Flavia Costa Nunes Machado

A case of primary spinal myoclonus: clinical presentation and possible mechanisms involved

Spinal myoclonus is a rare movement disorder characterized by myoclonic involvement of a group of muscles supplied by a few contiguous segments of the spinal cord. Structural lesions are usually the cause, but in primary spinal myoclonus the etiology remains unknown. We present the case of a 26-year-old woman with cervical spinal myoclonus in which both clinical and electromyographic findings pointed to the segment C1-C3 as the origin of the myoclonus. Laboratorial examinations were normal and no structural lesion was found in magnetic resonance imaging (MRI). Botulinum toxin type A was injected in infrahyoid muscles and cervical paraspinal musculature. The patient remained free of symptoms for almost five months. The pathophysiology of spinal myoclonus remains speculative, but there is evidence that various possible mechanisms can be involved: loss of inhibitory function of local dorsal horn interneurons, abnormal hyperactivity of local anterior horn neurons, aberrant local axons re-excitations and loss of inhibition from suprasegmentar descending pathways.

Espasmo hemifacial bilateral: relato de caso

Bilateral hemifacial spasm (BHS) is a rare focal movement disorder often associated with vascular compression of both facial nerves. The contractions are usually asymmetric and asynchronous. Typically, one side is affected first and there is a long but variable interval for the symptoms on the other side to occur. BHS must be differentiated from other conditions including blefarospasm, facial myokymia, facial tics, oromandibular dystonia, and hemimasticatory spasm. The most successful and non-invasive symtomatic treatment is botulinum toxin injections but microvascular decompression surgery is another therapeutic option. We report the case of a 70 years old man with bilateral hemifacial spasms and present a brief review of the literature.

Acute axonal polyneuropathy with predominant proximal involvement: an uncommon neurological complication of bariatric surgery

Bariatric surgery is frequently indicated in the treatment of morbid obesity. Previously unreported complications have been associated to this surgery; among them, neurological complications have gained attention. We report the case of a 25-year-old man submitted to gastric surgery for treatment of morbid obesity who developed, two months after surgery, acute proximal weakness in lower limbs. The electroneuromyography revealed axonal peripheral polyneuropathy with predominant proximal involvement. After treatment with immunoglobulin and vitamin supplementation, rapid clinical and neurophysiologic recovery was observed. We describe the clinical and electroneuromyographic features of this case, stressing the difficulty of initial diagnosis, particularly in the differential diagnosis with Guillain-Barré syndrome. We discuss the importance of nutritional follow-up and the eventual indication of routine vitamin supplementation in these patients.

EFEITOS HEMOSTATICO E ESTRUTURAL DA ESPONJA DE CELULOSE LIOFILIZADA

Os efeitos hemostaticos da celulose oxidada (Surgicel) sao bem conhecidos. Baseados na similaridade estrutural e em um possivel efeito hemostatico, estudamos a esponja de celulose liofilizada utilizando dois modelos experimentais. Fase I - Realizada em 12 caes, consistiu na provocacao de lesao cortical com sangramento, introducao de fragmento de esponja de celulose liofilizada no interior da lesao e medida do tempo necessario para obter-se hemostasia. Os animais foram sacrificados em 7, 30 e 90 dias. A hemostasia foi obtida, em media, apos 1 minuto e nenhum efeito colateral clinico foi detectado. A microscopia mostrou reacao histiocitaria leve aos 7 e 30 dias, com presenca de pequena quantidade de celulas gigantes tipo corpo estranho. A reacao histioplasmocitaria regrediu e, aos 90 dias, a celulose estava circundada por pobre reacao inflamatoria. A membrana liofilizada revelou ter aspecto peculiar, representado por filamentos eosinofilicos, circundados por reacao inflamatoria, que diminuiu com o tempo. Somente esparsos e irregulares filamenos eosinofilicos foram percebidos aos 90 dias. Fase II - Foram introduzidos fragmentos de dimensoes conhecidas de esponja de celulose, no interior do figado de 12 ratos, que foram sacrificados em 7, 30 e 90 dias. Na autopsia, a inspecao a olho desarmado constatou, aos 30 e 90 dias, a formacao de bridas peritoneais na altura do implante. Em todos os animais, especialmente aos 7 dias, a microscopia revelou intensa reacao histiolinfoplasmocitaria ao redor do implante. Em dois animais, aos 90 dias, detectaram-se grânulos refringentes a luz polarizada, no interior de celulas gigantes, demonstrando fagocitose ativa de celulose. Em conclusao, observou-se haver necessidade de modelo experimental comparativo para provar a existencia de propriedades hemostaticas na esponja. Conseguiu-se, no entanto, provar a existencia de reabsorcao da celulose em mamiferos atraves de fagocitose, fato este ainda nao relatado na literatura.

