Search

Non-volatile phase-change memory devices utilize local heating to toggle between crystalline and amorphous states with distinct electrical properties. Expanding on this kind of switching to two topologically distinct phases requires controlled non-volatile switching between two crystalline phases with distinct symmetries. Here, we report the observation of reversible and non-volatile switching between two stable and closely related crystal structures, with remarkably distinct electronic structures, in the near-room-temperature van der Waals ferromagnet Fe5-δGeTe2. We show that the switching is enabled by the ordering and disordering of Fe site vacancies that results in distinct crystalline symmetries of the two phases, which can be controlled by a thermal annealing and quenching method. The two phases are distinguished by the presence of topological nodal lines due to the preserved global inversion symmetry in the site-disordered phase, flat bands resulting from quantum destructive interference on a bipartite lattice, and broken inversion symmetry in the site-ordered phase.

The magnetic properties of the quasi-two-dimensional van der Waals magnet Fe5-δGeTe2 (F5GT), which has a high ferromagnetic ordering temperature TC∼315 K, remain to be better understood. It has been demonstrated that the magnetization of F5GT is sensitive to both the Fe deficiency δ and the thermal-cycling history. Here, we investigate the structural and magnetic properties of F5GT single crystals with a minimal Fe deficiency (|δ|≤0.1), utilizing combined x-ray and neutron scattering techniques. Our study reveals that the quenched F5GT single crystals experience an irreversible, first-order transition at TS∼110 K upon first cooling, where the stacking order partly or entirely converts from ABC-stacking order to AA-stacking order. Importantly, the magnetic properties, including the magnetic moment direction and the enhanced TC after the thermal cycling, are intimately related to the alteration of the stacking order. Our work highlights the significant influence of the lattice symmetry to the magnetism in F5GT.

During a band-gap-tuned semimetal-to-semiconductor transition, Coulomb attraction between electrons and holes can cause spontaneously formed excitons near the zero-band-gap point, or the Lifshitz transition point. This has become an important route to realize bulk excitonic insulators - an insulating ground state distinct from single-particle band insulators. How this route manifests from weak to strong coupling is not clear. In this work, using angle-resolved photoemission spectroscopy (ARPES) and high-resolution synchrotron x-ray diffraction (XRD), we investigate the broken symmetry state across the semimetal-to-semiconductor transition in a leading bulk excitonic insulator candidate system Ta2Ni(Se,S)5. A broken symmetry phase is found to be continuously suppressed from the semimetal side to the semiconductor side, contradicting the anticipated maximal excitonic instability around the Lifshitz transition. Bolstered by first-principles and model calculations, we find strong interband electron-phonon coupling to play a crucial role in the enhanced symmetry breaking on the semimetal side of the phase diagram. Our results not only provide insight into the longstanding debate of the nature of intertwined orders in Ta2NiSe5, but also establish a basis for exploring band-gap-tuned structural and electronic instabilities in strongly coupled systems.

We report the structural and magnetic ground state properties of the monoclinic compound barium iridium oxide Ba4Ir3O10 using a combination of resonant x-ray scattering, magnetometry, and thermodynamic techniques. Magnetic susceptibility exhibits a pronounced antiferromagnetic transition at TN≈25 K, a weaker anomaly at TS≈142 K, and strong magnetic anisotropy at all temperatures. Resonant elastic x-ray scattering experiments reveal a second order structural phase transition at TS and a magnetic transition at TN. Both structural and magnetic superlattice peaks are observed at L = half integer values. The magnetization anomaly at TS implies the presence of magnetoelastic coupling, which conceivably facilitates the symmetry lowering. Mean field critical scattering is observed above TS. The magnetic structure of the antiferromagnetic ground state is discussed based on the measured magnetic superlattice peak intensity. Our study not only presents essential information for understanding the intertwined structural and magnetic properties in Ba4Ir3O10 but also highlights the necessary ingredients for exploring novel ground states with octahedra trimers.

