Task-related brain activity in upper limb dystonia revealed by simultaneous fNIRS and EEG.

OBJECTIVE: The aim of this study was to explore differences in brain activity and connectivity using simultaneous electroencephalography and near-infrared spectroscopy in patients with focal dystonia during handwriting and finger-tapping tasks. METHODS: Patients with idiopathic right upper limb focal dystonia and controls were assessed by simultaneous near-infrared spectroscopy and electroencephalography during the writing and finger-tapping tasks in terms of the mu-alpha, mu-beta, beta and low gamma power and effective connectivity, as well as relative changes in oxyhemoglobin (oxy-Hb) and deoxyhemoglobin using a channel-wise approach with a mixed-effect model. RESULTS: Patients exhibited higher oxy-Hb levels in the right and left motor cortex and supplementary motor area during writing, but lower oxy-Hb levels in the left sensorimotor and bilateral somatosensory area during finger-tapping compared to controls. During writing, patients showed increased low gamma power in the bilateral sensorimotor cortex and less mu-beta and beta attenuation compared to controls. Additionally, patients had reduced connectivity between the supplementary motor area and the left sensorimotor cortex during writing. No differences were observed in terms of effective connectivity in either task. Finally, patients failed to attenuate the mu-alpha, mu-beta, and beta rhythms during the finger-tapping task. CONCLUSIONS: Cortical blood flow and EEG spectral power differ between controls and dystonia patients, depending on the task. Writing increased blood flow and altered connectivity in dystonia patients, and it also decreased slow-band attenuation. Finger-tapping decreased blood flow and slow-band attenuation. SIGNIFICANCE: Simultaneous fNIRS and EEG may show relevant information regarding brain dynamics in movement disorders patients in unconstrained environments.

Magnetic resonance imaging evaluation of nigrosome 1 and neuromelanin can assist Parkinson's disease diagnosis, but requires an expert neuroradiologist.

INTRODUCTION: Parkinson's disease (PD) is the second most common neurodegenerative disease. However, the rate of misdiagnosis remains high, even at specialized movement disorder centers. PURPOSE: To assess the accuracy of nigrosome 1 and midbrain neuromelanin evaluation in the diagnosis of PD, and to identify possible differences in diagnostic accuracy between neuroradiologists of different experience levels in analyzing these structures. METHODS: A case-control study was conducted between April 2017 and January 2019. We prospectively evaluated 41 PD patients and 21 control individuals. Participants underwent axial, T2*-weighted, multi-echo gradient echo (GRE), and susceptibility-weighted imaging phase (SWIp) magnetic resonance imaging (MRI) sequences to evaluate nigrosome 1 and axial, T1-weighted, turbo spin-echo magnetization transfer contrast (MTC) MRI sequences to evaluate midbrain neuromelanin. All MRI sequences were acquired at 3.0 T. The images were analyzed by two experienced neuroradiologists, one with and one without expertise in nigrosome 1 and neuromelanin imaging. The sensitivity, specificity, and accuracy of the diagnoses were calculated between PD patients vs. healthy participants and between the two neuroradiologists. RESULTS: The sensitivity and specificity of each imaging sequence for PD diagnosis were as follows: multi-echo, 100% and 86%; SWIp, 91% and 88%; and T1 MTC, 90% and 93%, respectively. The accuracy of clinical PD diagnosis was higher for the expert neuroradiologist compared to the neuroradiologist lacking expertise. CONCLUSION: Nigrosome 1 and midbrain neuromelanin represent useful tools for PD diagnosis. However, these structures should be evaluated by experienced neuroradiologists in order to ensure high accuracy and reproducibility.

Visual losses in early-onset and late-onset Parkinson's disease.

Patients with Parkinson's disease (PD) manifest visual losses. However, it is not known whether these losses are equivalent in both early-onset (EOPD) and late-onset (LOPD) patients. We evaluated contrast sensitivity and color vision in EOPD and LOPD patients and in age-matched controls. Losses occurred in both patient groups but were more pronounced in EOPD, consistent with the notion that non-motor symptoms are affected by age of symptom onset. More studies of visual function in EOPD and LOPD patients are needed to understand how aging is related to the pathophysiology of non-motor PD symptomatology. This would permit earlier diagnosis and, perhaps, better management of the disease.

Some aspects of the validity of the Montreal Cognitive Assessment (MoCA)for evaluating cognitive impairment in Brazilian patients with Parkinson's disease / Alguns aspectos da validade da MoCA (Montreal Cognitive Assessment - MoCA) para avaliação de comprometimento cognitivo em pacientes brasileiros com doença de Parkinson

ABSTRACT Background: The Montreal Cognitive Assessment (MoCA) is a short global cognitive scale, and some studies suggest it is useful for evaluating cognition in patients with Parkinson's disease (PD). However, its accuracy has been questioned in studies involving patients with low education. Objective: We sought to assess whether some of the MoCA subtests contribute to the low accuracy of the test. Methods: We performed a cross-sectional retrospective analysis of clinical data in a cohort of 71 patients with PD, most with less than 8 years of education. Patients were examined using the MDS-UPDRS, Hoehn and Yahr and the MoCA. The data were analyzed using mainly descriptive statistics. Results: We analyzed the data of 66 patients that were not demented according to the clinical evaluation and classified them using the proposed cut-off MoCA scores for diagnosis of MCI and dementia. Thirteen patients (19.7%) were classified as having normal cognition, 24 (36.3%) MCI and 29 (43.9%) dementia. Patients with dementia had longer disease duration (p=0.016) and lower education (p=0.0001). Total MoCA scores had a an almost normal distribution with a wide range of scores and only one maximum score. Performance on the MoCA was highly correlated with education (correlation coefficient=0.66, p=0.0001). At least five of the 10 MoCA subtests showed significant floor effects. Conclusion: We believe that some of the MoCA subtests may be too difficult to be completed by PD patients with low educational level, thus contributing to the test's poor diagnostic accuracy.

