Neuronopatía sensitiva paraneoplásica asociada a carcinoma escamoso de laringe / Paraneoplastic sensory neuropathy associated with squamous cell carcinoma of the larynx

No disponible

Parálisis facial bilateral secundaria a infección por virus de Epstein-Barr / Bilateral facial palsy due to Epstein-Barr virus infection

Nuestro objetivo es describir dos pacientes jóvenescon parálisis facial periférica bilateral. Ambos presentaroninicialmente afectación en un lado de la cara,seguida pocos días después de afectación contralateraljunto con sintomatología compatible con infecciónaguda por el virus de Epstein-Barr, que se confirmó conla serología. Uno de los pacientes experimentó mejoríacompleta mientras que en el otro la recuperación fuelenta y quedaron secuelas permanentes. La lesión bilateraldel nervio facial es una complicación infrecuentede la infección por el virus de Epstein-Barr cuya evoluciónno siempre es favorable. Se discute su mecanismo patogénico (AU)

Two young patients with bilateral facial palsy are described. They initially presented unilateral facial palsy,followed by contralateral facial nerve involvement afew days later, together with clinical and serologic evidenceof acute Epstein-Barr virus infection. The outcomewas favourable in one patient but severe sequelspersisted in the second. These two cases show that thisinfrequent complication of Epstein-Barr virus infectionmay not always have a good outcome. The pathogenic mechanism of bilateral facial palsy is discussed (AU)

Fisiopatología y técnicas de registro de los movimientos oculares / Physiopathology and recording techniques of ocular movements

En el control de la motilidad ocular intervienen varios sistemas funcionales. Los reflejos vestíbulo-oculares y optocinéticos son respuestas automáticas para compensar los movimientos de la cabeza y del entorno visual y poder estabilizar la imagen retiniana sobre un determinado punto de fijación. Los movimientos sacádicos son rápidos desplazamientos de la fijación de un punto a otro del campo visual. Los movimientos de persecución lenta consisten en el seguimiento de estímulos móviles con la mirada. Finalmente, existen movimientos involuntarios de muy escasa amplitud que se producen durante el mantenimiento de la fijación. Cada modalidad funcional de movimiento depende de circuitos neuronales específicos que trabajan coordinadamente para codificar la contracción de los músculos oculomotores correspondiente a la posición adecuada en cada momento. Estos sistemas neuronales pueden verse alterados por múltiples procesos neurológicos de diferente naturaleza y localización dando lugar a una variada gama de trastornos oculomotores. Se revisan los aspectos más destacados de la fisiopatología y de los sistemas de registro de los movimientos oculares (AU)

A number of functional systems are involved in the control of eye movements. The vestibulo-ocular and optokinetic reflexes are automatic responses that compensate for the movements of the head and those of the visual environment in order to stabilize the retinal image on a given fixation point. The saccadic movements are quick displacements of fixation from one to another point in the visual field. The smooth pursuit movements consist in the gaze following a moving target. Finally, there are some involuntary movements of very small amplitude during fixation maintenance. Each functional modality of movement depends on specific neuronal circuits that work in a coordinated manner for encoding the contraction of the oculomotor muscles to reach an adequate position at every moment. These neuronal systems can be altered by many neurological processes of different kinds and localizations, causing a broad variety of oculomotor disturbances. The most salient aspects of the physiopathology and the recording systems of eye movements are reviewed (AU)

Métodos de procesamiento y análisis de señales electromiográficas / Electromyographic signal processing and analysis methods

La electromiografía clínica es una metodología de registro y análisis de la actividad bioeléctrica del músculo esquelético orientada al diagnóstico de las enfermedades neuromusculares. Las posibilidades de aplicación y el rendimiento diagnóstico de la electromiografía han evolucionado paralelamente al conocimiento de las propiedades de la energía eléctrica y al desarrollo de la tecnología eléctrica y electrónica. A mediados del siglo XX se introdujo el primer equipo comercial de electromiografía para uso médico basado en circuitos electrónicos analógicos. El desarrollo posterior de la tecnología digital ha permitido disponer de sistemas controlados por microprocesadores cada vez más fiables y potentes para captar, representar, almacenar, analizar y clasificar las señales mioeléctricas. Es esperable que el avance de las nuevas tecnologías de la información y la comunicación pueda conducir en un futuro próximo a la aplicación de desarrollos de inteligencia artificial que faciliten la clasificación automática de señales así como sistemas expertos de apoyo al diagnóstico electromiográfico (AU)

Clinical electromyography is a methodology for recording and analysing the bioelectrical activity of the skeletal muscle tissue in order to diagnose neuromuscular pathology. The possibilities of application and the diagnostic performance of electromyography have evolved parallel to a growing understanding of the properties of electricity and the development of electrical and electronic technology. The first commercially available electromyography equipment for medical use was introduced in the middle of the 20th century. It was based on analog electronic circuits. The subsequent development of digital technology made available more powerful and accurate systems, controlled by microprocessors, for recording, displaying, storing, analysing, and classifying the myoelectric signals. In the near future, it is likely that advances in the new information and communication technologies could result in the application of artificial intelligence systems to the automatic classification of signals as well as expert systems for electromyographic diagnosis support (AU)

[Pseudo-conduction block in nonsystemic vasculitic neuropathy]. / Pseudobloqueo de conducción en vasculitis aislada del sistema nervioso periférico.

