Effects of Object Size on Unimanual and Bimanual Movements in Patients With Schizophrenia

Abstract

Schizophrenia affects not only mental function but also movement. We compared the movement of patients with mild schizophrenia and healthy control participants during a bimanual assembly task and examined whether changes in object size affected unimanual and bimanual movements. Fifteen patients with schizophrenia and 15 age- and gender-matched control participants were instructed to bimanually reach for and assemble objects. We manipulated the object size for the left hand (large vs. small) and measured movement time, peak velocity, and bimanual synchronization to represent movement speed, forcefulness, and bimanual coordination. Patients with schizophrenia showed slower and less forceful unimanual movements and less coordinated bimanual movements than control participants. Increasing the object size elicited faster and more forceful unimanual movements and more coordinated bimanual movements in patients. The results suggest the need for movement rehabilitation in patients with schizophrenia and the possibility of manipulating object size to optimize patients' movements. These results benefit the practice of evidence-based therapy.

Temporal differences in eye–hand coordination between children and adults during manual action on objects

“…Taken together, better eye–hand coordination could be characterised by not only shorter performance time but also relatively longer eye–hand arrival span, which could be facilitated by longer eye–hand departure span. This interval property of better eye–hand coordination is inconsistent with that of better bimanual coordination, defined as shorter intervals between hands (Wang et al., 2014; Wu et al., 2009). This discrepancy could be attributed to the fact that the serial relationship between the eye and the hand is different from parallel association between the two hands.…”

Effects of object size and distance on reaching kinematics in patients with schizophrenia

“…Movement onset was defined as the time point when wrist velocity reached 5% of its peak value (Lin, Chen, Chen, Wu, & Chang, 2010; Wu, Chuang, Lin, Chen, & Tsay, 2011). Movement end was defined as the time point when thumb velocity reached 0 mm/s (Wang et al., 2014). Kinematic variables included movement time , peak velocity , path length ratio , percentage of time to peak velocity , and number of movement units , which separately represent movement speed, forcefulness at movement initiation, spatial efficiency, control strategies, and smoothness.…”

An Instrumental Measure of Hand and Facial Movement Abnormalities in Patients With Schizophrenia

“…Two reflective markers were placed on the ulnar styloid process (representing the wrist) and the thumbnail of the right hand and additional two markers on the object (Figure 2). This right-hand task was adapted based on the tasks in previous studies that detected movement abnormalities in schizophrenia patients (25)(26)(27).…”

“…By recording movement trajectories of markers/sensors attached to the patient's body parts, motion capture systems make it possible to calculate kinematic variables that objectively and directly reflect movement speed and quality for each body part in the patient. Existing studies have applied motion capture systems to measuring hand movements in patients with schizophrenia (25)(26)(27). Nevertheless, to date, little has been known about whether motion capture systems reliably measured hand and facial bradykinesia and dyskinesia in schizophrenia patients.…”