The investigators have previously shown that safe, non-invasive methods of brain stimulation such as the administration of transcranial infrared light can result in improvements to cognition and emotion. The investigators hypothesize that transcranial photobiomodulation (tPBM) can be used in conjunction with attention bias assessment and modification to reduce anxiety symptoms in individuals with sub-clinical anxiety.
The investigators will conduct two studies: one examining the efficacy of transcranial photobiomodulation as a standalone treatment to alleviate sub-clinical anxiety symptoms and another evaluating the role of transcranial photobiomodulation as an adjunct to a form of cognitive behavioral therapy in anxiety treatment. The investigators will recruit individuals with sub-clinical anxiety and use attention bias assessment (ABA) to assess levels of anxiety, and then use attention bias modification (ABM) to reduce levels of anxiety. Brain activity will be monitored using functional near-infrared spectroscopy (fNIRS). An online prescreen questionnaire will be used to determine participant eligibility. No medical records are accessed/obtained for verifying inclusion/exclusion criteria. Informed consent is obtained during the first in-person visit. Participants fill out questionnaires to assess their medical history and anxiety/depression symptoms. The participants then participate in either ABA or ABA/ABM while wearing the fNIRS headset before and after transcranial photobiomodulation treatment or sham. Both studies will comprise three in-person visits with an online follow-up a week later. In this single-blind, sham-controlled experiment, block randomization will be performed to minimize selection bias and allocation bias.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
280
Attention bias assessment and modification involve two versions of the dot-probe task. These tasks are based on the premise that repeated attention shifts can retrain attentional biases, with the expectation that reducing attentional bias toward threats will alleviate sub-clinical anxiety symptoms.
Participants will receive near-infrared light at 1064 nanometers to the right side of the forehead for 8 minutes. The investigators have introduced this form of transcranial photobiomodulation (tPBM) as a means of human cognitive enhancement, and as an adjunct for attention bias modification for the reduction of symptoms of depression. In the present study, the investigators wish to extend these findings to the use of attention bias modification for the reduction of sub-clinical anxiety.
The University of Texas at Austin
Austin, Texas, United States
RECRUITINGComposite cognitive score in the dot-probe task
The participant pays attention to a fixation cross in the center of the screen, which is followed by the presentation of two images on the left and right of the screen. One of these new images is a "threat" image, while the other is neutral. Following each trial of stimuli presentation, a probe type ("\<" vs. "\>") will randomly appear in the same location previously occupied by either the threatening or neutral image and remain on the screen until the participant has responded. Participants respond to the probe type by pressing the "←" or the "→" arrow key, respectively, on the keyboard, as quickly but as accurately as possible. The probe randomly replaces the neutral or the negative stimulus with equal frequency (50/50). The single primary outcome is the composite cognitive score which is calculated on the basis of performance in this task.
Time frame: Visit 1 (baseline), Visit 2 (three days after Visit 1), Visit 3 (1 week after Visit 2)
Change in concentration of oxygenated hemoglobin as measured by functional near-infrared spectroscopy
Hemodynamic activity is assessed non-invasively using near-infrared spectroscopy. In this procedure, a participant wears an apparatus on the head which contains an array of light sources and detectors. Light is applied to the surface of the skin, and a small fraction of the light passes through the underlying tissue and reflects back to the surface, where it is detected and the number of photons at specific light wavelengths are counted by a computer. This photon count can be converted to changes in concentration of metabolic indices, such as oxygenated/deoxygenated hemoglobin.
Time frame: Visit 1 (baseline), Visit 2 (three days after Visit 1), Visit 3 (1 week after Visit 2)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.