RESUMO Embasamento: A MoCA é uma escala cognitiva global breve, e alguns estudos sugerem que ela seria útil para avaliar a cognição em pacientes com doença de Parkinson (DP). No entanto, sua acurácia foi questionada em estudos em pacientes com baixa escolaridade. Objetivo: Pretendeu-se avaliar se alguns dos subtestes da MoCA poderiam contribuir para a baixa precisão do teste. Métodos: Foi realizada uma análise transversal e retrospectiva de dados clínicos de uma coorte de 71 pacientes com DP, a maioria com menos de 8 anos de escolaridade. Os pacientes foram examinados usando o MDS-UPDRS, a Hoehn e Yahr e a MoCA. Os dados foram principalmente analisados pela estatística descritiva. Resultados: Foram analisados os dados de 66 pacientes que não foram diagnosticados com demência de acordo com a avaliação clínica. Eles foram em seguida classificados, usando as notas de corte MoCA propostos para diagnóstico de comprometimento cognitivo leve (CCL) e demência. Dessa forma, treze pacientes (19,7%) foram classificados como com a cognição normal, 24 pacientes (36,3%) com CCL e 29 pacientes (43,9%) como com demência. Os pacientes com demência tiveram maior duração da doença (p=0,016) e menor escolaridade (p=0,0001). A distribuição dos escores totais da MoCA apresentaram forma de distribuição normal com uma vasta gama de pontuações e apenas uma pontuação máxima. O desempenho no MoCA foi altamente correlacionado à escolaridade (coeficiente de correlação=0,66, p=0,0001). Pelo menos cinco dos 10 subtestes da MoCA mostraram efeitos piso significativos. Conclusão: Alguns dos subtestes MoCA podem ser muito difíceis de completar por pacientes com DP com baixa escolaridade, contribuindo assim para a baixa precisão diagnóstica do teste.

Some aspects of the validity of the Montreal Cognitive Assessment (MoCA) for evaluating cognitive impairment in Brazilian patients with Parkinson's disease.

BACKGROUND: The Montreal Cognitive Assessment (MoCA) is a short global cognitive scale, and some studies suggest it is useful for evaluating cognition in patients with Parkinson's disease (PD). However, its accuracy has been questioned in studies involving patients with low education. OBJECTIVE: We sought to assess whether some of the MoCA subtests contribute to the low accuracy of the test. METHODS: We performed a cross-sectional retrospective analysis of clinical data in a cohort of 71 patients with PD, most with less than 8 years of education. Patients were examined using the MDS-UPDRS, Hoehn and Yahr and the MoCA. The data were analyzed using mainly descriptive statistics. RESULTS: We analyzed the data of 66 patients that were not demented according to the clinical evaluation and classified them using the proposed cut-off MoCA scores for diagnosis of MCI and dementia. Thirteen patients (19.7%) were classified as having normal cognition, 24 (36.3%) MCI and 29 (43.9%) dementia. Patients with dementia had longer disease duration (p=0.016) and lower education (p=0.0001). Total MoCA scores had a an almost normal distribution with a wide range of scores and only one maximum score. Performance on the MoCA was highly correlated with education (correlation coefficient=0.66, p=0.0001). At least five of the 10 MoCA subtests showed significant floor effects. CONCLUSION: We believe that some of the MoCA subtests may be too difficult to be completed by PD patients with low educational level, thus contributing to the test's poor diagnostic accuracy.

EMBASAMENTO: A MoCA é uma escala cognitiva global breve, e alguns estudos sugerem que ela seria útil para avaliar a cognição em pacientes com doença de Parkinson (DP). No entanto, sua acurácia foi questionada em estudos em pacientes com baixa escolaridade. OBJETIVO: Pretendeu-se avaliar se alguns dos subtestes da MoCA poderiam contribuir para a baixa precisão do teste. MÉTODOS: Foi realizada uma análise transversal e retrospectiva de dados clínicos de uma coorte de 71 pacientes com DP, a maioria com menos de 8 anos de escolaridade. Os pacientes foram examinados usando o MDS-UPDRS, a Hoehn e Yahr e a MoCA. Os dados foram principalmente analisados pela estatística descritiva. RESULTADOS: Foram analisados os dados de 66 pacientes que não foram diagnosticados com demência de acordo com a avaliação clínica. Eles foram em seguida classificados, usando as notas de corte MoCA propostos para diagnóstico de comprometimento cognitivo leve (CCL) e demência. Dessa forma, treze pacientes (19,7%) foram classificados como com a cognição normal, 24 pacientes (36,3%) com CCL e 29 pacientes (43,9%) como com demência. Os pacientes com demência tiveram maior duração da doença (p=0,016) e menor escolaridade (p=0,0001). A distribuição dos escores totais da MoCA apresentaram forma de distribuição normal com uma vasta gama de pontuações e apenas uma pontuação máxima. O desempenho no MoCA foi altamente correlacionado à escolaridade (coeficiente de correlação=0,66, p=0,0001). Pelo menos cinco dos 10 subtestes da MoCA mostraram efeitos piso significativos. CONCLUSÃO: Alguns dos subtestes MoCA podem ser muito difíceis de completar por pacientes com DP com baixa escolaridade, contribuindo assim para a baixa precisão diagnóstica do teste.