Combined nerve conduction index in diabetic polyneuropathy.

UNLABELLED Diabetic polyneuropathy can be confirmed by nerve conduction studies. The data can be analyzed in the form of a combined index instead of individual parameters. METHODS The combined index included five parameters of nerve conduction studies commonly used for evaluation of polyneuropathies. We evaluated sensitivity in 100 diabetic patients with suspected polyneuropathy, and specificity in 200 non-diabetic patients with suspected lumbosacral radiculopathy. All results were expressed in number of standard deviations (SD). RESULTS The sensitivity of the combined index was 81 or 74%, and specificity was 97 or 98%, using respectively -2.0 or -2.5 SD as cutoff. The range of sensitivity of the other parameters was 57-65% or 48-56%, and specificity range was 96-98% or 98-100%, using the same criteria. DISCUSSION The combined index had higher sensitivity and equivalent specificity compared to isolated parameters.

Diagnostic accuracy of concentric needle jitter in myasthenia: Prospective study.

Introduction: The aim of this study was to estimate jitter parameters in the orbicularis oculi muscle using a concentric needle electrode (CNE) in patients with myasthenia gravis (MG) and to determine its diagnostic accuracy for jitter analysis (CNEMG‐jitter). Methods: CNEMG‐jitter was performed in 20 healthy subjects and 33 MG patients using the voluntary contraction technique. Receiver operating characteristic (ROC) curves were constructed to determine cut‐off points with the best sensitivity/specificity combination for jitter analysis. Results: CNEMG‐jitter yielded high positivity rates for ocular MG (92.3%) and generalized MG (100%). The ROC curve cut‐off point that provided the highest sensitivity without false positives was 24.7 μs for mean jitter and 33.1 μs for the 18th highest value. Sensitivity was 93.9% for both parameters. Diagnostic accuracy of CNEMG‐jitter was > 96%. Conclusions: CNEMG‐jitter yielded high sensitivity and specificity rates. Our reference values were lower than previously published values, possibly due to less technical variation between the different recordings. Muscle Nerve 55: 190–194, 2017

S102. Repetitive nerve stimulation: ROC curve analysis

Introduction Repetitive nerve stimulation (RNS) is the standard procedure to evaluate neuromuscular transmission disorders. The cut-off level is often arbitrary and is usually the same for every test, despite the peculiarities of each nerve-muscle setting. Our objective was to perform a ROC curve analysis of four different RNS techniques and define the best cut-off level for them. Methods We did a retrospective study of RNS with 20 patients with positive serologic confirmation of Myasthenia Gravis and 20 patients with negative acetylcholine receptor binding antibodies and normal jitter studies of both orbicularis oculi and of another symptomatic muscle. All patients were submitted to RNS with six stimuli at 3 or 2 Hz of the following nerves (muscles): ulnar (abductor digiti minimi), accessory (trapezius), facial (nasal), and axillary (deltoid). The decrement was calculated using the negative amplitude of the fourth potential in relation to the first. Recordings after maximal contraction were not considered for analysis. We calculated sensitivity and specificity at four different cut-off levels for each technique: 10%, 7.5%, 5%, and >0%. We constructed the ROC curve, compared the techniques, and suggested the best cut-off point for each test. Results The specificity was 100% for all tests using the classical decrement cut-off of 10%. Using this, sensitivity was: 5% (ulnar), 30% (accessory), 65% (facial), and 60% (axillary). The area bellow curve was 0.52 (ulnar), 0.58 (accessory), 0.83 (facial), and 0.86 (axillary). The best cut-off was a decrement above 7.5% for all tests, keeping specificity at 100% for all except accessory, which was 95%. Using this, sensitivity was: 20% (ulnar), 40% (accessory), 65% (facial), and 70% (axillary). Conclusion RNS of facial and axillary nerves had a better performance than ulnar and accessory nerves. The cut-off level suggested by our study is a decrement above 7.5% for all tests. Larger studies can propose different cut-off levels for each technique.

