Ravi Yadav

National Institute of Mental Health and Neuro Sciences | NIMHANS · Department of Neurology

Owing to the presence of multiple enzymatic domains, LRRK2 has been associated with a diverse set of cellular functions and signaling pathways. It also has several pathological mutant-variants, and their incidences show ethnicity biases and drug-response differences with expression in dopaminergic-neurons and astrocytes. Here, we aimed to assess th...

Psychotic symptoms occur in a majority of schizophrenia patients and in ~50% of all Parkinson’s disease (PD) patients. Altered grey matter (GM) structure within several brain areas and networks may contribute to their pathogenesis. Little is known, however, about transdiagnostic similarities when psychotic symptoms occur in different disorders, suc...

Background: Creutzfeldt-Jakob disease (CJD) is a rare neuro degenerative disease that is mainly characterized by rapidly progressive dementia along with a varying combination of myoclonus, visual, cerebellar, pyramidal/extrapyramidal and akinetic mutism. Several movement disorders phenomenologies can occurs either at onset, as presenting symptom o...

Introduction: Pantothenate kinase-associated neurodegeneration (PKAN) is the most common "Neurodegeneration with Brain Iron Accumulation" disorder. This study aimed to study the clinical, radiological and genetic profiling of a large cohort of patients with PKAN. Methods: This is an ambispective hospital-based single centre study conducted at a...

Objectives Evaluating “Fitness to Re-join Job” and certification in persons with Neuro-Psychiatric Disorders is an indispensable professional responsibility. However, there is little documented guidance on clinically approaching this particular issue. This study aimed to study the sociodemographic, clinical, and employment profile of patients who s...

Background: About 70-90% of Parkinson's disease (PD) patients have olfactory deficits which is considered as pre-motor symptom of PD. Lewy bodies have been demonstrated in the olfactory bulb (OB) in PD. Objective: To assess the OB volume (OBV), olfactory sulcus depth (OSD) in PD and compare with progressive supranuclear palsy (PSP), multiple sys...

Introduction: Patients with functional neurological disorders (FND) present with weakness, sensory or movement disorder without corresponding brain pathology. The current classificatory systems suggest an inclusionary approach to diagnose FND. Hence, there is a need to systematically evaluate the diagnostic accuracy of clinical signs and electroph...

Occasionally, movement disorders can occur following interventional procedures including but not limited to radiotherapy, dental procedures, and cardiac, cerebral and spinal surgeries. The majority of these disorders tend to be unexpected sequelae with variable phenomenology and latency, and they can often be far more disabling than the primary dis...

Introduction: Vascular Parkinsonism (VaP) is characterized by symmetric, predominantly lower limb bradykinesia and rigidity and no significant improvement with levodopa. We aimed to describe the clinical and radiological features of patients with VaP and the factors that determine levodopa responsiveness. Methods: This is a retrospective chart r...

Tardive dystonia (TD) can be a disabling condition and is usually refractory to medical therapy. Over the past decade, case reports and case series have demonstrated significant benefits of refractory TD with deep brain stimulation (DBS) of the globus pallidus interna (GPi). We present an illustrative case of refractory TD treated with GPi-DBS with...

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder. In India, an accurate number of PD patients remains uncertain owing to the unawareness of PD symptoms in the geriatric population and the large discrepancy between the number of PD patients and trained neurologists. Constructing additional neurological care centers al...

Fabry’s disease (FD) is an X-linked inherited lysosomal storage disease caused by a defect in the GLA gene, which encodes the lysosomal enzyme α-galactosidase A resulting in accumulation of glycosphingolipids—mainly globo triaosylceramide (Gb3)—in cells throughout the body, causing symptoms affecting multiple organs. Neurological symptoms in FD ar...

Objective: To differentiate genetic variants of spinocerebellar ataxia (SCA1 and SCA2) and healthy controls using machine learning on resting-state functional Magnetic Resonance Imaging graph features. Background: SCA is a group of hereditary ataxias and is identified by degeneration in the cerebellum and sometimes in the spinal cord. Early differ...

