@article{2998900,
    title = "Increased intra-subject reaction time variability in the volitional control of movement in schizophrenia",
    author = "Karantinos, T. and Tsoukas, E. and Mantas, A. and Kattoulas, E. and Stefanis, N.C. and Evdokimidis, I. and Smyrnis, N.",
    journal = "Psychiatry Research",
    year = "2014",
    volume = "215",
    number = "1",
    pages = "26-32",
    issn = "0165-1781",
    doi = "10.1016/j.psychres.2013.10.031",
    keywords = "neuroleptic agent, article;  clinical article;  controlled study;  decision making;  DSM-IV;  Finger Lift Reaction Time task;  frontal cortex;  human;  male;  motor system;  nerve cell network;  priority journal;  response time;  schizophrenia;  sensorimotor function;  statistical model;  task performance;  voluntary movement;  Voluntary Saccade Reaction Time task, Cognitive deficit;  Decision;  Ex-Gaussian;  Manual response;  Saccade;  Sensorimotor, Adult;  Frontal Lobe;  Humans;  Male;  Movement;  Photic Stimulation;  Psychomotor Performance;  Reaction Time;  Saccades;  Schizophrenia;  Young Adult",
    abstract = "Increased Reaction Time (RT) studies intra-subject variability is an emerging and consistent finding in RT studies of schizophrenia. A group of 23 patients suffering from DSM-IV schizophrenia and a group of 23 age-matched control subjects performed two RT tasks requiring basic sensorimotor processing and engaging two different motor systems: the Finger Lift Reaction Time task and the Voluntary Saccade Reaction Time task. The Ex-Gaussian model was applied to the RT distributions measuring the mean (mu), and standard deviation (sigma) of a Gaussian component thought to reflect sensorimotor processing and an exponential component (tau), thought to reflect an intermediate decision process. In both tasks, a significantly larger RT intra-subject variability effectively dissociated patients from controls. RT intra-subject variability in the two tasks was highly correlated only for patients. Both sigma and tau were significantly higher in the patient group with tau being the best predictor of schizophrenia. Furthermore, only in the patient group were sigma and tau highly correlated between the two tasks. The results reflect a deficit in information processing that may not be confined to decision processes related to the frontal cortex; rather, they may indicate dysfunction in distributed neural networks modulating adaptive regulation of performance. © 2013 Elsevier Ireland Ltd."
}