ABSTRACT
Objective:To explore the characteristics of local brain neural activity in post stroke aphasia (PSA) patients in different frequency bands and the relationship between Western Aphasia Battery (WAB) scores and specific frequency bands. Methods:From March, 2015 to May, 2018, 15 PSA patients, and 15 healthy adults as controls matched for age, gender and education were recruited. They were assessed with WAB and scaned with resting-state functional magnetic resonance imaging. The amplitude of low-frequency fluctuation (ALFF) and fractional amplitude of low-frequency fluctuation (fALFF) on the frequency bands of 0.01-0.08 Hz, 0.027-0.073 Hz, and 0.01-0.027 Hz were calculated. The ALFF and fALFF in different frequency bands were extracted and the correlation with the WAB scores in the patients were analyzed. Results:On 0.01-0.08 Hz, ALFF increased in the right precentral gyrus in the patients. On 0.027-0.073 Hz, ALFF increased values in the right precentral gyrus, and fALFF decreased in the right cerebellar Crus2 region; fALFF in the right cerebellar Crus2 region negatively correlated with the scores of information content (r = -0.576, P = 0.025), auditory comprehension (r = -0.658, P = 0.008), repetition (r = -0.616, P = 0.014) and aphasia quotient (r = -0.611, P = 0.016) of WAB. On 0.01-0.027 Hz, the fALFF decreased in the left inferior parietal limbic gyrus, and positively correlated with the scores of information content (r = 0.538, P = 0.039) and aphasia quotient (r = 0.526, P = 0.044). Conclusion:Resting-state fALFF abnormalities in PSA patients are frequency-dependent, which associate with some frequency-specific neurofunctional alterations.
ABSTRACT
OBJECTIVE: To investigate brain regional homogeneity (ReHo) changes of multiple sub-frequency bands in cirrhotic patients with or without hepatic encephalopathy using resting-state functional MRI. MATERIALS AND METHODS: This study recruited 46 cirrhotic patients without clinical hepatic encephalopathy (noHE), 38 cirrhotic patients with clinical hepatic encephalopathy (HE), and 37 healthy volunteers. ReHo differences were analyzed in slow-5 (0.010−0.027 Hz), slow-4 (0.027−0.073 Hz), and slow-3 (0.073−0.198 Hz) bands. Routine analysis of (0.010−0.080 Hz) band was used as a benchmark. Associations of abnormal ReHo values in each frequency band with neuropsychological scores and blood ammonia level were analyzed. Pattern classification analyses were conducted to determine whether ReHo differences in each band could differentiate the three groups of subjects (patients with or without hepatic encephalopathy and healthy controls). RESULTS: Compared to routine analysis, more differences between HE and noHE were observed in slow-5 and slow-4 bands (p 12, overall corrected p < 0.05). Sub-frequency band analysis also showed that ReHo abnormalities were frequency-dependent (overall corrected p < 0.05). In addition, ReHo abnormalities in each sub-band were correlated with blood ammonia level and neuropsychological scores, especially in the left inferior parietal lobe (overall corrected p < 0.05 for all frequency bands). Pattern classification analysis demonstrated that ReHo differences in lower slow-5 and slow-4 bands (both p < 0.05) and higher slow-3 band could differentiate the three groups (p < 0.05). Compared to routine analysis, ReHo features in slow-4 band obtained better classification accuracy (89%). CONCLUSION: Cirrhotic patients showed frequency-dependent changes in ReHo. Sub-frequency band analysis is important for understanding HE and clinical monitoring.