Introduction
Tremor, Rigidity, movement disorders, tremor, Parkinson's disease, tremors, rigidity, PD, Gait impairment, bradykinesia, gait disorder
MOVEMENT DISORDERS, DISEASE, PARKINSON'S DISEASE, ESSENTIAL TREMOR, DISEASES
Essential tremor (ET) and Parkinson's disease (PD) are two common movement disorders in older populations [Early-stage PD and ET can be distinguished by the following clinical symptoms: (1) Tremor features: rest tremor is usually an early sign in PD, while action tremor is usually an early sign of ET, and rest tremor may be present years after disease onset in ET. Re-emergent tremor can be present in PD but absent in ET. (2) Bradykinesia: bradykinesia is the prerequisite for PD diagnosis, and bradykinesia in patients with PD often manifests as poor hand flexibility in the early stages. However, ET is not usually associated with bradykinesia. (3) Rigidity: PD is associated with rigidity, whereas ET usually is not. (4) Gait: early-stage PD may manifest as reduced stride length, slow speed, poor symmetry, and reduced amplitude of arm swing on the affected side. However, gait disorder is usually not present in ET [However, despite the differences in the above symptoms between PD and ET, it is still challenging to distinguish early-stage PD from ET. First, rest tremor, postural tremor, or action tremor can be present in both ET and PD patients at the early stage. Second, some PD patients are only with tremor and other motor symptoms are very mild or not obvious, which are difficult to be detected by subjective observation and physical examination. Therefore, in recent years, some researchers have begun to use devices to quantitatively identify the above-mentioned motor symptoms, such as bradykinesia, tremor, and gait, hoping to achieve early diagnosis of PD.In previous studies, researchers have mainly focused on the characteristics of the patient’s tremors to differentiate the diseases [Gait impairment and bradykinesia have been reported in early-stage PD [Segmentation of the TUG test into phases provides additional parameters [