Ketan Jhunjhunwala’s research while affiliated with Dharwad Institute of Mental Health and Neurosciences and other places

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Publications (40)


Can yoga lead to maladaptive plasticity resulting in disorder of motor control?
  • Article
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November 2020

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126 Reads

Annals of Movement Disorders

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Ketan Jhunjhunwala

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The practice of yoga is based on the traditional Indian philosophy. Children during their development show adaptive neuroplasticity which is due to long-term potentiation that causes changes in the synaptic transmission. Excessive plasticity in the developing brain can lead to maladaptive neuronal circuits which can cause hyperkinetic movement disorders. It is not clear at what age yoga should be started and whether certain yogas or yogas done improperly can lead to maladaptive plasticity. We report here an unusual case of tic disorder which was precipitated by yoga.

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Gray matter correlates of progression of motor symptoms in patients with Parkinson’s disease

August 2019

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63 Reads

Abstract: OBJECTIVE: The objective of this study was to evaluate the gray matter (GM) volume alterations in different clinical stages of Parkinson’s disease (PD) through voxel-based morphometry (VBM). BACKGROUND: Assessment of the clinical stages of PD is usually carried out using the Hoehn and Yahr (H–Y) scale. However, there is paucity of literature on the association of GM atrophy with the progression of motor symptoms in PD. METHODS: Forty-five patients with a diagnosis of PD (H–Y I: 15, H–Y II: 15, H–Y III: 15) and 45 healthy controls (HC) were recruited. T1-weighted images were obtained through a 3-Tesla magnetic resonance imaging machine. VBM was used to compare the regional changes in the GM volume of the three groups. RESULTS: No significant differences were observed in the demographic and clinical characteristics of the groups except in the duration of symptoms (H–Y I vs. H–Y III, 2.7 ± 1.9 vs. 7.4 ± 5.2 years, P < 0.01), and Unified Parkinson’s Disease Rating Scale III ON-state score (H–Y I vs. H–Y III, 16.2 ± 8.4 vs. 24.5 ± 8.3, P < 0.02). Volume of the left parahippocampal gyrus (Brodmann area 34) was significantly different among the four groups. Post hoc analysis revealed gradual reduction in the volume of the parahippocampal gyrus from H–Y stage I (highest) to H–Y stage III (lowest). CONCLUSION: There is progressive decrease in GM volume of the parahippocampal gyrus with the advancement of stage of PD. This result suggests that the volume of parahippocampal gyrus may represent one of the neuroimaging correlates of the H–Y staging of PD.


Basal ganglia contributions during the learning of a visuomotor rotation: Effect of dopamine, deep brain stimulation and reinforcement

June 2019

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118 Reads

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8 Citations

European Journal of Neuroscience

It is commonly thought that visuomotor adaptation is mediated by the cerebellum while reinforcement learning is mediated by the basal ganglia. In contrast to this strict dichotomy, we demonstrate a role for the basal ganglia in visuomotor adaptation (error‐based motor learning) in patients with Parkinson's disease (PD) by comparing the degree of motor learning in the presence and absence of dopamine medication. We further show similar modulation of learning rates in the presence and absence of subthalamic deep brain stimulation. We also report that reinforcement is an essential component of visuomotor adaptation by demonstrating the lack of motor learning in patients with PD during the ON‐dopamine state relative to the OFF‐dopamine state in the absence of a reinforcement signal. Taken together, these results raise the possibility that the basal ganglia modulate the gain of visuomotor adaptation based on the reinforcement received at the end of the trial. This article is protected by copyright. All rights reserved.


Posttraumatic movement disorders: A clinical and imaging profile of 30 patients

May 2019

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22 Reads

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4 Citations

Neurology India

Background: Posttraumatic movement disorders (PTMDs) are frequently associated with severe head injury. There are very few studies on the clinical phenomenology and radiological correlation of PTMD. Aims: To study the clinical phenomenology of patients with PTMD and correlate it with the site of lesion on brain imaging. Materials and methods: This was a prospective study of patients with suspected PTMD. All of these patients underwent neurological evaluation to characterize the phenomenology and imaging, such as computed tomography/magnetic resonance imaging (CT/MRI), to localize the site of lesion. Results: The age of the patients was 32.6 ± 16.4 years and the age at onset was 29.1 ± 16.0 years. Right upper limb was the initial body part affected in 36.7% patients. Tremor (alone or with dystonia) was the most common movement disorder (MD; 44.7%) followed by parkinsonism (17.2%), dystonia (13.8%), dystonia plus (dystonia associated with choreoathetosis: 10.3%), mixed MD (more than one MD: 10.3%), and myoclonus (3.4%). MRI was performed in 23 patients and the rest seven patients underwent CT brain. Normal MRI was observed in one patient with parkinsonism. Isolated, discrete lesions were found in six (27.3%) patients. Basal ganglia was the most common site of involvement (66.7%) followed by thalamus (16.7%) and brainstem (16.7%). Diffuse white matter involvement was the most common radiological lesion in patients with tremor. Conclusions: Our study describes the clinical phenomenology of patients with PTMDs and its radiological correlation. Tremor (alone or in combination with dystonia) was the most common MD observed and diffuse white matter lesions without affection of the basal ganglia was the most common site of lesion.


