Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Psychiatry Neurosci ; 47(6): E367-E378, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36318983

RESUMO

BACKGROUND: A hyperactive default mode network (DMN) has been observed in people with major depressive disorder (MDD), and weak DMN suppression has been linked to depressive symptoms. However, whether dysregulation of the DMN contributes to blunted positive emotional experience in people with MDD is unclear. METHODS: We recorded 128-channel electroencephalograms (EEGs) from 24 participants with MDD and 31 healthy controls in a resting state (RS) and an emotion-induction state (ES), in which participants engaged with emotionally positive pictures. We combined Granger causality analysis and data-driven decomposition to extract latent brain networks shared among states and groups, and we further evaluated their interactions across individuals. RESULTS: We extracted 2 subnetworks. Subnetwork 1 represented a delta (δ)-band (1~4 Hz) frontal network that was activated more in the ES than the RS (i.e., task-positive). Subnetwork 2 represented an alpha (α)-band (8~13 Hz) parietal network that was suppressed more in the ES than the RS (i.e., task-negative). These subnetworks were anticorrelated in both the healthy control and MDD groups, but with different sensitivities: for participants with MDD to achieve the same level of task-positive (subnetwork 1) activation as healthy controls, more suppression of task-negative (subnetwork 2) activation was necessary. Furthermore, the anticorrelation strength in participants with MDD correlated with the severity of 2 core MDD symptoms: anhedonia and rumination. LIMITATIONS: The sample size was small. CONCLUSION: Our findings revealed altered coordination between 2 functional networks in MDD and suggest that weak suppression of the task-negative α-band parietal network contributes to blunted positive emotional responses in adults with depression. The subnetworks identified here could be used for diagnosis or targeted for treatment in the future.


Assuntos
Transtorno Depressivo Maior , Adulto , Humanos , Anedonia , Vias Neurais , Imageamento por Ressonância Magnética , Mapeamento Encefálico
2.
Commun Biol ; 5(1): 1076, 2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36216885

RESUMO

The human brain is proposed to harbor a hierarchical predictive coding neuronal network underlying perception, cognition, and action. In support of this theory, feedforward signals for prediction error have been reported. However, the identification of feedback prediction signals has been elusive due to their causal entanglement with prediction-error signals. Here, we use a quantitative model to decompose these signals in electroencephalography during an auditory task, and identify their spatio-spectral-temporal signatures across two functional hierarchies. Two prediction signals are identified in the period prior to the sensory input: a low-level signal representing the tone-to-tone transition in the high beta frequency band, and a high-level signal for the multi-tone sequence structure in the low beta band. Subsequently, prediction-error signals dependent on the prior predictions are found in the gamma band. Our findings reveal a frequency ordering of prediction signals and their hierarchical interactions with prediction-error signals supporting predictive coding theory.


Assuntos
Encéfalo , Eletroencefalografia , Encéfalo/fisiologia , Humanos
3.
Sci Rep ; 12(1): 17031, 2022 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-36220896

RESUMO

Electroencephalography (EEG) signals measured under fixed conditions have been exploited as biometric identifiers. However, what contributes to the uniqueness of one's brain signals remains unclear. In the present research, we conducted a multi-task and multi-week EEG study with ten pairs of monozygotic (MZ) twins to examine the nature and components of person-identifiable brain signals. Through machine-learning analyses, we uncovered a person-identifying EEG component that served as "base signals" shared across tasks and weeks. Such task invariance and temporal stability suggest that these person-identifying EEG characteristics are more of structural brainprints than functional mindprints. Moreover, while these base signals were more similar within than between MZ twins, it was still possible to distinguish twin siblings, particularly using EEG signals coming primarily from late rather than early developed areas in the brain. Besides theoretical clarifications, the discovery of the EEG base signals has practical implications for privacy protection and the application of brain-computer interfaces.


