Harmonic Distortion Aspects in Upper Limb Swings during Gait in Parkinson’s Disease

Parkinson disease (PD) seriously affects suffering people with a broad spectrum of signs and symptoms, among which relevant motor issues are assessed by rating scales by clinical experts and, in recent times, more and more evidenced by objective data gathered by technology- based systems. In particular, wearable devices have been adopted to measure gait capabilities to evidence features that underline differences with respect to gait capabilities of heathy people. However, despite the key role that upper limb swings play during walking, no works have been focused on the harmonic content of the swing, so that this work is devoted to that aspect. To this aim, walking tasks were conducted to groups of PD patients (in particular de-novo patients and subjects under chronic dopaminergic treatment when OFF state of therapy) and healthy subjects and recorded by means of IMU sensors. The collected data have been analysed with FFT to study the frequency content of arm swing. According to the obtained results, PD patients present arms swings less rich in harmonics with respect to their healthy counterparts, underlying higher limb rigidity.