Schizoaffective Disorder, Schizophrenia
Conditions
Keywords
tACS, tDCS, sham, auditory hallucinations, Schizophrenia, Schizoaffective Disorder
Brief summary
Investigating the effects of non-invasive transcranial current stimulation as a treatment for auditory hallucinations in patients with schizophrenia.
Detailed description
The investigator's primary objective is to conduct a pilot clinical trial to establish the feasibility and to collect first effectiveness data for the use of transcranial alternating current stimulation (tACS) to re-normalize pathological alpha oscillations in dorso-lateral prefrontal cortex (dl-PFC) of patients with schizophrenia or schizoaffective disorder by comparing Auditory Hallucination Rating Scale (AHRS) scores immediately before the first stimulation session and immediately after the last stimulation session. As a secondary objective the investigators will assess the differential clinical effects of sham, 10 Hz and 2 mA transcranial direct current stimulation (tDCS) on electroencephalogram (EEG) measures of alpha oscillations.
Interventions
DEVICEtACS (alpha)
DEVICEtDCS
Sponsors
National Institute of Mental Health (NIMH)
University of North Carolina, Chapel Hill
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* DSM-IV diagnosis of schizophrenia, any subtype, or schizoaffective disorder, with refractory auditory hallucinations. Duration of illness \>1 year * 18-70 years old * Clinically stable for at least 12 weeks, i.e. not requiring hospitalization or a change in level of care * On current antipsychotic doses for at least 4 weeks * Stable auditory hallucinations as demonstrated by having less than or equal to 20% change in AHRS scores across a 2 week interval during the screening period. * Capacity to understand all relevant risks and potential benefits of the study and to provide written informed consent, OR has a legal guardian who can provide informed consent on the patient's behalf with the patient providing written assent to participate.
Exclusion criteria
* DSM-IV diagnosis of alcohol of substance abuse (other than nicotine) within the last month or a DSM-IV diagnosis of alcohol or substance dependence (other than nicotine) within the last 6 months * Medical or neurological illness (unstable cardiac disease, AIDS, malignancy, liver or renal impairment) or treatment for a medical disorder that could interfere with study participation * History of traumatic brain injury that required subsequent cognitive rehabilitation, or caused cognitive sequelae * Prior brain surgery * Any brain devices/implants, including cochlear implants and aneurysm clips * Co-morbid neurological condition (e.g. seizure disorder, brain tumor) * Non English speakers * Female participants who are pregnant, nursing, or unwilling to use an adequate method of contraception during study participation for those of childbearing potential * Positive urine test for cannabis, cocaine, amphetamine, barbiturates, benzodiazepines, opiates
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | Baseline, five days post baseline, 2 weeks post baseline, 5 weeks post baseline | The Auditory Hallucination Rating Scale (AHRS) measures the severity of auditory hallucinations in the past week. The scale assesses frequency, duration, location, loudness, belief of origin of voices, negative content, distress, disruption to life, and control over voices. All items are measured on a scale of 0 to 4, with a total possible score of 44. Higher scores indicate higher severity of auditory hallucinations. The investigators will compare the AHRS scores from immediately before the first stimulation and immediately after the last stimulation session as the investigator's primary outcomes measure. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Alpha Oscillations Measured With Electroencephalogram (EEG) Resting State From Baseline | Baseline, five days post baseline | The investigators will compare alpha oscillation power from resting state EEG recordings on the first and last day of stimulation. The investigators will also collect EEG recordings data at the one week and one month follow up visits. The investigators will use each of the four EEG recordings as data to analyze alpha frequency activity as a pilot study for derivation of EEG biomarkers. |
| Change in Positive and Negative Syndrome Scale (PANSS) Scores | baseline, five days post baseline, five weeks post baseline | The investigators will compare the PANSS total scores immediately before first stimulation session and immediately after last stimulation session as secondary outcome measures. Scores range from 30 to 210, with higher scores indicating more severe symptomology. |