Objective: To ascertain the role of resting-state functional MRI (rsfMRI)-based modularity in differentiating spinocerebellar ataxia type 1 (SCA1) and spinocerebellar ataxia type 2 (SCA2). Background: Although SCA1 and SCA2 tend to possess certain distinct clinical features, there may be no definite distinctions on imaging, especially in the early...

Objective: To assess the predictive power of Diffusion Kurtosis Imaging (DKI) parameters obtained from Neurite orientation dispersion and density imaging tool (NODDI) to differentiate between Parkinson’s disease (PD) subjects and Healthy Controls (HC). Background: Diffusion indices have been utilized by researchers to check for pathological abnorm...

Erdheim Chester Disease (ECD) is a rare histiocytic neoplasm affecting multiple tissues, with Central Nervous System (CNS) involvement in 40-50% of cases. Although known to be posterior fossa predominant, widespread neurologic involvement throughout the brain, spinal cord, meninges, orbits, and pituitary has recently been described with the involve...

Background Huntington’s disease (HD), caused by a pathogenic expansion of CAG triplet repeats in exon 1 of the Huntingtin (HTT) gene, has also been linked to three major haplogroups (A, B, and C), which may impact the prevalence of HD. The distribution of these haplotypes in diverse populations is thus important. Aim To study the haplotype structu...

Introduction: Niemann-Pick disease type C (NPC) is an autosomal recessive neurovisceral lipid storage disorder caused by mutations in the NPC 1 or 2 genes. Movement disorders can occur as the first symptom and as predominant symptom mainly in juvenile-onset. The frequency and heterogeneity of movement disorders in NPC are not well described. We st...

Being a large multidomain protein, LRRK2 has several confirmed pathological mutant variants for PD, and the incidence of these variants shows ethnicity biases. I1371V, a mutation in the GTPase domain, has been reported in East-Asian populations, but there are no studies reported on dopaminergic (DA) neurons differentiated from this variant. The aim...

INTRODUCTION: The coronavirus disease-19 (COVID-19) pandemic is a global health crisis that has directly and indirectly impacted almost all populations globally. In this study, we aimed to study the impact of the COVID-19 pandemic on motor and nonmotor symptoms in patients with various movement disorders who visited our outpatient department. MATER...

Background: Emerging evidence supports the view that brain stimulation might improve essential tremor (ET) by altering brain dynamics and facilitating brain plasticity. Yet, we are still missing a mechanistic explanation of the whole brain dynamics underlying these plasticity-defining changes. Method: In this study, we explored the effect of low-fr...

Introduction: Movement disorders can present in emergency services in an acute severe form which can be life threatening if not recognized. The relative frequency and spectrum of movement disorder emergencies have not been studied extensively. We studied the frequency, spectrum, and outcome of patients presenting with movement disorders emergencie...

Parkinson's disease (PD) is a genetically heterogeneous neurodegenerative disease with poorly defined environmental influences. Genomic studies of PD patients have identified disease‐relevant monogenic genes, rare variants of significance, and polygenic risk‐associated variants. In this study, whole genome sequencing data from 90 young onset Parkin...

BACKGROUND: There is definite evidence for the involvement of retina in Parkinson's disease (PD). However, a specific pattern has not been clear due to the cross-sectional nature of the majority of the previous studies. OBJECTIVE: The aim of this work was to study the pattern of changes in the retinal layers in patients with PD on longitudinal fol...

Woodhouse‐Sakati syndrome (WSS) is an extremely rare multi‐systemic disorder with neuroendocrine dysfunctions. It is characterized by hypogonadism, alopecia, diabetes mellitus, intellectual disability and progressive extrapyramidal syndrome along with radiological features of small pituitary gland, progressive frontoparietal white matter changes an...

Background: Rare movement disorders (RMDs) throw remarkable challenges to their appropriate management particularly when they are medically refractory. We studied the outcome of functional neurosurgery among patients with RMDs. Methods: Retrospective chart-review from 2006 to 2021 of patients with RMDs who underwent either Deep brain Stimulation...

