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1.
Arq. neuropsiquiatr ; 80(2): 208-210, Feb. 2022. graf
Article in English | LILACS | ID: biblio-1364371

ABSTRACT

ABSTRACT In 1951, the physiologist George Duncan Dawson presented his work with the averaging of the signal in the evoked potentials (EPs), opening a new stage in the development of clinical neurophysiology. The authors present aspects of Professor Dawson's biography and a review of his work on the EPs and, mainly, the article reveals the new technique in detail that would allow the growth of the clinical application of the visual, auditory, and somatosensory EPs.


RESUMO Em 1951 o fisiologista George Duncan Dawson apresentou seu trabalho com a promediação de sinal nos potenciais evocados, abrindo uma nova etapa no desenvolvimento da neurofisiologia clínica. Os autores apresentam aspectos da biografia do professor Dawson e uma revisão de seus trabalhos sobre os potenciais evocados, principalmente do artigo que mostrava a nova técnica, que viria a permitir o crescimento da aplicação clínica dos potenciais evocados visual, auditivo e somatossensitivo.


Subject(s)
Humans , History, 20th Century , Inventions , Neurophysiology/methods , Evoked Potentials , Evoked Potentials, Somatosensory , Evoked Potentials, Visual
2.
Article in Chinese | WPRIM | ID: wpr-936350

ABSTRACT

OBJECTIVE@#To investigate the therapeutic effect of Epothilone D on traumatic optic neuropathy (TON) in rats.@*METHODS@#Forty-two SD rats were randomized to receive intraperitoneal injection of 1.0 mg/kg Epothilone D or DMSO (control) every 3 days until day 28, and rat models of TON were established on the second day after the first administration. On days 3, 7, and 28, examination of flash visual evoked potentials (FVEP), immunofluorescence staining and Western blotting were performed to examine the visual pathway features, number of retinal ganglion cells (RGCs), GAP43 expression level in damaged axons, and changes of Tau and pTau-396/404 in the retina and optic nerve.@*RESULTS@#In Epothilone D treatment group, RGC loss rate was significantly decreased by 19.12% (P=0.032) on day 3 and by 22.67% (P=0.042) on day 28 as compared with the rats in the control group, but FVEP examination failed to show physiological improvement in the visual pathway on day 28 in terms of the relative latency of N2 wave (P=0.236) and relative amplitude attenuation of P2-N2 wave (P=0.441). The total Tau content in the retina of the treatment group was significantly increased compared with that in the control group on day 3 (P < 0.001), showing a consistent change with ptau-396/404 level. In the optic nerve axons, the total Tau level in the treatment group was significantly lower than that in the control group on day 7 (P=0.002), but the changes of the total Tau and pTau-396/404 level did not show an obvious correlation. Epothilone D induced persistent expression of GAP43 in the damaged axons, detectable even on day 28 of the experiment.@*CONCLUSION@#Epothilone D treatment can protect against TON in rats by promoting the survival of injured RGCs, enhancing Tau content in the surviving RGCs, reducing Tau accumulation in injured axons, and stimulating sustained regeneration of axons.


Subject(s)
Animals , Disease Models, Animal , Epothilones , Evoked Potentials, Visual , Nerve Regeneration/physiology , Optic Nerve Injuries/metabolism , Rats , Rats, Sprague-Dawley , Retinal Ganglion Cells/physiology
3.
Neuroscience Bulletin ; (6): 741-752, 2022.
Article in English | WPRIM | ID: wpr-939833

ABSTRACT

Environmental threats often trigger innate defensive responses in mammals. However, the gradual development of functional properties of these responses during the postnatal development stage remains unclear. Here, we report that looming stimulation in mice evoked flight behavior commencing at P14-16 and had fully developed by P20-24. The visual-evoked innate defensive response was not significantly altered by sensory deprivation at an early postnatal stage. Furthermore, the percentages of wide-field and horizontal cells in the superior colliculus were notably elevated at P20-24. Our findings define a developmental time window for the formation of the visual innate defense response during the early postnatal period and provide important insight into the underlying mechanism.


Subject(s)
Animals , Evoked Potentials, Visual , Fear/physiology , Mammals , Mice , Mice, Inbred C57BL , Neurons/physiology , Superior Colliculi/physiology
4.
Article in Chinese | WPRIM | ID: wpr-928239

ABSTRACT

Brain-computer interface (BCI) systems based on steady-state visual evoked potential (SSVEP) have become one of the major paradigms in BCI research due to their high signal-to-noise ratio and short training time required by users. Fast and accurate decoding of SSVEP features is a crucial step in SSVEP-BCI research. However, the current researches lack a systematic overview of SSVEP decoding algorithms and analyses of the connections and differences between them, so it is difficult for researchers to choose the optimum algorithm under different situations. To address this problem, this paper focuses on the progress of SSVEP decoding algorithms in recent years and divides them into two categories-trained and non-trained-based on whether training data are needed. This paper also explains the fundamental theories and application scopes of decoding algorithms such as canonical correlation analysis (CCA), task-related component analysis (TRCA) and the extended algorithms, concludes the commonly used strategies for processing decoding algorithms, and discusses the challenges and opportunities in this field in the end.