Assuntos
Interfaces Cérebro-Computador , Gêmeos Dizigóticos , Encéfalo , Eletroencefalografia , Humanos , Gêmeos Monozigóticos
4.
Artigo em Inglês | MEDLINE | ID: mdl-35575457

RESUMO

A proximity effect facilitates the penetration of Cooper pairs that permits superconductivity in a normal metal, offering a promising approach to turn heterogeneous materials into superconductors and develop exceptional quantum phenomena. Here, we have systematically investigated proximity-induced anisotropic superconductivity in a monolayer Ni-Pb binary alloy by combining scanning tunneling microscopy/spectroscopy (STM/STS) with theoretical calculations. By means of high-temperature growth, the (33×33)R30o Ni-Pb surface alloy has been fabricated on Pb(111) and the appearance of a domain boundary as well as a structural phase transition can be deduced from a half-unit-cell lattice displacement. Given the high spatial and energy resolution, tunneling conductance (dI/dU) spectra have resolved the reduced but anisotropic superconducting gap ΔNiPb ≈ 1.0 meV, in stark contrast to the isotropic ΔPb ≈ 1.3 meV. In addition, the higher density of states at the Fermi energy (D(EF)) of the Ni-Pb surface alloy results in an enhancement of coherence peak height. According to the same Tc ≈ 7.1 K with Pb(111) from the temperature-dependent ΔNiPb and the short decay length Ld ≈ 3.55 nm from the spatially monotonic decrease of ΔNiPb, both results are supportive of a proximity-induced superconductivity. Despite a lack of a bulk counterpart, the atomically thick Ni-Pb bimetallic compound opens a pathway to engineer superconducting properties down to the two-dimensional limit, giving rise to the emergence of anisotropic superconductivity via a proximity effect.

5.
Occup Ther Int ; 2022: 1409320, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35359430

RESUMO

Objectives: Rumination, a response style characterized by self-reflection loops of negative thoughts, tends to exacerbate depressive symptoms and may impair daily functional behaviors of individuals with depression. However, the specific impacts of rumination on activity participation remain unclear. The current study was aimed at examining the differences in daily activity participation profiles between clinically depressed people with higher versus lower rumination tendencies, with the hope to provide insightful suggestions for improving the quality of life of ruminative individuals with major depression. Methods: We recruited 143 participants with a depression-related diagnosis from psychiatric daycare centers or clinics and analyzed the differences in activity participation profiles between individuals with higher versus lower rumination tendencies. Results: Although compared to those with lower rumination tendencies, participants with higher rumination tendencies spent a longer time in activity participation; they experienced lower participation quality during these activities. Furthermore, their activity participation was primarily motivated by meeting others' expectations rather than self-interest. They also misattributed participation restriction to "lack of family support," indicating that the unhealthy rumination pattern might be the cause of their lack of positive feelings from engaging in meaningful daily activities. Conclusions: The current results suggest that the unhealthy motivation behind activity participation seems to be an important factor that decreases the quality of participation in individuals with higher rumination tendency. Establishing a healthy motivation for activity participation is therefore critical for improving their quality of participation. As an initial step, OT interventions could put a focus on helping them clarify and escape from the source of negative rumination cycles that impede their positive feeling of activity participation.


Assuntos
Transtorno Depressivo Maior , Terapia Ocupacional , Atividades Cotidianas , Transtorno Depressivo Maior/psicologia , Emoções , Humanos , Qualidade de Vida
6.
Biosensors (Basel) ; 11(12)2021 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-34940256

