Neurophysiological studies in acute transverse myelitis

A systematic evaluation of anterior horn cell, motor and sensory pathways is possible by electromyography (EMG), motor (MEPs) and somatosensory (SEPs) evoked potentials, respectively, which may provide valuable information on acute transverse myelitis (ATM). In a prospective hospital-based study, EMG, MEP and SEP studies were carried out on admission and after 3 months in 39 patients with ATM. All the patients also underwent detailed clinical evaluation, and spinal magnetic resonance imaging (MRI) was performed in 28. Outcome was defined at the end of 3 months as poor, partial or complete recovery on the basis of functional status. Spinal MRI revealed hyperintense signal changes in T2 extending for two segments to the entire spinal cord. Central motor conduction time to tibialis anterior (CMCT-TA) was more frequently abnormal (90%), followed by tibial SEP (77%). CMCT to abductor digiti minimi (ADM) was abnormal in 30% and median SEP in 15% of patients. Evidence of denervation on EMG was present in 51% of patients. The CMCT-TA improved in 48% patients and tibial SEP in 32%. Median SEP improved in all patients, and CMCT-ADM remained prolonged in two. At 3 months 2 patients had died, and 18 had poor, 10 partial and 9 complete recovery. CMCT was correlated with miscle power, tone, reflec and MRI changes. Patients' outcome of was correlated with CMCT, SEP and EMG. These results are consistent with pronounced involvement of dorsal region of spinal cord in ATM. MEP is more frequently abnormal than SEP

Central motor conduction studies in internal capsule and corona radiata infarction

Clinical and evoked-potential studies in internal capsule and corona radiata infarction are lacking. We report the results of a clinical and central motor conduction time (CMCT) study in 16 patients with internal capsule and 17 with computed tomography (CT)-proven corona radiata infarction. Patient's outcome was defined at the end of 3 months on the basis of the Barthel Index score. Four patients with type A capsular infarction (middle third of posterior limb of internal capsule) all had severe weakness, while 2 also had persistently unrecordable CMCT and poor outcome. Twelve patients with type B internal capsular infarction (genu, anterior limb, anterior or posterior third of posterior limb) had a milder degree of weakness, and CMCT was recordable in 9. At 3 months' follow-up, however, CMCT was recordable in all 12 patients. All of these patients had a partial (n = 4) or complete (n = 5) recovery. Thirteen patients with type A corona radiata infarction (middle third of corona radiata) had more pronounced weakness, and CMCT was unrecordable in all of these patients except 1 on initial examination. Follow-up after 3 months was possible in 8 patients, and CMCT became recordable in 3. One of these patients had complete, 3 partial, and 4 poor recovery. In type B corona radiata infarction (anterior or posterior third of corona radiata), the clinical signs and CMCT did not follow a regular pattern. Clinical and CMCT abnormalities in internal capsular infarction followed a more predictable pattern compared with those in corona radiata infarction. A less predictable pattern of weakness and CMCT change in corona radiata infarction may be attributed to a less definite organisation of motor pathways compared with the internal capsule

Tutorial: Cavity Quantum Optomechanics

Exploring quantum physics in macroscopic systems and manipulating these systems for various technological applications has been a topic of intense research in the last one decade or so. In this regard, the field of cavity quantum optomechanics turns out to be one of the most rapidly emerging area of research. It has opened many doors to study various open ended fundamental questions in quantum physics, apart from numerous possible applications. A typical cavity optomechanical system consists of two mirrors, one fixed while the other one is movable. These systems may be of micrometer or nano-meter in dimensions. The electromagnetic radiation incident on the system may get coupled to the mechanical motion of the movable mirror. This opto-mechanical coupling is the root of all phenomena such as quantum entanglement, state-transfer, squeezing and so on. In this short tutorial, basic concepts of cavity quantum optomechanics are discussed. We hope that this tutorial would motivate readers, both theorists and experimentalists, to take up advanced studies in this immensely fruitful area of research.Comment: 20 pages, 8 figures, tutorial, manuscript submitted to IJPAP, contains exercises for the reader and their solutions as appendi

Vitamin B12 deficiency neurological syndromes: correlation of clinical, MRI and cognitive evoked potential

Objective: To evaluate cognitive function in B12 deficiency neurological syndromes and response to B12 therapy. Methods: Patients were diagnosed on the basis of low serum B12 or megaloblastic bone marrow or both. Detailed neurological examination was performed and mental status was evaluated by the Mini Mental State Examination (MMSE).Hemo-globin, RBC indices, blood counts, serum chemistry, HIV, thyroid profile, antiparietal cell antibody and craniospinal MRI were done. Cognitive evoked potential was carried out using the odd ball auditory paradigm and recording was achieved from Fz, Cz and Pz referred to mastoid. P3 latency and amplitude were measured and compared with 33 age and sex matched controls. Three months following B12 therapy, clinical and P3 values were reevaluated and compared with the baseline values. Results: 36 patients, aged 16-80 years were included; 32 patients were above 40 years of age. Their median education level was 14 years. The presenting syndrome was myeloneurocognitive in 9, myeloneuropathy in 10,myelocognitive in 8,myelopathy in 8 and only cognitive in 1 patient.MMSE was abnormal in 17; between 28-19 in 14 and 18-11 in 3 patients. Cranial MRI carried out in 14 patients revealed multiple white matter hyperintensity in T2 in 3 and cortical atrophy in 1. P3 was unrecordable in 7 and latency was prolonged in 8 out of 33 patients. P3 latency was significantly prolonged in patients compared to controls and both MMSE and P3 latency improved significantly at the 3-month followup. Conclusion: MMSE was abnormal in 47 % and P3 in 45.5% of patients with B12 deficiency neurological syndromes which improved following treatment. Significance: There is high incidence of reversible cognitive impairment and P3 abnormalities in B12 deficiency neurological syndromes

Audit Quality Review: An Analysis Projecting the Past, Present, and Future

Literature on audit quality remains plenteous, with researchers contemplating the area for 'forever and a day’. The present study proposes synthesising the existing literature on audit quality, discerning the prominent themes and providing future research avenues. This paper attempts to analyse and synthesise the dynamics of audit quality research by employing the diminuendos of systematic literature review with bibliometric and content analysis. Scopus database has been gleaned to systematically retrieve the literature on audit quality from 1981-2022. Analysing the 1101 relevant articles under review makes the USA the highest contributor. It is, however, enthralling to note that developing countries have also registered increased interest in the topic. Apart from the other documented findings, the study concluded that research has witnessed impeccable growth over the years under various lenses, which have been precisely synthesised into six clusters. While various reviews have been conducted using innumerable qualitative methods, this study attempts to employ quantitative methods to synthesise the extant literature, which is a rarity

Collapsible and Spiky Wave for Dust Acoustic Waves in Dusty Plasmas

In multicomponent dusty plasma, the Sagdeev Potential (SP) approach is employed to formulate the Energy Equation for arbitrary amplitude dust acoustic waves (DAWs), where an amount of electrons is trapped in potential well. The dependence of amplitude and width of the solitons of Sagdeev Potential on plasma parameters is widely discussed. The range of Mach number has determined for solitary waves (SWs) with the help of critical Mach number. The solution of the Energy Equation obtained, has been discussed by expanding the expression for SP in the higher terms of φ . The different solutions of Energy Equation give us SWs, breakable waves, collapsible waves and SWs with spiky and explosive nature. The role of temperature ratio on the transformation of SWs to collapsible waves is discussed. With the help of standard values of plasma parameters relevant to such plasma environment, the results so obtained, are discussed. These results may help us to explain the nature of SWs in different astrophysical situations