Assessing bradykinesia in Parkinson's disease using gyroscope signals

Parkinson's disease (PD) is a neurodegenerative brain disorder that slowly brings on the dopaminergic neurons death. The depletion of the dopaminergic signal causes the onset of motor symptoms such as tremor, bradykinesia and rigidity. Usually, neurologists regularly monitor motor symptoms and motor fluctuations using the MDS-UPDRS part III clinical scale. Nevertheless, to have a more objective and quantitative evaluation, it is possible to assess the cardinal motor symptoms of PD using wearable sensors and portable robotic devices. Unfortunately while there are several research papers on the use of these devices on PD patients, their use is not so common in clinical practice. In this work we recorded specific MDS-UPDRS motor tasks using magneto-inertial devices, worn by seven PD subjects and seven age-matched controls, in order to deeply analyze the kinematic and dynamic characteristics of goal-directed movements of upper limb, in addition to extract quantitative indices (peak velocity, smoothness, etc) useful for the assessment of motor symptoms. Using only gyroscope signals we looked at those parameters useful to assess bradykinesia. We observed parameters changes from OFF to ON phase congruent with the MDS-UPDRS changes, especially in the frequency domain. Our results suggest the prono-supination task is the more consistent to describe the bradykinesia symptom with the gyroscopes. Probably because of the amplitude of the movement performed. Moreover the peak power looks appropriate for bradykinesia symptom evaluation. We can conclude that, similar to the studies in which tremor symptom is evaluated, it is possible to monitor the bradykinesia using few wearable sensors and few simple parameters.