| Change in Brief Assessment of Cognition in Schizophrenia (BACS) Score | baseline, five days post baseline, five weeks post baseline | The Brief Assessment of Cognition in Schizophrenia (BACS) is a battery of cognitive assessments assessing verbal memory and learning, working memory, motor function, verbal fluency, speed of processing, and executive function. Higher scores indicate better cognitive performance. The investigators will compare the BACS total scores immediately before first stimulation session and immediately after last stimulation session as secondary outcome measures. Verbal Memory: Score out of 75 Digit Sequencing: Score out of 28 Token Motor: Score out of 100 Fluency: No score limit Symbol Coding: Score out of 110 Tower of London: Score out of 22 Reported score is the mean of these 6 subtests. Healthy controls (Keefe et al., 2006) scored 45.6 as a comparison. |
| Change in Peak Frequency of Functional Connectivity From Baseline Measured With Electroencephalogram (EEG) Resting State | Baseline, five days post baseline | The investigators will compare peak frequency of functional connectivity from resting state EEG recordings on the first and last day of stimulation. The investigators will also collect EEG recordings data at the one week and one month follow up visits. The investigators will use each of the four EEG recordings as data to analyze the change in peak frequency of functional connectivity as a pilot study for derivation of EEG biomarkers. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Change in Electroencephalogram (EEG) Auditory Tasks: Oddball Task From Baseline | baseline, five days post baseline | The investigators will compare auditory responses during auditory tasks EEG recordings on the first and last day of stimulation. The investigators will also collect EEG recordings data at the one week and one month follow up visits. The investigators will use each of the four EEG recordings as data to analyze alpha frequency activity as a pilot study for derivation of EEG biomarkers and look for increase in auditory responses. Auditory oddball paradigm is an experimental design that has standard (low-pitch) and deviant (high-pitch) stimuli. Differences in ERP from these two stimuli can measure functions of sensory processing. Patients with schizophrenia often exhibit abnormal responses to the stimuli thus its discrepancy compared to healthy human participants can be a hallmark of symptoms in schizophrenia. |
| Change in Electroencephalogram (EEG) Auditory Tasks: Click Train Task From Baseline | baseline, five days post baseline | The investigators will compare auditory responses during auditory tasks EEG recordings on the first and last day of stimulation. The investigators will also collect this data at the one week and one month follow up visits. Auditory steady-state response (ASSR) from EEG data elicited by auditory click trains is considered as a hallmark of network dysfunction in schizophrenia. To obtain ASSR, auditory tones at a specific frequency (e.g., 40Hz) are presented for multiple trials and EEG data is analyzed to extract brain responses to the stimuli. One common way to extract the brain responses from this task is phase coherence between trials. When external stimuli (click trains) occur, brain signals are synchronized to these stimuli and its coherence should be the highest at the stimulation frequency. Phase information for calculating the coherence can be obtained by time-frequency analysis. Averaged coherence across the multiple trials can represent the inter-trial phase coherence. |
Countries
United States
Participant flow
Recruitment details
Participants recruited through medical providers or ads. Providers knew study criteria and discussed the study with patients during regular appointments. Interested participants contacted the study team, or were contacted by study team. Participants recruited from STEP clinic, Chapel Hill and Raleigh, and local clinics. Recruitment 4/15 to 12/16.
Pre-assignment details
Participants randomly assigned to 1 of 3 arms, tDCS, tACS, or active sham. tDCS, tACS current delivered during awake, resting state for 20 minutes twice daily on 5 consecutive days. Sham stimulation was delivered for equal period of time and number of sessions. 33 participants signed consent, 7 screen fails, 1 withdrew.
