Motor behavior reflects reduced hemispheric asymmetry in the psychosis risk period.
BACKGROUND
A body of work focusing on brain connectivity, language dominance, and motor laterality research suggests that reduced hemispheric asymmetry is a core feature in schizophrenia. However, there is little consensus about whether reduced dominance is present in those at ultrahigh risk (UHR) for psychosis.


METHODS
A total of 94 demonstrated right-handed neuroleptic free participants (38 UHR and 56 matched healthy controls) were assessed with structured clinical interviews and completed an innovative handwriting task using a digital tablet computer. A laterality quotient (LQ) was calculated using kinematic variables from the participant's left and right hands. A subset of the sample (26 UHR and 29 controls) returned after 12-months to complete clinical interviews in order to examine relationships between handwriting laterality and progression of psychosis risk symptoms.


RESULTS
The UHR group showed decreased dextrality compared to healthy controls. At the 12-month follow-up, decreased dextrality accounted for 8% of the variance in worsened positive symptoms within the UHR group.


CONCLUSIONS
The current results suggest that disrupted cerebral dominance is also present in the ultrahigh risk period and that decreased dextrality may serve as a novel biomarker for the progression of psychosis risk.
University of Colorado Boulder, Department of Psychology and Neuroscience, United States; University of Colorado Boulder, Center for Neuroscience, United States. Electronic address: derek.dean@colorado.edu.
Derek J
DJ
Dean
Texas A&M University, Department of Psychology, United States.
Joseph M
JM
Orr
University of Colorado Boulder, Department of Psychology and Neuroscience, United States.
Raeana E
RE
Newberry
Northwestern University, Department of Psychology, United States.
Vijay A
VA
Mittal
D000293:Adolescent; D001696:Biomechanical Phenomena; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006236:Handwriting; D006801:Humans; D007406:Interview, Psychological; D016014:Linear Models; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D011618:Psychotic Disorders / Q000503:physiopathology*; D012306:Risk; D055815:Young Adult
Cerebral dominance; Dextrality; Handwriting; Laterality; Psychosis; Ultrahigh risk