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RESPONSE AND CONTROL OF HEART RATE VIA POSTURE
AND MOVEMENT
Martin Wieser
1,2
, Rafael M Ruest
1,3
, Lilith Bütler
1,4
and Robert Riener
1,2
1
Sensory-Motor Systems Lab, Institute of Robotics and Intelligent Systems (IRIS)
ETH Zurich, Tannenstrasse 1, 8092 Zurich, Switzerland
2
Spinal Cord Injury Center, University Hospital Balgrist, Switzerland
3
Institute of Human Movement Sciences and Sport, ETH Zurich, Switzerland
4
HUMAINE Clinic Zihlschlacht, Switzerland
Keywords: Cardiovascular system, Mobilization, Tilt table, Heart rate, Control, Rehabilitation.
Abstract: After a few days of immobilization, patients need some form of treatment to stabilize their cardiovascular
system. It is known that mobilization has a major influence on the cardiovascular system and, therefore, is
an important component in neurorehabilitation. In this study a strategy is presented to control the heart rate
using two mechanical stimuli: body inclination angle and stepping frequency. First, we could show that the
heart rate of healthy subjects, as well as minimally conscious patients, shows a clear and repeatable
response to body tilting and stepping. Furthermore, first experiments demonstrated the feasibility to control
the heart rate of healthy subjects. Future experiments are required to optimize the control strategy with
healthy subjects and to present the feasibility of the controller for use with patients. The long term goal will
be to control heart rate, systolic and diastolic blood pressure, as well as respiration frequency, in order to
stabilize the patients’ cardiovascular system and improve their health state with a reduced amount of
pharmaceutical medication.
1 INTRODUCTION
An important therapeutic strategy in an early phase
of neurorehabilitation is mobilization by stepping of
the legs, and body tilting. Leg mobilization itself has
a major influence on the cardiovascular system.
Cardiovascular adaptation to an upright posture
depends on the proper interplay of the hemodynamic
system and the reflex mechanism that maintain
blood pressure homeostasis (Held, 2004; Hainsworth
and Al-Shamma, 1988).
First applications with the dynamic tilt table
Erigo showed a positive effect on blood circulation
in healthy adults (Czell et al., 2004) as well as in
patients (Luther et al., 2008). The Erigo enables two
sensory stimulation inputs to be applied. Firstly, the
subject can be tilted to different inclination angles
and secondly, the legs can be mobilized by a
stepping pattern. During tilting the stepping
mechanism supports blood circulation, providing a
significant reduction in the number of syncopes
observed by Czell (2004) and Luther (2008). As a
consequence, it was possible to integrate body tilting
more intensively into patient therapy and, hence,
improve the rehabilitation process.
In this project we investigated the relationship
between the two inputs provided by the Erigo, and
the cardiovascular output of the human. Many
research groups have previously performed classical
tilt table experiments to show a steady state response
of heart rate (HR) as well as blood pressure and the
occurrence of syncopes (Hainsworth and Al-
Shamma, 1988; Mukai and Hayano, 1995; Petersen
et al., 2000). However, an open question remains as
to how well the cardiovascular system reacts to
simultaneous leg mobilization and body tilting.
Thus, in our study, continuous data were measured
in order to observe also the behavior during the
transient state in the tilting phase, in addition to a
steady state.
The results presented in this paper show the
reaction of the HR in healthy subjects and minimally
conscious patients. Based on these results we
performed a first feasibility study to control the HR
of healthy subjects.
Our results form the basis to control the
77
Wieser M., Ruest R., Bütler L. and Riener R. (2010).
RESPONSE AND CONTROL OF HEART RATE VIA POSTURE AND MOVEMENT.
In Proceedings of the Third International Conference on Health Informatics, pages 77-81
DOI: 10.5220/0002743400770081
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