Leprous Neuropathy: Observational Study Highlighting the Role of Electrophysiology in Early Diagnosis

Background Worldwide leprosy is a common cause of peripheral neuropathy. Electrophysiology is underutilized in its diagnosis. Objective This study aims to evaluate the usefulness of electrophysiological study in the diagnosis of leprous neuropathy. Materials and Methods Clinical and electrophysiological abnormalities of 36 histopathology proven leprosy patients from January 2015 to January 2017 were studied. Statistical Analysis Proportions were compared by Chi-square test. Results Total patients were 36. Thirty-four patients had abnormal electrophysiology and 34 had neurological deficits like weakness, sensory changes, and thickening. By clinical examination, multiple nerve involvement (motor weakness, sensory changes, and nerve thickening) occurred in 29, single nerve in 5, and no nerve involvement in 2. With electrophysiology, multiple nerve involvement (mononeuritis multiplex) was present in 32, single nerve in 2, and normal conduction parameters in 2. From the 36 patients, a total of 1,008 nerves were subjected to clinical examination and 132 were picked up clinically as affected, (13.1%). Electrophysiological study was done in 504 nerves, and 215 were found to be involved, (43%). Nerve abnormality detected by electrophysiology is significantly higher than clinical detection. (Chi-square =164.4054; p = 0.0000). Clinically, the most commonly affected nerve was unar (27) and the least affected was median (2) nerve. Electrophysiology detected 69% of nerves with demyelination and 35% of nerves with axonal features (mosaic pattern). Discussion There was subclinical neuropathy with electroclinical dissociation, as evidenced by more abnormality in electrophysiology than clinical examination. The nerve involvement was mononeuritis or mononeuritis multiplex pattern, both clinically and electrophysiologically. Electrophysiology showed both axonal and demyelinating nerve involvement (mosaic pattern). All the three features are present in leprous neuropathy. In corollary, if a patient has these electrophysiological features, he should be thoroughly investigated for leprosy. Conclusion Triple findings, such as subclinical neuropathy with electroclinical dissociation, mononeuritis multiplex, and mosaic pattern of demyelination and axonopathy, suggest leprous neuropathy

Gross and Micro-Anatomical Study of the Cavernous Segment of the Abducens Nerve and Its Relationships to Internal Carotid Plexus: Application to Skull Base Surgery

The present study aims to provide detailed observations on the cavernous segment of the abducens nerve (AN), emphasizing anatomical variations and the relationships between the nerve and the internal carotid plexus. A total of 60 sides underwent gross-anatomical study. Five specimens of the AN were stained using Sihler’s method. An additional five specimens were subjected to histological examination. Four types of AN course were observed: a single nerve along its entire course, duplication of the nerve, division into separate rootlets at the point of contact with the cavernous part of the internal carotid artery (ICA), and early-branching before entering the orbit. Due to the relationships between the ICA and internal carotid plexus, the cavernous segment of the AN can be subdivided into a carotid portion located at the point of contact with the posterior vertical segment of the cavernous ICA and a prefissural portion. The carotid portion of the cavernous AN segment is a place of angulation, where the nerve always directly adheres to the ICA. The prefissural portion of the AN, in turn, is the primary site of fiber exchange between the internal carotid plexus and either the AN or the lateral wall of the cavernous sinus.

Electrophysiology using coaxial atom probe array: Live imaging reveals hidden circuits of a hippocampal neural network

Since the 1960s, it is held that when a neuron fires, a nerve spike passes only through the selective branches, the calculated choice is a key to learning by rewiring. It is argued by chemically estimating the membrane's ion channel density that different axonal branches get active to pass the spike -branches blink at firing at different time domains. Here, using a new time-lapse dielectric imaging, we visualize the classic branch selection process, hidden circuits operating at different time domains become visible. The fractal grid of coaxial probes captures wireless snapshots of material's vibration at various depths below the membrane by setting a suitable frequency. Thus far, branch selection observed emitted energy or particle but never the emitters, what they do. Since each dielectric material transmits & reflects signals of different frequencies, we image live how filaments search for many branch-made-circuits, choose an unique pathway 103 times faster than a single nerve spike. It reveals that neural branches and circuit visible in a microscope is not absolute, there coexist many circuits each operating in different dime domains, operating at a time.

