Development of Physiological Signal Feedback Control Tilt Table System for Physiotherapy and Quantification of Orthostatic Syncope in Patient with Spinal Cord Injury

• Main Authors: David-S Liu, 劉士偉
• Other Authors: Walter H. Chang
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/86522218061271320130

博士 === 中原大學 === 醫學工程研究所 === 97 === Tilt-table training is commonly used in clinical physiotherapy to overcome orthostatic syncope in patient with spinal cord injury (SCI), but this also relies on careful manual control of the tilt angle and training time by the experience of therapist. To estimate the symptoms of orthostatic syncope to avoid the physiological damage by excessive hypotension is an important issue in rehabilitation of the patient with SCI. For these reasons, we attempted to investigate the relationship between the levels of orthostatic presyncope symptoms (PS) and the physiological signals, and to develop a physiological signal feedback control tilt table system to increase the safety and efficiency during tilt-table training. The feedback tilt-table was designed with automatic training maneuvers and three closed feedback loops that included controlling the tilting maneuvers, monitoring the acquisition of physiological signals from patients, and monitoring the feedback of presyncope symptoms to regulate the angle of tilt. The results showed that the levels of PS, tilt angle and ASIA grade (level of injury) could affect the physiological signals during head-up tilting in quadriplegic SCI patients, and the mean blood pressure (MBP), Oxygen satureation (SpO2) and ratio of hent rate variability (LF/HF) ratio are the suitable signals to determine the threshold of physiological feedback for the physiological feedback control tilt table system. Although the appears to be the most sensitive factor in the determination of PS, it is necessary to consider the complex effects of tilt angle and severity of the SCI, and it could only provide the transient information of PS. For reason, we developed a mathematical formula for the calculation of the recovery index which was proven workable and capable of estimating the orthostatic syncope status of SCI patients during tilt-table training. The results showed that the recovery index accurately estimated the process of recovery from orthostatic syncope of SCI patients and might provide the information required to forecast the training course that could be required for complete recovery from orthostatic hypotension. The parameters of SpO2 and recovery index should provide safe and efficient normative data for the physiotherapist, and help in the design of the training courses in the feedback-controlled tilt-table system.