Subject(s)
Algorithms , Brain-Computer Interfaces , Electroencephalography , Evoked Potentials, Visual , Photic Stimulation
5.
Article in Chinese | WPRIM | ID: wpr-928214

ABSTRACT

Steady-state visual evoked potential (SSVEP) is one of the commonly used control signals in brain-computer interface (BCI) systems. The SSVEP-based BCI has the advantages of high information transmission rate and short training time, which has become an important branch of BCI research field. In this review paper, the main progress on frequency recognition algorithm for SSVEP in past five years are summarized from three aspects, i.e., unsupervised learning algorithms, supervised learning algorithms and deep learning algorithms. Finally, some frontier topics and potential directions are explored.


Subject(s)
Algorithms , Brain-Computer Interfaces , Electroencephalography/methods , Evoked Potentials, Visual , Photic Stimulation
6.
Arq. neuropsiquiatr ; 79(5): 437-446, May 2021. tab, graf
Article in English | LILACS | ID: biblio-1278401

ABSTRACT

ABSTRACT Background: Intracranial pressure (ICP) monitoring has been used for decades in management of various neurological conditions. The gold standard for measuring ICP is a ventricular catheter connected to an external strain gauge, which is an invasive system associated with a number of complications. Despite its limitations, no noninvasive ICP monitoring (niICP) method fulfilling the technical requirements for replacing invasive techniques has yet been developed, not even in cases requiring only ICP monitoring without cerebrospinal fluid (CSF) drainage. Objectives: Here, we review the current methods for niICP monitoring. Methods: The different methods and approaches were grouped according to the mechanism used for detecting elevated ICP or its associated consequences. Results: The main approaches reviewed here were: physical examination, brain imaging (magnetic resonance imaging, computed tomography), indirect ICP estimation techniques (fundoscopy, tympanic membrane displacement, skull elasticity, optic nerve sheath ultrasound), cerebral blood flow evaluation (transcranial Doppler, ophthalmic artery Doppler), metabolic changes measurements (near-infrared spectroscopy) and neurophysiological studies (electroencephalogram, visual evoked potential, otoacoustic emissions). Conclusion: In terms of accuracy, reliability and therapeutic options, intraventricular catheter systems still remain the gold standard method. However, with advances in technology, noninvasive monitoring methods have become more relevant. Further evidence is needed before noninvasive methods for ICP monitoring or estimation become a more widespread alternative to invasive techniques.


RESUMO Introdução: O uso da monitorização da pressão intracraniana (PIC, em sua sigla em inglês) é adotado há décadas no manejo de diversas condições neurológicas. O padrão ouro atual é a monitorização invasiva intraventricular, que está relacionada a inúmeras complicações. Apesar dessas limitações, até o momento nenhum método de monitorização não invasiva (niPIC, em sua sigla em inglês) conseguiu substituir a técnica invasiva. Objetivos: Revisar os métodos não invasivos de monitorização da PIC. Métodos: As diferentes modalidades e abordagens foram agrupadas de acordo com o mecanismo utilizado para detectar elevação da PIC ou suas consequências. Resultados: As técnicas descritas foram: o exame físico, neuroimagem (tomografia computadorizada e ressonância magnética de crânio), estimativas indiretas da PIC (fundoscopia, deslocamento da membrana timpânica, elasticidade craniana), avaliação do fluxo cerebral (doppler transcraniano e doppler da artéria oftálmica), alterações metabólicas (Espectroscopia próxima do infravermelho) e estudos neurofisiológicos (eletroencefalograma, potencial evocado visual e emissões otoacústicas). Conclusão: Considerando a acurácia, confiabilidade e opções terapêuticas, o sistema de cateteres intraventricular ainda permanece como padrão ouro. No entanto, com os avanços tecnológicos, os métodos não invasivos têm se tornados mais relevantes. Mais evidências são necessárias antes que essas modalidades de monitorização ou estimativas não invasivas se tornem uma alternativa mais robusta às técnicas invasivas.