Background: Transcranial Doppler ultrasonography (TCD) is being increasingly used for its ability to provide cerebral hemodynamic information in stroke. Few studies have explored its association with cerebral arteriographic changes and stroke subtype. This study explored the relation of TCD changes in acute stroke with stroke subtypes, MR cerebral arteriography and clinical outcome in Omani population.Methods: Adult patients presenting with acute ischemic stroke within 4 days of stroke onset were subjected to TCD through the temporal and suboccipital windows using a 2 MHz probe; flow velocities, pulsatility and direction of flow were recorded from arteries at the skull base. MR arteriographic (MRA) changes on corresponding arteries were graded on a scale of 1-4. ANOVA, student's t test and ROC analysis were used to evaluate TCD in relation to stroke type, outcome and stenosis on MRA.Results: Of 60 patients recruited, 52 (M:F::36:16; mean age: 60 + 13 years) had adequate bone window for TCD study. Large artery stroke occurred in 30 (58%) patients; lacunar stroke-11 (21%); cardioembolic and mixed groups 9 (17%), other specificed causes-2 (4%). 86.5% had evidence of intracranial disease. 10/52 patients (19%) died while 33 (63%) had good outcome (modified Rankin Score 0-3). Of the 186 arteries studied by the two methods, 52 had TCD evidence of stenosis while 42 were abnormal on MRA, giving a sensitivity of 60%, specificity: 81.25%; positive likelihood ratio: 3.18 and negative likelihood ratio: 0.5. 29/52 (56%) of patients had TCD changes in the arteries corresponding to stroke location. Abnormal TCD was associated with large artery strokes (p = 0.007), poor outcome (p = 0.038) and mortality (p = 0.01).Conclusion: This study of TCD in acute stroke in Omani population demonstrates a relatively higher burden of intracranial arterial disease. TCD changes are associated with type of stroke and outcome in this population. TCD is a simple and fairly useful method of evaluation in patients with acute stroke. Adopting TCD in evaluation of stroke patients may provide useful information regarding the pathophysiology which could enhance patient management. [ABSTRACT FROM AUTHOR]

This 10-year follow-up report describes the interdisciplinary comprehensive management of a patient with aneurysmal bone cyst of the maxilla in a 24-year-old patient. The treatment included resection and primary reconstruction with vascularized deep circumflex iliac artery-based composite free flap, implant placement, and peri-implant soft tissue management using denture-guided epithelial regeneration with interim dentures. Definitive management was done using implant-supported cast partial dentures, and the patient followed up for 10 years., (© The Association of Oral and Maxillofacial Surgeons of India 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Surgical reconstruction of the missing external ear is difficult, and the results are often far from satisfactory. An implant-retained auricular prosthesis is a suitable alternative. Microtia, malformation, deformity, and partial or complete loss of the external ear may be due to various congenital or acquired factors. A case series of three patients treated with implant-retained auricular prostheses is presented in this article. For each missing pinna, two titanium implants were placed in the temporal bone. After 6 months of osseointegration, the implants were loaded. All three cases were rehabilitated with a bar and clip retained prosthesis. There were two male and one female patient with an average age of 16.6 years. One patient had unilateral absence of external ear and two had bilateral absence. A total of 10 implants were placed, 4 on the right side and 6 on the left. The average post rehabilitation follow-up was 18 months. Peri-implant tissue reactions were observed at two sites. The implant-retained auricular prosthesis is an alternative treatment approach with good retention and patient satisfaction. Long-term follow-up is required to assess delayed sequelae., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 National Journal of Maxillofacial Surgery.)

Purpose: Status Epilepticus (SE) is a common medical emergency carrying a high morbidity and mortality. Levetiracetam (LEV) is a novel anticonvulsant effective against varied seizures. Few prospective studies have addressed its use in SE. We aimed to examine the efficacy of intravenous LEV in controlling SE and cluster attacks of seizures (CS), in comparison with IV phenytoin (DPH), using a prospective, randomized study design., Method: Adult patients with SE or CS, following an initial dose of IV benzodiazepine to control ongoing seizure, were randomized to receive either medication. Rates of seizure control over 24h, adverse effects and outcomes were compared. A logistic regression model was used to identify outcome predictors., Results: 52 patients with SE and 63 with CS received either LEV or DPH. In the SE group, LEV was effective in18/22(82%) and DPH in 22/30(73.3%) patients in controlling seizures. Among patients with CS, LEV was effective in 31/38(81.6%) and DPH in 20/25(80%). With the use of LEV, DPH or both, SE and CS were controlled among 92% and 96% of patients respectively. Adverse events included hypotension (in 2 on DPH) and transient agitation (2 on LEV)., Conclusions: IV Levetiracetam controls status epilepticus or cluster seizures with an efficacy comparable to that of phenytoin. Use of these two agents consecutively may control >90% of all such conditions without resort to anaesthetic agents. Further studies should explore its efficacy in larger cohorts of epileptic emergencies., (Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Background: In patients with reconstructed mandibles using free fibula flaps, management of soft tissues around implants supporting dental rehabilitation, is often a clinical problem., Aim: The aim of this paper is to describe a new technique, namely "Sub-periosteal dissection and denture-guided epithelial regeneration (SD-DGER)", as a method of peri-implant soft tissue management in these patients., Materials and Methods: The technique consists of performing a subperiosteal dissection with creation of buccal and lingual flaps. These flaps form the buccal and lingual vestibule. Implants are placed and an interim denture is immediately loaded onto the implants to guide the regenerated epithelium. A keratinized mucosal layer is formed on the bare fibula bone in six months time., Results: This technique was successful in producing fixed keratinized epithelial tissue around implants in patients with mandibles reconstructed using the free fibula flap in patients who did not undergo radiotherapy., Conclusion: The sub-periosteal dissection with denture guided epithelial regeneration is a predictable form of peri-implant soft tissue management in selected patients with reconstructed jaws., Competing Interests: Vinay V. Kumar, P. C. Jacob and Moni A. Kuriakose declare that they have no conflict of interests. Ethical Approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed Consent Informed consent was obtained from all individual participants included in the study.

