Vascular response to the microcirculation in the fingertip by local vibration with varied amplitude.

Objectives: We investigated the effect of local vibration intensity on the vascular response to the microcirculation of the finger. Materials and methods: We performed hand-transmitted vibration experiments combined with laser Doppler flowmetry (LDF) to measure the blood perfusion signals of fingertips in the vibrated hand and the contralateral middle finger under the same frequency and different amplitude vibration, and to analyze the changes of microcirculatory blood perfusion levels in the fingers, and to investigate the effects of vibration stimulation on the endothelial, neural and myogenic regulatory frequency ranges of fingertips based on wavelet analysis. Furthermore, the transparent silicone films were fabricated and cultured with vascular endothelial cell (EC), which will undergo the local vibration with varied amplitude. And the expression of inflammatory factors was detected in the ECs. Results: Low-frequency vibration leads to a decreased blood flow in fingertip, and the degree of reduction in fingertip blood flow increases as the amplitude gradually increases, and the period required for blood flow to return to normal level after hand-transmitted vibration gradually increases. The decrease in blood flow is more pronounced in the vibrating hand than in the contralateral hand. In addition, nuclear factor-κB (NF-κB) expression increased significantly with the increase of vibration amplitude. Conclusion: High amplitude vibrations caused the inflammatory reaction of ECs which will lead to the altered endothelial regulatory activity. The endothelial regulatory activity is closely related to the blood perfusion in the microcirculation.

Design of Virtual Guiding Tasks With Haptic Feedback for Assessing the Wrist Motor Function of Patients With Upper Motor Neuron Lesions.

Impaired motor function is a common consequence of upper motor neuron lesions (UMNLs). Fine motor skills involved in small movements occurring in the fingers, hand, and wrist are usually regained by patient self-training at home. Most studies focus on the rehabilitation of the fingers but ignore the recovery of wrist motor function. In this paper, three virtual guiding tasks were designed to assess wrist motor functions, including the basic motor flexibility, motion stability, and a range of active motion. A haptic device was used to provide haptic feedback to users who performed virtual tasks in a virtual reality (VR) environment. In total, 46 healthy subjects and 10 UMNL patients were included to test the effectiveness of the designed tasks on improving wrist motor assessments. Quantitative performances, including the completion time, contact force, and motion trajectory, were automatically acquired during the tasks. Measurements for 95% of control subjects were used to establish normative references. Patient deficiencies in the wrist motor function were identified when their quantitative performances were outside the normative control ranges. The results suggest that the designed virtual tasks are sensitive for patients in the later period of rehabilitation, making the assessment suitable for using at home.