F93. Probabilistic jitter characterization

Introduction Bayesian probabilistic characterization has already been used for quantitative electromyography but not for jitter analysis. Instead of classical statistical method, probabilistic characterization uses sequential cumulative probability. Our objective was to evaluate the performance of probabilistic characterization for jitter assessment. Methods We analyzed 20 controls and 20 patients with serologically confirmed Myasthenia Gravis (MG). All patients were submitted to orbicularis oculi concentric needle voluntary jitter measurements of 20 pairs of ASFAP, adding up 797 MCD measurements. Jitter was characterized in four different levels: A: μ s; B: 25–45  μ s; C: 45–65  μ s; and D: >65  μ s. We calculated the probability of an abnormal result for each jitter level. Then, we used the Bayesian sequential approach in each subject until the cumulative probability of a normal or abnormal result was >99%. Results The probability of abnormality for each jitter level was: A: 20%; B: 73%; C: 95%; and D: 99%. The cumulative probability achieved more than 99% up to the sixth potential in 77% of the subjects. However, one control subject was labeled as abnormal while four MG subjects were labeled as normal studies. Additionally, two control subjects could not be characterized up to the 20th recording. The method accuracy was 82%. Conclusion Probabilistic characterization requires fewer recordings than the statistical method. However, our study showed poor accuracy for jitter characterization. One possible reason is that MCD values in each patient are not randomly scattered during the entire exam, but rather clustered according to the sampled region.

70. Combined nerve conduction index for evaluation of diabetic polyneuropathy

generative disorder involving the basal ganglia and it is thought to spare the peripheral nervous system. However, ambiguous sensory symptoms including pain and numbness are recognized non-motor manifestations that affect between 40% and 75% of IPD patients. Objectives: The association of peripheral neuropathy and sensory symptoms of IPD were investigated through electrophysiological tests. Methods: Twenty-five patients with IPD associated with ambiguous sensory symptoms were recruited. The Hoehn and Yahr scale was used to evaluate disease severity in the IPD patients and electrophysiological tests of the ulnar, median, peroneal, posterior tibial, and sural nerves were performed. The association between sensory symptoms and the levodopa daily dose was analyzed. The patients were also categorized into two groups according to their Hoehn and Yahr stage and analyzed the correlation between the severity of IPD and peripheral nerve disorder. Results: Only 10 patents showed normal findings on nerve conduction tests. In these studies, there were significant abnormal findings of sensory conduction of the ulnar and sural nerves and terminal latency of the peroneal and posterior tibial motor nerves. Abnormal findings of sensory nerves significantly correlated with a high dose of levodopa and long disease duration. But there was no significant difference of eletrophysological tests between disease severity. Conclusion: It was shown that IPD patients with sensory symptoms might have electrophysiological abnormalities regardless of disease severity. The authors suggest that IPD is neurodegenerative disease involving the peripheral nerve system exhibiting as non-motor symptoms.

126. Suprascapular nerve neuropathy: A series of thirteen patients

NCSs and EMG performed within 14 days of diagnosis, had denervation while 100% (n = 3) had denervation when the studies were conducted after 14 days. Conclusion: Denervation can be seen early in axonal GBS. Additionally, large scale studies are needed to establish whether this finding has relation to favorable outcomes in axonal variants of GBS. G.S. Dahani is a recipient of the 2008 IFCN, North American Chapter Fellowship Award.