Objectives: The objective of this study was to assess the difference in success rates of implants when using two or four implant-supported-overdentures following segmental mandibular reconstruction with fibula free flap., Methods and Designs: This prospective, parallel designed, randomized clinical study was conducted with 1:1 ratio. At baseline, all participants already had segmental reconstruction of mandible with free fibula flap. The participants were randomized into two groups: Group-I received implant-supported-overdentures on two tissue-level implants and Group-II received implant-supported-overdentures on four tissue-level implants. Success rates of the implants were evaluated at 3 months, 6 months and 12 months following implant loading using marginal bone level changes as well as peri-implant indices (Buser et al., 1990)., Results: 52 patients were randomized into two treatment groups (26 each), out of which 18 patients (36 implants) of Group-I and 17 patients (68 implants) of Group-II were evaluated. One implant in Group-I was lost due to infective complications and one patient in the same group had superior barrel necrosis. There was a statistically significant increase at both time points (p = 0.03, p = 0.04 at 6 months, 12 months) in the amount of marginal bone loss in Group-I (0.4 mm, 0.5 mm at 6 months, 12 months) as compared to Group-II (0.1 mm, 0.2 mm at 6 months, 12 months). There were no clinically significant changes peri-implant parameters between both groups. Peri-implant soft tissue hyperplasia was seen in both groups, 32% of implants at 3-months, 26% at 6-months and 3% at 12-months follow-up., Conclusion: The results of this study show that patients with 2-implant-supported-overdentures had higher marginal bone loss as compared to patients with 4-implant-supported-overdentures. There were no clinically significant differences in peri-implant soft tissue factors in patients with 2- or 4-implant-supported-overdentures. Hyperplastic peri-implant tissues are common in the early implant-loading phase and tend to decrease over time under appropriate management., (Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Aim: The aim of this clinical paper is to introduce a technique to plan for functional maxillofacial reconstructions., Materials and Methods: Preoperative dental casts were made of the patient and mock surgery performed on the casts. A fibula analogue was then placed in an ideal functional reconstruction position. New dentures were fabricated on the fibula analogue and drill holes for the placement of implants were placed through the denture. This denture formed as a guide to position the fibula transplant during surgery., Results: This technique was useful in producing functional and rehabilitative outcomes in cases of both maxillary and mandibular reconstructive surgeries., Conclusion: The Jugaad technique-denture based inverse planning-is a cost effective method for planning and executing maxillofacial reconstructions using mock surgery on casts and interim dentures., Competing Interests: All the authors declare that they have no conflict of interests.

Purpose: The primary objective of this study was to assess the difference in quality of life (QoL) in patients with dental rehabilitation using two or four implant-supported overdentures following segmental mandibulectomy defect reconstruction with fibula free flap., Material and Methods: This prospective, parallel designed, randomized clinical study was conducted with a 1:1 ratio. At baseline, all participants already had fibula flap reconstruction for segmental defects of the mandible and rehabilitation with conventional (non-implant supported) removable partial dentures. The participants were then randomized into two groups. Group I received implant supported overdentures on two implants, and Group II received four implants. QoL outcomes were evaluated using standardized questionnaires (EORTC_QLQ c30, H&N35, OHIP, DSI). Outcomes of treatment were evaluated at 6 months (T1) and 1 year (T2) following rehabilitation., Results: A total of 52 patients were randomized into two treatment groups (26 each). After accounting for the loss to lack of follow-up, 22 patients in Group I and 24 patients in Group II were evaluated for QoL at the end of the study. There was a significant improvement in QoL with implant-assisted dental rehabilitation. However there were no significant differences in QoL between the two-implant and four-implant groups., Conclusion: Implant-supported removable overdentures improve QoL outcomes in patients with reconstructed mandibles. This study showed no significant difference in QoL outcomes in patients with two- or four-implant supported removable prostheses., (Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

