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Neuromodulatory Effects of Adjunctive High Definition Transcranial Direct Current Stimulation (HDtDCS) on Auditory Verbal Hallucinations in Schizophrenia Patients: A Sham Controlled Diffusion Tensor Imaging Study
- Apurba Narayan Mahato, Sanjay Kumar Munda, Alok Pratap
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- Journal:
- BJPsych Open / Volume 8 / Issue S1 / June 2022
- Published online by Cambridge University Press:
- 20 June 2022, p. S59
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Aims
To see the neuromodulatory effects of adjunctive HD-tDCS on white matter connectivity by using Diffusion Tensor Imaging (DTI) in schizophrenia patients with Auditory Verbal Hallucinations (AVH)
MethodsThis was a randomized, double blind, sham controlled study. 40 patients of schizophrenia with prominent auditory verbal hallucinations and 10 age sex matched healthy controls were selected. The patients were randomly assigned to 2 groups and were given active or sham adjunctive HDtDCS (Active Treatment = 10 sessions of 2 mA current applied for 20 minutes, twice daily for 5 days, at left temporo-parietal Junction (TPJ); Sham treatment = 10 sessions of 1 mA current, twice daily for 5 days was applied for 30 sec at left TPJ). Fractional anisotropy of left arcuate fasciculus by Diffusion tensor imaging was assessed and severity of schizophrenia symptoms and auditory hallucinations were rated on PANSS and PSYRATS-AH at baseline, after 1st week (i.e. end of HDtDCS sessions) and 4 weeks after the end of the HDtDCS sessions). Patients received stable dose of antipsychotics for the total study duration (equivalent to or more than 400 mg of chlorpromazine) to eliminate confounding bias. Fractional anisotropy of left arcuate fasciculus by Diffusion tensor imaging was assessed in healthy controls. DTI data were analysed by DSI Studio software. Statistical analysis was done by SPSS version 25.
Results1. Both the patient groups were comparable with regard to socio-demographic variables and baseline clinical variables.
2. There was no significant difference in the values of Fractional Anisotropy in Left Arcuate Fasciculus among the patients and healthy controls at baseline.
3. The group receiving active adjunctive HDtDCS, showed significant improvement in the frequency domain of AVH over time, in time*group comparison by repeat measure ANOVA with Mauchly's test of sphericity and Greenhouse-Geisser correction [p = 0.011 and partial eta square = 0.129].
4. There was no significant difference in change in the Fractional anisotropy of the left arcuate fasciculus noted between the groups over time.
5. Application of HDtDCS was not associated with significant side effects, minor itching and mild burning sensation being the only reported side effects
ConclusionAdjunctive active HD-tDCS to the left temporo-parietal junction showed a statistically significant improvement in frequency of auditory verbal hallucinations (AVH) in schizophrenia patients, when compared to sham stimulation.
Eight - The Evolution of Community Epidemiological Studies in India: A Subaltern Critique
- Edited by Anne M. Lovell, Institut national de la santé et de la recherche médicale, Paris, Gerald M. Oppenheimer, City University of New York and Columbia University, New York
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- Book:
- Reimagining Psychiatric Epidemiology in a Global Frame
- Published by:
- Boydell & Brewer
- Published online:
- 15 February 2024
- Print publication:
- 03 June 2022, pp 250-282
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Summary
A Subaltern Framework for Psychiatric Epidemiology in India
The World Health Organization (WHO) international program on the epidemiology of mental disorders began in the 1950s. By the 1960s, ground rules had been established for what was becoming the scientific discipline of psychiatric epidemiology and for facilitating its expansion throughout the world. Non-Western countries like India soon initiated studies in this area within their own constraints. By the 1960s, psychiatric epidemiology articles first appeared in the Indian Journal of Psychiatry. They borrowed methods and tools from the Western epidemiological canon but for different purposes and with markedly different results than those produced in wealthier countries. In retrospect, dissimilarities between findings in India and in Western countries tended to be attributed to methodological rather than contextual factors.
This chapter explores the specificity and evolution of the epidemiology of mental disorders in India and their social, cultural, and political significance. Numerous scholars claim that the history of psychiatry in India began in a period of Indian subalternity to British colonizers, who represented the diversity of “Indian” pasts through a homogenizing narrative of transition from a “medieval” period to “modernity.” We argue that psychiatric epidemiology in post-Independent India also exists in a position of subalternity but to a globalized psychiatry that has developed in the global North. This chapter further addresses subalternity within India by focusing on the mental health of lower castes, slum-dwellers, and other subpopulations that exist in a subaltern relation to social groups in their own country.
The “subaltern,” as we use the term, stands in an ambiguous relation to power, subordinate to it without fully consenting to its rule. Nor does it accept the point of view or vocabulary of dominant powers as a valid expression of its own subaltern identity. The Italian Marxist Antonio Gramsci (1981–1937) used the term subaltern to designate social groups subjected to the hegemonic power of a society's ruling class. In the 1980s, the Subaltern Studies Group, a collective of radical historians from the Indian subcontinent, re-conceptualized the term, focusing their attention on the disenfranchised peoples of India. “Subaltern studies” came to signify a “history from below.” Proponents of subaltern studies have produced counter-discourses that contest the dominant colonial, postcolonial, and post-imperial narratives, with the hope of connecting their analytic work to acts of resistance by oppressed peoples themselves.
Shock induced aerobreakup of a droplet
- Shubham Sharma, Awanish Pratap Singh, S. Srinivas Rao, Aloke Kumar, Saptarshi Basu
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- Journal:
- Journal of Fluid Mechanics / Volume 929 / 25 December 2021
- Published online by Cambridge University Press:
- 27 October 2021, A27
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The multiscale dynamics of a shock–droplet interaction is crucial in understanding the atomisation of droplets due to external airflow. The interaction phenomena are classified into wave dynamics (stage I) and droplet breakup dynamics (stage II). Stage I involves the formation of different wave structures after an incident shock impacts the droplet surface. These waves momentarily change the droplet's ambient conditions, while in later times they are mainly influenced by shock-induced airflow. Stage II involves induced airflow interaction with the droplet that leads to its deformation and breakup. Primarily, two modes of droplet breakup, i.e. shear-induced entrainment and Rayleigh–Taylor piercing (RTP) (based on the modes of surface instabilities) were observed for the studied range of Weber numbers $(We\sim 30\text{--}15\,000)$. A criterion for the transition between two breakup modes is obtained, which successfully explains the observation of RTP mode of droplet breakup at high Weber numbers $(We\sim 800)$. For $We > 1000$, the breakup dynamics is governed by the shear-induced surface waves. After formation, the Kelvin–Helmholtz waves travel on the droplet surface and merge to form a liquid sheet near the droplet equator. Henceforth, the liquid sheet undergoes breakup processes via nucleation of several holes. The breakup process is recurrent until the complete droplet disintegrates or external drag acting on the droplet is insufficient for further disintegration. At lower Weber numbers, the droplet undergoes complete deformation like a flattened disk, and a multibag mode of breakup based on RTP is observed.