tACS for Working Memory in Schizophrenia
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-50
SponsorCentral South University
About this trial
This study is a randomized, single-blind, sham-controlled crossover trial enrolling 30 schizophrenia patients, each receiving one active and one sham tACS session (7-day washout), targeting P3/P4 at individual alpha frequency (2mA, 30min) during a working memory task, with accuracy and reaction time as primary outcomes, alongside EEG and neurophysiological measures, to test the efficacy and mechanisms of individualized alpha-tACS on working memory.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Aged 18-50 years, meeting the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria for schizophrenia, confirmed by the Structured Clinical Interview for DSM-5 (SCID-5).
Spatial span T-score <40 on the MATRICS Consensus Cognitive Battery (MCCB).
Taking 1-2 antipsychotic medications, with stable dosage for at least 1 week prior to enrollment. No use of mood stabilizers, antidepressants, or excessive benzodiazepines (lorazepam equivalent >2 mg/day). The type and dosage of antipsychotic medications remain unchanged during the treatment period.
Impaired functioning in daily activities.
Disqualifiers
Previously diagnosed with or comorbid any other DSM-5 mental disorder besides schizophrenia.
Presence of significant mood symptoms or substance use disorder (other than caffeine and/or tobacco).
Presence of any contraindication to transcranial alternating current stimulation (tACS).
Received other forms of electrical or magnetic stimulation therapy within 1 month prior to enrollment.
Trial design
Design model
Parallel
Treatments tested in this trial
transcranial alternating current stimulation
DeviceFor montage 1, active electrode at P3 (10-10 system), return electrodes at P1, P5, PO3, CP3. For montage 2, active electrode at P4, return electrodes at P2, P6, PO4, CP4. Conductive paste ensures impedance \<10 kΩ. Individual alpha frequency is used, calculated before each session from mean EEG at P3/P4 during SIRP task. Stimulation intensity is 2 mA (peak-to-zero) via electric field modeling. Stimulation is delivered during SIRP task, 30 min total per session (including 15s ramp-up/down), with continuous sine wave output.
sham stimulation
DeviceSham stimulation provides only a 15-second ramp-up and ramp-down current at the beginning and end of each session to mimic the initial tingling or itching sensation on the scalp produced by real stimulation, but delivers no effective stimulation current during the main phase of the task period.
Treatment groups
30 Participants
are divided into 2 treatment groupsGroup A: sham groupSham comparator 1 intervention
Group B: active groupExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Working Memory Accuracy
Assessment of task accuracy on the Sternberg Item Recognition Paradigm (SIRP). Participants are required to judge whether a probe stimulus belongs to a previously memorized set, with memory set sizes of 1 and 5. The outcome is measured as the percentage of correct responses (0-100%) across all trials, with higher scores indicating better working memory performance.
Time frame
Day 1 (baseline, prior to first intervention); within 15 minutes after Session 1; Day 9 (prior to second intervention, after 7-day washout); within 15 minutes after Session 2.2
Working Memory Reaction Time
Assessment of response speed on the Sternberg Item Recognition Paradigm (SIRP). Participants are required to judge whether a probe stimulus belongs to a previously memorized set, with memory set sizes of 1 and 5. The outcome is measured as the mean response latency for correct responses only, calculated from stimulus onset to the participant's button press, with shorter times indicating faster processing speed.
Time frame
Day 1 (baseline, prior to first intervention); within 15 minutes after Session 1; Day 9 (prior to second intervention, after 7-day washout); within 15 minutes after Session 2.Secondary outcomes
1
Changes in MCCB Performance
Assessment of cognitive function using the MATRICS Consensus Cognitive Battery (MCCB), a standardized cognitive assessment tool designed for schizophrenia and other neuropsychiatric conditions. The MCCB evaluates 9 cognitive domains: attention, information processing speed, verbal learning and memory, visual learning and memory, spatial working memory, reasoning and problem solving, social cognition, executive function, and fine motor skills. The overall cognitive composite score ranges from 20 to 100 (T-score), with higher scores indicating better cognitive performance.
Time frame
Baseline, on the day after each of the two interventions2
Changes in Positive and Negative Symptom Scale (PANSS) Scores
Scores range from 30 to 210, with higher scores indicating more severe positive and negative symptoms.
Time frame
Before and one week after each of the two interventions.3
Changes in Scale for the Assessment of Negative Symptoms (SANS) Scores
Scores range from 0 to 120; higher scores indicate more severe negative symptoms.
Time frame
Before and one week after each of the two interventions.4
Changes in Calgary Depression Scale for Schizophrenia (CDSS) Scores
Scores range from 0 to 27; higher scores indicate more severe affective symptoms.
Time frame
Before and one week after each of the two interventions.Sponsors and contacts
Click on the lead sponsor to view all of their trials.
Central South University
Lead sponsor
Second Xiangya Hospital of Central South University
Sponsor institution
Source ClinicalTrials.gov