Comparison of quantitative analysis of hand movements with gyroscope between early stage Parkinson's disease and scans without evidence of dopaminergic deficit (SWEDD)

Abstract

Scans without evidence of dopaminergic deficit (SWEDD) is a radiological nomenclature, which refers to patients with a normal dopamine transporter scan presumed to have parkinsonism. It is important to differentiate SWEDD from Parkinson's disease (PD) in the early stage of disease because they have similar clinical features. As bradykinesia is a cardinal clinical feature of parkinsonism, we quantitatively investigated detailed presentations of hand movement by using an angular measurement system in SWEDD and PD patients, and normal controls. Twenty-three patients with SWEDD, 23 patients with drug-naïve early stage PD, and 23 age-matched healthy controls participated in this study. Angular velocity was measured during finger-tapping and forearm-rotation movement for assessment of bradykinesia. RMS (root mean square) velocity and amplitude, and movement irregularity were derived from the gyro sensor signal. SWEDD patients presented a greater average speed, a larger average amplitude, and more irregular speed and amplitude only during forearm rotation compared to PD patients (p < .05). SWEDD patients also exhibited a smaller average speed and average amplitude, and a more irregular velocity usually during finger tapping compared to controls (p < .05). Quantitative variables of forearm rotation movement showed significant differences between SWEDD and PD patients, and quantitative variables of finger tapping movement showed a significant difference between SWEDD patients and the control group. These results suggest that quantitatively determined/assessed variables using biomedical engineering devices can distinguish SWEDD patients from PD patients as well as from normal subjects.