Participants by arm
| Arm | Count |
|---|---|
| tACS (Alpha) 10Hz tACS with a peak-to-peak amplitude of 2mA for 20 minutes twice daily
tACS (alpha) | 8 |
| tDCS 2mA stimulation for 20 minutes twice daily
tDCS | 7 |
| Sham Stimulation Will include 10 seconds of ramp in to 1 minutes of 10 Hz tACS with a ramp out of 10 seconds for a total of 80 seconds of stimulation twice daily.
tACS (alpha) | 7 |
| Total | 22 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 |
|---|---|---|---|---|
| Overall Study | Self-discontinued medication | 0 | 1 | 0 |
| Overall Study | Unstable symptoms during screening | 0 | 0 | 1 |
| Overall Study | Withdrawal by Subject | 1 | 0 | 0 |
Baseline characteristics
| Characteristic | tACS (Alpha) | tDCS | Sham Stimulation | Total |
|---|---|---|---|---|
| Age, Continuous | 47 years STANDARD_DEVIATION 9.72 | 29.75 years STANDARD_DEVIATION 10.97 | 38.86 years STANDARD_DEVIATION 10.01 | 38.86 years STANDARD_DEVIATION 12.19 |
| Auditory Hallucination Rating Scale | 25.88 units on a scale STANDARD_DEVIATION 3.8 | 23.00 units on a scale STANDARD_DEVIATION 6.9 | 24.71 units on a scale STANDARD_DEVIATION 5.91 | 24.59 units on a scale STANDARD_DEVIATION 5.47 |
| Brief Assessment of Cognition in Schizophrenia | 31.21 units on a scale STANDARD_DEVIATION 5.68 | 38.26 units on a scale STANDARD_DEVIATION 9.01 | 38.93 units on a scale STANDARD_DEVIATION 7.17 | 35.91 units on a scale STANDARD_DEVIATION 7.87 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 8 Participants | 7 Participants | 5 Participants | 20 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 2 Participants | 2 Participants |
| Positive and Negative Syndrome Scale | 52.75 units on a scale STANDARD_DEVIATION 7.74 | 58.86 units on a scale STANDARD_DEVIATION 14.66 | 57.00 units on a scale STANDARD_DEVIATION 11.6 | 56.05 units on a scale STANDARD_DEVIATION 11.27 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Black or African American | 6 Participants | 3 Participants | 2 Participants | 11 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 2 Participants | 4 Participants | 4 Participants | 10 Participants |
| Region of Enrollment United States | 8 participants | 7 participants | 7 participants | 22 participants |
| Sex: Female, Male Female | 1 Participants | 3 Participants | 3 Participants | 7 Participants |
| Sex: Female, Male Male | 7 Participants | 4 Participants | 4 Participants | 15 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 8 | 0 / 7 | 0 / 7 |
| other Total, other adverse events | 0 / 8 | 0 / 7 | 0 / 7 |
| serious Total, serious adverse events | 0 / 8 | 0 / 7 | 0 / 7 |
Outcome results
Primary
Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score
The Auditory Hallucination Rating Scale (AHRS) measures the severity of auditory hallucinations in the past week. The scale assesses frequency, duration, location, loudness, belief of origin of voices, negative content, distress, disruption to life, and control over voices. All items are measured on a scale of 0 to 4, with a total possible score of 44. Higher scores indicate higher severity of auditory hallucinations. The investigators will compare the AHRS scores from immediately before the first stimulation and immediately after the last stimulation session as the investigator's primary outcomes measure.
