Quantitative Analysis of Bradykinesia and Rigidity in Parkinson’s Disease

Abstract

BackgroundIn the last decades, several studies showed that wearable sensors, used for assessing Parkinson’s disease (PD) motor symptoms and recording their fluctuations, could provide a quantitative and reliable tool for patient’s motor performance monitoring.ObjectiveThe aim of this study is to make a step forward the capability of quantitatively describing PD motor symptoms. The specific aims are: identify the most sensible place where to locate sensors to monitor PD bradykinesia and rigidity, and identify objective indexes able to discriminate PD OFF/ON motor status, and PD patients from healthy subjects (HSs).MethodsFourteen PD patients (H&Y stage 1–2.5), and 13 age-matched HSs, were enrolled. Five magneto-inertial wearable sensors, placed on index finger, thumb, metacarpus, wrist, and arm, were used as motion tracking systems. Sensors were placed on the most affected arm of PD patients, and on dominant hand of HS. Three UPDRS part III tasks were evaluated: rigidity (task 22), finger tapping (task 23), and prono-supination movements of the hands (task 25). A movement disorders expert rated the three tasks according to the UPDRS part III scoring system. In order to describe each task, different kinematic indexes from sensors were extracted and analyzed.ResultsFour kinematic indexes were extracted: fatigability; total time; total power; smoothness. The last three well-described PD OFF/ON motor status, during finger-tapping task, with an index finger sensor. During prono-supination task, wrist sensor was able to differentiate PD OFF/ON motor condition. Smoothness index, used as a rigidity descriptor, provided a good discrimination of the PD OFF/ON motor status. Total power index, showed the best accuracy for PD vs healthy discrimination, with any sensor location among index finger, thumb, metacarpus, and wrist.ConclusionThe present study shows that, in order to better describe the kinematic features of Parkinsonian movements, wearable sensors should be placed on a distal location on upper limb, on index finger or wrist. The proposed indexes demonstrated a good correlation with clinical scores, thus providing a quantitative tool for research purposes in future studies in this field.

Role of data measurement characteristics in the accurate detection of Parkinson’s disease symptoms using wearable sensors

“…These fluctuations are captured by both gyroscope and accelerometer sensors and seem to be detected similarly when using either sensor type alone. Bradykinesia is defined as slowness to voluntarily initiate movement, with decreasing speed and amplitude over time [23,24]. In addition, bradykinesia-focused items in the MDS-UPDRS generally have more subjective descriptions of different scores than tremor-focused items.…”

“…Previous studies have demonstrated that relative utility of data is highly dependent on body location and the intended application [22,34]. For instance, sensors collecting data from a distal limb location are most effective for identifying symptoms in that limb [24], whereas more proximal sensor locations may be helpful for monitoring gait and posture [35]. This study focused on motor symptoms of the upper limb using a flexible sensor on the hand, but other sensor placements may be relevant for monitoring global presentations of symptoms.…”

Quantitative Measurement of Rigidity in Parkinson’s Disease: A Systematic Review

“…The objective and standardized clinical evaluation of the motor signs of PD, especially for rigidity, is based on a semi-quantitative scoring system through clinical scales such as the Unified Parkinson's disease Rating Scale (UPDRS) [5]. However, even a neurologist with expertise in movement disorders can commit an error of up to 20% in the accuracy of the diagnosis [6]. In recent decades, objective methods have been developed to quantify muscle tone.…”

“…Technologies such as portable sensors, which include inertial measuring units (IMUs) with accelerometers, gyroscopes, and magnetometers or potentiometers, offer systems that are non-invasive, trustworthy, quick, remote, economical, and objective [6]. Although they are not especially up-to-date (they were first used in this population in the 1990s) [6], their use has been recently included and extended in research and clinical environments for the evaluation of subjects with PD [10].…”

iHandU: A Novel Quantitative Wrist Rigidity Evaluation Device for Deep Brain Stimulation Surgery

“…Similarly, Angeles et al used inertial motion, muscle activity and force sensors to measure both elbow and wrist rigidity to assess the impact of DBS therapy on the rigidity symptom [17]. Di Biase et al, on the other hand, measured elbow and wrist rigidity and their changes during DBS procedure, using magnetic-inertial wearable sensors [18]. More recently, Perera et al developed a new system to measure the rigidity of the metacarpophalangeal joint, consisting of a miniature motor to flex the third digit of the hand.…”