Background: Oculomotor abnormalities are one of the cardinal clinical features of progressive supranuclear palsy (PSP). Vertical saccadic slowing is an early sign of PSP. The association between oculomotor abnormalities and sleep architecture has not been studied so far. Objectives: To study the association of oculomotor abnormalities of PSP wit...

Background PLA2G6-Associated Neurodegeneration, PLAN, is subdivided into: Infantile neuroaxonal dystrophy, atypical neuroaxonal dystrophy, and adult-onset dystonia parkinsonism [1]. It is elicited by a biallelic pathogenic variant in phospholipase A2 group VI (PLA2G6) gene. In this study we describe new cases and provide a comprehensive review of p...

Background Psychotic symptoms occur in a majority of schizophrenia patients, and in approximately 50% of all Parkinson’s disease (PD) patients. Altered grey matter (GM) structure within several brain areas and networks may contribute to their pathogenesis. Little, however, is known about transdiagnostic similarities when psychotic symptoms occur in...

Purpose: Psychiatric comorbidity in Parkinson's disease (PD) and atypical parkinsonian syndromes (APS) has been consistently associated with poor outcomes. However, the co-occurrence of multiple psychiatric disorders has been sparsely studied. This study examines the prevalence, patterns, and correlates of psychiatric comorbidity and multimorbidit...

Progressive supranuclear palsy (PSP) is the second most common Parkinsonian disorder with complex etiology. The underlying molecular mechanism of PSP pathogenesis remains unclear. The present study aims to find the feasibility of using plasma miRNAs as novel biomarkers. Plasma-focused qPCR panels were used for microRNA profiling and identified diff...

Non-motor symptoms (NMS) are common among Parkinson's disease (PD) patients and have a significant impact on quality of life. NMS such as deficits in emotion perception are gaining due focus in the recent times. As emotion perception and cognitive functions share certain common neural substrates, it becomes pertinent to evaluate existing emotion pe...

Background: Progressive supranuclear palsy (PSP) is a rapidly progressive primary tauopathy characterized by vertical gaze palsy, postural instability, and mild dementia. PSP shows high clinical and pathologic heterogeneity. Although a few risk factors exist, such as advanced age and environmental toxins, the precise etiology remains largely elusiv...

Introduction: Spinocerebellar ataxia type-12 (SCA12) is a rare form of SCA, most commonly reported from the Indian Agarwal and related families. In this study we describe the clinical, genetic, and radiological characteristics of a sizeable cohort of genetically proven SCA12. Methods: A retrospective chart-review of the genetically confirmed SCA...

Background: Sleep disturbances have been reported to occur in progressive supranuclear palsy (PSP). The anatomical regions affected in PSP and those regulating sleep and wake cycle like dorsal raphe nucleus, locus coeruleus (LC), and pedunculopontine nucleus (PPN) overlap. There is a paucity of polysomnographic studies in PSP and they have shown a...

Objective: This study aims to identify the demographic, clinical, and therapeutic characteristics of four patients with hemimasticatory spasm (HMS) seen in our outpatient department over a period of 20 years. Methods: We performed a retrospective chart review of four patients with HMS who visited outpatient services in the Department of Neurolog...

Objective: With the use of next-generation sequencing in clinical practice, several genetic etiologies of dystonia have been identified. This study aimed to ascertain the utility of clinical exome sequencing (CES) in dystonia and factors suggestive of a genetic etiology. Methods: This study was a retrospective chart review of patients with dysto...

Background : ChAdOx1-S (Covishield™/Vaxzervria, AstraZeneca) and BBV152 (Covaxin) SARS-CoV-2 vaccines are proven to be safe and effective, but rare complications have been reported. Objective : To describe reports of central nervous system (CNS) demyelination following ChAdOx1-S and BBV152 vaccinations. Methods & Results : We report 29 (17 female...

Background: The traditional Neurology exit examination in India has remained unchanged over the last few decades. In developed countries, objective evaluation methods have replaced the traditional ones. A need for such methods has not been explored in India. Objective: We aimed to study the perceptions and key recommendations of Neurology examin...