SUMMARY: Introduction. Nonsystemic vasculitic neuropathy (NSVN) is an inflammatory disorder of the vasa nervorum which usually is expressed as a mononeuritis multiplex. We present a patient with NSVN with histological confirmination focused on the neurophysiological findings at the early stages. CASE REPORT: A 36 years-old woman presented with paresthesia and weakness in her right hand followed by left footdrop. The first neurophysiologic examination showed low amplitude of the right median nerve (RMN) CMAP with proximal stimulation. A second examination showed signs of axonal damage in several nerves, including the RMN. CONCLUSIONS: The acute ischemic damage of a nerve can give a pattern of conduction block in the electroneurographic study as in the RMN of the presented case. This phenomenon is referred as "pseudo-conduction block", since it is transient and evolves towards a definite pattern of axonal neuropathy. When a vasculitic neuropathy is suspected, repeated neurophysiologic studies are necessary in order to ensure a proper (appropriate) characterization of the lesional patterns.

Pseudobloqueo de conducción en vasculitis aislada del sistema nervioso periférico / Pseudo-conduction block in nonsystemic vasculitic neuropath

Fundamento. La vasculitis aislada del sistema nerviosoperiférico (VASNP) afecta selectivamente a los vasanervorum, expresándose generalmente como una mononeuropatíamúltiple. Presentamos un caso de VASNPconfirmado histológicamente, destacando los hallazgosneurofisiológicos en fase aguda.Observación clínica. Mujer de 36 años con parestesiasy debilidad en mano derecha seguidas de paresia parala dorsiflexión del pie izquierdo. El primer estudio neurofisiológicomostraba amplitud reducida del potencialmotor del mediano derecho con estímulos proximales.Un segundo estudio mostraba signos de lesión axonalen varios nervios, incluyendo el mediano derecho.Conclusiones. La lesión isquémica aguda de un nerviopuede dar lugar a un patrón electroneurográfico debloqueo de conducción, como en el mediano derechodel caso descrito. Este fenómeno es conocido como“pseudobloqueo”, dado su carácter transitorio, conevolución a un patrón de neuropatía axonal. La sospechade VASNP requiere estudios neurofisiológicosseriados para una correcta tipificación de los patrones lesionales(AU)

Summary. Introduction. Nonsystemic vasculitic neuropathy(NSVN) is an inflammatory disorder of the vasanervorum which usually is expressed as a mononeuritismultiplex. We present a patient with NSVN with histologicalconfirmination focused on the neurophysiologicalfindings at the early stages.Case report. A 36 years-old woman presented with paresthesiaand weakness in her right hand followed byleft footdrop. The first neurophysiologic examinationshowed low amplitude of the right median nerve (RMN)CMAP with proximal stimulation. A second examinationshowed signs of axonal damage in several nerves, includingthe RMN.Conclusions. The acute ischemic damage of a nerve cangive a pattern of conduction block in the electroneurographicstudy as in the RMN of the presented case. Thisphenomenon is referred as “pseudo-conduction block”,since it is transient and evolves towards a definite patternof axonal neuropathy. When a vasculitic neuropathyis suspected, repeated neurophysiologic studiesare necessary in order to ensure a proper (appropriate)characterization of the lesional patterns(AU)

[Physiopathology and recording techniques of the ocular movements]. / Fisiopatología y técnicas de registro de los movimientos oculares.

A number of functional systems are involved in the control of eye movements. The vestibulo-ocular and optokinetic reflexes are automatic responses that compensate for the movements of the head and those of the visual environment in order to stabilize the retinal image on a given fixation point. The saccadic movements are quick displacements of fixation from one to another point in the visual field. The smooth pursuit movements consist in the gaze following a moving target. Finally, there are some involuntary movements of very small amplitude during fixation maintenance. Each functional modality of movement depends on specific neuronal circuits that work in a coordinated manner for encoding the contraction of the oculomotor muscles to reach an adequate position at every moment. These neuronal systems can be altered by many neurological processes of different kinds and localizations, causing a broad variety of oculomotor disturbances. The most salient aspects of the physiopathology and the recording systems of eye movements are reviewed.