Time frame: Baseline, five days post baseline, 2 weeks post baseline, 5 weeks post baseline
Population: Per protocol; All eligible participants who completed every session of the study from the initial session through the one month follow-up that followed study protocol.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| tACS (Alpha) | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 5 days from baseline | 0.85 proportion to baseline | Standard Deviation 0.13 |
| tACS (Alpha) | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 5 weeks from baseline | 0.85 proportion to baseline | Standard Deviation 0.16 |
| tACS (Alpha) | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 2 weeks from baseline | 0.84 proportion to baseline | Standard Deviation 0.19 |
| tDCS | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 5 weeks from baseline | 1.01 proportion to baseline | Standard Deviation 0.14 |
| tDCS | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 2 weeks from baseline | 0.94 proportion to baseline | Standard Deviation 0.2 |
| tDCS | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 5 days from baseline | 0.94 proportion to baseline | Standard Deviation 0.36 |
| Sham Stimulation | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 2 weeks from baseline | 0.92 proportion to baseline | Standard Deviation 0.11 |
| Sham Stimulation | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 5 days from baseline | 0.91 proportion to baseline | Standard Deviation 0.08 |
| Sham Stimulation | Proportional Change From Baseline in Auditory Hallucination Rating Scale (AHRS) Score | 5 weeks from baseline | 0.85 proportion to baseline | Standard Deviation 0.09 |
Comparison: The null hypothesis was that there is no difference between the changes in the AHRS score from baseline to 5 days between the groups.H0: μ1=μ2=μ3 μ1: mean(difference 5 days-baseline) for tACS group (n=8) μ2: mean(difference 5 days-baseline) for tDCS group (n=7) μ3: mean(difference 5 days-baseline) for sham group (n=7)p-value: 0.47ANOVA
Secondary
Change in Alpha Oscillations Measured With Electroencephalogram (EEG) Resting State From Baseline
The investigators will compare alpha oscillation power from resting state EEG recordings on the first and last day of stimulation. The investigators will also collect EEG recordings data at the one week and one month follow up visits. The investigators will use each of the four EEG recordings as data to analyze alpha frequency activity as a pilot study for derivation of EEG biomarkers.
Time frame: Baseline, five days post baseline
Population: Per protocol; All eligible participants who completed every session of the study from the initial session through the one month follow-up that followed the study protocol.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| tACS (Alpha) | Change in Alpha Oscillations Measured With Electroencephalogram (EEG) Resting State From Baseline | 1.5 decibel (dB) | Standard Deviation 0.2 |
| tDCS | Change in Alpha Oscillations Measured With Electroencephalogram (EEG) Resting State From Baseline | 0.3 decibel (dB) | Standard Deviation 0.1 |
| Sham Stimulation | Change in Alpha Oscillations Measured With Electroencephalogram (EEG) Resting State From Baseline | 0.4 decibel (dB) | Standard Deviation 0.2 |
Secondary
Change in Brief Assessment of Cognition in Schizophrenia (BACS) Score
The Brief Assessment of Cognition in Schizophrenia (BACS) is a battery of cognitive assessments assessing verbal memory and learning, working memory, motor function, verbal fluency, speed of processing, and executive function. Higher scores indicate better cognitive performance. The investigators will compare the BACS total scores immediately before first stimulation session and immediately after last stimulation session as secondary outcome measures. Verbal Memory: Score out of 75 Digit Sequencing: Score out of 28 Token Motor: Score out of 100 Fluency: No score limit Symbol Coding: Score out of 110 Tower of London: Score out of 22 Reported score is the mean of these 6 subtests. Healthy controls (Keefe et al., 2006) scored 45.6 as a comparison.
Time frame: baseline, five days post baseline, five weeks post baseline
Population: Per protocol; All eligible participants who completed every session of the study from the initial session through the one month follow-up that followed study protocol.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| tACS (Alpha) | Change in Brief Assessment of Cognition in Schizophrenia (BACS) Score | 5 days from baseline | 31.58 scores on a scale | Standard Deviation 5.77 |
| tACS (Alpha) | Change in Brief Assessment of Cognition in Schizophrenia (BACS) Score | 5 weeks from baseline | 29.81 scores on a scale | Standard Deviation 5.5 |
| tDCS | Change in Brief Assessment of Cognition in Schizophrenia (BACS) Score | 5 days from baseline | 42.05 scores on a scale | Standard Deviation 10.82 |
| tDCS | Change in Brief Assessment of Cognition in Schizophrenia (BACS) Score | 5 weeks from baseline | 39.71 scores on a scale | Standard Deviation 9.39 |
| Sham Stimulation | Change in Brief Assessment of Cognition in Schizophrenia (BACS) Score | 5 days from baseline | 41.50 scores on a scale | Standard Deviation 10.52 |
| Sham Stimulation | Change in Brief Assessment of Cognition in Schizophrenia (BACS) Score | 5 weeks from baseline | 40.83 scores on a scale | Standard Deviation 9.71 |
Comparison: The null hypothesis was that there is no difference between the changes in the BACS score from baseline to 5 days between the groups:~H0: μ1=μ2=μ3 μ1: mean(difference 5 days-baseline) for tACS group (n=8) μ2: mean(difference 5 days-baseline) for tDCS group (n=7) μ3: mean(difference 5 days-baseline) for sham group (n=7)p-value: 0.11ANOVA
Secondary
Change in Peak Frequency of Functional Connectivity From Baseline Measured With Electroencephalogram (EEG) Resting State
The investigators will compare peak frequency of functional connectivity from resting state EEG recordings on the first and last day of stimulation. The investigators will also collect EEG recordings data at the one week and one month follow up visits. The investigators will use each of the four EEG recordings as data to analyze the change in peak frequency of functional connectivity as a pilot study for derivation of EEG biomarkers.
