At-risk individuals in the experimental group will undergo upper-limb movement training with the aid of music beat serving as a type of rhythmic auditory stimulation (RAS).

At-risk individuals in the control group will receive upper-limb training without the aid of RAS.

Schizophrenia patients in the experimental group will undergo upper-limb movement training with the aid of RAS.

Schizophrenia patients in the control group will receive upper-limb training without the aid of RAS.

The song named 'Sign of The Times' is played and recorded by the research personnel beforehand. The beat of the song will serve as RAS. The computer software "Audacity" will be used to adjust tempi of RAS. Before intervention, the participant is required to execute the movement task without the aid of RAS as quickly as possible for 30 seconds, so that we obtain his/her baseline movement tempo. For each 40-minute training session in the first training week, three RAS tempi will be provided for the first, second, and last 10 minutes with a five-minute break in between: normal (100% of the baseline tempo), quick (105% of the baseline tempo), and fast (110% of the baseline tempo). With each training week, the three RAS tempi will be increased by 5%. Participants in the experimental groups are required to use their right hand to pick up beads from source bowls to the target bowl when listening to the song. The 3-week intervention program will include 21 40-minute daily training sessions.

normalized movement time (representing severity of bradykinesia). Unit: second/mm

normalized movement time (representing severity of bradykinesia). Unit: second/mm

normalized number of movement units (representing severity of dyskinesia). Unit: units/mm

normalized number of movement units (representing severity of dyskinesia). Unit: units/mm