Figure 1: Experiment setup and design: (A) Subjects made point-to-point reaching
Figure 2: Ataxia patients in visuomotor adaptation. (A) The maximum error in pre-
Figure 4: Parkinson's patients with subthalamic deep brain stimulation (A) Maximum error
Figure 5: Parkinson's patients without reinforcement in visuomotor adaptation (A) Maximum
Figure 7: Correlation between differences in UPDRS scores with the differences in learning
Basal ganglia contributions during the learning of a visuomotor rotation: effect of dopamine, deep brain stimulation and reinforcement

April 2019

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130 Reads

It is commonly thought that visuomotor adaptation is mediated by the cerebellum while reinforcement learning is mediated by the basal ganglia. In contrast to this strict dichotomy, we demonstrate a role for the basal ganglia in visuomotor adaptation (error-based motor learning) in patients with Parkinsons disease (PD) by comparing the degree of motor learning in the presence and absence of dopamine medication. We further show similar modulation of learning rates in the presence and absence of subthalamic deep brain stimulation. We also report that reinforcement is an essential component of visuomotor adaptation by demonstrating the lack of motor learning in patients with PD during the ON-dopamine state relative to the OFF-dopamine state in the absence of a reinforcement signal. Taken together, these results suggest that the basal ganglia modulate the gain of visuomotor adaptation based on the reinforcement received at the end of the trial.


Phenotypic Variability of Essential Tremor Based on the Age at Onset

January 2019

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54 Reads

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13 Citations

The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques

Background: Essential tremor (ET) is reported to have a bimodal distribution of age at onset (AAO) with phenotypic variability based on the AAO. This study aims to explore the distribution of AAO based on mathematical modeling and ascertain the differences, if any, in the clinical features of groups. Methods: A chart review was conducted for 252 patients with ET diagnosed based on the Consensus statement of the Movement Disorder Society on Tremor. Finite mixture modeling was performed to identify groups of the cohort based on the AAO. Results: Three groups were defined: early onset (EO): AAO ≤ 22 years, n = 63, intermediate onset (IO): 23 ≤ AAO ≤ 35 years, n = 43, and late onset (LO): AAO ≥ 36 years, n = 146. There were no significant differences related to family history or responsiveness to alcohol. The EO group had significantly higher prevalence of upper limb and lower limb tremor. Head tremor and voice tremor was more prevalent in the IO and LO groups. Cerebellar signs showed a significant increase with an increase in AAO. Conclusions: ET shows significant phenotypic variability based on the AAO. Patients with an early AAO are more likely to develop an appendicular tremor, whereas the probability of axial tremor and cerebellar signs increases with increasing AAO.


Clinical Utility of Longitudinal Measurement of Motor Threshold in Wilson’s Disease

January 2019

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32 Reads

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16 Citations

The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques

This study describes the longitudinal changes of resting motor threshold (RMT) and central motor conduction time (CMCT) in 18 patients with Wilson’s disease (WD). The RMT, CMCT, and Global Assessment Scale for Wilson Disease (GAS-WD) were measured at baseline and at follow-up after 12.94 ± 7.23 months. There was a significant decrease in the RMT (72.11 ± 18.62 vs. 63.7 ± 15.52%; p -value = 0.002) and GAS-WD scores (14.38 ± 5.35 vs. 9.77 ± 6.47 ms; p -value = 0.04). CMCT did not improve despite chelation therapy. Hence, RMT may serve as a marker of chelation efficacy in WD.


Implications of secondary unresponsiveness to dopaminergic drugs with preserved response to subthalamic nucleus stimulation in Parkinson's disease

March 2018

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37 Reads

Neurology India

Improvement in motor symptoms with levodopa is one of the hallmark features of Parkinson’s disease (PD). The response to levodopa may reduce during the course of the illness. Few studies have also reported reduced response to levodopa in patients with PD several years after deep brain stimulation (DBS) of the subthalamic nucleus (STN) on both the sides. In this study, we report an extreme unresponsiveness to levodopa in the presence of a good response to STN stimulation in a patient 5 years after the DBS proceudre had been carried out. The implications of this phenomenon are also discussed.


