Schizoaffective Disorder, Schizophrenia
Conditions
Brief summary
This study investigates whether visual attention can be improved in individuals with schizophrenia by stimulating the brain via transcranial Direct Current Stimulation (tDCS).
Detailed description
Individuals with schizophrenia tend to display abnormal visual attention when performing visual tasks, typically spending less time on salient features of the stimuli (e.g. core facial features or body movement in social tasks), and instead focusing on idiosyncratic features of an image or video. Poor visual attention in schizophrenia has been directly linked to poorer social cognitive performance (e.g. recognizing emotional expressions or social cues) which can impact an individual's day to day functioning. Transcranial Direct Current Stimulation (tDCS) is a form of noninvasive neurostimulation which has been proposed as a therapeutic procedure in numerous psychiatric disorders. TDCS in schizophrenia has been demonstrated to improve a wide range of cognitive processes, and in healthy adults, tDCS has been demonstrated to improve aspects of social cognition. TDCS thus appears to be a promising therapeutic technique that may be useful for improving visual attention in patients with schizophrenia, and potentially impact social cognitive performance via an underlying mechanism tying the two. This study will compare visual performance in individuals with schizophrenia across two conditions: active anodal tDCS and sham tDCS, while also comparing between brain stimulation sites: rTPJ and dmPFC.
Interventions
DEVICEActive anodal tDCS
active anodal tDCS with behavioral tasks to assess visual attention
DEVICESham tDCS
sham tDCS with behavioral tasks to assess visual attention
Sponsors
The University of Texas at Dallas
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Intervention model description
Participants will be paired based on key demographic criteria and assigned to one of two stimulation locations (rTPJ or dmPFC), participants will then complete active and sham stimulation sessions in a randomized, counterbalanced order approximately one week apart.
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
No
Inclusion criteria
* DSM-IV-TR or DSM-5 diagnosis of schizophrenia or schizoaffective disorder and clinically stable (i.e. no hospitalizations) for at least 8 weeks prior to informed consent and be on a stable medication regimen for at least 6 weeks with no dose changes for a minimum of 2 weeks prior to informed consent.
Exclusion criteria
* The presence or history of a pervasive developmental disorder or mental retardation as defined by a premorbid IQ \< 70 * Presence or history of medical or neurological disorders in which neural stimulation would be contraindicated (e.g. presence of epilepsy or history of seizures) * Presence of sensory limitations, including visual or hearing impairments that interfere with assessment * History of electroconvulsive therapy * Not proficient in English * Presence of substance abuse in the past one month or dependence not in remission in the past six months
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Visual Attention to Static Faces | Assessment will be completed 30 minutes after completion of the active/sham stimulation | Visual attention measured via eye-tracking (percentage of time attending to investigator designated AOIs) when viewing static, emotional faces (stimuli: Emotion Recognition - 40). AOIs for static faces will be defined as core facial features (i.e. eyes, nose, mouth). |
| Visual Attention to Dynamic Actor | Assessment will be completed 30 minutes after completion of the active/sham stimulation | Visual attention measured via eye-tracking(percentage of time attending to investigator designated AOIs) when viewing videos of a single actor (stimuli: Bell Lysaker Emotion Recognition Task). AOIs for this task will be defined as core facial features (i.e. eyes, nose, and mouth). |
| Visual Attention to Dynamic Social Scenes | Assessment will be completed 30 minutes after completion of the active/sham stimulation | Visual attention measured via eye-tracking (percentage of time attending to investigator designated AOIs) when viewing videos of two or more actors in a scene (stimuli: The Awareness of Social Inference Task Part 3, Version A). AOIs for this task will be defined as salient social and contextual stimuli (e.g. social stimuli are faces of actors, while contextually salient stimuli include items actors are talking about, such as a plate full of food or an empty wallet). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Fixation Stabilization | Assessment will be completed 30 minutes after completion of the active/sham stimulation | Stabilization of visual fixation on fixation circle positioned in middle of screen. Participants will be placed in front of an eyetracking device and asked to keep their eyes focused on a circle in the middle of the screen. Stabilization will be measured via eye-tracking as the deviation from a single point on screen, calculated by assessing the sum of squares of both the x and y axis (output from eyetracking device). Higher number indicates more movement, and thus less stabilization. |
Countries
United States
Participant flow
Recruitment details
81 participants were recruited to the study between March 2019 and March 2020 at a university site in Dallas, TX.
