Automatic removal algorithm of electrooculographic artifacts in non-invasive brain-computer interface based on independent component analysis / 生物医学工程学杂志

The non-invasive brain-computer interface (BCI) has gradually become a hot spot of current research, and it has been applied in many fields such as mental disorder detection and physiological monitoring. However, the electroencephalography (EEG) signals required by the non-invasive BCI can be easily contaminated by electrooculographic (EOG) artifacts, which seriously affects the analysis of EEG signals. Therefore, this paper proposed an improved independent component analysis method combined with a frequency filter, which automatically recognizes artifact components based on the correlation coefficient and kurtosis dual threshold. In this method, the frequency difference between EOG and EEG was used to remove the EOG information in the artifact component through frequency filter, so as to retain more EEG information. The experimental results on the public datasets and our laboratory data showed that the method in this paper could effectively improve the effect of EOG artifact removal and improve the loss of EEG information, which is helpful for the promotion of non-invasive BCI.

Eletronistagmografia versus videonistagmografia: [revisão] / Electronystagmography versus videonystagmography: [review]

Electronystagmography (ENG) and videonystagmography (VNG) are eye movement recording methods used for the evaluation of balance disorders. AIM: To compare literature information on the similarities, differences, advantages e disadvantages between ENG and VNG. MATERIALS AND METHODS: review of the scientific literature. RESULTS: ENG and VNG are very helpful methods for evaluating balance disorders, due to their capacity to recognize signs of peripheral or central vestibular dysfunction and to pinpoint the side of the lesion. Major advantages of VNG are related to calibration, temporospatial resolution, and recording of horizontal, vertical and torsional eye movements. CONCLUSION: VNG is a new technology that presents advantages in the evaluation of eye movements; however, despite its disadvantages, ENG is still considered a valuable test in the clinical setting

A eletronistagmografia (ENG) e a videonistagmografia (VNG) são métodos de registro dos movimentos oculares, empregados na avaliação dos distúrbios do equilíbrio corporal. OBJETIVO: Comparar as informações da literatura sobre as semelhanças, diferenças, vantagens e desvantagens da ENG e da VNG. MATERIAL E MÉTODO: Estudo de revisão da literatura científica pertinente. RESULTADOS: A ENG e a VNG são sistemas muito úteis no diagnóstico dos distúrbios do equilíbrio corporal, diante da sua capacidade de identificar sinais de disfunção vestibular periférica ou central e determinar o lado da lesão. As principais vantagens da VNG estão relacionadas com calibração, resolução têmporo-espacial e gravação dos movimentos oculares horizontais, verticais e torsionais. CONCLUSÃO: A VNG é uma nova tecnologia que apresenta vantagens na avaliação dos movimentos oculares, mas a ENG, apesar de suas desvantagens, é ainda considerada um procedimento de valor na rotina clínica

The medial septum acts through the medial preoptic area for thermoregulation and works with it for sleep regulation.

The chronic changes in sleep-wakefulness (S-W), body temperature (Tb), locomotor activity (LMA) and thermal preference were studied in male Wistar rats after the destruction of neurons in both the medial preoptic area (mPOA) and the medial septum (MS) by intracerebral injection of N-methyl-D-aspartic acid. An increase in the Tb, and a preference for higher ambient temperature (Tamb) of 30 degrees C were observed after the combined lesion of the mPOA and the MS. Similar changes were reported to occur after the lesion that was restricted to the mPOA. But these alterations were in contrast to the decrease in Tb and preference for lower Tamb, observed after the MS lesion. The thermostat of the brain would have been reset at a higher level after the combined lesion, as there was an increase in Tb, along with a preference for a higher Tamb, and an increase in LMA. There was a reduction in the frequency and the duration of the slow wave sleep (SWS) episodes, and a reduction in the frequency of the paradoxical sleep (PS) episodes after the combined lesion. The destruction of the MS neurons was probably responsible for the reduction in the frequency of SWS, whereas the loss of mPOA neurons was responsible for the decrease in the duration of SWS and frequency of PS. It can be suggested that the MS exerts its influence on thermoregulation through the mPOA. However, the MS and the mPOA seem to play independent, but complementary roles in sleep promotion.

Medición electro-oculográfica del reflejo vestibulo-ocular de alta velocidad en sujetos sanos y en pacientes con lesión vestibular periférica / Electro-oculographic measures of the vestibulo ocular reflex in patients with peripheric vestibular lesions and healthy control group

El reflejo vestíbulo-ocular (RVO) es un reflejo que mantiene la estabilidad de la mirada al producir movimientos compensatorios oculares en dirección opuesta al movimiento cefálico. Cuando la cabeza se mueve de forma pasiva o activa a gran velocidad se produce un movimiento ocular que se ha denominado RVO de alta velocidad o alta frecuencia. Se ha estudiado clínicamente y se ha observado en sujetos con patología vestibular periférica que el reflejo es deficiente y tiene que ser ayudado con movimientos sacádicos compensatorios. Cuando se daña el aparato vestibular, ya sea en forma unilateral o bilateral este reflejo se altera en forma característica. Sin embargo, hay pocos estudios que registrén de manera objetiva las características fisiológicas del RVO de una manera útil en la clínica. La electro-oculografía (EOG) convencional mide el reflejo a velocidades bajas (entre 10 y 20 mm/seg ) y también con sensibilidad baja.Objetivo. Medición del (RVO-AV) mediante electro-oculografía (EOG) digitalizada de alta sensibilidad y alta velocidad (de 60 a 150 mm/seg) en pacientes con lesión vestibular periférica. Pacientes y métodos. Se estudió la morfología, la duración y la amplitud del RVO-AV en ocho pacientes de 25 a 63 años de edad, tres del sexo femenino y cinco del masculino y se comparó con un grupo control. Los pacientes y sujetos se dividieron en tres grupos: seis con lesión vestibular periférica (LVP) unilateral por neuronitis vestibular (grupo I), dos pacientes con LVP bilateral secundaria a ototoxicidad por fármacos (grupo II) y se comparó con un tercer grupo de 20 sujetos sanos (grupo III). El RVO-AV fue evocado con rotaciones cefálicas bruscas y repentinas en un plano horizontal alrededor del eje vertical; se estudiaron cuatro paradigmas: pasivo-activo con los ojos abiertos fijando un punto, y pasivo-activo, ojos cubiertos fijando un punto imaginario. Resultados. 1. El RVO-AV se apreció fragmentado, por la presencia de movimientos sacádicos en dirección del movimiento reflejo, con rotación cefálica hacia el lado afectado en el grupo I, y hacia ambos lados en el grupo II. En los sujetos normales el reflejo está caracterizado por un movimiento suave sin la presencia de movimientos sacádicos. 2. La duración del RVO-AV en los grupos I y II fue mayor hacia el lado afectado que en el grupo control. 3. Las amplitudes del RVO-AV no se afectaron de manera significativa en los grupos I y II en relación al grupo III

Coroiditis multifocal: presentación de un caso / Multifocal choroiditis. A case report

Presentamos la evolución clínica de una paciente de 11 años de edad con panuveítis bilateral recurrente, caracterizada por la presencia de múltiples focos de coroiditis, atrofia peripapilar y fibrosis subretiniana. Se hacen consideraciones acerca del diagnóstico diferencial y tratamiento.