Cerebral Haemodynamic Changes in Type 2 Diabetes Mellitus Following a Three-Month Yoga Intervention: A Randomized Controlled Trial.

Background and purpose Cerebral haemodynamics and cognitive performance may be adversely affected in type 2 diabetes mellitus (T2DM). Previous studies reported reduced cerebral blood flow (CBF) and altered cerebrovascular reactivity (CVR) in T2DM. Yoga, an ancient holistic health approach, is known to be beneficial for T2DM. We hypothesized that yoga practice may alter CBF and the flow resistance in the middle cerebral artery (MCA) and improve cognition in T2DM. Our secondary objective was to explore the relationship between changes in cerebral haemodynamics and cognition in T2DM. Materials and methods Participants were randomly allotted into the yoga and control groups based on the eligibility criteria. One hour of yoga intervention specific to type 2 diabetes was provided to the yoga group for three months, while conventional treatment was provided to the control group. A transcranial Doppler was used to evaluate longitudinal changes in cerebral haemodynamics in MCA. A Corsi block tapping test was used to assess visio-spatial working memory. Results There were 75 participants recruited, of whom 38 participated in yoga and 37 participated in a control group. Both intention to treat and per protocol analysis showed significant results. At day 90, intention-to-treat analysis showed significant changes in CBF velocities (mean difference -10.85%, 95% CI (-13.26, -6.15), p<0.001), cerebral vasodilatory reserve (mean difference -0.23%, 95% CI (-0.43, -0.03), p=0.02) and cognition (mean difference -12.13%, 95% CI (-17.48, -6.78), p≤0.001). There was no between-group effect. Also, the correlation between the CBF and cognition did not show any significant results. Conclusion The three-month yoga intervention was associated with an improvement in cerebral hemodynamics. The study also revealed an improvement in visio-spatial working memory among patients with T2DM. The study did not show any correlation between the improvement in cerebral haemodynamics and working memory. We recommend larger and longer studies on yoga intervention for T2DM patients to evaluate whether such benefits are sustained and improve their quality of life.

Transformer-Based Automated Segmentation of the Median Nerve in Ultrasound Videos of Wrist-to-Elbow Region.

Segmenting the median nerve is essential for identifying nerve entrapment syndromes, guiding surgical planning and interventions, and furthering understanding of nerve anatomy. This study aims to develop an automated tool that can assist clinicians in localizing and segmenting the median nerve from the wrist, mid-forearm, and elbow in ultrasound videos. This is the first fully automated single deep learning model for accurate segmentation of the median nerve from the wrist to the elbow in ultrasound videos, along with the computation of the cross-sectional area (CSA) of the nerve. The visual transformer architecture, which was originally proposed to detect and classify 41 classes in YouTube videos, was modified to predict the median nerve in every frame of ultrasound videos. This is achieved by modifying the bounding box sequence matching block of the visual transformer. The median nerve segmentation is a binary class prediction, and the entire bipartite matching sequence is eliminated, enabling a direct comparison of the prediction with expert annotation in a frame-by-frame fashion. Model training, validation, and testing were performed on a dataset comprising ultrasound videos collected from 100 subjects, which were partitioned into 80, ten, and ten subjects, respectively. The proposed model was compared with U-Net, U-Net++, Siam U-Net, Attention U-Net, LSTM U-Net, and Trans U-Net. The proposed transformer-based model effectively leveraged the temporal and spatial information present in ultrasound video frames and efficiently segmented the median nerve with an average dice similarity coefficient (DSC) of approximately 94% at the wrist and 84% in the entire forearm region.

Cross-Sectional Area Reference Values of Nerves in the Upper and Lower Extremities using Ultrasonography in the Indian Population.

