This study investigates whether visual attention can be improved in individuals with schizophrenia by stimulating the brain via transcranial Direct Current Stimulation (tDCS).
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
81
active anodal tDCS with behavioral tasks to assess visual attention
sham tDCS with behavioral tasks to assess visual attention
The University of Texas at Dallas
Richardson, Texas, United States
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
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
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
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.
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Time frame: Assessment will be completed 30 minutes after completion of the active/sham stimulation