Subject(s)
Humans , Intracranial Pressure , Intracranial Hypertension , Skull , Reproducibility of Results , Evoked Potentials, Visual
7.
Arq. bras. oftalmol ; 84(2): 140-148, Mar,-Apr. 2021. tab, graf
Article in English | LILACS | ID: biblio-1153128

ABSTRACT

ABSTRACT Purpose: To determine visual impairment due to optic pathway tumors in children unable to perform recognition acuity tests. Methods: Grating visual acuity scores, in logMAR, were obtained by sweep visually evoked potentials (SVEP) in children with optic pathway tumors. The binocular grating visual acuity deficit was calculated by comparison with age-based norms and then assigned to categories of visual impairment as mild (from 0.10 to 0.39 logMAR), moderate (from 0.40 to 0.79 logMAR), or severe (≥0.80 logMAR). Interocular differences were calculated by subtraction and considered increased if >0.10 logMAR. Results: The participants were 25 children (13 boys; mean ± SD age, 35.1 ± 25.9 months; median age, 32.0 months) with optic pathway tumors (24 gliomas and 1 embryonal tumor), mostly located at the hypothalamic-chiasmatic transition (n=21; 84.0%) with visual abnormalities reported by parents (n=17; 68.0%). The mean grating acuity deficit was 0.60 ± 0.36 logMAR (median, 0.56 logMAR). Visual impairment was detected in all cases and was classified as mild in 10 (40.0%), moderate in 8 (32.0%), and severe in 7 (28.0%) children, along with increased interocular differences (>0.1 logMAR) (n=16; 64.0%). The remarkable ophthalmological abnormalities were nystagmus (n=17; 68.0%), optic disc cupping and/or pallor (n=13; 52.0%), strabismus (n=12; 48.0%), and poor visual behavior (n=9; 36.0%). Conclusion: In children with optic pathway tumors who were unable to perform recognition acuity tests, it was possible to quantify visual impairment by sweep-visually evoked potentials and to evaluate interocular differences in acuity. The severity of age-based grating visual acuity deficit and interocular differences was in accordance with ophthalmological abnormalities and neuroimaging results. Grating visual acuity deficit is useful for characterizing visual status in children with optic pathway tumors and for supporting neuro-oncologic management.(AU)


RESUMO Objetivo: Determinar o grau de deficiência visual em crianças com tumores da via óptica incapazes de informar a acuidade visual de reconhecimento. Método: A acuidade visual de grades, em logMAR, foi estimada por potenciais visuais evocados de varredura em crianças com tumores das vias ópticas. O déficit da acuidade visual de grades binocular foi calculado em relação ao valor mediano normativo esperado para a idade e a deficiência visual, classificada como leve (0,10 a 0,39 logMAR), moderada (0,40 a 0,79 logMAR) ou grave (≥0,80 logMAR). Diferenças inter-oculares foram calculadas por subtração e consideradas aumentadas se >0,10 logMAR. Resultados: Foram avaliadas 25 crianças (13 meninos; média de idade ± DP=35,1± 25,9 meses; mediana=32,0 meses) com tumores da via óptica (24 gliomas e 1 tumor embrionário) localizados particularmente na transição hipotalâmico-quiasmática (n=21; 84,0%) e com anormalidades visuais detectadas pelos pais (n=17; 68,0%). A média do déficit da acuidade de grades foi 0,60 ± 0,36 logMAR (mediana=0,56 logMAR). Observou-se deficiência visual leve em 10 (40,0%), moderada em 8 (32,0%) e grave em 7 (28,0%), além de aumento da diferença interocular da acuidade visual (n=16; 64,0%). As principais alterações oftalmológicas encontradas foram: nistagmo (n=17; 68,0%), aumento da escavação do disco óptico e/ou palidez (n=13; 52,0%), estrabismo (n=12; 48,0%) e comportamento visual pobre (n=9; 36,0%). Conclusão: Em crianças com tumor da via óptica e incapazes de responder aos testes de acuidade visual de reconhecimento, foi possível quantificar deficiência visual por meio dos potenciais visuais evocados de varredura e avaliar a diferença interocular da acuidade visual de grades. A gravidade do déficit da acuidade visual de grades relacionado à idade e a diferença interocular da acuidade visual de grades foram congruentes com alterações oftalmológicas e neuroimagem. O déficit da acuidade visual de grades foi útil à caracterização do estado visual em crianças com tumores da via óptica e ao embasamento da assistência neuro-oncológica.(AU)


Subject(s)
Humans , Child , Visual Pathways/pathology , Visual Acuity , Optic Nerve Glioma/pathology , Vision Disorders/etiology , Evoked Potentials, Visual
8.
Article in Chinese | WPRIM | ID: wpr-877668

ABSTRACT

OBJECTIVE@#To observe the effect of five-element acupuncture on the cognitive function repair of migraine patients with depression/anxiety disorder.@*METHODS@#The migraine patients with depression/anxiety disorder (19 cases, 5 cases dropped off) were taken as the observation group, and received five-element acupuncture twice a week for 8 weeks. Healthy subjects (19 cases) were selected by demographic data matching as the control group. The cognitive function was evaluated with the event related potential (ERP) technique, and the latency and amplitude of visual evoked potential P300 were adopted as the observation indexes. The headache days (every 4 weeks), headache intensity [visual analogue scale(VAS) score], and headache impact test-6 (HIT-6) score, Hamilton depression scale (HAMD) score and Hamilton anxiety scale (HAMA) score were used as the observation indexes for curative effect.@*RESULTS@#Before the treatment, latency of target stimulus at Fz [ (417.5±34.3) ms] in the observation group was extended compared with the healthy subjects of the control group [(388.6±42.1) ms, @*CONCLUSION@#There are some cognitive impairments in migraine patients with depression/anxiety disorder. Five-element acupuncture not only relieves headache, anxiety and depression effectively, but also improves the activation level of the frontal lobe. It significantly repairs the impaired cognitive function.