Background and Purpose: Cross-sectional area (CSA) is the most important parameter to study peripheral nerves by high-resolution ultrasonography. The aim was to acquire normative data of CSA of the main upper and lower limb nerves in the Indian population. Methods: CSA of nerves was determined in 100 healthy volunteers at 11 predetermined sites: median and ulnar at the wrist, mid-forearm, elbow; radial (spiral groove); tibial (popliteal fossa, medial malleolus); common peroneal (CPN, fibular head) and sural (lateral malleolus). Results: The mean age of participants was 40.7 ± 13.0 years (range: 18-79). Fifty were < 40 years of age. The mean height, weight and BMI were 161.5 ± 8.3 centimeters (range: 145-179), 58.6 ± 10.1 kilograms (range: 32-90) and 22.4 ± 3.2 kilogram/square meter (range: 14.03-30.44), respectively. The median and ulnar nerve measurements were non-uniform throughout its course, and the CSA was largest at the elbow and ulnar groove, respectively. With advancing age, there was a significant difference for median and ulnar nerves at the wrist (median P = 0.002, ulnar P = 0.009) and tibial nerve (popliteal fossa, P = 0.045, medial malleolus, P = 0.005), CPN (P = 0.047). Men had greater CSA of upper limb nerves and tibial nerves at popliteal fossa (P < 0.05) as compared to women. A positive correlation was noted with weight. Conclusion: It is apt for every defined population to have its own set of normative data of CSA as it varies with ethnicity, age, and the built of individuals. We provide a valuable set of CSA data for nerves in the Indian population, which can be used for comparison while investigating peripheral nerve disorders.

Transcranial Doppler studies in Type 2 diabetes mellitus: A systematic review.

BACKGROUND: Type II Diabetes mellitus (T2DM) patients are at the risk of developing cerebrovascular diseases, often contributed by altered cerebral haemodynamics. We present a systematic review of studies on cerebral haemodynamics assessment using transcranial Doppler (TCD) in T2DM. REVIEW METHOD: A systematic review of the published articles in the English language between 1991 to 2021. DATA SOURCES: Articles were retrieved via Pubmed and Cochrane library. We included Cross-sectional, prospective, retrospective, randomized controlled, and cross-over studies for this review. RESULTS: A total of 25 articles met the inclusion criteria, which provided data for 3212 patients. CONCLUSION: Cerebral autoregulation is often impaired among patients with T2DM. The risk increased with the duration of T2DM, related complications and presence of comorbidities.

Pictorial Essay of Cervical Duplex Ultrasonography.

Objectives: Cervical duplex ultrasonography (CDU) is a simple, non-invasive, portable technique, that provides valuable high-quality visual information about the integrity of the carotid and vertebral vessels, plaque morphology and flow hemodynamics. CDU is useful in the assessment and follow up of patients with cerebrovascular disease as well as other conditions like inflammatory vasculitis, carotid artery dissection and carotid body tumours. CDU is inexpensive and invaluable in smaller centres. Methods: CDU was performed in all patients in both longitudinal and transverse planes in the out-patient clinic. Brightness mode (B-mode) and Doppler waveforms were obtained. Relevant findings were presented. Results: CDU provides real time visualisation of plaque characteristics and follow up, hemodynamic characteristics in Takayasu arteritis, visualisation of dissection. Conclusion: With availability of MR/CT angiography, CDU can be an adjuvant in follow up, triage and early bed-side diagnosis of the vascular diseases. We present our experience with CDU in the out-patient clinics in this pictorial essay.

MRI outcomes in patients with acute-onset vertigo in the emergency department - A prospective study.

