Objective Assessment of Bradykinesia Estimated from the Wrist Extension in Older Adults and Patients with Parkinson's Disease.

Parkinson's disease (PD) presents several motor signs, including tremor and bradykinesia. However, these signs can also be found in other motor disorders and in neurologically healthy older adults. The incidence of bradykinesia in PD is relatively high in all stages of the disorder, even when compared to tremor. Thus, this research proposes an objective assessment of bradykinesia in patients with PD (G PD: 15 older adults with Parkinson's disease, 65.3 ± 9.1 years) and older adults (G HV: 12 healthy older adults, 60.1 ± 6.1 years). The severity of bradykinesia in the participants of G PD was assessed using the Unified Parkinson's Disease Rating Scale. Movement and muscular activity were detected by means of inertial (accelerometer, gyroscope, magnetometer) and electromyographic sensors while the participants performed wrist extension against gravity with the forearm on pronation. Mean and standard error of inertial and electromyographic signal parameters could discriminate PD patients from healthy older adults (p value <0.05). In discriminating patients with PD from healthy older adults, the mean sensitivity and specificity were respectively 86.67 and 83.33%. The discrimination between the groups, based on the objective evaluation of bradykinesia, may contribute to the accurate diagnosis of PD and to the monitoring of therapies to control parkinsonian bradykinesia, and opens the possibility for further comparative studies considering individuals suffering from other motor disorders.

Acoustic elastography under dynamic compression using one-dimensional track motion.

This work provides an detailed analysis of a method for ultrasound-based elasticity image formation using dynamic compression technique. Radiofrequency (RF) data acquired from a homogenous phantom, where both mechanical and acoustic proprieties were set equivalent to biologic tissues, were used to validate our results. Local strains were obtained by speckle tracking of the acoustic scatterers motion between a pair of RF echo fields acquired when the phantom was dynamically deformed at low frequency (approximately 1 Hz). In this work we investigated the dynamic compression technique as an alternate to the conventional quasi-static compression. In particular, we studied the improvement on strain estimation by varying the size of 1-D kernel during the tracking between the pre- and pos-deformed RF fields.