Subject(s)
Acupuncture Points , Acupuncture Therapy , Anxiety Disorders , Cognition , Depression/therapy , Evoked Potentials, Visual , Humans , Migraine Disorders/therapy , Treatment Outcome
9.
Article in Chinese | WPRIM | ID: wpr-877546

ABSTRACT

OBJECTIVE@#To observe clinical effect of acupuncture combined with conventional visual stimulation on cerebral visual impairment (CVI) in children aged 3-10 years and influence on the pattern visual evoked potential (P-VEP).@*METHODS@#A total of 60 cases of children aged 3-10 years with CVI were randomly divided into an observation group and a control group, 30 cases in each group. The children in the control group received conventional visual stimulation therapy, 1 month as a course of treatment. On the basis of the control group, the children in the observation group was treated with acupuncture at Baihui (GV 20), Jingming (BL 1), Taiyang (EX-HN 5), Sibai (ST 2), etc. 3 times a week, and the treatment was given 4 weeks continuously as a course. Both groups received 3 courses of treatment. The visual acuity and P-VEP improvement were compared between the two groups before and after treatment.@*RESULTS@#After treatment, the incubation period (P100-L) of the two groups was shorter than before treatment, and the amplitude (P100-A) was higher than before treatment (@*CONCLUSION@#Acupuncture combined with conventional visual stimulation can improve the incubation period (P100-L) and amplitude (P100-A) of P-VEP in children with CVI, and improve the best corrected visual acuity in children, the clinical effect is better than the conventional visual stimulation alone.


Subject(s)
Acupuncture Points , Acupuncture Therapy , Brain Diseases , Child , Child, Preschool , Evoked Potentials, Visual , Humans , Vision Disorders/therapy
10.
Article in Chinese | WPRIM | ID: wpr-888204

ABSTRACT

Brain-computer interface (BCI) has great potential to replace lost upper limb function. Thus, there has been great interest in the development of BCI-controlled robotic arm. However, few studies have attempted to use noninvasive electroencephalography (EEG)-based BCI to achieve high-level control of a robotic arm. In this paper, a high-level control architecture combining augmented reality (AR) BCI and computer vision was designed to control a robotic arm for performing a pick and place task. A steady-state visual evoked potential (SSVEP)-based BCI paradigm was adopted to realize the BCI system. Microsoft's HoloLens was used to build an AR environment and served as the visual stimulator for eliciting SSVEPs. The proposed AR-BCI was used to select the objects that need to be operated by the robotic arm. The computer vision was responsible for providing the location, color and shape information of the objects. According to the outputs of the AR-BCI and computer vision, the robotic arm could autonomously pick the object and place it to specific location. Online results of 11 healthy subjects showed that the average classification accuracy of the proposed system was 91.41%. These results verified the feasibility of combing AR, BCI and computer vision to control a robotic arm, and are expected to provide new ideas for innovative robotic arm control approaches.


Subject(s)
Augmented Reality , Brain-Computer Interfaces , Computers , Electroencephalography , Evoked Potentials, Visual , Humans , Photic Stimulation , Robotic Surgical Procedures
11.
Rev. cuba. pediatr ; 91(4): e744, oct.-dic. 2019. tab, graf
Article in Spanish | LILACS, CUMED | ID: biblio-1093732

ABSTRACT

Introducción: El potencial evocado visual es una técnica que permite la evaluación de la integridad funcional de la vía visual; su aplicación en niños pequeños resulta de gran dificultad. Objetivo: Caracterizar desde el punto de vista fisiológico el potencial evocado visual en niños menores de 5 años. Métodos: Estudio descriptivo transversal, donde se registran respuestas visuales obtenidas con diodos (montados en gafas) en 112 niños sanos (65 varones, 47 hembras) con rango de edad entre 3 meses y 5 años. Se calcularon los valores medios y desviación estándar de latencias y amplitudes de cada componente de la respuesta y se estimaron sus dinámicas madurativas en función de la edad. Se utilizó un análisis de componentes principales para explicar la variabilidad morfológica (complejo N1-P1-N2) y, se calculó una ecuación discriminante (con indicadores de replicación y relación señal/ruido), para evaluar la contribución en su mejor detección. Resultados: La morfología típica encontrada resultó consistente, replicable y mostró un nivel de detección visual > 90 por ciento (para cada componente), con 85 por ciento de acierto global (clasificaciones correctas) mediante la ecuación discriminante. El complejo N1-P1-N2, consigue explicar > 70 por ciento de la varianza de esta respuesta. Se demostró un acortamiento significativo de latencia con la edad (regresión, p≤ 0,05) para los componentes N1, P1 (marginal, N2). Los valores de amplitud resultaron de mayor dispersión y su tendencia al incremento no alcanzó significación. Conclusiones: El registro del potencial evocado visual mediante diodos/gafas demuestra la obtención de respuestas fisiológicas consistentes y replicables (alta detectabilidad) con una variabilidad morfológica controlable(AU)