INTRODUCTION: Vertigo is an abnormal sensation of motion which arises due to a mismatch between various sensory modalities involved in maintaining balance. Vertigo can be due to central or peripheral causes and intensely debilitating for some patients. Acute onset vertigo is defined as the commencement of vertigo within 24 h. This can present with a variety of overlapping symptoms, making it difficult to distinguish central from peripheral causes. In the emergency setting, mis-diagnosing acute onset vertigo as benign may have serious implications. METHODS: This prospective study included consecutive patients presenting to our Emergency Department with acute vertigo between March 2019 and March 2020. We aimed to evaluate and validate the utility of magnetic resonance imaging (MRI) of the brain among patients with acute onset vertigo. RESULTS: A total of 70 patients with acute onset vertigo were recruited. MRI of the brain revealed acute changes in 23 (32.9%) out of the 70 patients included in the study. Even among the 29 (41.4%) patients who presented with isolated vertigo without any other clinical signs, MRI of the brain showed acute changes in 3 (10.3%) of them. CONCLUSION: MRI is a useful tool in diagnosing and differentiating peripheral from a central cause of vertigo. It avoids misdiagnosis in the emergency setting and facilitates early administration of appropriate treatment.

Sonographic pattern of median nerve enlargement in Hansen's neuropathy.

OBJECTIVES: Median nerve enlargement in leprosy seems to be more proximal than in carpal tunnel syndrome (CTS), but this feature has not been studied systematically. The aim of the study was to compare the sites of median nerve enlargement in patients with leprosy with that of patients with CTS. MATERIALS AND METHODS: Transverse sections of the median nerve were recorded from wrist to the mid-forearm (at distal wrist crease and at 2-cm: M1, 4-cm: M2, 6-cm: M3, 8-cm: M4 and 10-cm: M5, proximal to the distal wrist crease in the forearm) in patients with leprosy, CTS and healthy subjects using high-resolution ultrasound. RESULTS: Twenty-six patients each with leprosy and CTS were compared with healthy controls. Patients with leprosy included 6 (23.1%), 7 (26.9%), 7 (26.9%) and 6 (23.1%) patients with borderline tuberculoid, borderline-borderline, borderline lepromatous and lepromatous leprosy, respectively. Cross-sectional area (CSA) of median nerve was increased in all patients with leprosy as compared to healthy controls at all points of measurement. CSA was higher among patients with leprosy as compared to CTS at all points except at the wrist. In patients with leprosy, the maximal enlargement was noted 2-cm (M1) proximal to the wrist crease with gradual tapering of the CSA proximally (p < .05). In contrast, in patients with CTS the median nerve was maximally enlarged at the distal wrist crease (p<.05). CONCLUSIONS: Median nerve enlargement 2-cm proximal to the distal wrist crease distinguishes leprosy from CTS. This important discriminating sign can be used at point-of-care to identify patients with leprosy.

A rare cause of median neuropathy at the carpal tunnel: Thrombosis of the persistent median artery.

Carpal tunnel syndrome is a common peripheral nerve entrapment neuropathy caused due to compression of the median nerve at the level of the wrist joint. Bifid median nerve associated with a persistent median artery is a rare entity and in itself asymptomatic anatomical variant. However, distension of the persistent median artery due to a thrombus can be symptomatic due to compression on the median nerve and can compromise the blood flow to the palm. We report a case of persistent median artery thrombosis in a young female patient who presented with symptoms of carpal tunnel syndrome diagnosed on the ultrasonography and confirmed on the MRI with subsequent improvement post anticoagulation therapy.

Cerebrovascular Hemodynamics During the Practice of Bhramari Pranayama, Kapalbhati and Bahir-Kumbhaka: An Exploratory Study.

Various pranayama techniques are known to produce different physiological effects. We evaluated the effect of three-different pranayama techniques on cerebrovascular hemodynamics. Eighteen healthy volunteers with the mean ± standard deviation age of 23.78 ± 2.96 years were performed three-different pranayama techniques: (1) Bhramari, (2) Kapalbhati and (3) Bahir-Kumbhaka in three-different orders. Continuous transcranial Doppler (TCD) monitoring was performed before, during and after the pranayama techniques. TCD parameters such as peak systolic velocity, end diastolic velocity (EDV), mean flow velocity (MFV) and pulsatility index (PI) of right middle cerebral artery were recorded. Practice of Kapalbhati showed significant reductions in EDV and MFV with significant increase in PI while, Bahir-Kumbhaka showed significant increase in EDV and MFV with significant reduction in PI. However, no such significant changes were observed in Bhramari pranayama. Various types of pranayama techniques produce different cerebrovascular hemodynamic changes in healthy volunteers.