[Electromyographic signal processing and analysis methods]. / Métodos de procesamiento y análisis de señales electromiográficas.

Clinical electromyography is a methodology for recording and analysing the bioelectrical activity of the skeletal muscle tissue in order to diagnose neuromuscular pathology. The possibilities of application and the diagnostic performance of electromyography have evolved parallel to a growing understanding of the properties of electricity and the development of electrical and electronic technology. The first commercially available electromyography equipment for medical use was introduced in the middle of the 20th century. It was based on analog electronic circuits. The subsequent development of digital technology made available more powerful and accurate systems, controlled by microprocessors, for recording, displaying, storing, analysing, and classifying the myoelectric signals. In the near future, it is likely that advances in the new information and communication technologies could result in the application of artificial intelligence systems to the automatic classification of signals as well as expert systems for electromyographic diagnosis support.

Estudio clínico y neuropatológico en dos hermanos con síndrome de Cockayne / Clinical and neuropathological study of two brothers with cockayne syndrome

Introducción. El síndrome de Cockayne es una rara enfermedad de herencia autosómica recesiva que asocia retraso de crecimiento, retraso mental, déficit neurológico progresivo, fotosensibilidad y otras alteraciones cutáneas. Generalmente también presentan alteraciones oftalmológicas, así como otros hallazgos clínicos, radiológicos y anatomopatológicos heterogéneos entre los que destacan lesiones leucodistróficas y calcificaciones en sistema nervioso central y desmielinización en el sistema nervioso periférico. Casos clínicos. Presentamos dos hermanos, hijos de padres sanos no consanguíneos.El primero consultó a los 8 meses por retraso psicomotor y el segundo a los 5 meses por una catarata. A los 2 años de edad ambos ya mostraban un cuadro más abigarrado con fotosensibilidad, retraso de crecimiento, retraso mental, neuropatía periférica, sordera neurosensorial, y en las pruebas de neuroimagen, signos de atrofia y calcificaciones encefálicas. Durante los siguientes años el paciente mayor desarrolló signos de leve insuficiencia renal, cataratas, retinopatía, y falleció a los 9 años por infección respiratoria. El estudio neuropatológico mostró una discreta pérdida neuronal y desmielinización parcheada con depósitos de calcio en la sustancia blanca y ganglios basales. En la actualidad el segundo paciente tiene 8 años y ha presentado una evolución similar a la de su hermano. Conclusión. Los hallazgos clínicos, radiológicos y neuropatológicos en nuestros pacientes apoyan el diagnóstico de síndrome de Cockayne tipo II (AU)

[Clinical and neuropathological study of two brothers with Cockayne syndrome]. / Estudio clínico y neuropatológico en dos hermanos con síndrome de Cockayne.

INTRODUCTION: Cockayne syndrome (CS) is a rare autosomal recessive disease which is characterized by physical and mental retardation, progressive neurological disfunction, photosensitivity and other cutaneous features. Usually they present ophthalmologic abnormalities as well as other heterogenous clinical, radiological and pathologic features as leucodistrophy and calcifications in central nervous system and segmental demyelination in peripheral nervous system. CLINICAL CASES: Two brothers, sons of healthy unrelated parents, are presented. The first patient was referred at 8 months of age because of psychomotor retardation and the second one at 5 months old because of a cataract. At the age of 2 years both presented a complex clinical picture with photosensitivity, growth and mental retardation, peripheral neuropathy, neurosensorial deafness, and cerebral atrophy and calcifications in neuroimaging diagnosis tests. In the following years the older brother presented signs of renal failure, cataracts and retinopathy, and died at 9 years old because of a respiratory infection. The neuropathologic study showed a discrete neuronal loss and diffuse demyelination with calcium deposits in cerebral white matter and basal ganglia. Today the second patient is 8 years old and shows a clinical course similar to that of his brother. CONCLUSIONS: Clinical, radiologic and pathologic features in our patients support the diagnosis of CS type II.

Quantification of jiggle in real electromyographic signals.

Two parameters have been defined for quantifying jiggle: normalized consecutive amplitude differences (CAD) and the cross-correlational coefficient of consecutive discharges (CCC). In real recordings, artifacts from several sources may increase the variability of these parameters as they were originally defined. Two methodological modifications designed to overcome such a limitation are proposed: estimation of baseline fluctuation from segments of the recording free from nearby concurrent motor unit potentials (MUPs), and waveform alignment of consecutive discharges by correlation maximization (CM). The results obtained by the original and modified methods were compared for MUPs from normal subjects and patients with amyotrophic lateral sclerosis and chronic neurogenic diseases. With the modified method, CAD and CCC showed fewer extreme values and less scatter. The number of successfully aligned MUPs with the CM method was 18.8% higher (n = 394; Chi-square = 54.6; P < 0.001), including irregular and unstable MUPs. The proposed modifications improve our capability to quantify the jiggle of real signals and reduce the necessity of manual interventions although low-interference recordings and operator supervision are still required.