Introduction: The Visual Evoked Potentials is a neurophysiological technique to provide an objective assessment of the functional integrity of the visual pathway. However, the young children population is a particularly difficult (uncooperative) group to obtain visual responses. Objective: The purpose of this study was to describe electrophysiological characteristics of the visual response in children. Methods: Descriptive, cross-sectional study. Transient visual evoked potentials with goggles were recorded from 112 healthy children (65 males, 47 females) aged between 3 months to 5 years old. The mean (and standard deviations) for latencies and amplitudes of each component was calculated and both statistical significance in function of age was analyzed (linear regression model). Principal component analysis is use to explain the visual waveform variability. A discriminant equation (with indicators of reliability and noise/signal ratio) is calculate to evaluate contribution in detectability. Results: The typical waveform of (N1, P1, N2, components) is consistent and reliable and showed a visual detection level >90 percent (for each component) and 85 percent of global success (good classifications) with the discriminant equation. N1-P1-N2 complex is able to explain >70 percent of the visual response variance. A significant reduction of N1, P1 (N2, marginal) latencies with increasing age is demonstrated (linear regression, p≤0.05). There was no significant difference for age-dependent increased pattern of amplitude data (high variability). Conclusions: The visual evoked potentials/goggles obtained in infants and young children are consistent and reliable physiological responses (high detectability) with recognizable morphological variability(AU)


Subject(s)
Humans , Male , Female , Child, Preschool , Evoked Potentials, Visual/physiology , Eyeglasses/standards , Epidemiology, Descriptive , Cross-Sectional Studies
12.
Medicina (B.Aires) ; 79(1,supl.1): 51-56, abr. 2019. graf
Article in Spanish | LILACS | ID: biblio-1002605

ABSTRACT

Para evaluar los procesos atencionales a estímulos visuales que no requieren repuesta motora, se llevó a cabo un estudio con potenciales evocados a 17 niños con trastornos del déficit de atención/ hiperactividad (TDAH-I) con predominio inatento y a 15 controles de edades entre 7 y 11 años. Se analizó la latencia y localización de fuentes de los potenciales evocados visuales tempranos P100 y N100 durante la realización de una tarea oddball visual (20% rayas horizontales y 80% verticales) en que las rayas verticales no exigían respuesta motora. Los resultados indican que los niños con TDAH-I procesan la información visual que no requiere respuesta motora con un mayor aumento de la actividad cerebral y mediante la vía temporal ventral mientras que el grupo control lo hace mediante la vía parietal dorsal. Este proceso neurobiológico de procesamiento de la información visual vía temporal ventral de los niños con TDAH-I podría deberse a alteraciones en los procesos emocionales que influyen directamente en el reconocimiento visual o a un déficit en el control de los procesos atencionales por parte de la vía parietal dorsal.


To evaluate attentional processes to visual stimuli that do not require motor response, a study with evoked potentials was carried out on 17 children with attention deficit disorder predominantly inattentive (ADDH-I) and 15 controls between the ages of 7 and 11 years. The latency and localization of sources of the early visual evoked potentials P100 and N100 were analyzed during the performance of a visual oddball task (20% horizontal and 80% vertical lines) where the vertical lines did not require motor response. The results indicate that ADDH-I group process visual information that does not require motor response with a greater increase in brain activity and through the ventral temporal pathway, while the control group does so by means of the dorsal parietal stream. This neurobiological process of visual information processing by ventral temporal pathway of ADDH-I group could be due to alterations in emotional processes that directly influence visual recognition or as consequence of deficit in the control of attentional processes by the dorsal parietal pathway.


