Table 1.

Examples of studies using objective quantification of PD motor symptoms.

Study	Measurement system	Placement on body	Parameters
Bradykinesia
Dunnewold et al. 5	Accelerometer	Wrist	Mean acceleration Tap rate Time of movement interval
Tavares et al. 36	Quantitative digitography using a computerized-interfaced keyboard	Not applicable	Time of movement interval Velocity Frequency
Koop et al. 20	Gyroscope	Hand	Root mean square angular velocity
Keijsers et al. 19	Accelerometer	Several body parts	Mean velocity
Salarian et al 32	Gyroscope	Forearm	Root mean square angular velocity Amplitude Total range of motion
Tabbal et al. 35	Gyroscope	Forearm	Root mean square angular velocity
Jun et al. 18	Gyroscope	Hand	Root mean square angle and angular velocity Peak power and total power of angular velocity
Endo et al. 8	Magnetic sensor consisting of two coils	Thumb and tip of index finger	Maximum velocity Amplitude of position data Time of movement interval
Pulliam et al. 31	Accelerometer and gyroscope	Index finger	Amplitude Velocity Rhythm
Mentzel et al. 23	Accelerometer and gyroscope Magnetometers	Forearm Upper arm Waist	Time of movement interval Amplitude Velocity
Djuric-Jovicic et al. 3	Gyroscopes	Thumb and tip of index finger	Time of movement interval Angular velocity Total angular range of motion (aperture)
Tremor
Keijsers et al. 19	Accelerometer	Several body parts	Percentage peak frequencies above 4 Hz
Salarian et al. 32	Gyroscope	Forearm	Root mean square angular velocity Amplitude Total range of motion
Giuffrida et al. 12	Accelerometer and gyroscope	Middle finger	Peak power acceleration and angular velocity Frequency of the peak power Root mean square of angular velocity and of angle
Gallego et al. 11	Gyroscope	Forearm Hand	Amplitude angular velocity Frequency
Mostile et al. 24	Accelerometer and gyroscope	Middle finger	Root mean square amplitude Peak power angular velocity and acceleration
Heldman et al. 16	Accelerometer and gyroscope	Index finger	Peak power of angular velocity
Scanlon et al. 33	Accelerometer	Upper and lower limbs	Root mean square of acceleration
Daneault et al. 1	Accelerometer (in smart phone)	Unknown	Maximum amplitude acceleration Peak power, median power and power distribution of acceleration
Pulliam et al. 31	Accelerometer and gyroscope	Index finger	Amplitude
Rigidity
Prochazka et al. 30	Hand-held force sensing device (air-filled pads) combined with a compliant displacement gauge	Wrist	Impedance Viscous damping constant Elastic stiffness
Fung et al. 10	Torque motor Electromyography	Forearm Hand	Impulse Work
Patrick et al. 27	Pads connected to a force transducer Gyroscope	Elbow Wrist	Elastic stiffness Viscous damping constant Impedance
Sepheri et al. 34	Test rig with strain gage force transducer and potentiometer	Elbow	Range of motion Viscous damping constant Elastic stiffness
Tabbal et al. 35	Pads connected to a force transducer Gyroscope	Elbow Wrist	Impedance
Park et al. 26	Torque motor Potentiometer Load cell Accelerometer	Wrist	Torque Viscous damping constant Elastic stiffness Work Impulse
Endo et al. 7,8	Force sensor Gyroscope Electromyography	Wrist	Torque Elastic coefficient
Powell et al. 29	Torque motor Electromyography	Wrist	Work Impulse Reflex responses
Kwon et al. 22	Load cell Potentiometer Accelerometer	Wrist	Viscous damping constant Elastic stiffness Impulse Impedance