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1.
Front Neurosci ; 14: 746, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32848543

RESUMEN

As functional near-infrared spectroscopy (fNIRS) is developed as a neuroimaging technique and becomes an option to study a variety of populations and tasks, the reproducibility of the fNIRS signal is still subject of debate. By performing test-retest protocols over different functional tasks, several studies agree that the fNIRS signal is reproducible over group analysis, but the inter-subject and within-subject reproducibility is poor. The high variability at the first statistical level is often attributed to global systemic physiology. In the present work, we revisited the reproducibility of the fNIRS signal during a finger-tapping task across multiple sessions on the same and different days. We expanded on previous studies by hypothesizing that the lack of spatial information of the optodes contributes to the low reproducibility in fNIRS, and we incorporated a real-time neuronavigation protocol to provide accurate cortical localization of the optodes. Our proposed approach was validated in 10 healthy volunteers, and our results suggest that the addition of neuronavigation can increase the within-subject reproducibility of the fNIRS data, particularly in the region of interest. Unlike traditional approaches to positioning the optodes, in which low intra-subject reproducibility has been found, we were able to obtain consistent and robust activation of the contralateral primary motor cortex at the intra-subject level using a neuronavigation protocol. Overall, our findings support the hypothesis that at least part of the variability in fNIRS cannot be only attributed to global systemic physiology. The use of neuronavigation to guide probe positioning, as proposed in this work, has impacts to longitudinal protocols performed with fNIRS.

2.
Neurophotonics ; 7(1): 015001, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31956662

RESUMEN

Monitoring speech tasks with functional near-infrared spectroscopy (fNIRS) enables investigation of speech production mechanisms and informs treatment strategies for speech-related disorders such as stuttering. Unfortunately, due to movement of the temporalis muscle, speech production can induce relative movement between probe optodes and skin. These movements generate motion artifacts during speech tasks. In practice, spurious hemodynamic responses in functional activation signals arise from lack of information about the consequences of speech-related motion artifacts, as well as from lack of standardized processing procedures for fNIRS signals during speech tasks. To this end, we characterize the effects of speech production on fNIRS signals, and we introduce a systematic analysis to ameliorate motion artifacts. The study measured 50 healthy subjects performing jaw movement (JM) tasks and found that JM produces two different patterns of motion artifacts in fNIRS. To remove these unwanted contributions, we validate a hybrid motion-correction algorithm based sequentially on spline interpolation and then wavelet filtering. We compared performance of the hybrid algorithm with standard algorithms based on spline interpolation only and wavelet decomposition only. The hybrid algorithm corrected 94% of the artifacts produced by JM, and it did not lead to spurious responses in the data. We also validated the hybrid algorithm during a reading task performed under two different conditions: reading aloud and reading silently. For both conditions, we observed significant cortical activation in brain regions related to reading. Moreover, when comparing the two conditions, good agreement of spatial and temporal activation patterns was found only when data were analyzed using the hybrid approach. Overall, the study demonstrates a standardized processing scheme for fNIRS data during speech protocols. The scheme decreases spurious responses and intersubject variability due to motion artifacts.

3.
Rev. MED ; 27(2): 113-120, jul.-dic. 2019. graf
Artículo en Español | LILACS | ID: biblio-1115233

RESUMEN

Resumen: La encefalitis por anticuerpos contra el receptor de NMDA es un desorden grave, tratable y potencialmente reversible, caracterizado por la presencia de alteraciones en el comportamiento, convulsiones y trastornos del movimiento. La presencia de anticuerpos contra el receptor del glutamato (anti-NMDA) en plasma o líquido cefalorraquídeo es específico para el diagnóstico de la enferme -dad. El reconocimiento temprano de la enfermedad es vital para el pronóstico del paciente, dado que el manejo precoz facilita la recuperación y reducción de la morbimortalidad. El tratamiento consiste en la utilización de corticoides, inmunoglobulina intravenosa o plasmaféresis como primera línea de terapia; además de otros inmunomoduladores, como ciclofosfamida o rituximab, como segunda línea. La recuperación es lenta, pero presenta mejoría en la medida en que los títulos de anticuerpos disminuyen y llega a una recuperación completa hasta en 75 % de los pacientes.


Abstract: Anti-NMDA receptor encephalitis is a severe, treatable, and potentially reversible disorder characterized by the presence of behavioral disturbances, seizures, and movement disorders. The presence of antibodies against the glutamate receptor (anti-NMDA) in plasma or cerebrospinal fluid is specific to the diagnosis of the disease. Early recognition of the disease is vital for the patient's prognosis since early management facilitates recovery and reduction of morbidity and mortality. Treatment consists of corticosteroids, intravenous immunoglobulin, or plasmapheresis as the first line of therapy, in addition to other immunomodulators, such as cyclophosphamide or rituximab, as the second line. Recovery is slow but improves as antibody titers decrease. Complete recovery occurs in up to 75 % of patients.


