Motor behavior reflects reduced hemispheric asymmetry in the psychosis risk period

Abstract

Background A body of work focusing on brain connectivity, language dominance, and motor laterality research suggests 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. Conclusion 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.

Research domain criteria (RDoC) grows up: Strengthening neurodevelopment investigation within the RDoC framework

“…Our group has begun to employ strain gauge and handwriting kinematic assessments of motor pathology, which provide continuous variables that are more sensitive than observer-based methods, identifying individuals with overt dyskinesias as well as those who only have subclinical movement pathology (Cortese et al, 2005; Dean and Mittal, 2015; Dean et al, 2016; Dean et al, 2013). Our earlier work combining observer-based ratings of dyskinetic movement abnormalities with cognitive deficits in adolescents with prodromal syndromes showed some promise for predicting psychosis (sensitivity= 60.0%, specificity = 76.0%, PPV = 43.0%, NPV = 86.3%) (Mittal et al, 2010).…”

Dysfluent Handwriting in Schizophrenic Outpatients

“…Decreased automatization of movement results in dysfluent movement, disturbances in movement and is thought to be associated with neurobiological dispositions in people within schizophrenia spectrum connected with dysfunctional neural connections between cortical and subcortical regions or abnormalities in hemispheric specialization (Gallucci et al, 1997;Gupta et al, 1995;Wiser et al, 1998). It suggests that subtle disturbances of handwriting in outpatients with schizophrenia may be present independent of the acute side effect of medication, and of chronic movement abnormalities such as tardive dyskinesia, and in populations at risk for psychosis (Dean, Orr, Newberry, & Mittal, 2016).…”

“…Possibly among the patients with schizophrenia were those with subtle psychomotor slowing and they performed the experimental task more slowly (ICD-10, 1992). Hyperkinetic and hypokinetic movement abnormalities have been reported for patients with schizophrenia (Dean et al, 2016). Thus, although the speed of dictation of the text and the time of the tasks were controlled, the performance (including calligraphic forms) may be affected by individual differences in speed of handwriting.…”

The computational analyses of handwriting in individuals with psychopathic personality disorder

“…There is extensive data indicating that motor impairments are associated with mental disorders within schizophrenia spectrum or affective disorders [1][2][3][4][5]. These motor disorders can be manifested in hand movement and measured through handwriting examination tools.…”