Extensive sonographic ulnar nerve enlargement above the medial epicondyle is a characteristic sign in Hansen's neuropathy.

OBJECTIVE: Earlier studies have shown sonographic enlargement of the ulnar nerve in patients with Hansen's neuropathy. The present study was performed to determine whether sonography or electrophysiological studies can detect the specific site of ulnar nerve pathology in leprosy. METHODS: Eighteen patients (thirty arms) with Hansen's disease and an ulnar neuropathy of whom 66% had borderline tuberculoid (BT), 27% lepromatous leprosy (LL) and 7% mid-borderline (BB) leprosy were included in the study. Cross-sectional area (CSA) of ulnar nerve was measured every two centimeters from wrist to medial epicondyle and from there to axilla. All patients underwent standard motor and sensory nerve conduction studies of the ulnar nerve. Thirty age and sex matched controls underwent similar ulnar nerve CSA measurements and conduction studies. RESULTS: Ulnar nerve was clinically palpable in 19 of the 30 arms of patients. Motor and sensory nerve conduction studies of the ulnar nerve showed a reduced compound motor action potential and sensory nerve action potential amplitude in all patients. Motor Conduction Velocity (MCV) in patients were slower in comparison to controls, especially at the elbow and upper arm, but unable to exactly locate the site of the lesion. In comparison to controls the ulnar nerveCSA was larger in the whole arm in patients and quite specific the maximum enlargement was seen between nulnar sulcus and axilla, peaking at four centimeters above the sulcus. CONCLUSIONS: A unique sonographic pattern of nerve enlargement is noted in patients with ulnar neuropathy due to Hansen's disease, while this was not the case for the technique used until now, the electrodiagnostic testing. The enlargement starts at ulnar sulcus and is maximum four centimeters above the medial epicondyle and starts reducing further along the tract. This characteristic finding can help especially in diagnosing pure neuritic type of Hansen's disease, in which skin lesions are absent, and alsoto differentiate leprosy from other neuropathies in which nerve enlargement can occur.

Cerebrovascular hemodynamics during pranayama techniques.

BACKGROUND: Pranayama techniques are known to produce variable physiological effects on the body. We evaluated the effect of the two commonly practiced Pranayama techniques on cerebral hemodynamics. MATERIALS AND METHODS: Fifteen healthy male volunteers, trained in Yoga and Pranayama, were included in the study. Mean age was 24 years (range 22-32 years). Study participants performed 2 Pranayamas in 2 different orders. Order 1 (n = 7) performed Bhastrika (bellows breaths) followed by Kumbhaka (breath retention) while order 2 (n = 8) performed Kumbhaka followed by Bhastrika. Both breathing techniques were performed for 1 min each. Continuous transcranial Doppler (TCD) monitoring was performed during the breathing techniques. TCD parameters that were recorded included peak systolic velocity (PSV), end-diastolic velocity (EDV), mean flow velocity (MFV), and pulsatility index (PI) of the right middle cerebral artery at baseline, 15, 30, 45, and 60 s. RESULTS: Significant reductions in EDV (3.67 ± 6.48; P < 0.001) and MFV (22.00 ± 7.30; P < 0.001) with a significant increase in PI (2.43 ± 0.76; P < 0.001) were observed during Bhastrika. On the contrary, a significant increase in PSV (65.27 ± 13.75; P < 0.001), EDV (28.67 ± 12.03; P < 0.001), and MFV (43.67 ± 12.85; P < 0.001) with a significant reduction in PI (0.89 ± 0.28; P < 0.01) was observed only during Kumbhaka. CONCLUSION: Bhastrika and Kumbhaka practices of Pranayama produce considerable and opposing effects on cerebral hemodynamic parameters. Our findings may play a potential role in designing the Pranayama techniques according to patients' requirements.

