Abstract
Objective: To examine whether subacute stroke patients would exhibit abnormal dynamic characteristics of brain activity relative to healthy controls (HC) and to investigate whether the altered dynamic regional indexes were associated with clinical behavior in stroke patients.Methods: The dynamic amplitude of low-frequency fluctuations (dALFF) and dynamic regional homogeneity (dReHo) in 42 subacute stroke patients and 55 healthy controls were compared. Correlation analyses between dALFF and dReHo in regions showing significant intergroup differences and clinical scores (i.e., the National Institutes of Health Stroke Scale, Fugl-Meyer assessment and lesion volume size) were conducted in stroke patients. Receiver operating characteristic (ROC) curve analysis was used to determine the potential value of altered dynamic regional indexes to identify stroke patients.Results: Significantly dALFF in the bilateral cerebellum posterior lobe (CPL), ipsilesional superior parietal lobe, ipsilesional inferior temporal gyrus (ITG), the midline supplementary motor area (SMA), ipsilesional putamen and lentiform nucleus were detected in stroke patients compared to HC. Relative to the HC group, the stroke patients showed significant differences in dReHo in the contralesional rectal gyrus, contralesional ITG, contralesional pons, ipsilesional middle frontal gyrus (MFG). Significant correlations between dALFF variability in midline SMA and Fugl-Meyer assessment (FMA) scores or between dReHo variability in the ipsilesional MFG and FMA scores were detected in stroke patients. Furthermore, the ROC curve revealed that dynamic ALFF at SMA and ReHo at ipsilesional MFG might have the potential to distinguish stroke patients.Conclusion: The pattern of intrinsic brain activity variability is altered in stroke patients compared with HC, and dynamic ALFF/ReHo might be potential tools to assess stroke patients’ motor function.
Highlights
Stroke is the most common cause leading to varying degrees of neurological dysfunction with a very high likelihood of long-term disability (Liu et al, 2011; Yang et al, 2013)
The inclusion criteria for stroke patients were as follows: (1) they were aged 40–80 years; (2) it was a first-onset stroke with a single lesion in right-side subcortical regions as verified by diffusion-weighted imaging (DWI); (3) they were examined within 1–3 weeks after stroke symptom onset; (4) they were clinical evidence of a motor deficit based on neurological examination; and (5) they were right-handed before the stroke
The results demonstrated that the area under the curves (AUC) of supplementary motor area (SMA) and ipsilesional middle frontal gyrus (MFG) were 0.965 and 0.911, respectively (Figure 4), which suggested that dynamic amplitude of low-frequency fluctuations (ALFF) in SMA and regional homogeneity (ReHo) values in the ipsilesional MFG might have the potential to distinguish the stroke patients from healthy subjects
Summary
Stroke is the most common cause leading to varying degrees of neurological dysfunction with a very high likelihood of long-term disability (Liu et al, 2011; Yang et al, 2013). The ALFF is correlated with field potential activity in local brain regions (Logothetis et al, 2001), and the amplitude of oscillations can be applied as an index to examine alterations in neural function (Mohamed et al, 2004). Another approach is regional homogeneity (ReHo), which reflects the statistical similarity of local neural activity among spatially adjacent regions (Zang et al, 2004). These two approaches have been widely adopted for evaluating local neural function in neurologic disorders and neuropsychiatric diseases (Qiu et al, 2011; Li et al, 2012; Liu et al, 2012, 2013)
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