Subject(s)
Humans , Male , Female , Child , Attention Deficit Disorder with Hyperactivity/physiopathology , Evoked Potentials, Visual/physiology , Parietal Lobe/physiology , Attention/physiology , Temporal Lobe/physiology , Visual Perception/physiology , Electroencephalography , Evoked Potentials/physiology
13.
Rev. cuba. invest. bioméd ; 38(1): e162, Jan.-Mar. 2019.
Article in English | LILACS, CUMED | ID: biblio-1093383

ABSTRACT

A descriptive and traverse study was performed in patients with diagnosis of optic neuritis, that attended to the neuro ophthalmology service of the ophthalmological center, at the Santiago General Hospital Dr. Juan Bruno Zayas Alfonso , from the province of Santiago de Cuba, with less than a week of evolution of the disease, and visual acuity greater than 0.3, cooperatives and without refractive opacities, or neuro ophthalmologic diseases, during the period from December 2017 to November 2018. Ophthalmological clinical evaluations and electrophysiological studies of visual evoked potentials to pattern reversal, at diagnosis and eight weeks of evolution were carried out. Objective: To identify the relationship possible between the electrophysiological parameters obtained by visual evoked potentials with the ophthalmological clinical evaluation. Results: alterations predominantly of the parameters of latency and duration of the visual evoked potentials, in relation to the impairment of the clinical evaluations explored. Conclusions: The visual evoked potentials are an effective tool in diagnosis, and complement the clinical evaluation of patients with optic neuritis(AU)


Subject(s)
Visual Acuity , Optic Neuritis , Evoked Potentials, Visual , Epidemiology, Descriptive , Cross-Sectional Studies
14.
Article in English | WPRIM | ID: wpr-765114

ABSTRACT

BACKGROUND: It has been frequently reported that non-negligible numbers of individuals have steady-state visual evoked potential (SSVEP) responses of low signal-to-noise-ratio (SNR) to specific stimulation frequencies, which makes detection of the SSVEP difficult especially in brain–computer interface applications. We investigated whether SSVEP can be modulated by anodal transcranial direct-current stimulation (tDCS) of the visual cortex. METHODS: Each participant participated in two 20-min experiments—an actual tDCS experiment and a sham tDCS experiment—that were conducted on different days. Two representative electroencephalogram (EEG) features used for the SSVEP detection, SNR and amplitude, were tested for pre- and post-tDCS conditions to observe the effect of the anodal tDCS. RESULTS: The EEG features were significantly enhanced by the anodal tDCS for the electrodes with low pre-tDCS SNR values, whereas the effect was not significant for electrodes with relatively higher SNR values. CONCLUSION: Anodal tDCS of the visual cortex may be effective in enhancing the SNR and amplitude of the SSVEP response especially for individuals with low-SNR SSVEP.


Subject(s)
Electrodes , Electroencephalography , Evoked Potentials, Visual , Transcranial Direct Current Stimulation , Visual Cortex
15.
Article in Chinese | WPRIM | ID: wpr-774151

ABSTRACT

Attention can concentrate our mental resources on processing certain interesting objects, which is an important mental behavior and cognitive process. Recognizing attentional states have great significance in improving human's performance and reducing errors. However, it still lacks a direct and standardized way to monitor a person's attentional states. Based on the fact that visual attention can modulate the steady-state visual evoked potential (SSVEP), we designed a go/no-go experimental paradigm with 10 Hz steady state visual stimulation in background to investigate the separability of SSVEP features modulated by different visual attentional states. The experiment recorded the EEG signals of 15 postgraduate volunteers under high and low visual attentional states. High and low visual attentional states are determined by behavioral responses. We analyzed the differences of SSVEP signals between the high and low attentional levels, and applied classification algorithms to recognize such differences. Results showed that the discriminant canonical pattern matching (DCPM) algorithm performed better compared with the linear discrimination analysis (LDA) algorithm and the canonical correlation analysis (CCA) algorithm, which achieved up to 76% in accuracy. Our results show that the SSVEP features modulated by different visual attentional states are separable, which provides a new way to monitor visual attentional states.


Subject(s)
Algorithms , Attention , Electroencephalography , Evoked Potentials, Visual , Humans , Photic Stimulation
16.
Rev. chil. endocrinol. diabetes ; 11(1): 20-27, 2018. tab
Article in Spanish | LILACS | ID: biblio-999030

