This study will examine brain metabolic and excitatory/inhibitory mechanisms related to cognitive and visual functioning in adults with schizophrenia and healthy control participants. Participants will complete behavioral assessments, cognitive testing, electroencephalography, magnetic resonance imaging, and magnetic resonance spectroscopy assessments. After baseline assessments, participants will be randomly assigned to one of two computerized cognitive training programs: perceptual discrimination training or cognitive control training. Each training program will include approximately 10 hours of training over 2 to 6 weeks. The study will evaluate changes in cognitive and visual task performance, EEG measures, and brain metabolite concentrations before and after cognitive training. Some participants may also complete optional extended baseline assessments before cognitive training.
Schizophrenia is associated with cognitive and visual impairments that can persist across the lifespan and are not fully addressed by current antipsychotic treatments. These impairments may be related to disruptions in brain metabolism and excitatory/inhibitory balance. This study is designed to better understand neurochemical and neurophysiological mechanisms of cognitive and visual functioning in schizophrenia and to evaluate whether these mechanisms change following cognitive training. The study will enroll adults with schizophrenia or schizoaffective disorder and demographically similar healthy control participants. Participants will complete baseline clinical assessments, cognitive and visual tasks, electroencephalography, structural magnetic resonance imaging, and magnetic resonance spectroscopy. Magnetic resonance spectroscopy will be used to measure brain metabolite concentrations, including metabolites related to brain metabolism and excitatory/inhibitory function. After baseline assessments, participants will be randomly assigned to one of two computerized cognitive training programs: perceptual discrimination training or cognitive control training. Both training programs are delivered through the BrainHQ platform and include approximately 10 hours of training over a 2- to 6-week period. Perceptual discrimination training focuses on visual stimulus discrimination, signal-to-noise resolution, and attentional control. Cognitive control training focuses on maintaining cognitive context in working memory during response selection. After completing cognitive training, participants will return for follow-up assessments, including repeat clinical assessments, cognitive and visual tasks, EEG, MRI, and magnetic resonance spectroscopy. Participants may also choose to complete an optional extended baseline component with additional baseline scanning visits before cognitive training. The primary outcomes include behavioral performance on the DPX task variant, EEG variables related to excitatory/inhibitory balance, and magnetic resonance spectroscopy measures of neurometabolite concentrations. Secondary outcomes include symptom and functioning measures such as the Brief Psychiatric Rating Scale, Scale for the Assessment of Negative Symptoms, Scale for the Assessment of Positive Symptoms, World Health Organization Disability Assessment Schedule, and Global Functioning Social/Role scales.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
168
Perceptual discrimination training is a computerized cognitive training program delivered through the BrainHQ platform. Training involves Gabor patch and other visual stimulus discrimination exercises that focus on improving signal-to-noise resolution and attentional control. On each training trial, participants distinguish a target stimulus among distractor stimuli. Training difficulty adapts based on participant performance. Participants complete approximately 10 hours of training over 2 to 6 weeks.
Cognitive control training is a computerized cognitive training program delivered through the BrainHQ platform. Training involves maintaining accurate representations of cognitive context in working memory during response selection. Training difficulty adapts based on participant performance by changing the speed of stimulus presentation or working memory load. Participants complete approximately 10 hours of training over 2 to 6 weeks.
Center for Magnetic Resonance Research, University of Minnesota
Minneapolis, Minnesota, United States
Change in DPX Task Performance
Behavioral performance on the DPX task variant will be assessed as a measure of cognitive control. Trial-by-trial behavioral data will be used to derive observed behavioral and computational metrics of cognitive control. The DPX task variant consists of a series of pattern sequences. One pattern is designated the "A" cue followed by the "X" cue, which requires one response (AX, 60-70% of trials, e.g. respond with the left button), while other pattern sequences require a different response (AY or BX, 12-15% of trials each, or BY, 6-10% of trials, e.g. respond with the right button). Given the strong expectation that X's evoke a valid response, BX trials place demands on cognitive control via the fidelity (stability, memory) of the "B" cue representation to overcome this tendency. Unit of Measure: Mean and standard deviation for BX trial error rate
Time frame: Baseline to post-training follow-up, up to 7 months; or baseline to post-training follow-up, up to 42 months for participants completing the optional extended baseline component
Number of participants with pre/post EEG data
The final sample size (participants with resting electroencephalography before and after intervention) will be reported to facilitate future analyses of change in EEG variables, which could include phase synchrony, slope of the spectral power density indexing excitatory/inhibitory balance, and/or prefrontal/parietal theta as a measure of perceptual noise. Units of Measure: Number of participants with pre/post EEG data
Time frame: Baseline to post-training follow-up, up to 7 months; or baseline to post-training follow-up, up to 42 months for participants completing the optional extended baseline component
Number of participants with pre/post Magnetic Resonance Spectroscopy data
Magnetic resonance spectroscopy (MRS) will be used to measure neurometabolite concentrations, including but not limited to glutamate, GABA, glutathione, and glucose. MRS measurements will be collected from prefrontal and occipital cortex. The final sample size (participants with MRS before and after intervention) will be reported to facilitate future analyses of change in MRS variables. Units of Measure: Number of participants with pre/post MRS data
Time frame: Baseline to post-training follow-up, up to 7 months; or baseline to post-training follow-up, up to 42 months for participants completing the optional extended baseline component
Change in Brief Psychiatric Rating Scale Score
Psychiatric symptoms will be assessed using the Brief Psychiatric Rating Scale.Brief Psychiatric Rating Scale (BPRS) items are scored between 1-7 with higher scores meaning more severe symptoms (i.e., worse outcomes). The minimum score is 24, and the maximum score is 168.
Time frame: Baseline to post-training follow-up, up to 7 months; or baseline to post-training follow-up, up to 42 months for participants completing the optional extended baseline component
Change in Positive Symptom Scores
Positive symptoms will be assessed using the Scale for the Assessment of Positive Symptoms(SAPS). Items are scored from 0 to 5, with higher scores indicating more severe symptoms and a worse outcome. Total scores range from 0 to 170.
Time frame: Baseline to post-training follow-up, up to 7 months; or baseline to post-training follow-up, up to 42 months for participants completing the optional extended baseline component
Change in Negative Symptom Scores
Negative symptoms will be assessed using the Scale for the Assessment of Negative Symptoms(SANS). Items are scored from 0 to 5, with higher scores indicating more severe symptoms and a worse outcome. Total scores range from 0 to 125.
Time frame: Baseline to post-training follow-up, up to 7 months; or baseline to post-training follow-up, up to 42 months for participants completing the optional extended baseline component
Change in World Health Organization Disability Assessment Schedule Score
Functioning will be assessed using the World Health Organization Disability Assessment Schedule, which assesses domains including cognition, mobility, self-care, social interaction, and social and participatory activities. The World Health Organization Disability Assessment Schedule (WHODAS) is scored so that higher values indicate more severe impacts of disability (i.e., a worse outcome). Each item is scored between 0-4 with a minimum score of zero and a maximum score of 48.
Time frame: Baseline to post-training follow-up, up to 7 months; or baseline to post-training follow-up, up to 42 months for participants completing the optional extended baseline component
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Change in Global Functioning Role Scale Score
Real-world role functioning in work or school will be assessed using the Global Functioning Role Scale. This scale is rated from 1 to 10, with higher scores indicating better role functioning. A score of 10 represents superior functioning.
Time frame: Baseline to post-training follow-up, up to 7 months; or baseline to post-training follow-up, up to 42 months for participants completing the optional extended baseline component