Mechano-neurophysiological model of the fingertip for spatiotemporal firing pattern prediction of SA1 mechanoreceptors during embossed letter scanning

Numerical simulation can be used to observe spatiotemporal firing responses of tactile receptors during dynamic tactile exploration, and it provides a more understanding of the mechanism of tactile perception. In this study, we developed an improved mechano-neurophysiological model of the fingertip that employs a realistic fingertip structure and accurate contact mechanics while scanning embossed letters. To confirm the potential of the model, we simulated the spatiotemporal firing patterns of slowly adapting type-1 (SA1) mechanoreceptors while scanning the embossed letter “G” and compared the simulation result with the existing experimental data in neurophysiology. Although the experimental data were reconstructed from a single nerve fiber, the simulation simultaneously observed the responses of multiple SA1 receptors, which resulted in a more obscure “G” spatiotemporal firing pattern than that in the previous experiment. This result supports existing data from another psychophysical experiment that demonstrates that it is harder to recognize embossed letter “G” accurately during letter scanning. This finding suggests that the spatiotemporal firing pattern from multiple SA1 receptors may show an obscure “G” pattern while scanning the embossed letter “G”.

A Linear Variant of Segmental Schwannomatosis Localized to the Upper Extremity

Introduction Schwannomas represent benign peripheral nerve sheath tumors. Their phenotypic presentations in schwannomatosis and segmental schwannomatosis have been well described. To date, however, cases of schwannomatosis or multiple schwannomas localized to a single nerve fascicle have been limited in the literature. Case Presentation In this study, we identify a case of a 48 year-old non-neurofibromatosis male who presented with symptomatic schwannomas localized to a single nerve fascicle of the upper extremity. Intraoperative exploration revealed four schwannomas arising from a 15-cm segment of ulnar nerve fascicle. Surgical excision was successful, without neurological deficit or recurrence. Conclusion This study identifies a case of schwannomatosis localized to a single nerve fascicle that may represent a linear variant of segmental schwannomatosis. The presentation may represent a temporary linear appearance in progression to “nonlinear” segmental variant; however, a molecularly distinct subset of schwannomas cannot be excluded.

Pressure-clamped single-fiber recording technique: A new recording method for studying sensory receptors

An electrophysiological technique that can record nerve impulses from a single nerve fiber is indispensable for studying modality-specific sensory receptors such as low threshold mechanoreceptors, thermal receptors, and nociceptors. The teased-fiber single-unit recording technique has long been used to resolve impulses that are likely to be from a single nerve fiber. The teased-fiber single-unit recording technique involves tedious nerve separation procedures, causes nerve fiber impairment, and is not a true single-fiber recording method. In the present study, we describe a new and true single-fiber recording technique, the pressure-clamped single-fiber recording method. We have applied this recording technique to mouse whisker hair follicle preparations with attached whisker afferents as well as to skin-nerve preparations made from mouse hindpaw skin and saphenous nerves. This new approach can record impulses from rapidly adapting mechanoreceptors (RA), slowly adapting type 1 mechanoreceptors (SA1), and slowly adapting type 2 mechanoreceptors (SA2) in these tissue preparations. We have also applied the pressure-clamped single-fiber recordings to record impulses on Aβ-fibers, Aδ-fibers, and C-fibers. The pressure-clamped single-fiber recording technique provides a new tool for sensory physiology and pain research.

Clinical study of herpes zoster in 109 patients in central referral hospital, Gangtok

<p class="abstract"><strong>Background:</strong> Herpes zoster results from the reactivation of varicella-zoster virus lying dormant in the dorsal root ganglia following an earlier primary infection (chickenpox), usually in childhood. The reactivation occurs due to multifactorial causes leading to decreased immunity.</p><p class="abstract"><strong>Methods:</strong> This study was conducted on 109 cases of herpes zoster. Patient’s particulars were noted. A detailed history was recorded; morphology, the site and side of skin lesions were recorded. Any other associated diseases were noted.<strong></strong></p><p class="abstract"><strong>Results:</strong> Out of 109 patients 66 were male and 43 were female. The total of 53 (48.6%) patients were under the age of 40 years and 56 (51.4%) patients above 40 years. Bhutias were affected in highest number (18.4%) followed by Sharma community (15.6%). The ophthalmic division of trigeminal nerve was the most commonly affected single nerve with 13.8% followed by T10 and T7 dermatome at 9.17% and 7.3% respectively. Thoracic nerves the most commonly involved thoracic nerves with 44 cases. Single dermatomal eruptions were found in 55 patients. The dissemination of herpes zoster was although very rare but was present in three patients. Type 2 diabetes mellitus was the common associated systemic illness with 10.09% of patients.</p><p class="abstract"><strong>Conclusions:</strong> From this study it was revealed that both young adults and older age group people were affected almost equally. The male: female ratio was 1.5:1 with Bhutia community being mostly affected. Thoracic dermatome was the most common dermatome involved and in half the patients some form of associated disease noted.</p>