Shaky and unsteady: Dynamic posturography in essential tremor

December 2017

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114 Reads

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13 Citations

Journal of the Neurological Sciences

Background: The spectrum of symptoms exhibited by patients with essential tremor (ET) extends far beyond the classical tremor. This study aims to explore and establish the presence of subtle balance abnormalities in ET using dynamic posturography (DP). Methods: DP was performed on 18 patients with ET and 26 controls. Diagnosis of ET was based on the Consensus Statement of the Movement Disorder Society on Tremor. Dynamic stability which included the overall balance index, anterior-posterior index and mediolateral index, and limits of stability were measured. Results: Patients with ET had significantly impaired balance indices. Impairment of dynamic stability revealed poor static balance control in all directions. Lower limits of stability scores indicated a smaller range of motion prior to which patients have to shift foot balance. No correlations were observed between age at evaluation, age at onset, duration of illness and the balance indices. Conclusions: Dynamic posturography reveals significant balance impairment in patients with ET which is unrelated to the age at onset, age at evaluation or duration of illness. This finding concurs with pre-existing reports and adds to the growing body evidence of cerebellar involvement in ET.


Experience of pallidal deep brain stimulation in dystonia at a tertiary care centre in India: An initial experience

November 2017

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45 Reads

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13 Citations

Neurology India

INTRODUCTION: Dystonia is one of the most prevalent forms of movement disorders and is characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. Dystonia causes significant morbidity with an adverse impact on the quality of life. When dystonia is medically refractory, causing severe pain and impairment in activities of daily living, deep brain stimulation (DBS) of the globus pallidus interna (GPi) is a potential option to reduce disability. MATERIALS AND METHODS: This is a chart review of patients who underwent DBS for dystonia (from 2009 to 2015) at our tertiary referral centre. A total of ten patients (7 males, 3 females) underwent DBS for non-parkinsonian conditions. The patients were selected after failure of adequate medical management. All the patients had a severe disability with normal cognitive (Mini-Mental State Examination) and psychiatric profile. They also had to have a suitable GPi for DBS based on magnetic resonance imaging. RESULTS: The mean baseline Burke-Fahn-Marsden dystonia movement score of the 10 patients selected for surgery was 60.3 ± 27.3 (ranging from 19 to 104). On repeated-measures analysis of variance, there was significant difference in the different time points (pre-DBS, post-DBS at 3 months, 6 months, and 1 year) F (3, 5) = 7.68, P = 0.026. The data showed that there was a maximum improvement after 1 year of stimulation (pre-DBS vs. 3 months 12.9 ± 1.9 vs 8.8 ± 2.1, P = 0.01; pre-DBS vs. 6 months 12.9 ± 1.9 vs 7.4 ± 1.6, P = 0.04; pre-DBS vs. 1 year, 12.9 ± 1.9 vs. 7 ± 2.4. CONCLUSION: In medically refractory primary or secondary dystonia patients, bilateral GPi DBS can be considered as an option. Patients with disabling symptoms that significantly deteriorate activities of daily life may consider DBS before these symptoms become fixed.


Citations (29)


... Familial, otherwise inherited, form of essential tremor constitutes of approximately 50% of cases. ET is manifested primarily by bilateral postural and kinetic tremor of the upper limbs with or without neurological symptoms, cognitive deficits, with some patients experiencing tremors of the head, neck or lower limbs, face, and vocal cords (3)(4)(5)(6). Patients report difficulties with daily activities including eating, drinking, dressing, and writing. ET disrupts daily tasks and causes mental distress (1). ...

Reference:

Stereotactic radiosurgery in the treatment of essential tremor – a systematic review
The Non-motor Features of Essential Tremor: A Primary Disease Feature or Just a Secondary Phenomenon?

Tremor and Other Hyperkinetic Movements

... A man who had a severe traumatic head injury following a 10-meter fall with frontal lesion presented frontal lobe disorder and chorea. Post-traumatic movement disorders are well known, and chorea is a rare complication of head injury [50][51][52][53]. ...

