Postural Stability of Patients with Schizophrenia during Challenging Sensory Conditions: Implication of Sensory Integration for Postural Control

Abstract

Postural dysfunctions are prevalent in patients with schizophrenia and affect their daily life and ability to work. In addition, sensory functions and sensory integration that are crucial for postural control are also compromised. This study intended to examine how patients with schizophrenia coordinate multiple sensory systems to maintain postural stability in dynamic sensory conditions. Twenty-nine patients with schizophrenia and 32 control subjects were recruited. Postural stability of the participants was examined in six sensory conditions of different level of congruency of multiple sensory information, which was based on combinations of correct, removed, or conflicting sensory inputs from visual, somatosensory, and vestibular systems. The excursion of the center of pressure was measured by posturography. Equilibrium scores were derived to indicate the range of anterior-posterior (AP) postural sway, and sensory ratios were calculated to explore ability to use sensory information to maintain balance. The overall AP postural sway was significantly larger for patients with schizophrenia compared to the controls [patients (69.62±8.99); controls (76.53±7.47); t1,59 = -3.28, p<0.001]. The results of mixed-model ANOVAs showed a significant interaction between the group and sensory conditions [F5,295 = 5.55, p<0.001]. Further analysis indicated that AP postural sway was significantly larger for patients compared to the controls in conditions containing unreliable somatosensory information either with visual deprivation or with conflicting visual information. Sensory ratios were not significantly different between groups, although small and non-significant difference in inefficiency to utilize vestibular information was also noted. No significant correlations were found between postural stability and clinical characteristics. To sum up, patients with schizophrenia showed increased postural sway and a higher rate of falls during challenging sensory conditions, which was independent of clinical characteristics. Patients further demonstrated similar pattern and level of utilizing sensory information to maintain balance compared to the controls.

Addiction vulnerability trait impacts complex movement control: Evidence from sign-trackers

“…Sign-tracking behavior signals the presence of an endophenotype, or a transdiagnostic risk factor, for a range of neuropsychiatric disorders characterized by a limited capacity for goal-directed, or top-down attentional control and associated executive deficits [58,59]. This view then also predicts the presence of gait and movement abnormalities in patients sharing this endophenotype, such as schizophrenia, as was observed by Bleuler [“...der Gang ist oft auffallend.” Translation: “.the gait is often conspicuous.”; [60], see also [61,62].…”

Postural Sway Abnormalities in Schizotypal Personality Disorder

“…SPD has been associated with excessively increased force and variability in a motor stability task in adults 19 and adolescents, 16 decreased performance on motor learning tasks, 20 and increased white matter volume in motor pathways, 15 as well as movement abnormalities. 19,21,22 Individuals with schizophrenia have increased postural sway, indicating impaired postural control [23][24][25][26][27][28][29][30][31] ; this has also been shown in individuals at risk for psychosis. 32,33 This likely reflects abnormalities in brain structures critical for postural control, the cerebellum, and basal ganglia.…”

Postural Control and Verbal and Visual Working Memory Correlates in Nonclinical Psychosis

“…With respect to this last point, there is good preliminary evidence to suggest that motor behaviors linked to cerebellar-thalamic-cortical-cerebellar (CTCC) circuit dysfunction are implicated in psychosis. CTCC circuit function is critically implicated in conceptual models of schizophrenia [24,25] and, thus far, related motor symptoms have been well recorded in populations at a clinical high risk (CHR) for transitioning to psychosis [16,17,21,26] as well as in schizophrenia patients [19,[27][28][29][30][31][32]. Moreover, a recent study by our group demonstrated potential cerebellar deficits in the NCP population.…”

“…First, select abnormal movement signs may be unique to psychosis risk domain [13][14][15], and this may be helpful in isolating a weaker signal. Second, our ability to detect subtle aberrations in motor behavior which, if present, are likely to characterize populations lower on the continuum, has dramatically improved in recent years due to the more widespread adoption of instrumental assessment modalities [16][17][18][19][20]. Third, there is preliminary evidence to suggest that some motor deficits have already been detected in NCP, including variable force [12,18].…”