RESUMO

Major depressive disorder (MDD) is a global healthcare issue and one of the leading causes of disability. Machine learning combined with non-invasive electroencephalography (EEG) has recently been shown to have the potential to diagnose MDD. However, most of these studies analyzed small samples of participants recruited from a single source, raising serious concerns about the generalizability of these results in clinical practice. Thus, it has become critical to re-evaluate the efficacy of various common EEG features for MDD detection across large and diverse datasets. To address this issue, we collected resting-state EEG data from 400 participants across four medical centers and tested classification performance of four common EEG features: band power (BP), coherence, Higuchi's fractal dimension, and Katz's fractal dimension. Then, a sequential backward selection (SBS) method was used to determine the optimal subset. To overcome the large data variability due to an increased data size and multi-site EEG recordings, we introduced the conformal kernel (CK) transformation to further improve the MDD as compared with the healthy control (HC) classification performance of support vector machine (SVM). The results show that (1) coherence features account for 98% of the optimal feature subset; (2) the CK-SVM outperforms other classifiers such as K-nearest neighbors (K-NN), linear discriminant analysis (LDA), and SVM; (3) the combination of the optimal feature subset and CK-SVM achieves a high five-fold cross-validation accuracy of 91.07% on the training set (140 MDD and 140 HC) and 84.16% on the independent test set (60 MDD and 60 HC). The current results suggest that the coherence-based connectivity is a more reliable feature for achieving high and generalizable MDD detection performance in real-life clinical practice.


Assuntos
Transtorno Depressivo Maior , Eletroencefalografia , Transtorno Depressivo Maior/diagnóstico , Humanos , Aprendizado de Máquina , Máquina de Vetores de Suporte
7.
Phys Rev Lett ; 127(21): 217202, 2021 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-34860095

RESUMO

The study of the magnonic thermal Hall effect in magnets with Dzyaloshinskii-Moriya interaction (DMI) has recently drawn attention because of the underlying topology. Topological phase transitions may arise when there exist two or more distinct topological phases, and they are often revealed by a gap-closing phenomenon. In this work, we consider the magnons in honeycomb ferromagnets described by a Heisenberg Hamiltonian containing both an out-of-plane DMI and a Zeeman interaction. We demonstrate that the magnonic system exhibits temperature (or magnetic field) driven topological phase transitions due to magnon-magnon interactions. Specifically, when the temperature increases, the magnonic energy gap at Dirac points closes and reopens at a critical temperature, T_{c}. By showing that the Chern numbers of the magnonic bands are distinct above and below T_{c}, we confirm that the gap-closing phenomenon is indeed a signature for the topological phase transitions. Furthermore, our analysis indicates that the thermal Hall conductivity in the magnonic system exhibits a sign reversal at T_{c}, which can serve as an experimental probe of its topological nature. Our theory predicts that in CrI_{3} such a phenomenon exists and is experimentally accessible.

8.
Front Comput Neurosci ; 15: 700467, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34421565

RESUMO

Individuals with mild cognitive impairment (MCI) are at high risk of developing into dementia (e. g., Alzheimer's disease, AD). A reliable and effective approach for early detection of MCI has become a critical challenge. Although compared with other costly or risky lab tests, electroencephalogram (EEG) seems to be an ideal alternative measure for early detection of MCI, searching for valid EEG features for classification between healthy controls (HCs) and individuals with MCI remains to be largely unexplored. Here, we design a novel feature extraction framework and propose that the spectral-power-based task-induced intra-subject variability extracted by this framework can be an encouraging candidate EEG feature for the early detection of MCI. In this framework, we extracted the task-induced intra-subject spectral power variability of resting-state EEGs (as measured by a between-run similarity) before and after participants performing cognitively exhausted working memory tasks as the candidate feature. The results from 74 participants (23 individuals with AD, 24 individuals with MCI, 27 HC) showed that the between-run similarity over the frontal and central scalp regions in the HC group is higher than that in the AD or MCI group. Furthermore, using a feature selection scheme and a support vector machine (SVM) classifier, the between-run similarity showed encouraging leave-one-participant-out cross-validation (LOPO-CV) classification performance for the classification between the MCI and HC (80.39%) groups and between the AD vs. HC groups (78%), and its classification performance is superior to other widely-used features such as spectral powers, coherence, and the complexity estimated by Katz's method extracted from single-run resting-state EEGs (a common approach in previous studies). The results based on LOPO-CV, therefore, suggest that the spectral-power-based task-induced intra-subject EEG variability extracted by the proposed feature extraction framework has the potential to serve as a neurophysiological feature for the early detection of MCI in individuals.

