Objective. Previous neuroimaging studies mainly focused on static characteristics of brain activity, and little is known about its characteristics over time, especially in post-stroke (PS) patients. In this study, we aimed to investigate the static and dynamic characteristics of brain activity after stroke using functional magnetic resonance imaging (fMRI). Approach.Twenty ischemic PS patients and nineteen healthy controls (HCs) were recruited to receive a resting-state fMRI scanning. The static amplitude of low-frequency fluctuations (sALFF) and fuzzy entropy of dynamic ALFF (FE-dALFF) were applied to identify the stroke-induced alterations. Main results. Compared with the HCs, PS patients showed significantly increased FE-dALFF values in the right angular gyrus (ANG), bilateral precuneus (PCUN), and right inferior parietal lobule (IPL) as well as significantly decreased FE-dALFF values in the right postcentral gyrus (PoCG), right dorsolateral superior frontal gyrus (SFGdor), and right precentral gyrus (PreCG). The ROC analyses demonstrated that FE-dALFF and sALFF possess comparable sensitivity in distinguishing PS patients from the HCs. Moreover, a significantly positive correlation was observed between the FE-dALFF values and the Fugl-Meyer Assessment (FMA) scores in the right SFGdor (r =0.547), right IPL (r =0.522), and right PCUN (r =0.486). Significance. This study provided insight into the stroke-induced alterations in static and dynamic characteristics of local brain activity, highlighting the potential of FE-dALFF in understanding neurophysiological mechanisms and evaluating pathological changes.
BackgroundDysphagia is one of the major post‐stroke complications, understanding post‐stroke changes in cortical excitability and promoting early remodeling of swallowing‐related cortical areas to enable accurate treatment is essential for recovery of patients.ObjectivesWe aimed to investigate hemodynamic signal changes and functional connectivity in acute stroke patients with dysphagia compared to age‐matched healthy participants in response to volitional swallowing using functional near‐infrared spectroscopy (fNIRS) in this pilot study.MethodsPatients with first‐ever post‐stroke dysphagia having an onset of 1–4 weeks and age‐matched right‐handed healthy subjects were recruited in our study. fNIRS with 47 channels was utilized to detect the oxyhemoglobin (HbO2) and reduced hemoglobin (HbR) concentration changes when volitional swallowing. Cohort analysis was performed by a one‐sample t‐test. Two‐sample t‐test was utilized to compare the difference in cortical activation between patients with post‐stroke dysphagia and healthy subjects. Furthermore, the relative changes in the concentration of the HbO2 throughout the experimental procedure were extracted for the functional connectivity analysis. The Pearson correlation coefficients of the HbO2 concentration of each channel were analyzed on a time series, and then a Fisher Z transformation was then performed, and the transformed values were defined as the functional connection strengths between the channels.ResultsIn this present study, a total of nine patients with acute post‐stroke dysphagia were enrolled in the patient group and nine age‐matched healthy participants in the healthy control group. Our study observed that the extensive regions of the cerebral cortex were activated in the healthy control group, while the activation area of patient group's cortical regions was quite limited. The mean functional connectivity strength of participants was 0.485 ± 0.105 in the healthy control group, and 0.252 ± 0.146 in the patient group, with a significant difference between the two groups (p = 0.001).ConclusionCompared to the healthy individuals, cerebral cortex regions of acute stroke patients were only marginally activated during volitional swallowing task, and the average functional connectivity strength of cortical network in patients was relatively weaker.
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