Posttraumatic movement disorders: A clinical and imaging profile of 30 patients
  • Citing Article
  • May 2019

Neurology India

... However, substantial evidence indicates a facilitative effect on short-term non-speech motor learning occurring during DBS-ON over DBS-OFF states. STN-DBS stimulation facilitates motor learning in tasks involving sequential cursor movements (Carbon and Eidelberg, 2006;Mure et al., 2012), sequential finger tapping (Muehlberg et al., 2023), single-target cursor movements (de Almeida Marcelino et al., 2019), and visuomotor perturbation adaptation (Singh et al., 2019). One study which measured regional cerebral blood flow during task performance found that STN-DBS-facilitated learning is associated with increased activity in lateral cerebellum and dorsal premotor cortex, coupled with reduced activity in supplementary motor area (Mure et al., 2012). ...

Basal ganglia contributions during the learning of a visuomotor rotation: Effect of dopamine, deep brain stimulation and reinforcement
  • Citing Article
  • June 2019

European Journal of Neuroscience

... However, the age of the individual may be more important than the ET duration. In a cross-sectional study of 363 patients, older (> 60 years) vs. younger (< 40 years) patients with disease duration greater than 10 years experienced head tremor in 42.8% (121/283) vs. 7.4% (2/27) of cases, respectively [9] . A multivariate logistic regression analysis revealed that only age (P < 0.001), but not duration (P = 0.26) or family history (P = 0.35), was independently associated with head tremor. ...

Phenotypic Variability of Essential Tremor Based on the Age at Onset
  • Citing Article
  • January 2019

The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques

... This comprehensive approach underscores the complexity of diagnosing WD and the necessity for heightened clinical awareness and multidisciplinary evaluation. [1,4,17] Treatment: ...

Clinical Utility of Longitudinal Measurement of Motor Threshold in Wilson’s Disease
  • Citing Article
  • January 2019

The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques

... Previous reports highlighted essential tremor, action myoclonus, generalized polymyoclonus, myoclonic tremor, exaggerated clonus, parkinsonism and normal pressure hydrocephalus as differential diagnoses. [27][28][29] The diagnosis most commonly considered with the complaint of shaking when standing is OT. However, in our sample, orthostatic myoclonus (OM) was more prevalent than OT. ...

Shaky and unsteady: Dynamic posturography in essential tremor
  • Citing Article
  • December 2017

Journal of the Neurological Sciences

... [9][10][11][12][13][14][15][16] Remarkable short-term benefits of DBS in children in a wide variety of dystonia subtypes are reported, but long-term results are sparse and the evidence comes from small, heterogeneous case series. [17][18][19][20][21][22][23][24][25][26][27][28][29] DBS seems to be more effective in non-degenerative, genetic dystonias than in acquired or degenerative dystonias. [1,16,30] However, the response magnitude is highly variable between genetic etiologies. ...

Experience of pallidal deep brain stimulation in dystonia at a tertiary care centre in India: An initial experience
  • Citing Article
  • November 2017

Neurology India

... The role of the cerebellum was highlighted in hand-eye coordination 13,14 , handwriting 15 , drawing 16 , stereopsis 17 , mental rotation 18 , spatial and cognitive tasks 19 , intentional tremor 20 , fine movement and coordination control 21 , motor learning 22 , perceptual processes 23 and learning fine dexterous skills such as playing the keyboard 24 . Plasticity of the human brain in response to learning and experience has been reported by several earlier studies 25 . ...

Abnormalities of Eye-Hand Coordination in Patients with Writer's Cramp: Possible Role of the Cerebellum

Tremor and Other Hyperkinetic Movements

... The properties of the functional networks were considered as N × N (i.e., 160 × 160) by the undirected graph of a binary network, G(N,E), in which G denotes the non-zero subset. G consists of edges denoted by E that are coefficients obtained by intermodal correlation (i.e., Fisher's Z values) and nodes (N-ROIs) as a number of operational links/connectivity amongst N number of nodes [19]. The proposed study employs an undirected binary network graph to compute the properties, enabling the comparison of nodal characteristics across participants and groups. ...

Altered brain network measures in patients with primary writing tremor

Neuroradiology

... Furthermore, several frontal lobe WM tracts which showed changes in DTI studies were included [45,50], such as the fronto-occipital fascicle, uncinate fascicle, and superior longitudinal fascicle. The CC, particularly its anterior part, has shown involvement in PSP in numerous studies [8,[51][52][53][54], leading to the inclusion of its anterior three segments (areas I, II, and III according to the definition by Hofer and Frahm [32]). In addition, the anterior limb of the internal capsule [55,56] and the corticostriatal tract were included due to their connections with the thalamus, striatum, and frontal lobe. ...

Role of Corpus Callosum Volumetry in Differentiating the Subtypes of Progressive Supranuclear Palsy and Early Parkinson's Disease
  • Citing Article
  • February 2017

Movement Disorders Clinical Practice