[Multiple sclerosis and epileptic seizures]. / Esclerosis múltiple y crisis epilépticas.

INTRODUCTION: Although epileptic seizures are uncommon in multiple sclerosis they are more prevalent than in the general population, which supports an aetiological relationship. Similarly in a considerable proportion of patients with multiple sclerosis and epileptic seizures, alterations in magnetic resonance and electroencephalogram studies which could be correlated with the clinical features of epilepsy were observed. Nevertheless, it is difficult to establish definite clinical characteristics in these patients since the underlying pathogenic mechanisms are poorly understood and there is great variability with regard to the type of seizure, point at which this occurs during the course of the disease, degree of recurrence and other aspects. CLINICAL CASE: We report the clinical, electroencephalographical and neuroimaging findings of seven patients with multiple sclerosis who had epileptic seizures and those in whom there was no evidence of other potentially epileptogenic pathology. In two patients the epileptic seizures formed part of the first episode of their illness. One patient presented more than one type of epileptic seizure. These seizures were generalized in two cases, partial sensory and/or motor with secondary generalization in three, simple partial motor in one and partial complex in two. The epileptic seizures coincided with other clinical features of episodes in three cases and the electroencephalogram showed anomalies in five cases. CONCLUSIONS: The findings observed were of a wide variety, as was found in other reported series. We point out certain correlations between the clinical data, magnetic resonance and electroencephalogram which may help to orientate the management of these patients.

Esclerosis múltiple y crisis epilépticas / Multiple sclerosis and epileptic seizures

Introduction. Although epileptic seizures are uncommon in multiple sclerosis they are more prevalent than in the general population, which supports an aetiological relationship. Similarly in a considerable proportion of patients with multiple sclerosis and epileptic seizures, alterations in magnetic resonance and electroencephalogram studies which could be correlated with the clinical features of epilepsy were observed. Nevertheless, it is difficult to establish definite clinical characteristics inthese patients since the underlying pathogenic mechanisms are poorly understood and there is great variability with regard to the type of seizure, point at which this occurs during the course of the disease, degree of recurrence and other aspects. Clinical case. We report the clinical, electroencephalographical and neuroimaging findings of seven patients with multiple sclerosis who had epileptic seizures and those in whom there was no evidence of other potentially epileptogenic pathology. In two patients the epileptic seizures formed part of the first episode of their illness. One patient presented more than one type of epileptic seizure. These seizures were generalized in two cases, partial sensory and/or motor with secondary generalization in three, simple partial motor in one and partial complex in two. The epileptic seizures coincided with other clinical features of episodes in three cases and the electroencephalogram showed anomalies in five cases. Conclusions. The findings observed were of a wide variety, as was found in other reported series. We point out certain correlations between the clinical data, magnetic resonance and electroencephalogram which may help to orientate the management of these patients (AU)

Introducción. Aunque las crisis epilépticas son infrecuentes en la esclerosis múltiple, su prevalencia en esta enfermedad es superior a la de la población general, lo que apoya la existencia de una relación etiológica. Asimismo, en gran parte de los pacientes con esclerosis múltiple y crisis epilépticas se han observado alteraciones en los estudios de resonancia magnética y electroencefalografía correlacionables con la clínica epiléptica. No obstante, es difícil establecer unos rasgos clínicos definidos en estos pacientes, dado que los mecanismos patogénicos subyacentes no son bien conocidos y existe una importante variabilidad respecto al tipo de crisis, momento evolutivo en que aparecen, grado derecurrencia y otros aspectos. Casos clínicos. Presentamos los datos clínicos, electroencefalográficos y de neuroimagen recogidos en siete casos de esclerosis múltiple que cursaron con crisis epilépticas y enlos que no se encontraron evidencias de otras patologías potencialmente epileptógenas. En dos pacientes, las crisis epilépticas formaron parte del primer brote de la enfermedad. Un paciente presentó más de un tipo de crisis. Éstas fueron generalizadas en dos casos, parciales sensitivas y/o motoras con generalización secundaria en tres, parciales motoras simples en uno y parciales complejas en dos. Las crisis epilépticas coincidieron con otras manifestaciones clínicas de brote en tres casos y el electroencefalograma presentaba anomalías en cinco. Conclusiones. Los hallazgos observados muestran una amplia heterogeneidad, semejante a la de otras series comunicadas. Destacamos algunas correlaciones entre los datos clínicos, resonancia magnética y electroencefalografía que pueden servir para orientar el manejo de este tipo de enfermos (AU)