Motor Deficits in Schizophrenia Quantified by Nonlinear Analysis of Postural Sway

Abstract

Motor dysfunction is a consistently reported but understudied aspect of schizophrenia. Postural sway area was examined in individuals with schizophrenia under four conditions with different amounts of visual and proprioceptive feedback: eyes open or closed and feet together or shoulder width apart. The nonlinear complexity of postural sway was assessed by detrended fluctuation analysis (DFA). The schizophrenia group (n = 27) exhibited greater sway area compared to controls (n = 37). Participants with schizophrenia showed increased sway area following the removal of visual input, while this pattern was absent in controls. Examination of DFA revealed decreased complexity of postural sway and abnormal changes in complexity upon removal of visual input in individuals with schizophrenia. Additionally, less complex postural sway was associated with increased symptom severity in participants with schizophrenia. Given the critical involvement of the cerebellum and related circuits in postural stability and sensorimotor integration, these results are consistent with growing evidence of motor, cerebellar, and sensory integration dysfunction in the disorder, and with theoretical models that implicate cerebellar deficits and more general disconnection of function in schizophrenia.

Standing postural instability in patients with schizophrenia: Relationships with psychiatric symptoms, anxiety, and the use of neuroleptic medications

“…We speculate that the associations between postural sway and the psychiatric symptoms in patients with EPS might be masked by the influence of confounding factors, including chronic neuroleptic treatment and structural brain degeneration [28]. We also examined the effect of medication dose on postural sway, which has been a matter of controversy [9,14,15,25]. No such correlation was found in the current study.…”

“…This indicates that healthy individuals are more sensitive to proprioceptive information in the absence of visual information [24]. The overall deficits of postural control in schizophrenia suggest that increased postural sway may reflect motor dysfunction present in schizophrenia [25].…”

Kinematic parameters of throwing performance in patients with schizophrenia using a markerless motion capture system

“…Because the motor task assessment required a short range of motion and a slow throw, schizophrenia patients exhibited less effective postural adjustment with the hip strategy to compensate for the movements that occurred in the upper limbs (Yiou et al 2012). Abnormal postural adaptation in schizophrenia patients was also found by Kent et al (2012), who observed increased postural sway and less complex postural responses when the visual input was removed compared with participants from the control group. According to Girolami et al (2010), anticipatory activation of the trunk muscles along with changes in the center of pressure are present in children with typical development as young as 7 years of age, and are sustained in adulthood.…”

“…Motor abnormalities are frequent in schizophrenia and have been reported since early descriptions of the illness (Manschreck 1992;Kent et al 2012). These deficits have assumed particular clinical importance in schizophrenia and undoubtedly have an impact on long-term outcomes, affecting social, academic, emotional, and daily functioning (Manschreck 1992;Putzhammer and Klein 2006;Varlet et al 2012).…”

“…The results showed that schizophrenia patients have difficulty performing these tasks mainly with a reduction of regularity, amplitude, and peak velocity Tigges et al 2000;Klausmann 2003;Putzhammer et al 2005aPutzhammer et al , 2005b. Other studies also using kinematic analysis of motion revealed alterations in gait velocity by a decrease in stride length (Putzhammer and Klein 2006) and alterations in the postural sway area (Kent et al 2012). However, little is known about kinematic parameters of fundamental motor behaviors frequently used in daily life.…”