Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Changes in thalamocortical functional connectivity (FC) |
Most participants will complete MRI sessions on a 3T scanner located in the Center for Magnetic Resonance Research (CMRR) at the University of Minnesota. To calculate FC, we will characterize the global and local network connectivity using a graph theory analysis. This will be formed by extracting the fMRI time courses from ninety regions of interest, based on ROIs defined by the freesurfer T1 parcellation. We will focus on low frequency (0.06-0.125 Hz) oscillations in the BOLD signal. We will estimate the functional connectivity by computing the absolute value of the Pearson's correlation between all possible pairs of time series, creating a 90 x 90 (N x N) connectivity matrix. The network topology metrics, characteristic path length and clustering coefficient, will be computed from the connectivity matrix, averaged over a threshold range representing .1 to .3 of the maximum possible number of edges in the graph. We will also measure global strength and diversity of the nodes. |
baseline; mid-test (week 6); post-test (week 12) |
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Primary |
Changes in task-dependent thalamocortical functional connectivity (fMRI) during the N-back task. |
Task-dependent thalamocortical connectivity associated with the N-back task will be identified by modeling the block task design together with the thalamic regressor . The primary analysis for the N-Back tasks will consider the 2-back conditions alone. Subsequent analyses will examine the 2 > 0-back contrast to strengthen interpretation of any observed changes in task-dependent thalamocortical connectivity. Main effects of hemisphere (right active-tDCS vs left active-tDCS and sham-tDCS ), length of treatment , and modeled dosage will be examined for the N-back fMRI dataset . Group x Time (pre, mid, and post-intervention) interactions will also be examined for the N-back fMRI dataset. |
baseline; mid-test (week 6); post-test (week 12); |
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Primary |
Changes in task-dependent thalamocortical functional connectivity (fMRI) during the DPX task. |
Task-dependent thalamocortical connectivity associated with the DPX task demands will be identified by analyzing cue and probe events together with the thalamic regressor. Preliminary analysis for the DPX task will examine B-cue related connectivity alone. Subsequent analyses will strengthen interpretation by examining both B-cue > A-cue related connectivity, as well as connectivity changes associated with response-related, or reactive, control (during the AY condition). Main effects of hemisphere (right active vs . left active and sham-tDCS ), length of treatment , and modeled dosage will be examined for the DPX fMRI dataset . Group x Time interactions will also be examined for the DPX fMRI dataset. |
baseline; mid-test (week 6); post-test (week 12); |
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Primary |
Change in N-back performance |
The n-back measures working memory capacity. The participant is presented with a series of stimuli and instructed to indicate with a button press when the current stimulus matches the stimulus that appeared a pre-determined number (n) of trials before. Both accuracy (percentage of correct responses) and reaction time (milliseconds) will be recorded, and d' (d prime) will be calculated as a measure of signal detection. Increase in d' signifies improved signal detection, i.e. a better outcome. |
baseline; mid-test (week 6); post-test (week 12); |
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Primary |
Change in DPX performance |
The DPX task is an adaptation of the expectancy AX task that uses pairs of simple dot patterns rather than letter pairs as stimuli. DPX task will be performed in 3 blocks. Each trial consists of a cue dot pattern followed by a probe dot pattern. Different combinations of cues and probes enable the identification of a specific deficit in a subject's ability to maintain goal-relevant information throughout a trial. Timing will be jittered and each block of the DPX task will consist of 40 trials: 24 AX (60%), 6 AY (15%), 6 BX (15%) and 4 BY (10%). Each block will last 6 minutes. d'-context will be calculated as a measure of signal detection. Increase in d' -context signified improved signal detection, i.e. a better outcome. |
baseline; mid-test (week 6); post-test (week 12); |
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Primary |
Change in Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) composite score |
Intends to provide a relatively brief evaluation of key cognitive domains relevant to schizophrenia and related disorders. The composite score is calculated as a sum of T scores from the battery's available sub tests. Composite scores range from 213 (0.1 %tile) to 487 (99.9 %tile). |
baseline; mid-test (week 6); post-test (week 12); follow-up (week 24) |
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Secondary |
Change in University of California San Diego Performance-Based Skills Assessment - Brief (UPSA-B) |
Measures functional capacity by assessing skills involved in everyday tasks important to daily living. Points are scored for each of two sub scales based on the participant's correct performance of items in the sub scale (incorrect: 0 points, correct: 1 or 2 points). Points are used to derive a sub scale score by dividing points scored by the number of items in the sub scale (percentage correct) and multiplied by 50. The two sub scale scores are then added to derive the total score, with a possible range of 0-100. Higher scores represent better outcomes. |
baseline; mid-test (week 6); post-test (week 12); follow-up (week 24) |
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Secondary |
Change in Brief Psychiatric Rating Scale (BPRS) score |
Measures symptom severity in patients with schizophrenia. Scores are assigned for symptom categories based on a semi-structured clinical interview with anchored severity scales (1-7) for each symptom category. Total score is derived by adding up individual symptom scores, resulting in a total score range of 24-168. Higher scores indicate greater symptom severity. A decrease in scores over time would indicate symptom reduction, i.e. a better outcome. |
baseline; mid-test (week 6); post-test (week 12); follow-up (week 24) |
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Secondary |
Change in Brief Negative Symptom Scale (BNSS) score |
Measures of symptom severity in patients with schizophrenia with an emphasis on negative symptoms. Scores are assigned to symptom categories based on a semi-structured clinical interview with anchored severity scales (0-6 or 0-9). Total score is derived by adding up individual symptom scores, resulting in a total score range of 0-90. Higher scores indicate greater symptom severity. A decrease in scores over time would indicate symptom reduction, i.e. a better outcome. |
baseline; mid-test (week 6); post-test (week 12); follow-up (week 24) |
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