Resumo: A encefalite causada por anticorpos contra o receptor NMDA é um distúrbio grave, tratável e potencialmente reversível, caracterizado pela presença de alterações comportamentais, convulsões e transtornos de movimento. A presença de anticorpos contra o receptor de glutamato (anti-NMDA) no plasma ou no líquido cefalorraquidiano é específica para o diagnóstico da doença. O reconhecimento precoce da doença é vital para o prognóstico do paciente, visto que o tratamento precoce facilita a recuperação e a redução da morbimortalidade. O tratamento consiste no uso de corticoides, imunoglobulina intravenosa ou plasmaférese como primeira linha de terapia. Além de outros imunomoduladores, como ciclofosfamida ou rituximabe, como segunda linha. A recuperação é lenta, mas apresenta melhora à medida que os títulos de anticorpos diminuem e a recuperação completa ocorre em até 75% dos pacientes.


Asunto(s)
Humanos , Femenino , Niño , Encefalitis Antirreceptor N-Metil-D-Aspartato , Factores Inmunológicos , Encefalitis , Encefalitis/tratamiento farmacológico
4.
Acta neurol. colomb ; 35(2): 74-88, abr.-jun. 2019. tab, graf
Artículo en Español | LILACS | ID: biblio-1010941

RESUMEN

RESUMEN INTRODUCCIÓN: El estado epiléptico (EE) es una condición ocasionada por la falla en los mecanismos de supresión de las crisis epilépticas. Se considera como una urgencia neurológica y obliga al profesional de la salud a conocer las características de presentación para poder estabilizar al paciente. La mortalidad varía entre el 2 % y el 50 % según el grupo etario. OBJETIVO: Construir una serie de sugerencias para el tratamiento del EE, como resultado del consenso por común acuerdo de expertos en epilepsia, teniendo en cuenta el contexto colombiano. MÉTODOS: Se llevó a cabo un consenso formal de expertos con 16 neurólogos-epileptólogos de adultos y niños. Las preguntas y sugerencias fueron revisadas en dos fases, donde fueron calificadas y consensuadas por los participantes. RESULTADOS: Se evaluaron 15 preguntas, con sus respectivas sugerencias sobre el manejo del estado epiléptico, se tuvieron en cuenta referencias bibliográficas relevantes consideradas por los expertos y de acuerdo con el contexto colombiano. CONCLUSIONES: Los resultados de este consenso presentan una serie de sugerencias para el tratamiento del estado epiléptico tanto en los primeros niveles de atención como en los de alta complejidad para mejorar el pronóstico del paciente, de acuerdo con el contexto colombiano.


SUMMARY INTRODUCTION: Status epilepticus is a condition caused by failure in the mechanisms of suppression of epileptic seizures. It is considered a neurological emergency, and mortality varies between 2 % to 50 % according to the age group. Due to the above, it is relevant that health professionals know the characteristics of SE in order to stabilize the patient. OBJECTIVE: To define a series of propositions for the treatment of SE, as a result of consensus by common agreement of experts in epilepsy, taking into account the Colombian context. METHODS: A formal consensus of experts was carried out with 16 adult and pediatric neurologists-epilep-tologists. The questions and propositions were reviewed in two phases, where they were graded and agreed by the participants. RESULTS: Fifteen questions were evaluated on the management of status epilepticus. Relevant bibliographic references were considered by the experts according to the Colombian context. CONCLUSIONS: As results of this consensus we present a series of propositions for the treatment of status epilepticus for the primary level of care and high complexity level of care in order to improve the patient's prognosis, according to the Colombian context.


Asunto(s)
Movilidad en la Ciudad
5.
Acta neurol. colomb ; 33(3): 173-178, jul.-set. 2017. graf
Artículo en Español | LILACS | ID: biblio-886443

RESUMEN

RESUMEN La estimulación del nervio vago es una técnica aprobada por la FDA, para epilepsia focal refractaria. Presentamos un caso de un paciente, con epilepsia de probable origen frontal, el cual cumplió criterios para epilepsia refractaria, y fue llevado a implantación de estimulador del nervio vago, quedando libre de crisis.


SUMMARY Vagal nerve stimulation is an FDA-approved technique for focal refractory epilepsy. We present the case of a patient, with epilepsy of probable frontal origin, who met criteria for refractory epilepsy, and was taken to implantation of vagus nerve stimulator, currently free of crisis.


Asunto(s)
Epilepsias Parciales , Estimulación del Nervio Vago , Epilepsia Refractaria
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