ABSTRACT

BACKGROUND: Diabetic vascular complications are associated with elevated concentrations of advanced glycation end-products (AGEs). These substances can be originated endogenously by hyperglycaemia and oxidative stress, but also by dietary intake. There is indirect evidence suggesting that these complications can be prevented by lowering AGEs levels by dietary or pharmacological interventions, however its clinical benefits are still not clear enough because this would require long periods of treatment. Specific neuro-ophthalmologic tests like Multifocal Electroretinogram (MFERG) and visual evoked potentials (VEP) can detect retinal and myelinic nerve early changes, and thus could represent good methods to study the results of certain interventions in shorter lapses. The aim of this preliminary study was to evaluate the effects of a pharmacological intervention designed to lower AGEs levels, on these variables. PATIENTS AND METHODS: We included 7 patients with type 2 diabetes (DM2), with more than 5 and less than 10 years of disease, without clinically evident micro and macrovascular disease, without renal failure, hypothyroidism nor vitamin B12 deficiency, whose AGEs dietary intake was moderately elevated or high (according to dietary recalls). Upon admission, a clinical evaluation, urine and blood samples were obtained for routine labs, plus ultrasensitive C Reactive Protein (usCRP) as an inflammatory marker, and carboxymethyl-lysine (CML) as representative of AGEs. Then a complete ophthalmologic evaluation was performed, including fundus, MFERG and VEP. After the initial evaluation, placebo capsules were prescribed (12 daily capsules, 4 with each main meal) during 3 months, repeating the same initial evaluation at completion of this period. Then the active treatment followed, with capsules containing cholestyramine (4 capsules containing 500 mg each, totaling 6 g per day). Patients were cited each month, to register adverse events and repeating the same evaluation after this second 3 months period. RESULTS: The sample was composed of 2 male patients, mean age was 55.1 ± 3.8 years, and diabetes was managed with metformin plus other oral agents or o insulin (4 cases). In addition, 4 patients received lipid lowering and 4 antihypertensive drugs. Metabolic control and lipid levels were variable (ranges of HbA1c 6.2-8.4%, LDL cholesterol 45-141 mg/dL, triglycerides 70-220 mg/dL). AGEs levels represented by CML were highly variable (median 31.7, range min-max 3.4-58.9 ug/uL). Basal usCRP was also variable (median 405.9, range min-max 265.6-490.7 mg/L). The treatment was well tolerated, except for mild constipation associated with cholestiramine intake. No significant changes in electroretinography or evoked potentials were observed when comparing the initial placebo period with cholestyramine treatment. A significant increase in triglyceride levels and decrease of vitamin D levels after cholestyramine treatment was observed. No changes were detected in serum concentrations of CML, usCRP or glycemic control, after treatment. The latter variables were not correlated with neurophthalmologic studies. DISCUSSION: In this preliminary study we did not observe changes in MFERG nor VEP after 6 g/day cholestyramine treatment, which did not induce lowering of CML levels. This could be attributed to the many limitations of a pilot study, such as a small sample size, short duration of treatment, reduced doses. However this design allowed to evaluate the patients´ tolerance to the drug and rule out adverse effects, in order to plan further studies using the necessary doses to obtain lowering of AGEs


Subject(s)
Humans , Male , Female , Middle Aged , Retina , Cholestyramine Resin/administration & dosage , Glycation End Products, Advanced/drug effects , Diabetes Mellitus, Type 2 , Electroretinography , Pilot Projects , Glycation End Products, Advanced/blood , Evoked Potentials, Visual , Lysine/analogs & derivatives , Lysine/drug effects , Lysine/blood
17.
Article in English | WPRIM | ID: wpr-718213

ABSTRACT

Preliminary studies have claimed that short term fasting would negatively affect school performance and cognition. In contrast some other studies have reported not important decline in cognition and executive function as a result of fasting. Also limited attention was generally devoted to dietetic regimens, nutritional status and body weight. Yet neuroscience and neuro-cognitive aspects of acute hunger on the electroencephalogram and differences between obese and non-obese cases is not well understood. Hence, we decided to design and perform a case study in a more controlled situation similar to reality. Therefore, we performed several examinations including subjective tests (for eating status) and objective tests (cognitive tests such as Stroop effect and Sternberg search and electroencephalogram measures such as steady-state visual evoked potential and auditory steady-state responses) for an obese and a non-obese academic case before and after a simple breakfast. The results showed that the breakfast effects on the neuro-cognitive functions depend on either obesity status, nutritional status of the case or the type of cognitive task (visual or auditory). This paper would open a new insight to answer some important questions about the neuro-cognitive implications of fasting and feeding in obese and non-obese human cases.


Subject(s)
Body Weight , Breakfast , Cognition , Eating , Electroencephalography , Evoked Potentials, Visual , Executive Function , Fasting , Humans , Hunger , Neurosciences , Nutritional Status , Obesity , Stroop Test
18.
Article in English | WPRIM | ID: wpr-714335

ABSTRACT

BACKGROUND AND PURPOSE: Optical coherence tomography (OCT) and visual evoked potentials (VEPs) can be used to detect optic neuritis (ON). However, the comparative sensitivities of OCT and VEPs for detecting ON in neuromyelitis optica spectrum disorder (NMOSD) are unclear, and so we assessed these sensitivities. METHODS: This cross-sectional study included 73 patients with aquaporin-4 antibody-seropositive NMOSD, and 101 eyes with ON. The clinical characteristics, visual acuity (VA), Expanded Disability Status Scale (EDSS) scores, OCT peripapillary retinal nerve fiber layer (RNFL) thickness, and VEPs of the patients were evaluated. RESULTS: OCT and VEPs were abnormal in 68% and 73% of eyes with a history of ON, respectively, and in 2% and 9% of eyes without ON. Test sensitivities were influenced by the number of ON episodes: the OCT RNFL thickness and VEPs were abnormal in 50% and 67% of the eyes with first-ever ON episode, respectively (p=0.041), with the combination of both tests detecting abnormalities in up to 75% of the eyes. The sensitivities of the OCT RNFL thickness and VEPs increased to 95% and 83%, respectively, after the second or subsequent ON episode (p=0.06), with the combination of both tests detecting abnormalities in 95% of cases. The OCT RNFL thickness and VEP latency/amplitude were correlated with EDSS scores and VA. CONCLUSIONS: VEPs were superior for detecting subclinical or first-ever ON, while OCT was better for detecting eyes with multiple ON episodes. The correlations of OCT and VEPs with clinical disability measures indicate that these tests are potential markers of the disease burden in NMOSD.


