug-refractory and may evolve into tonic or complex partial seizures. (C) 2016 Elsevier Inc. All rights reserved.
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    Mucolipidosis and progressive myoclonus epilepsy: A distinctive phenotype
    (NEUROLOGY INDIA, 2013) Menon, RN; Jagtap, S; Thakkar, R; Narayanappa, G; Nair, M
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    Ultrasensitive Detection of Blood-Based Alzheimer’s Disease Biomarkers: A Comprehensive SERSImmunoassay Platform Enhanced by Machine Learning
    (ACS Chemical Neuroscience, 2024-11) Resmi, AN; Nazeer, SS; Dhushyandhun, ME; Paul, Willi; Chacko, BP; Menon, RN; Jayasree, RS
    Accurate and early disease detection is crucial for improving patient care, but traditional diagnostic methods often fail to identify diseases in their early stages, leading to delayed treatment outcomes. Early diagnosis using blood derivatives as a source for biomarkers is particularly important for managing Alzheimer’s disease (AD). This study introduces a novel approach for the precise and ultrasensitive detection of multiple core AD biomarkers (Aβ40, Aβ42, p-tau, and t-tau) using surface-enhanced Raman spectroscopy (SERS) combined with machine-learning algorithms. Our method employs an antibody-immobilized aluminum SERS substrate, which offers high precision, sensitivity, and accuracy. The platform achieves an impressive detection limit in the attomolar (aM) range and spans a wide dynamic range from aM to micromolar (μM) concentrations. This ultrasensitive and specific SERS immunoassay platform shows promise for identifying mild cognitive impairment (MCI), a potential precursor to AD, from blood plasma. Machine-learning algorithms applied to the spectral data enhance the differentiation of MCI from AD and healthy controls, yielding excellent sensitivity and specificity. Our integrated SERS-machine-learning approach, with its interpretability, advances AD research and underscores the effectiveness of a cost-efficient, easy-to-prepare Al-SERS substrate for clinical AD detection.
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    Use of Electrographic Seizures and Interictal Epileptiform Discharges for improving performance in Seizure Prediction
    (PROCEEDINGS OF THE 2015 IEEE RECENT ADVANCES IN INTELLIGENT COMPUTATIONAL SYSTEMS (RAICS), 2015) Sudalaimani, C; Asha, SA; Parvathy, K; Thomas, ET; Devanand, P; Sasi, PM; Menon, RN; Ashalatha, R; Thomas, SV
    Electroencephalography (EEG) is an important tool in analyzing brain activity. EEG recording is effectively used for detection and prediction of electrophysiological abnormalities due to epilepsy. Epileptic seizure is a brain disorder which affects the patients acutely. Seizures are controllable with medication in 70% of the cases, however the rest may continue to have recurring epileptic seizures despite medications. Since seizures are unpredictable clinically, these patients will also live with perpetual anxiety about the onset of seizure, apart from being affected by the seizure consequences such as drowsiness, headache, vomiting, etc. The seizures can cause injury to the patients, and in some cases may even result in death. Seizure prediction can aid patients with disabling seizure by detecting the seizure precursors in advance and alerting the patients or their caregivers. If the seizure is predicted in advance it can be aborted by fast acting Anti-epileptic drugs (AEDs) or other treatment procedures. This will also aid pre-surgical video EEG monitoring wherein prediction of the ictal onset zone is paramount and machine alarms can be devised. In this paper, we are comparing the results of our research work related to the seizure prediction models. First model, as in usual practice, differentiates between preictal and interictal data segments only. The other seizure prediction model uses Interictal Epileptiform Discharges (IEDs), Electrographic Seizures (ES) and ictal data segments in addition to the first model. We found that the latter one provided better results and improved the seizure prediction performance.
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    Validity of Montreal Cognitive Assessment in Non-English speaking patients with Parkinson's disease
    (NEUROLOGY INDIA, 2015) Krishnan, S; Justus, S; Meluveettil, R; Menon, RN; Sarma, SP; Kishore, A
    Background: The Montreal Cognitive Assessment is a brief and easy screening tool for accurately testing cognitive dysfunction in Parkinson's disease. We tested its validity for use in non-English (Malayalam) speaking patients with Parkinson's disease. Materials and Methods: We developed a Malayalam (a south-Indian language) version of Montreal Cognitive Assessment and applied to 70 patients with Parkinson's disease and 60 age-and education-matched healthy controls. Metric properties were assessed, and the scores were compared with the performance in validated Malayalam versions of Mini Mental Status Examination and Addenbrooke's Cognitive Examination. Results: The Montreal Cognitive Assessment-Malayalam showed good internal consistency and test-retest reliability and its scores correlated with Mini Mental Status Examination (patients: R = 0.70; P < 0.001; healthy controls: R = 0.26; P = 0.04) and Addenbrooke's Cognitive Examination (patients: R = 0.8; P < 0.001; healthy controls: R = 0.52; P < 0.001) scores. Conclusion: This study establishes the reliability of cross-cultural adaptation of Montreal Cognitive Assessment for assessing cognition in Malayalam-speaking Parkinson's disease patients for early screening and potential future interventions for cognitive dysfunction.