Fine Motor Performance in Schizophrenia

Abstract

Peripheral and central aspects of motor dysfunction were assessed in 12 schizophrenic and 12 normal subjects, using a test of control of finger movement based on the widely used smooth pursuit eye movement task. This was performed in order to investigate the basis of neuromotor dysfunction in schizophrenia. In this task, subjects used finger movement to track a visual target. Simultaneously, an electromyogram of the extensor digitorum commu-nis, the primary muscle utilized in the task, was recorded. Smooth pursuit eye movements were also assessed. Accuracy of finger-based and smooth-pursuit eye movement tracking was analyzed by fast Fourier transform and expressed as a log signal-to-noise ratio. The electromyograms were analyzed by motor unit potential discrimination and by interspike interval histography. Schizophrenics demonstrated significantly poorer finger tracking than did controls, with a mean score of 2.01 ± 0.63 (SD) versus 2.81 ± 0.42 (t = 3.52, d.f. = 21, p < 0.005). However, there was no evidence for motor-unit dysfunction. Schizophrenics also performed more poorly on smooth-pursuit eye movement, with a mean score of 2.06 ± 0.62 versus 3.33 ± 1.21 (t= 3.21, d.f. = 22, p < 0.005). Severity of extrapyramidal symptoms was correlated with poorer performance on the finger tracking task, but not smooth-pursuit eye movement. These findings support the hypothesis that schizophrenics’ tracking abnormalities are due to central nervous system deficits rather than peripheral pathology.

Personality Differences in Schizophrenia Are Related to Performance on Neuropsychological Tasks

“…C ognitive deficits in schizophrenia include impaired attention (Franke et al, 1994;Nuechterlein and Asarnow, 1989) and executive functions (Rund and Borg, 1999), particularly cognitive flexibility and forward planning (Morice and Delahunty, 1996); and motor abnormalities (Wolff and O'Driscoll, 1999), including fine motor skills (Griffith et al, 1994;Vrtunski et al, 1989). Cognitive abnormalities may be present long before illness onset in individuals who develop schizophrenia (Cuesta et al, 2001).…”

Effects of different types of sensory signals on reaching performance in persons with chronic schizophrenia

“…Previous studies have reported that persons with schizophrenia show slower motor performance in the pegboard tasks [10,11], poorer performance in the finger tracking task [12], and impaired motor dexterity on a finger movement test [11] compared to normal controls. All those tasks measure the speed and accuracy of the hand movement performance.…”