Transcranial Doppler: Techniques and advanced applications: Part 2.

Transcranial Doppler (TCD) is the only diagnostic tool that can provide continuous information about cerebral hemodynamics in real time and over extended periods. In the previous paper (Part 1), we have already presented the basic ultrasound physics pertaining to TCD, insonation methods, and various flow patterns. This article describes various advanced applications of TCD such as detection of right-to-left shunt, emboli monitoring, vasomotor reactivity (VMR), monitoring of vasospasm in subarachnoid hemorrhage (SAH), monitoring of intracranial pressure, its role in stoke prevention in sickle cell disease, and as a supplementary test for confirmation of brain death.

Difference in normal values of median nerve cross-sectional area between Dutch and Indian subjects.

INTRODUCTION: Ultrasound (US) measurement of the median nerve cross-sectional area (CSA) at the wrist is a useful diagnostic test for carpal tunnel syndrome (CTS). We compared median nerve normal values between samples of Indian and Dutch populations. METHODS: The median nerve was examined by US at the wrist in 100 healthy volunteers in India and 137 volunteers in The Netherlands using the same protocol. RESULTS: Median nerve CSA at the wrist (7.0 ± 1.1 mm(2)) in the Indian cohort was lower in comparison to the Dutch cohort (8.3 ± 1.9 mm(2) ; P < 0.05). This difference was still present after controlling for age, height, and weight (P = 0.001). CONCLUSIONS: CSA normal values for the median nerve were different between the examined population samples even after correcting for age, height, and weight. This enforces the idea that laboratories around the world should obtain their own normative data.

Normal values of median nerve cross-sectional area obtained by ultrasound along its course in the arm with electrophysiological correlations, in 100 Asian subjects.

INTRODUCTION: The objective of this study is to obtain normative cross-sectional area (CSA) values for median nerve by ultrasound at predetermined sites and correlate them with electrophysiological variables in healthy Asian subjects. METHODS: The median nerve was examined ultrasonographically in 100 healthy volunteers, mean age 39 years (range, 18­75 years). CSA of the median nerve was measured at wrist, mid-forearm, mid-arm, and axilla. All subjects underwent simultaneous standardized nerve conduction studies. RESULTS: The mean median nerve CSAs ± SD at the distal wrist crease was 7.2 ± 1 mm2; mid-forearm 4.8 ± 0.9 mm2; mid-arm 6.1 ± 1 mm2; axilla 5.9 ± 0.9 mm2. The CSA at the wrist was the largest compared with other levels (P < 0.001), and it increased with advancing age (P < 0.002). CONCLUSIONS: These normative data show that median nerve CSA is not uniform along its length. There are differences between gender, and values increase with advancing age.

Transcranial doppler: Technique and common findings (Part 1).

Transcranial Doppler (TCD) can be aptly called as the doctor's stethoscope of the brain. Since its introduction in 1982, by Rune Aaslid, TCD has evolved as a diagnostic, monitoring, and therapeutic tool. During evaluation of patients with acute ischemic stroke, TCD combined with cervical duplex ultrasonography provides physiological information on the cerebral hemodynamics, which is often complementary to structural imaging. Currently, TCD is the only diagnostic tool that can provide real time information about cerebral hemodynamics and can detect embolization to the cerebral vessels. TCD is a noninvasive, cost-effective, and bedside tool for obtaining information regarding the collateral flow across various branches of the circle of Willis in patients with cerebrovascular disorders. Advanced applications of TCD help in the detection of right-to-left shunts, vasomotor reactivity, diagnosis, and monitoring of vasospasm in subarachnoid hemorrhage and as a supplementary test for confirmation of brain death. This article describes the basic ultrasound physics pertaining to TCD insonation methods, for detecting the flow in intracranial vessels in addition to the normal and abnormal spectral flow patterns.

