First of all, I used the x-IMU to measure balance and its data to create an objective number for balance assessment. This device includes an accelerometer, a magnetometer and a gyroscope and it has got a graphical user interface called GUI. I used the Euler angles (three-dimensional rotations around the three axes) to make a number, that represents balance well. People had to complete five tasks: standing on both feet, standing without breathing, standing with eyes closed, standing on one feet (left, then right). Every measurement takes 20 seconds. I process the data which was recorded by x-IMU with MATLAB.
I had 31 patients and 40 records of them. Based on these, I made conclusions and categories for people: very good, average and bad. I have results of 9 people after six months again, so I can prove that the number I created is stationary.
On the other hand, I dealt with defining stress using a photoplethysmography sensor. To determine HRV (heart rate variability) I used MATLAB software again. Depending on the results I can define stress only when I have a previous record of the patient (measured at rest) too, just like the ground for the analysis.
At the end, I examined the contact between balance and the HRV parameters. I noticed that it is good to measure them together to define the matter of instability. It can happen because of stress or the decadency of coordination.