We assessed the EEG patterns and their prognostic significance in critically ill adult patients with encephalopathy, by digital EEGs lasting lip to 1 hour Of the 110 patients (age: 43.8 ± 19.4 years, male: female:1.6:1) studied, 32% had hypoxic ischemic encephalopathy (HIE), 17% severe infections, and 14.5% stroke. Observed EEG patterns were diffuse slowing (41%), low-voltage cerebral activity (LVCA, 18%), nonconvulsive status epilepticus (NCSE, 13.6%), and periodic abnormalities (9.1%). LVCA, age, Glasgow Coma Score (GCS) < 8, HIE, and modified Hockaday's EEG grades of IV and V were associated with poor outcome (p < 0.005) at hospital discharge; generalized slowing was associated with a relatively good outcome (p = 0.003). On multivariate analysis, factors independently predictive of mortality were LVCA, older age, and poor GCS. In conclusion, LVCA and generalized background slowing were common EEG patterns among critically ill intensive care unit (ICU) patients with encephalopathy of varied etiologies. While LVCA was associated with a poor outcome, generalized background slowing predicted better prognosis. Conventional short-duration, bedside EEG studies could aid in the recognition of electrographic patterns of prognostic importance in facilities where continuous EEG monitoring is lacking.

Varicella zoster virus (VZV) pneumonitis and brainstem encephalitis developed in an immunocompetent adult without rash. Chest computed tomography exhibited nodularity; lung biopsy revealed multinucleated giant cells, Cowdry A inclusions, VZV antigen, and DNA. Varicella zoster virus central nervous system disease was verified by cerebrospinal fluid (CSF) anti-VZV IgG antibody with reduced serum/CSF ratios.

Purpose: Full Outline of UnResponsiveness, or FOUR score (FS), is a recently described scoring system for evaluation of altered sensorium. This study examined interrater reliability for FS and Glasgow Coma Scale (GCS) among medical patients with altered mental status and compared outcome predictability of GCS, FS, and Sequential Organ Failure Assessment score., Patients and Methods: Adult patients with altered mental status due to medical causes were rated by neurology consultants and internal medicine residents on FS and GCS. Interobserver reliability for GCS and FS was assessed using κ score. Relation with outcomes was explored using univariate and multivariate analyses., Main Results: Of the 100 patients (age, 62 ± 17 years), 60 had neurologic conditions; 26, metabolic encephalopathy; 9, infections; and 7, others. Thirty-nine patients died at 3 months. κ Scores ranged from 0.71 to 0.85 for GCS and from 0.71 to 0.95 for FS. On multivariate analysis, GCS was predictive of outcome at 3 months; FS was predictive of mortality. Area under the receiver operating characteristic curves suggested equivalent performance of both scoring systems., Conclusions: Interrater reliability and outcome predictability for FS were comparable with those for GCS. This study supports the use of FS for evaluation of altered mental status in the medical wards., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Eating epilepsy (EE), where seizures are triggered by eating, is rare and has not been reported in the Gulf region. In EE, the ictal semiology includes partial or generalised seizures. Focal brain changes on imaging, if present, are often confined to the temporal lobe or perisylvian region. Therapeutic options, especially in those patients who are refractory to pharmacotherapy, have not been well-established. We report a series of five patients with EE from Oman, a country located in the eastern part of the Arabian Gulf region, and highlight the usefulness of temporal lobectomy in one patient who had medically-intractable EE. Surgical intervention could be considered as a potential therapeutic option in carefully selected patients with medically-intractable seizures.

Intracranial developmental venous anomalies (DVAs), also called venous angiomas, and Wilson's disease are both considered rare disorders with varying degrees of neurologic and systemic manifestations; yet the coexistence of the two disorders is considered extremely rare, bearing in mind the low prevalence of each disorder. Epilepsy is a recognised presentation in these disorders and will be the focus of discussion in our report of a 21-year-old male patient who, based on a clinical examination and laboratory and neuroimaging results, was diagnosed with both Wilson's disease and DVA. He presented initially at Sultan Qaboos University Hospital, Oman with tremors and writing difficulties in the right hand followed by the development of epilepsy, and was treated medically by de-coppering and antiepileptic medications. We also present a brief literature review of both disorders, their association with epilepsy, and treatment options. Family screening for patients with Wilson's disease is pivotal in preventing unfavourable outcomes.