Time frame: Baseline, five days post baseline
Population: Per protocol; All eligible participants who completed every session of the study from the initial session through the one month follow-up that followed the study protocol.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| tACS (Alpha) | Change in Peak Frequency of Functional Connectivity From Baseline Measured With Electroencephalogram (EEG) Resting State | 10 Hertz (Hz) | Standard Deviation 0 |
| tDCS | Change in Peak Frequency of Functional Connectivity From Baseline Measured With Electroencephalogram (EEG) Resting State | 8 Hertz (Hz) | Standard Deviation 0.5 |
| Sham Stimulation | Change in Peak Frequency of Functional Connectivity From Baseline Measured With Electroencephalogram (EEG) Resting State | 11 Hertz (Hz) | Standard Deviation 0.5 |
Secondary
Change in Positive and Negative Syndrome Scale (PANSS) Scores
The investigators will compare the PANSS total scores immediately before first stimulation session and immediately after last stimulation session as secondary outcome measures. Scores range from 30 to 210, with higher scores indicating more severe symptomology.
Time frame: baseline, five days post baseline, five weeks post baseline
Population: Per protocol; All eligible participants who completed every session of the study from the initial session through the one month follow-up that followed study protocol.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| tACS (Alpha) | Change in Positive and Negative Syndrome Scale (PANSS) Scores | 5 weeks from baseline | 51.13 scores on a scale | Standard Deviation 9.95 |
| tACS (Alpha) | Change in Positive and Negative Syndrome Scale (PANSS) Scores | 5 days from baseline | 51.25 scores on a scale | Standard Deviation 8.19 |
| tDCS | Change in Positive and Negative Syndrome Scale (PANSS) Scores | 5 weeks from baseline | 52.86 scores on a scale | Standard Deviation 7.47 |
| tDCS | Change in Positive and Negative Syndrome Scale (PANSS) Scores | 5 days from baseline | 54.71 scores on a scale | Standard Deviation 11.84 |
| Sham Stimulation | Change in Positive and Negative Syndrome Scale (PANSS) Scores | 5 days from baseline | 55.29 scores on a scale | Standard Deviation 10.86 |
| Sham Stimulation | Change in Positive and Negative Syndrome Scale (PANSS) Scores | 5 weeks from baseline | 51.57 scores on a scale | Standard Deviation 12.2 |
Comparison: The null hypothesis was that there is no difference between the changes in the PANSS score from day 5 to baseline. H0: μ1=μ2=μ3 μ1: mean(difference 5 days-baseline) for tACS group (n=8) μ2: mean(difference 5 days-baseline) for tDCS group (n=7) μ3: mean(difference 5 days-baseline) for sham group (n=7)p-value: 0.37ANOVA
Other Pre-specified
Change in Electroencephalogram (EEG) Auditory Tasks: Click Train Task From Baseline
The investigators will compare auditory responses during auditory tasks EEG recordings on the first and last day of stimulation. The investigators will also collect this data at the one week and one month follow up visits. Auditory steady-state response (ASSR) from EEG data elicited by auditory click trains is considered as a hallmark of network dysfunction in schizophrenia. To obtain ASSR, auditory tones at a specific frequency (e.g., 40Hz) are presented for multiple trials and EEG data is analyzed to extract brain responses to the stimuli. One common way to extract the brain responses from this task is phase coherence between trials. When external stimuli (click trains) occur, brain signals are synchronized to these stimuli and its coherence should be the highest at the stimulation frequency. Phase information for calculating the coherence can be obtained by time-frequency analysis. Averaged coherence across the multiple trials can represent the inter-trial phase coherence.