Charcot-Marie-Tooth disease, type 4D (CMT4D) is a progressive, autosomal recessive form of CMT, characterized by distal muscle weakness and atrophy, foot deformities, severe motor sensory neuropathy, and sensorineural hearing impairment. Mutations in NDRG1 gene cause neuropathy in humans, dogs, and rodents. Here, we describe clinical and genetic fe...

Parasomnias are defined as a group of sleep disorders that are characterized by abnormal, unpleasant motor, verbal, or behavioral events that occur during entry into sleep, within sleep, and during arousals from sleep. Hence unusual behavioral events are an integral part and parcel of these disorders. They may be associated with a variety of sensor...

This study describes the generation and characterization of 3 induced pluripotent stem cell lines (iPSCs) generated by somatic reprogramming of peripheral blood mononuclear cells (PBMCs) obtained from healthy individuals. The reprogramming was carried out using non-integrating Sendai virus vectors expressing hKOS, hc-myc and hKlf4. The donors did n...

Objective Cognition has been reported to be involved in patients with multiple system atrophy (MSA), although initially it was considered an exclusion in the diagnosis of MSA. We assessed cognition in these patients and compared it with age and education matched healthy controls and correlated with the gray matter volume using voxel-based morphomet...

Cognitive impairment of different severity with eventual progression to dementia in Parkinson’s disease (PD) appears during the course of the disease. In this study, transcranial magnetic stimulation (TMS) was used to assess cortical excitability changes in PD patients with varying cognitive impairment. We aimed to identify the TMS parameters that...

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare white matter degenerative disease manifesting as progressive cognitive decline, pyramidal, and extrapyramidal features resulting from mutations in the colony-stimulating factor-1 receptor (CSF1R) gene. We describe a sporadic case of a young man who developed f...

Background: Progressive supranuclear palsy [PSP] is a neurodegenerative condition with characteristic clinical and imaging features. Aim: This is an exploratory MRS study to look at metabolic changes that occur due to the disease by using MR spectroscopic methods in subtypes of the PSP, that is, classic [PSP-c] and Parkinsonian [PSP-p]. Materia...

Background: Cerebral venous sinus thrombosis (CVST) is a life-threatening condition with a predilection for a younger age group. Patients with CVST can have features of raised intracranial pressure that can be suspected clinically based on ophthalmological findings such as bilateral abduction restriction, papilledema. Case description: A 27-year...

INTRODUCTION: Dystonia is one of the most common hyperkinetic movement disorders observed in children with neurological disorders. The objective of this study was to evaluate the demographic, etiological, and radiological profile of childhood dystonia.

INTRODUCTION: Psychosis is one of the incapacitating non-motor symptoms of Parkinson’s disease (PD). Although several risk factors that include older age, rapid eye movement sleep (REM) behavior disorder (RBD), depression, and cognitive dysfunction have been identified, the exact neural correlates remain elusive. As cognitive impairment has a close...

Background Huntington’s disease (HD) is a progressive neurodegenerative disorder characterised by chorea, cognitive impairment, psychiatric and behavioral disturbances. Sleep disturbances including reduced REM sleep have been observed in HD. Objectives The aim of the study was to study the polysomnography findings in HD and to assess whether oculo...

Introduction We aimed to study the cortical and intracortical functions in patients of ET using transcranial magnetic stimulation (TMS) and to evaluate the effect of continuous theta burst stimulation (cTBS) on the tremor characteristics. Methods Ten ET and 20 healthy controls were included in the study. All the participants were evaluated with TM...

Objectives: The objective of this study is to describe the clinical, biochemical, radiological, and genetic profile of patients presenting with progressive spastic paraparesis due to homocysteine remethylation pathway defect. Methods: This was a retrospective study conducted by reviewing the medical records of patients with serum homocysteine le...

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Objective: Joubert syndrome (JS) is a rare syndrome characterized by ataxia and the molar tooth sign (MTS) on imaging. The present study aims to explore the clinical and radiological features in a cohort of patients with JS. Methods: This was a retrospective chart review of patients with JS evaluated by movement disorder specialists. Results:...