9.
Am J Occup Ther ; 74(2): 7402205090p1-7402205090p9, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32204787

RESUMO

IMPORTANCE: Children with hemiplegic cerebral palsy (CP) demonstrate spatial attention disregard, but the rehabilitation approach to CP is traditionally motor oriented. OBJECTIVE: To explore spatial attention disregard in children with hemiplegic CP and its relationship to their motor performance in daily activities. DESIGN: Cross-sectional study. SETTING: Community. PARTICIPANTS: Twenty-five children with hemiplegic CP and 25 age-matched typically developing children. OUTCOMES AND MEASURES: For spatial attention performance, the Random Visual Stimuli Detection Task; for developmental disregard, the Observatory Test of Capacity, Performance, and Developmental Disregard; and for motor performance, the Melbourne Assessment 2. RESULTS: Children with hemiplegic CP evidenced spatial attention disregard on their more affected sides, and this phenomenon was correlated with developmental disregard. CONCLUSIONS AND RELEVANCE: Children with hemiplegic CP demonstrate developmental disregard in both the motor and the visual-spatial attention domains. Including evaluation of and intervention for visual-spatial attention for children with hemiplegic CP in the traditionally motor-oriented rehabilitation approach is recommended. WHAT THIS ARTICLE ADDS: This research provides evidence that children with hemiplegic CP demonstrate disregard in the domain of visual-spatial attention. The findings suggest that evaluation of and intervention for visual-spatial attention should be included in CP rehabilitation in addition to the traditionally motor-oriented approach.


Assuntos
Paralisia Cerebral , Hemiplegia/fisiopatologia , Atenção/fisiologia , Estudos de Casos e Controles , Criança , Estudos Transversais , Humanos
10.
Disabil Rehabil ; 41(22): 2683-2687, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-29954229

RESUMO

Purpose: To investigate the responsiveness and predictive validity of the computerized digit vigilance test (C-DVT) in inpatients receiving rehabilitation following stroke. Methods: Forty-nine patients completed the C-DVT and the Barthel Index (BI) after admission to and before discharge from the rehabilitation ward. The standardized response mean (SRM) was used to examine the responsiveness of the C-DVT. We used a paired t-test to determine the statistical significance of the changes in scores on the C-DVT. We estimated the predictive validity of the C-DVT with the Pearson correlation coefficient (r) to investigate the association between the scores of the C-DVT at admission and the scores of the BI at discharge. Results: Our data showed a small SRM (-0.31) and a significant difference (paired t-test, p = 0.034) between the C-DVT scores at admission and discharge. These findings indicate that the C-DVT can appropriately detect changes in sustained attention. In addition, we found a moderate association (r = 0.48) between the scores of the C-DVT at admission and the scores of the BI at discharge, suggesting the sufficient predictive validity of the C-DVT. Conclusions: Our results showed that the C-DVT had adequate responsiveness and sufficient predictive validity in inpatients receiving rehabilitation following stroke. Implications for rehabilitation The computerized digit vigilance test (C-DVT) had adequate responsiveness to be an outcome measure for assessing the sustained attention in inpatients receiving rehabilitation after stroke. The C-DVT had sufficient predictive validity to predict daily function in inpatients receiving rehabilitation after stroke.


