Neurophysiological Targets for Cognitive Training in Schizophrenia
Condition: Schizophrenia
MeSH terms: Schizophrenia
Study type: Interventional

Summary: 
      The purpose of this study is to determine whether computer-based training of auditory and
      visual processing results in corresponding improvement in brain function in individuals with
      schizophrenia.
    

Detailed description: 
      Schizophrenia is recognized as one of the leading causes of medical disability worldwide,
      ranked 9th overall by the World Health Organization, and affects more than 2 million
      Americans per year. There is considerable evidence to suggest that disability status in
      schizophrenia relates more directly to cognitive Impairment, involving attention, reasoning,
      and memory, than to characteristic symptoms of psychosis. Accordingly, the evaluation and
      advancement of interventions designed to restore cognitive function, generally termed
      cognitive remediation, is of critical importance to our rehabilitation mission. Recent
      randomized controlled trials of cognitive remediation in schizophrenia have found moderate
      gains in cognitive function and improved outcomes in important areas of community living.
      However, despite these encouraging findings, there remains sparse evidence in support of
      assumptions that (1) cognitive outcomes represent benefits of training-induced adaptive
      learning, (2) that training effects are specific to method of intervention, or (3) that
      change in cognitive test performance occurs through restoration of impaired neural circuitry
      in schizophrenia. This project will begin to address these issues by examining
      modality-specific effects of computer-based cognitive training on psychophysiological
      measures of sensory information processing. Training will be administered using two
      commercially available computer-based software packages, separately targeting auditory and
      visually-mediated processes using principles of bottom-up perceptual learning. Two
      psychophysiological paradigms, mismatch negativity (MMN) and P300 generation, will be
      administered as tests of early visual and auditory processing. MMN and P300 have been studied
      extensively in human neuroscience as probes of sensory echoic memory and attention engagement
      to contextually relevant information. Furthermore, reductions in MMN and P300 generation are
      reliably observed in schizophrenia, follow the course of a progressive neuropathological
      process, and correlate with severity of cognitive impairment. The specific aims of this study
      are to determine: (1) whether training selectively influences bottom-up (MMN) or top-down
      (P300) information processing, (2) whether training effects are modality (auditory vs.
      visual) specific, (3) whether baseline MMN and P300 predict, or rate-limit, training
      progress, and (4) whether pre-post change in cognitive test performance is mediated by
      neural-level change in MMN and P300 generation. Answers to these questions will provide
      information needed to structure cognitive training for maximum benefit in schizophrenia.
    

Intervention name(s): Auditory Cognitive Training; Visual Cognitive Training
Intervention type(s): Behavioral; Behavioral
Intervention description(s): The program entails six computer-based exercises that are designed to be very easy to use and require no computer experience. The exercises are calibrated to individual performance at the onset of training and adapt in difficulty to individual performance, giving constant feedback about progress. Each of the six exercises focuses on a distinct process: (1) auditory processing speed, (2) discriminating sounds, (3) sound precision, (4) sound sequencing, (5) working memory, and (6) narrative memory. Training was administered in a supervised clinical laboratory setting at a frequency of five 60-minute sessions per week over 4 weeks.; The program entails five computer-based exercises that are designed to be very easy to use and require no computer experience. The exercises are calibrated to individual performance at the onset of training and, following our laboratory procedures, calibration testing is repeated every 5th session. Exercises adapt in difficulty to individual performance, giving constant feedback about progress. Each of the five exercises focuses on a distinct process: (1) visual precision, (2) visual processing speed, (3) divided attention, (4) visual working memory, and (5) useful field of view. Training was administered in a supervised clinical laboratory setting at a frequency of five 40-minute sessions per week over 4 weeks.
Other intervention name(s): Brain Fitness by Posit Science; Cortex with Insight by Posit Science
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: schizophrenia; cognitive remediation; rehabilitation; electrophysiology; neuropsychology