NEW METHOD: To overcome these limitations, we propose a new statistical model that smooths out the noise by exploiting the geometric structure of correlation matrices. The dynamic correlation matrix is modeled as a linear combination of symmetric positive-definite matrices combined with cosine series representation. The resulting smoothed dynamic correlation matrices are clustered into disjoint brain connectivity states using the k-means clustering algorithm.
RESULTS: The proposed model preserves the geometric structure of underlying physiological dynamic correlation, eliminates unwanted noise in connectivity and obtains more accurate state spaces. The difference in the estimated dynamic connectivity states between males and females is identified.
COMPARISON WITH EXISTING METHODS: We demonstrate that the proposed statistical model has less rapid state changes caused by noise and improves the accuracy in identifying and discriminating different states.
CONCLUSIONS: We propose a new regression model on dynamically changing correlation matrices that provides better performance over existing windowed correlation and is more reliable for the modeling of dynamic connectivity.
OBJECTIVES: This study aims to examine the effect of 20-minute mindful breathing on the rapid reduction of dyspnea at rest in patients with lung cancer, chronic obstructive pulmonary disease, and asthma.
METHODS: We conducted a parallel-group, nonblinded, randomized controlled trial of standard care plus 20-minute mindful breathing vs. standard care alone for patients with moderate to severe dyspnea due to lung disease, named previously, at the respiratory unit of University Malaya Medical Centre in Malaysia, from August 1, 2017, to March 31, 2018.
RESULTS: Sixty-three participants were randomly assigned to standard care plus a 20-minute mindful breathing session (n = 32) or standard care alone (n = 31), with no difference in their demographic and clinical characteristics. There was statistically significant reduction in dyspnea in the mindful breathing group compared with the control group at minute 5 (U = 233.5, n1 = 32, n2 = 31, mean rank1 = 23.28, mean rank2 = 37.72, z = -3.574, P