Assuntos
Alta do Paciente , Tempo de Reação , Reabilitação do Acidente Vascular Cerebral/métodos , Análise e Desempenho de Tarefas , Idoso , Diagnóstico por Computador/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde/métodos , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Resultado do Tratamento
11.
Front Hum Neurosci ; 12: 23, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29456496

RESUMO

Trust is essential for mutually beneficial human interactions in economic exchange and politics and people's social identities notably have dramatic effects on trust behaviors toward others. Previous literature concerning social identities generally suggests that people tend to show in-group favoritism toward members who share the same identity. However, how our brains process signals of identity while facing uncertain situations in interpersonal interactions remains largely unclear. To address this issue, we performed an fMRI experiment with 54 healthy adults who belonged to two identity groups of opposing political orientations. The identity information of participants was extracted from a large-scale social survey on the 2012 Taiwan presidential election. Accordingly, participants were categorized as either the Kuomintang (KMT) or the Democratic Progressive Party (DPP) supporters. During the experiment, participants played trust games with computer agents with labels of the same or the opposing political identity. Interestingly, our results suggest that the behaviors of the two groups cannot be equally attributed to in-group favoritism. Behaviorally, only the DPP supporter group showed a significant trust preference toward in-group members, which did not hold for the KMT supporter group. Consistently, neurophysiological findings further revealed that only the DPP supporter group showed neuronal responses to both unexpected negative feedback from in-group members in anterior insula, temporoparietal junction, and dorsal lateral prefrontal cortex, as well as to unexpected rewards from out-group members in caudate. These findings therefore suggest that acquired identities play a more complex role in modulating people's social expectation in interpersonal trust behaviors under identity-relevant contexts.

12.
Arch Clin Neuropsychol ; 33(2): 227-237, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28981615

RESUMO

OBJECTIVE: The purposes of this study were to examine the test-retest reliability, concurrent validity, and ecological validity of the Computerized Digit Vigilance Test (C-DVT) in patients with schizophrenia. METHOD: Each participant was assessed four times, with 1-week intervals. In each assessment, the participants completed both the C-DVT and the original DVT. The participants were also assessed using the Lawton Instrumental Activities of Daily Living Scale (LIADL) and the Personal and Social Performance Scale (PSP). RESULTS: Forty-nine participants were recruited in this study. The results showed that the test-retest agreement of the C-DVT was good-to-excellent (intraclass correlation coefficient = 0.71-0.89). The random measurement errors of the C-DVT were acceptable (percentages of minimal detectable change = 12.9%-24.1%). The practice effect of the C-DVT reached a plateau after three assessments (effect size <0.20). The concurrent validity of the C-DVT was good (r = .75-.79 with DVT) when we controlled for the randomized administration order of the two tests. The ecological validity of the C-DVT was good (r = -.44 with the LIADL; r = -.45 with the PSP). CONCLUSIONS: The C-DVT had acceptable test-retest reliability, sound concurrent validity, and sound ecological validity in patients with schizophrenia. These findings indicate that the C-DVT has the potential to be a reliable and valid test of sustained attention in patients with schizophrenia.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Esquizofrenia/complicações , Psicologia do Esquizofrênico , Atividades Cotidianas , Adulto , Ecologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Escalas de Graduação Psiquiátrica , Reprodutibilidade dos Testes , Fatores de Tempo
13.
J Autism Dev Disord ; 48(3): 784-795, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29119522

RESUMO

Whether action representation in individuals with autism spectrum disorder (ASD) is deficient remains controversial, as previous studies of action observation or imitation report conflicting results. Here we investigated the characteristics of action representation in adolescents with ASD through motor imagery (MI) using a hand rotation and an object rotation task. Comparable with the typically-developing group, the individuals with ASD were able to spontaneously use kinesthetic MI to perform the hand rotation task, as manifested by the significant biomechanical effects. However, the ASD group performed significantly slower only in the hand rotation task, but not in the object rotation task. The findings suggest that the adolescents with ASD showed inefficient but functional kinesthetic MI, implicating that their action representation might be preserved.