Pre-assignment details
At enrollment, all participants were matched in pairs based upon key demographic factors (i.e., age, race, gender, and education), and pairs were randomly assigned to stimulation condition, resulting in separate rTPJ and dmPFC stimulation groups. 5 participants did not complete both study visits, with 4 participants not returning to their second visit, and 1 participant discontinuing their first visit prior to stimulation procedures.
Participants by arm
| Arm | Count |
|---|---|
| Anodal/Sham Stimulation tDCS to rTPJ Within subject design - sham and anodal tDCS to the rTPJ followed by behavioral testing
Active anodal tDCS: active anodal tDCS with behavioral tasks to assess visual attention Sham tDCS: sham tDCS with behavioral tasks to assess visual attention | 42 |
| Anodal/Sham Stimulation tDCS to dmPFC Within subject design - sham and anodal tDCS to the dmPFC followed by behavioral testing
Active anodal tDCS: active anodal tDCS with behavioral tasks to assess visual attention Sham tDCS: sham tDCS with behavioral tasks to assess visual attention | 39 |
| Total | 81 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 |
|---|---|---|---|---|---|
| 1 Week Washout/ Delay | Incompatibility with technical component (eyetracking) | 0 | 0 | 1 | 0 |
| 1 Week Washout/ Delay | Lost to Follow-up | 0 | 1 | 0 | 0 |
| 1 Week Washout/ Delay | Withdrawal by Subject | 0 | 0 | 2 | 0 |
| First Visit | Withdrawal by Subject | 1 | 0 | 0 | 0 |
Baseline characteristics
| Characteristic | Anodal/Sham Stimulation tDCS to rTPJ | Anodal/Sham Stimulation tDCS to dmPFC | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 42 Participants | 39 Participants | 81 Participants |
| Age, Continuous | 40.74 years STANDARD_DEVIATION 10.58 | 40.79 years STANDARD_DEVIATION 11.55 | 40.77 years STANDARD_DEVIATION 10.99 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 7 Participants | 6 Participants | 13 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 35 Participants | 33 Participants | 68 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Black or African American | 25 Participants | 22 Participants | 47 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 17 Participants | 14 Participants | 31 Participants |
| Region of Enrollment United States | 42 participants | 39 participants | 81 participants |
| Sex: Female, Male Female | 19 Participants | 18 Participants | 37 Participants |
| Sex: Female, Male Male | 23 Participants | 21 Participants | 44 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 38 | 0 / 41 | 0 / 39 | 0 / 38 |
| other Total, other adverse events | 0 / 38 | 1 / 41 | 0 / 39 | 0 / 38 |
| serious Total, serious adverse events | 0 / 38 | 0 / 41 | 0 / 39 | 0 / 38 |
Outcome results
Primary
Visual Attention to Dynamic Actor
Visual attention measured via eye-tracking(percentage of time attending to investigator designated AOIs) when viewing videos of a single actor (stimuli: Bell Lysaker Emotion Recognition Task). AOIs for this task will be defined as core facial features (i.e. eyes, nose, and mouth).