Cerebrovascular ultrasonography: Technique and common pitfalls.

Although the clinical features in some patients with cerebrovascular ischemia may be ill defined, majority of the patients present with focal neurological deficits caused by an arterial occlusion, and the clinical presentations are usually referable to the involved arterial territory. Therefore, vascular imaging constitutes an important component of the diagnostic workup. Cervical duplex ultrasonography of carotid and vertebral arteries is employed to evaluate the extracranial vasculature while transcranial Doppler provides important information about intracranial hemodynamic changes in cerebrovascular ischemia. These two components of cerebrovascular ultrasonography are fast and reproducible, and can be performed at the bedside. They provide real-time information about the status of cervico-cranial arterial patency and various hemodynamic alterations, including collateral flow. The information obtained from cerebrovascular ultrasonography is useful for diagnostic as well as prognostic purposes. Furthermore, it can be used to monitor cerebral blood flow for extended periods and aid in decision making for various interventions. The hemodynamic information obtained from cerebrovascular ultrasonography helps in determining the underlying mechanisms of brain ischemia, and is complementary to the clinical examination and other imaging modalities.We describe the technique of performing cervical duplex sonography, diagnostic criteria for arterial stenosis, characterizing plaque morphology, measuring intima-media thickness and various pitfalls while performing the test.

Ultrasonographic cross-sectional area normal values of the ulnar nerve along its course in the arm with electrophysiological correlations in 100 Asian subjects.

INTRODUCTION: Normative cross-sectional areas (CSAs) have been obtained for the Western population. We obtained CSAs of normal ulnar nerves at predetermined sites and correlate them with electrophysiological variables in Asian subjects. METHODS: One hundred healthy volunteers, mean age 39 ± 14 years (range, 18-75 years), were recruited for the study after obtaining informed consent. The ulnar nerve was examined ultrasonographically from wrist to axilla, and CSA was measured at predetermined sites. All subjects underwent a simultaneous standardized nerve conduction study. RESULTS: Men had larger CSAs, and CSAs increased with advancing age. There was a statistically significant correlation between CSA at the wrist and distal ulnar motor latency (P = 0.005). CONCLUSIONS: Ulnar CSA correlated with age, gender, and distal motor latency. No correlations were observed with height, weight, or body mass index.

Population pharmacokinetics of lamotrigine in Indian epileptic patients.

PURPOSE: The aim of this analysis was to describe the pharmacokinetics of oral lamotrigine (LTG) in Indian epileptic patients using a population pharmacokinetic (PPK) modeling approach to confirm that the PK is similar to that of the Caucasian population, and to evaluate and confirm the impact of covariates predictive of inter-individual variability using a simulation platform. METHODS: Blood samples were obtained from 95 patients, and LTG plasma concentrations were determined. Population PK modeling was performed using NONMEM. A one-compartment PK model with first-order absorption and elimination was used to describe the LTG PK. Log-likelihood profiling and normalized prediction distribution errors (NPDE) were used for model evaluation. A simulation study was performed to investigate dose regimens. RESULTS: Clearance (CL) was estimated to be 2.27 L/h with inter-individual variability (IIV) of 29 CV%. Volume of distribution (V) was estimated to be 53.6 L (31 CV% IIV). Body weight and concurrent use of carbamazepine and valproate were identified as significant covariates on clearance. Log-likelihood profiling indicated that parameters could be estimated with adequate precision, and NPDE indicated that the model adequately described the data observed. The simulation study illustrated the impact of carbamazepine and valproate on LTG PK, and negligible differences in PK between Indian and Caucasian patients. CONCLUSIONS: This is the first PK analysis of LTG in Indian patients. The population PK model developed adequately described the data observed. Comparison of identified PK parameters with previous PK analyses in Caucasian patients indicates that CL of LTG is similar, while V is somewhat lower compared with Caucasian patients, but this is not expected to lead to relevant differences in PK profiles during steady state.