Assuntos
Transtorno do Espectro Autista/fisiopatologia , Transtorno do Espectro Autista/psicologia , Imaginação/fisiologia , Cinestesia/fisiologia , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Adolescente , Transtorno do Espectro Autista/diagnóstico , Criança , Feminino , Mãos/fisiologia , Humanos , Masculino , Estimulação Luminosa/métodos , Tempo de Reação/fisiologia
14.
Psychiatry Res ; 260: 199-206, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29202384

RESUMO

We aimed to compare the test-retest agreement, random measurement error, practice effect, and ecological validity of the original and Tablet-based Symbol Digit Modalities Test (T-SDMT) over five serial assessments, and to examine the concurrent validity of the T-SDMT in patients with schizophrenia. Sixty patients with chronic schizophrenia completed five serial assessments (one week apart) of the SDMT and T-SDMT and one assessment of the Activities of Daily Living Rating Scale III at the first time point. Both measures showed high test-retest agreement, similar levels of random measurement error over five serial assessments. Moreover, the practice effects of the two measures did not reach a plateau phase after five serial assessments in young and middle-aged participants. Nevertheless, only the practice effect of the T-SDMT became trivial after the first assessment. Like the SDMT, the T-SDMT had good ecological validity. The T-SDMT also had good concurrent validity with the SDMT. In addition, only the T-SDMT had discriminative validity to discriminate processing speed in young and middle-aged participants. Compared to the SDMT, the T-SDMT had overall slightly better psychometric properties, so it can be an alternative measure to the SDMT for assessing processing speed in patients with schizophrenia.


Assuntos
Atividades Cotidianas , Disfunção Cognitiva/diagnóstico , Computadores de Mão , Diagnóstico por Computador/normas , Testes Neuropsicológicos/normas , Psicometria/normas , Desempenho Psicomotor/fisiologia , Esquizofrenia/diagnóstico , Adulto , Disfunção Cognitiva/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria/instrumentação , Reprodutibilidade dos Testes , Esquizofrenia/complicações
15.
Sensors (Basel) ; 17(6)2017 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-28613237

RESUMO

Major depressive disorder (MDD) has become a leading contributor to the global burden of disease; however, there are currently no reliable biological markers or physiological measurements for efficiently and effectively dissecting the heterogeneity of MDD. Here we propose a novel method based on scalp electroencephalography (EEG) signals and a robust spectral-spatial EEG feature extractor called kernel eigen-filter-bank common spatial pattern (KEFB-CSP). The KEFB-CSP first filters the multi-channel raw EEG signals into a set of frequency sub-bands covering the range from theta to gamma bands, then spatially transforms the EEG signals of each sub-band from the original sensor space to a new space where the new signals (i.e., CSPs) are optimal for the classification between MDD and healthy controls, and finally applies the kernel principal component analysis (kernel PCA) to transform the vector containing the CSPs from all frequency sub-bands to a lower-dimensional feature vector called KEFB-CSP. Twelve patients with MDD and twelve healthy controls participated in this study, and from each participant we collected 54 resting-state EEGs of 6 s length (5 min and 24 s in total). Our results show that the proposed KEFB-CSP outperforms other EEG features including the powers of EEG frequency bands, and fractal dimension, which had been widely applied in previous EEG-based depression detection studies. The results also reveal that the 8 electrodes from the temporal areas gave higher accuracies than other scalp areas. The KEFB-CSP was able to achieve an average EEG classification accuracy of 81.23% in single-trial analysis when only the 8-electrode EEGs of the temporal area and a support vector machine (SVM) classifier were used. We also designed a voting-based leave-one-participant-out procedure to test the participant-independent individual classification accuracy. The voting-based results show that the mean classification accuracy of about 80% can be achieved by the KEFP-CSP feature and the SVM classifier with only several trials, and this level of accuracy seems to become stable as more trials (i.e., <7 trials) are used. These findings therefore suggest that the proposed method has a great potential for developing an efficient (required only a few 6-s EEG signals from the 8 electrodes over the temporal) and effective (~80% classification accuracy) EEG-based brain-computer interface (BCI) system which may, in the future, help psychiatrists provide individualized and effective treatments for MDD patients.