Time frame: Assessment will be completed 30 minutes after completion of the active/sham stimulation
Population: Population analyzed were those that completed both active and sham stimulations (n=5 removed) with valid eyetracking data (n=2 removed)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal Stimulation tDCS to rTPJ | Visual Attention to Dynamic Actor | 0.47 proportion of time attending to AOIs | Standard Deviation 0.12 |
| Sham tDCS to rTPJ | Visual Attention to Dynamic Actor | 0.46 proportion of time attending to AOIs | Standard Deviation 0.11 |
| Anodal Stimulation tDCS to dmPFC | Visual Attention to Dynamic Actor | 0.47 proportion of time attending to AOIs | Standard Deviation 0.11 |
| Sham tDCS to dmPFC | Visual Attention to Dynamic Actor | 0.47 proportion of time attending to AOIs | Standard Deviation 0.11 |
Primary
Visual Attention to Dynamic Social Scenes
Visual attention measured via eye-tracking (percentage of time attending to investigator designated AOIs) when viewing videos of two or more actors in a scene (stimuli: The Awareness of Social Inference Task Part 3, Version A). AOIs for this task will be defined as salient social and contextual stimuli (e.g. social stimuli are faces of actors, while contextually salient stimuli include items actors are talking about, such as a plate full of food or an empty wallet).
Time frame: Assessment will be completed 30 minutes after completion of the active/sham stimulation
Population: Population analyzed were those that completed both active and sham stimulations (n=5 removed) with valid eyetracking data (n=2 removed)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal Stimulation tDCS to rTPJ | Visual Attention to Dynamic Social Scenes | 0.22 proportion of time attending to AOIs | Standard Deviation 0.06 |
| Sham tDCS to rTPJ | Visual Attention to Dynamic Social Scenes | 0.23 proportion of time attending to AOIs | Standard Deviation 0.07 |
| Anodal Stimulation tDCS to dmPFC | Visual Attention to Dynamic Social Scenes | 0.26 proportion of time attending to AOIs | Standard Deviation 0.07 |
| Sham tDCS to dmPFC | Visual Attention to Dynamic Social Scenes | 0.25 proportion of time attending to AOIs | Standard Deviation 0.07 |
Primary
Visual Attention to Static Faces
Visual attention measured via eye-tracking (percentage of time attending to investigator designated AOIs) when viewing static, emotional faces (stimuli: Emotion Recognition - 40). AOIs for static faces will be defined as core facial features (i.e. eyes, nose, mouth).
Time frame: Assessment will be completed 30 minutes after completion of the active/sham stimulation
Population: Population analyzed were those that completed both active and sham stimulations (n=5 removed) with valid eyetracking data (n=2 removed)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal Stimulation tDCS to rTPJ | Visual Attention to Static Faces | 0.54 proportion of time attending to AOIs | Standard Deviation 0.15 |
| Sham tDCS to rTPJ | Visual Attention to Static Faces | 0.52 proportion of time attending to AOIs | Standard Deviation 0.15 |
| Anodal Stimulation tDCS to dmPFC | Visual Attention to Static Faces | 0.57 proportion of time attending to AOIs | Standard Deviation 0.13 |
| Sham tDCS to dmPFC | Visual Attention to Static Faces | 0.53 proportion of time attending to AOIs | Standard Deviation 0.14 |
Secondary
Fixation Stabilization
Stabilization of visual fixation on fixation circle positioned in middle of screen. Participants will be placed in front of an eyetracking device and asked to keep their eyes focused on a circle in the middle of the screen. Stabilization will be measured via eye-tracking as the deviation from a single point on screen, calculated by assessing the sum of squares of both the x and y axis (output from eyetracking device). Higher number indicates more movement, and thus less stabilization.
Time frame: Assessment will be completed 30 minutes after completion of the active/sham stimulation
Population: Population analyzed were those that completed both active and sham stimulations (n=6 removed) with valid eyetracking data (n=2 removed)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal Stimulation tDCS to rTPJ | Fixation Stabilization | 0.10 pixels (equivalent: 1/96th in or 0.26mm) | Standard Deviation 0.24 |
| Sham tDCS to rTPJ | Fixation Stabilization | 0.08 pixels (equivalent: 1/96th in or 0.26mm) | Standard Deviation 0.14 |
| Anodal Stimulation tDCS to dmPFC | Fixation Stabilization | 0.05 pixels (equivalent: 1/96th in or 0.26mm) | Standard Deviation 0.1 |
| Sham tDCS to dmPFC | Fixation Stabilization | 0.07 pixels (equivalent: 1/96th in or 0.26mm) | Standard Deviation 0.14 |