Subject(s)
Cross-Sectional Studies , Evoked Potentials, Visual , Humans , Nerve Fibers , Neuromyelitis Optica , Optic Neuritis , Retinaldehyde , Tomography, Optical Coherence , Visual Acuity , Visual Pathways
19.
Article in English | WPRIM | ID: wpr-714270

ABSTRACT

OBJECTIVE: To investigate the neurodevelopmental outcomes in children with developmental disorder according to visual evoked potential (VEP) results. METHODS: We retrospectively analyzed children who visited our Department of Pediatric Rehabilitation Medicine with a chief complaint of developmental disability from January 2001 to July 2015. Of the 549 medical records reviewed, 322 children younger than 42 months who underwent both Bayley Scales of Infant and Toddler Development second edition (BSID-II) and VEP studies were enrolled. We compared the development of 182 children with normal VEP latency and 140 children with delayed VEP latency results using the BSID-II results. The Mann-Whitney U-test was used to analyze the differences between the two groups. RESULTS: There were no significant differences in baseline characteristics between the two groups. The delayed VEP latency group showed a significant delay in BSID-II index scores and developmental quotients compared with the normal VEP latency group. In addition, a comparative analysis of developmental quotients of mental and psychomotor domains according to age (younger than 12 months, 12–23 months, and 24–42 months) revealed significantly lower values in children with delayed VEP latency compared to children with normal VEP latency, younger than 12 months and from 12 to 23 months. CONCLUSION: Children with delayed VEP latency showed more developmental delay than children with normal VEP latency. It is suggested that VEP can be easily applied to children with suspected developmental delay when physicians have concerns about visual impairment. Furthermore, it is proposed that VEP results could provide an insight into children's development and serve as early indicators for consultation with an ophthalmologist for the existing problem.


Subject(s)
Child , Developmental Disabilities , Evoked Potentials, Visual , Humans , Infant , Medical Records , Rehabilitation , Retrospective Studies , Vision Disorders , Weights and Measures
20.
Chinese Medical Journal ; (24): 2164-2171, 2018.
Article in English | WPRIM | ID: wpr-690249

ABSTRACT

<p><b>Background</b>Facioscapulohumeral muscular dystrophy (FSHD) is characterized by asymmetric muscular deficit of facial, shoulder-girdle muscles, and descending to lower limb muscles, but it exists in several extramuscular manifestations or overlapping syndromes. Herein, we report a "complex disease plus" patient with FSHD1, accompanied by peripheral neuropathy and myoclonic epilepsy.</p><p><b>Methods</b>Standard clinical assessments, particular auxiliary examination, histological analysis, and molecular analysis were performed through the new Comprehensive Clinical Evaluation Form, pulsed-field gel electrophoresis-based Southern blot, Multiplex Ligation-dependent Probe Amplification (MLPA), whole exome sequencing (WES), and targeted methylation sequencing.</p><p><b>Results</b>The patient presented with mild facial weakness, humeral poly-hill sign, scapular winging, peroneal weakness, drop foot, pes cavus, and myoclonic epilepsy. Furthermore, electrophysiology revealed severely demyelinated and axonal injury. The muscle and nerve biopsy revealed broadly fiber Type II grouping atrophy and myelinated nerve fibers that significantly decreased with thin myelinated fibers and onion bulbs changes. Generalized sharp and sharp-slow wave complexes on electroencephalography support the diagnosis toward myoclonic epilepsy. In addition, molecular testing demonstrated a co-segregated 20-kb 4q35-EcoRI fragment and permissive allele A, which corresponded with D4Z4 hypomethylation status in the family. Both the patient's mother and brother only presented the typical FSHD but lacked overlapping syndromes. However, no mutations for hereditary peripheral neuropathy and myoclonic epilepsy were discovered by MLPA and WES.</p><p><b>Conclusions</b>The present study described a "tripe trouble" with FSHD, peripheral neuropathy, and myoclonic epilepsy, adding the spectrum of overlapping syndromes and contributing to the credible diagnosis of atypical phenotype. It would provide a direct clue on medical care and genetic counseling.</p>


Subject(s)
Adult , Child , Epilepsies, Myoclonic , Evoked Potentials, Visual , Humans , Male , Muscle, Skeletal , Muscular Dystrophy, Facioscapulohumeral , Peripheral Nervous System Diseases
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