Assuntos
Transtorno Depressivo Maior , Algoritmos , Interfaces Cérebro-Computador , Eletroencefalografia , Humanos , Processamento de Sinais Assistido por Computador , Máquina de Vetores de Suporte
16.
Front Hum Neurosci ; 10: 157, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27148014

RESUMO

The purpose of this study was to investigate the effectiveness of visual rehabilitation of a computer-based visual stimulation (VS) program combining checkerboard pattern reversal (passive stimulation) with oddball stimuli (attentional modulation) for improving the visual acuity (VA) of visually impaired (VI) children and children with amblyopia and additional developmental problems. Six children (three females, three males; mean age = 3.9 ± 2.3 years) with impaired VA caused by deficits along the anterior and/or posterior visual pathways were recruited. Participants received eight rounds of VS training (two rounds per week) of at least eight sessions per round. Each session consisted of stimulation with 200 or 300 pattern reversals. Assessments of VA (assessed with the Lea symbol VA test or Teller VA cards), visual evoked potential (VEP), and functional vision (assessed with the Chinese-version Functional Vision Questionnaire, FVQ) were carried out before and after the VS program. Significant gains in VA were found after the VS training [VA = 1.05 logMAR ± 0.80 to 0.61 logMAR ± 0.53, Z = -2.20, asymptotic significance (2-tailed) = 0.028]. No significant changes were observed in the FVQ assessment [92.8 ± 12.6 to 100.8 ±SD = 15.4, Z = -1.46, asymptotic significance (2-tailed) = 0.144]. VEP measurement showed improvement in P100 latency and amplitude or integration of the waveform in two participants. Our results indicate that a computer-based VS program with passive checkerboard stimulation, oddball stimulus design, and interesting auditory feedback could be considered as a potential intervention option to improve the VA of a wide age range of VI children and children with impaired VA combined with other neurological disorders.

17.
Disabil Rehabil ; 38(19): 1952-60, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26860823

RESUMO

PURPOSE: To develop a Tablet-based Symbol Digit Modalities Test (T-SDMT) and to examine the test-retest reliability and concurrent validity of the T-SDMT in patients with stroke. METHODS: The study had two phases. In the first phase, six experts, nine college students and five outpatients participated in the development and testing of the T-SDMT. In the second phase, 52 outpatients were evaluated twice (2 weeks apart) with the T-SDMT and SDMT to examine the test-retest reliability and concurrent validity of the T-SDMT. RESULTS: The T-SDMT was developed via expert input and college student/patient feedback. Regarding test-retest reliability, the practise effects of the T-SDMT and SDMT were both trivial (d=0.12) but significant (p≦0.015). The improvement in the T-SDMT (4.7%) was smaller than that in the SDMT (5.6%). The minimal detectable changes (MDC%) of the T-SDMT and SDMT were 6.7 (22.8%) and 10.3 (32.8%), respectively. The T-SDMT and SDMT were highly correlated with each other at the two time points (Pearson's r=0.90-0.91). CONCLUSIONS: The T-SDMT demonstrated good concurrent validity with the SDMT. Because the T-SDMT had a smaller practise effect and less random measurement error (superior test-retest reliability), it is recommended over the SDMT for assessing information processing speed in patients with stroke. Implications for Rehabilitation The Symbol Digit Modalities Test (SDMT), a common measure of information processing speed, showed a substantial practise effect and considerable random measurement error in patients with stroke. The Tablet-based SDMT (T-SDMT) has been developed to reduce the practise effect and random measurement error of the SDMT in patients with stroke. The T-SDMT had smaller practise effect and random measurement error than the SDMT, which can provide more reliable assessments of information processing speed.