Objective: To report the clinical and imaging findings in a patient with an initial fluctuating disconnection syndrome due to corpus callosal ischemia that ultimately culminated in infarction with persistent symptoms., Case Report: A 40-year-old, hypertensive, right-handed man presented with transient, stereotyped symptoms of corpus callosal disconnection (intermanual conflict, apraxia, dysgraphia and construction difficulties in his left hand). Serial magnetic resonance imaging scans demonstrated the ischemic nature of the initial fluctuating symptoms and later showed callosal infarction when the symptoms were persistent. Magnetic resonance angiogram did not reveal significant stenosis or occlusion of the internal carotid or proximal portion of anterior cerebral arteries. Patient received standard treatment for ischemic stroke and at follow-up 1 month later, had mild left hand apraxia, dysgraphia and construction difficulties., Conclusion: The case highlights the unusual occurrence of crescendo transient ischemic attacks culminating in infarction in the location of corpus callosum. We have termed this novel stroke syndrome as 'callosal warning syndrome' as the temporal profile was quite indistinguishable from that of relatively well-known stroke warning syndromes in the location of internal capsule and pontine tegmentum., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The autoimmune disease, myasthenia gravis (MG), can mimic a variety of neurological disorders leading to a delay in diagnosis and treatment. On occasions, misdiagnosis of MG could lead to unnecessary and potentially harmful therapeutic interventions. We report on a 12 year-old boy, in whom MG was mistaken for meningitic sequelae and subsequently for critical neuropathy/myopathy resulting in considerable morbidity for nearly a decade. Subsequent correct diagnosis and optimal management resulted in significant improvement in his functional status. We discuss the importance of considering MG as one of the potential differential diagnoses among cases of recurrent respiratory pump failure, or unexplained bulbar symptoms where documentary proof of the previous diagnoses including work-up for MG is lacking. We also review the literature on MG misdiagnosis and highlight the potential pitfalls in MG diagnosis.

MRI is an essential investigation in epilepsy and status epilepticus (SE) for determining the underlying cause. However, SE or prolonged seizures may themselves induce changes in the MRI resulting in difficulty in interpretation. This case report illustrates a patient who recovered completely from prolonged generalized idiopathic SE lasting more than 2 weeks and had transient bilateral external capsule, fronto-temporal, and insular cortical MRI changes. The mechanism of such MRI changes and their implications for survival even after prolonged SE are discussed., (Copyright © 2011 Informa Healthcare USA, Inc.)

Myoglobinuria occurs in a variety of systemic and neurological disorders and can pose diagnostic challenges. We report on a 23-year-old man in whom recurrent myoglobinuria was observed due to necrotizing vacuolar myopathy confirmed on muscle biopsy. Histopathologically the intramuscular vacuoles lacked the typical findings reported in vacuolar myopathy due to disorders of glycogen and lipid metabolism. We discuss the management approach to recurrent myoglobinuria. Recurrent myoglobinuria in the absence of toxin or drug exposure and seizure is more often due to primary muscle disease. Recognizing the presence of myoglobinuria and the proximate cause is essential in preventing the development of renal dysfunction and the future recurrence of symptoms.

Ischemic infarction is a rare cause of acute myelopathy. We report the case of a young woman admitted to Sultan Qaboos University Hospital, Oman, who developed extensive spinal cord infarction in the setting of surgical evacuation and packing of liver haematoma and post-operative epidural analgesia. She had no vascular risk factors for stroke. The vascular mechanism underlying ischemic myelopathy and the relationship to abdominal surgery and epidural analgesia are discussed.

Background: Hyponatremia is a fairly common metabolic disorder. Hyponatremic myelinolysis is a relatively rare, life threatening complication with poorly understood pathophysiology, varied clinical manifestations and uncertain treatment. This case report highlights the range of clinical and imaging phenomena associated with hyponatremic myelinolysis., Methods: Case report., Result: A middle aged lady presented with an acute delirious state, hypotension and severe hyponatremia on a background of skin hyper-pigmentation and weight loss. Her clinical course evolved to an akinetic-rigid state and later to parkinsonism. Extensive investigations for recognizing a primary neurologic disorder, including brain MRI and CSF analysis were normal, though she had disseminated miliary tuberculosis involving multiple organs. Brain MRI changes characteristic of extrapontine myelinolysis appeared two weeks after the onset of symptoms. The patient recovered completely over several weeks., Conclusion: This case of hyponatremic extrapontine myelinolysis occurred as the presenting manifestation of adrenal failure secondary to disseminated tuberculosis. Extraponine myelinolysis is difficult to diagnose in the context of delayed brain MRI changes and can have a favorable outcome with modern management.

