Three target bowls, labeled as the left, middle, and right target bowl, will be placed on the table at an equal distance from the main bowl. The distance between a target bowl and the main bowl is set at 30 cm. Wooden beads with a diameter of 2 cm will be put in target bowls. The main bowl will be placed in front of the patient.

Patients will be asked to use the right hand to take one bead at a time from the left target bowl to the main bowl, repeat this movement for the middle and right target bowls, and keep repeating this order. They are asked to execute the task as fast as possible.

Each daily training will consist of three rounds separated by two 5-minute breaks. Each round will consist of four consecutive sessions (for each session: 2-minute training followed by a 30-second break). The training will last for a total of 7 days.

The NHPT is a widely used measure of hand dexterity in a broad range of ages and populations.

The Jebsen Hand Function Test (JHFT) evaluated unimanual performance in activities of daily living through six standardized tasks: card turning, small object manipulation, simulated feeding, checker stacking, and moving both light and heavy objects. We modified the original seven-item test by excluding the writing task to accommodate Chinese-speaking participants, following established protocols for cross-cultural adaptation. Performance was measured by completion time for each task, with shorter times indicating better hand function. The JHFT demonstrates excellent test-retest reliability in PD patients (intraclass correlation coefficients: 0.89-0.97).

We assessed reaction time using the Ruler Drop Test (RDT). During this test, a ruler was positioned vertically between the participant's thumb and index finger, with its zero mark aligned at the fingertips. Following a ready signal from the participant, the examiner released the ruler without warning, requiring the participant to catch it as quickly as possible upon visual detection of movement. The falling distance was recorded, with greater distances indicating longer reaction times. The test was repeated three times, and the average distance was calculated. This measure reflects neuromotor processing speed, encompassing both visual information processing and movement initiation time.

We assessed reaction time using the Ruler Drop Test (RDT). During this test, a ruler was positioned vertically between the participant's thumb and index finger, with its zero mark aligned at the fingertips. Following a ready signal from the participant, the examiner released the ruler without warning, requiring the participant to catch it as quickly as possible upon visual detection of movement. The falling distance was recorded, with greater distances indicating longer reaction times. The test was repeated three times, and the average distance was calculated. This measure reflects neuromotor processing speed, encompassing both visual information processing and movement initiation time.