Assuntos
Transtornos Cognitivos/diagnóstico , Computadores de Mão , Erros de Diagnóstico , Testes Neuropsicológicos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/psicologia , Idoso , Transtornos Cognitivos/etiologia , Feminino , Humanos , Masculino , Processos Mentais , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Taiwan
18.
Neurosci Conscious ; 2016(1): niw017, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-30109130

RESUMO

In motion-induced blindness (MIB), a static target superimposed on a global moving pattern frequently disappears and reappears into consciousness. We previously reported an intriguing illusory temporal reversal whereby a new stimulus onset (e.g. a dot flash) presented during MIB triggers an early reappearance of the target, yet is systematically perceived as occurring after the target reappearance. This illusion implies that the unconscious target representation can be quickly reactivated, with a temporal advantage for its conscious reloading as compared to the conscious uploading of a newly presented visual stimulus. However, it remains unclear whether the temporal advantage for conscious representation reloading strengthens, decays, or remains constant over time after we lose the initial conscious access to the stimulus. To address this question, we examined the relation between the duration of MIB and the percentage of illusory temporal reversals, and we found a negative correlation between the two measures, both between and within observers. The results suggest that although the unconscious target representation retains a certain level of activation during MIB, the temporal advantage for reloading its preexisting representation into consciousness decays over time.

19.
Disabil Rehabil ; 38(1): 97-102, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25845658

RESUMO

PURPOSE: To examine the ecological validity, predictive validity, and responsiveness of the Five Digit Test (FDT) in patients with stroke. METHODS: We included inpatients with stroke (n = 144, 114 and 105 in the ecological validity, predictive validity, and responsiveness analysis, respectively) in the study. At admission, the FDT and Barthel Index (BI) were assessed; at discharge, the FDT, BI, Postural Assessment Scale for Stroke Patients (PASS), and Mobility Subscale of the Stroke Rehabilitation Assessment of Movement (MO-STREAM) were assessed. RESULTS: In the ecological validity analysis, the scores of the selective and alternating attention indices of the FDT were moderately correlated with those of the BI at admission and discharge (Spearman ρ = -0.38 to -0.45). In the predictive validity analysis, the scores of the two attention indices of the FDT at admission were moderately correlated with the scores of the BI, PASS, and MO-STREAM at discharge (ρ = -0.33 to -0.45). In the responsiveness analysis, the two attention indices of the FDT between admission and discharge had large differences (success rate difference = 0.56-0.67, Wilcoxon Z = -5.90 to -6.60). CONCLUSION: Our results indicate that the selective and alternating attention indices of the FDT have acceptable ecological validity, predictive validity, and good responsiveness in patients with stroke. IMPLICATIONS FOR REHABILITATION: The Five Digit Test (FDT), an efficient and culture-free assessment tool, has been used to assess selective attention and alternating attention The selective index and alternating attention index of the FDT showed acceptable ecological validity, predictive validity, and good responsiveness in patients with stroke.


Assuntos
Atenção , Avaliação da Deficiência , Movimento , Psicometria/métodos , Reabilitação do Acidente Vascular Cerebral , Idoso , Feminino , Humanos , Pacientes Internados , Masculino , Pessoa de Meia-Idade , Alta do Paciente , Reprodutibilidade dos Testes , Índice de Gravidade de Doença
20.
Phys Rev Lett ; 115(24): 240401, 2015 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-26705613

RESUMO

In this paper we follow the analysis and protocols of recent experiments, combined with simple theory, to arrive at a physical understanding of quasi-condensation in two dimensional Fermi gases. A key signature of quasi-condensation, which contains aspects of Berezinskii-Kosterlitz-Thouless behavior, is a strong zero momentum peak in the pair momentum distribution. Importantly, this peak emerges at a reasonably well defined onset temperature. The resulting phase diagram, pair momentum distribution, and algebraic power law decay are compatible with recent experiments throughout the continuum from BEC to BCS.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...