Objective: To describe the clinical characteristics of multiple sclerosis (MS) seen in Oman and compare it with those seen in the Arabian peninsula, the rest of Asia and the Western world., Methods: A hospital based case descriptive study of MS patients, seen at Sultan Qaboos University Hospital in the Sultanate of Oman, between June 1990- June 2000., Results: We saw a total of 30 patients during the study period, with a prevalence of 4/100,000. Mean age at onset was 27 and male to female ratio was 1.1:1. Visual and motor symptoms were the most common presenting features. Lesions were distributed in the optic nerve in 17, spinal cord in 16, cerebral hemispheres in 12 and brain stem and cerebellum in 10. One third of patients had the optico-spinal form of the disease. Twenty-three patients had a remitting and relapsing course, 4 had secondary progressive and 3 had a primary progressive course. Cerebrospinal fluid oligoclonal band was positive only in 20% of patients, and we carried out HLA analysis in 24 of these patients., Conclusion: The incidence of MS is low in Oman, but similar to other countries in the region. The optico-spinal form of the disease constituted 30% in this series, comparable to other series reported from Asia. Generally, the clinical profile of MS seen in Oman is very similar to those reported from the Arabian Peninsula and other Asian regions.

Neurocysticercosis is a common cause of adult onset epilepsy. Neurocysticercosis in pregnancy can present with convulsions and may be difficult to differentiate from a pregnancy related disorder. We present a case of neurocysticercosis diagnosed by magnetic resonance imaging.

We report a case of a 27-year-old Omani lady having a 3-year history of progressive skeletal muscle weakness with clinical and skeletal muscle changes of ALS, who during the course of investigations for ALS was found to have SLE. This association is not a simple coincidence but perhaps a causal relationship, opening vistas to explain the autoimmune pathogenesis and justification for immunosuppressive therapy in ALS. SLE presenting as ALS has not been reported earlier.

Objective: Clinical study and follow up of myasthenia gravis patients in Oman., Methods: Follow up of 50 consecutive myasthenia gravis patients referred to the Sultan Qaboos University Hospital, Oman for a median period of 3 years from 1997 to 2000. We based the diagnosis on the clinical picture, repetitive nerve stimulation tests and edrophonium test. We performed a computerized tomography scan of the chest and anti-acetylcholine receptor antibodies. We reviewed the results of immuno modulatory treatment including thymectomy and compared these with other studies, Results: Of 50 patients, 6 had purely ocular myasthenia. Of the 44 with generalized myasthenia, 28 had bulbar involvement and 12 required ventilatory support. Eight out of 29 thymectomized patients had drug free remission after 2 years. There was worsening of myasthenic symptoms in only one out of 8 pregnancies and deliveries., Conclusion: Bulbar and ventilatory involvement are more common in our series as compared with western data. Pregnancy and delivery were well tolerated.

The sympathetic skin response (SSR) is an evoked change in electrical skin potential and is an index of the function of sympathetic pathways. We studied the SSR evoked by electrical stimulation of the median nerve and recording from the contralateral hands in 30 patients with carpal tunnel syndrome (CTS) without clinical autonomic signs and compared the results to the SSR in 30 normal controls. The SSR was absent in the affected hands in seven (23%) patients. In the other carpal tunnel syndrome patients (77%), a significant reduction in the SSR area was seen in the records from the affected hands. Subclinical sympathetic nerve fibre involvement occurs in the affected median nerves in CTS.

We report a patient with muscle weakness secondary to elevated serum sodium level. The cause of the elevated sodium level and the mechanism involved in producing muscle weakness are discussed.

We report the case of a patient with postherpetic neuralgia who developed asterixis while being treated with gabapentin. We discuss the possible mechanism of asterixis in this patient.

Background: Pathological laughter can be a sign of epilepsy, psychiatric illness, effect of toxins or psychotropic drugs or of structural brain disease., Method: Case Studies., Result: Two patients developed inappropriate uncontrollable laughter following intravenous sodium valproate for treatment of epilepsy., Conclusion: Pathological laughter can be a side effect of intravenous sodium valproate.