fig4

Figure 4. Arterial pulse wave monitoring using the IBTS. (A) Pulse wave monitoring at the neck of a 25-year-old male volunteer using the sensor; (B) pulse wave monitoring at the superficial temporal artery (ear region); (C) pulse wave monitoring at the radial artery of the wrist; (D) pulse wave monitored at the fingertip (Scale bar: 2 cm); (E) PWV measurement based on carotid-radial pulse transit time; (F) The AIx estimation based on the radial artery waveform; (G) HR and K-value derived from pulse wave signals at the neck, ear, wrist, and fingertip; (H) PTT obtained from the radial artery pulse waveform. IBTS: Island-bridge microstructured triboelectric sensor; PWV: pulse wave velocity; AIx: augmentation index; HR: heart rate; PTT: pulse transit time.