Exploring the relationship between the speed-resolved perfusion of blood flux and HRV following different thermal stimulations using MSE and MFE analyses

Figures

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  Fig 1. Experimental design and case subject raw data. (a) Experimental design. (b) Thermal stimulation and recording point locations. The thermal stimulation point was located on the anterior aspect of the forearm, between the tendons of the palmaris longus and the flexor carpi radials, 5 B-cun proximal to the palmar wrist crease. Control point 1 was located 2 B-cun proximal to the palmar wrist crease, and control point 2 was located 8 B-cun proximal to the palmar wrist crease[30]. (c) Temperature (left), speed-resolved perfusion signal (middle) and blood perfusion signals at the control points (right). V1, low speed, <1 mm/s; V2, mid-speed, 1–10 mm/s; V3, high speed, >10 mm/s.

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  Fig 2. Speed-resolved perfusion at the stimulation point. (a) Low-speed component (V1, <1 mm/s), (b) Mid-speed component (V2, 1–10 mm/s). (c) High-speed component (V3, >10 mm/s). (d) Design of the comparison of speed-resolved perfusion at each time point. (e) Results of the comparison of the speed-resolved perfusion at each time point. Repeated measures ANOVA was calculated to analyze the between-subject factor, (V1: F(4,145) = 34.05, P<0.0001; V2: F(4,145) = 23.66, P<0.0001; V3: F(4,145) = 16.638, P<0.0001), and permutation tests (two-sided, 1000 permutations) were used as posttests. Yellow indicates P<0.01, and blue indicates P>0.01. BC, blank control; Data are presented as the mean±SE.

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  Fig 3. Blood perfusion at control points. (a) Control point 1. (b) Control point 2. (c) Design of the comparison of blood perfusion at each time point. (d) Results of the comparison of blood perfusion at each time point. Repeated measures ANOVA was calculated to analyze the between-subject factor, (P1: F(4,145) = 0.796, P = 0.529; P2: F(4,145) = 3.028, P = 0.02), and permutation tests (two-sided, 1000 permutations) were used as posttests. Yellow indicates P<0.01 and blue indicates P>0.01, permutation test (two-sided, 1000 permutations). P1, control point 1; P2, control point 2; BC, blank control; Data are presented as the mean±SE.

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  Fig 4. The complexity of speed-resolved perfusion at the stimulation point. (a) MSE result of the low-speed component (V1, <1 mm/s). (b) MSE result of the mid-speed component (V2, 1–10 mm/s). (c) MSE result of the high-speed component (V3, >10 mm/s). (d) MSE result of all speed components (V1+V2+V3). (e) MFE result of the low-speed component (V1, <1 mm/s). (f) MFE result of the mid-speed component (V2, 1–10 mm/s). (g) MFE result of the high-speed component (V3, >10 mm/s). (h) MFE result of all speed components (V1+V2+V3). (i) The complexity area index was obtained from the data of Fig 4A and Fig 4E. (j) Complexity area index obtained from the data of Fig 4B and Fig 4F. (k) Complexity area index obtained from the data of Fig 4C and Fig 4G. (m) Complexity area index obtained from the data of Fig 4D and Fig 4H. *, P<0.05; **, P<0.01, compared with BC, permutation test (two-sided, 1000 permutations). MSE, multiscale entropy; MFE; multiscale fuzzy entropy. BC, blank control; Data are presented as the mean±SE.

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  Fig 5. Complexity of blood perfusion at the control points. (a) MSE result of control point 1. (b) MSE result of control point 2. (c) MFE result of control point 1. (d) MFE result of control point 2. (e) Complexity area index obtained from the data of Fig 5A and Fig 5C. (f) Complexity area index obtained from the data of Fig 5B and Fig 4D. No significant difference was observed for the permutation test (two-sided, 1000 permutations). MSE, multiscale entropy; MFE; multiscale fuzzy entropy. BC, blank control; Data are presented as the mean±SE.

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  Fig 6. Relationship of the complexity between the composite blood perfusion (V1+V2+V3) and HRV. (a) MSE result of the blank control. (b) MFE result of the blank control. (c) MSE result of 38°C stimulation. (d) MFE result of 38°C stimulation. (e) MSE result of 40°C stimulation. (f) MFE result of 40°C stimulation. (g) MSE result of 42°C stimulation. (h) MFE result of 42°C stimulation. (i) MSE result of 44°C stimulation. (j) MFE result of 44°C stimulation. SCC, Spearman’s correlation coefficient; HRV, heart rate variability.