title: Less structured movement patterns predict severity of positive syndrome, excitement, and disorganization.
abstract: Disorganized behavior is a key symptom of schizophrenia. The objective assessment of disorganized behavior is particularly challenging. Actigraphy has enabled the objective assessment of motor behavior in various settings. Reduced motor activity was associated with negative syndrome scores, but simple motor activity analyses were not informative on other symptom dimensions. The analysis of movement patterns, however, could be more informative for assessing schizophrenia symptom dimensions. Here, we use time series analyses on actigraphic data of 100 schizophrenia spectrum disorder patients. Actigraphy recording intervals were set at 2 s. Data from 2 defined 60-min periods were analyzed, and partial autocorrelations of the actigraphy time series indicated predictability of movements in each individual. Increased positive syndrome scores were associated with reduced predictability of movements but not with the overall amount of movement. Negative syndrome scores were associated with low activity levels but unrelated with predictability of movement. The factors disorganization and excitement were related to movement predictability but emotional distress was not. Thus, the predictability of objectively assessed motor behavior may be a marker of positive symptoms and disorganized behavior. This behavior could become relevant for translational research.
authors.affiliation: To whom correspondence should be addressed; University Hospital of Psychiatry, Bolligenstrasse 111, 3060 Bern, Switzerland; tel: +41-31-930-9483, fax: +41-31-930-9404, e-mail: walther@puk.unibe.ch.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Walther
authors.forename: Fabian
authors.initials: F
authors.lastname: Ramseyer
authors.forename: Helge
authors.initials: H
authors.lastname: Horn
authors.forename: Werner
authors.initials: W
authors.lastname: Strik
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Tschacher
mesh_terms: D056044:Actigraphy; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011595:Psychomotor Agitation / Q000503:physiopathology*; D011618:Psychotic Disorders / Q000503:physiopathology / Q000523:psychology*; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D013577:Syndrome; D055815:Young Adult
keywords: actigraphy; behavior; negative symptoms; positive symptoms; schizophrenia; time series analysis