Time frame: baseline, five days post baseline
Population: Per protocol; All eligible participants who completed every session of the study from the initial session through the one month follow-up that followed study protocol.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| tACS (Alpha) | Change in Electroencephalogram (EEG) Auditory Tasks: Click Train Task From Baseline | topographical activity | 5 inter-trial phase coherence | Standard Deviation 0.1 |
| tACS (Alpha) | Change in Electroencephalogram (EEG) Auditory Tasks: Click Train Task From Baseline | time-frequency activity | 1 inter-trial phase coherence | Standard Deviation 0.01 |
| tDCS | Change in Electroencephalogram (EEG) Auditory Tasks: Click Train Task From Baseline | topographical activity | 0.5 inter-trial phase coherence | Standard Deviation 0.1 |
| tDCS | Change in Electroencephalogram (EEG) Auditory Tasks: Click Train Task From Baseline | time-frequency activity | 0.05 inter-trial phase coherence | Standard Deviation 0.01 |
| Sham Stimulation | Change in Electroencephalogram (EEG) Auditory Tasks: Click Train Task From Baseline | topographical activity | 0.5 inter-trial phase coherence | Standard Deviation 0.1 |
| Sham Stimulation | Change in Electroencephalogram (EEG) Auditory Tasks: Click Train Task From Baseline | time-frequency activity | 0.04 inter-trial phase coherence | Standard Deviation 0.01 |
Other Pre-specified
Change in Electroencephalogram (EEG) Auditory Tasks: Oddball Task From Baseline
The investigators will compare auditory responses during auditory tasks EEG recordings on the first and last day of stimulation. The investigators will also collect EEG recordings data at the one week and one month follow up visits. The investigators will use each of the four EEG recordings as data to analyze alpha frequency activity as a pilot study for derivation of EEG biomarkers and look for increase in auditory responses. Auditory oddball paradigm is an experimental design that has standard (low-pitch) and deviant (high-pitch) stimuli. Differences in ERP from these two stimuli can measure functions of sensory processing. Patients with schizophrenia often exhibit abnormal responses to the stimuli thus its discrepancy compared to healthy human participants can be a hallmark of symptoms in schizophrenia.
Time frame: baseline, five days post baseline
Population: Per protocol; All eligible participants who completed every session of the study from the initial session through the one month follow-up that followed study protocol.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| tACS (Alpha) | Change in Electroencephalogram (EEG) Auditory Tasks: Oddball Task From Baseline | standard tones | 0.6 micro volts | Standard Deviation 0.1 |
| tACS (Alpha) | Change in Electroencephalogram (EEG) Auditory Tasks: Oddball Task From Baseline | deviant tones | 0.3 micro volts | Standard Deviation 0.05 |
| tDCS | Change in Electroencephalogram (EEG) Auditory Tasks: Oddball Task From Baseline | standard tones | 0.4 micro volts | Standard Deviation 0.1 |
| tDCS | Change in Electroencephalogram (EEG) Auditory Tasks: Oddball Task From Baseline | deviant tones | 0.4 micro volts | Standard Deviation 0.1 |
| Sham Stimulation | Change in Electroencephalogram (EEG) Auditory Tasks: Oddball Task From Baseline | standard tones | 0.5 micro volts | Standard Deviation 0.1 |
| Sham Stimulation | Change in Electroencephalogram (EEG) Auditory Tasks: Oddball Task From Baseline | deviant tones | 0.3 micro volts | Standard Deviation 0.1 |