At a glance
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Influence of Low-Level Light Therapy on Attention Bias Modification and Mood Change in Dysphoric Individuals
In Brief
A clinical study evaluating Left Low Level Light Therapy, Attention bias modification, and 2 other interventions for Depression. Completed, enrolled 51 participants.
Detailed Summary
The goal of this project is to use low-level light therapy (LLLT) to enhance neural metabolism in the prefrontal cortex of humans, and measure the effects of LLLT on attentional bias change following a single session of attention bias modification (ABM). LLLT is non-invasive, therapeutically beneficial, and promotes a wide range of biological effects including enhancement of energy production, gene expression and prevention of cell death. Previous research has indicated that human participants show a beneficial psychological effect, including improved mood and greater sustained attention, following a single treatment of LLLT to the forehead. ABM is a computer-based cognitive task designed to decrease the mood-congruent negative attentional bias frequently observed in depressed and dysphoric individuals. Previous ABM studies have led to decrease in clinical symptoms relative to a control condition. This study will explore whether the effects of LLLT on mood and attention could improve the potency of ABM, leading to greater attention change and greater improvement of mood relative to sham LLLT.
Study Details
Timeline
Interventions
Administration of left LLLT consists of applying light of a specific wavelength (1064 nanometers) using a laser diode, the CG-5000 high density laser (Cell Gen Therapeutics, LLC). Left LLLT will target the left forehead. The diameter parameters of stimulation are the same that showed psychologically beneficial effects in Schiffer et al. (2009). At the power level described, the energy emitted by the CG-5000 at this setting is one quarter of the skin MPE (0.250 W/cm2), exposure to it is not deemed harmful to tissue, and it causes no detectable physical damage and negligible heat.
The task will consist of a modified dot-probe paradigm. A pair of stimuli depicting a negative word and a neutral word will be presented, randomly located to the right and left side of the computer screen. The words will be presented for 1000 ms. The words will then disappear and a dot-probe will appear in the center of the screen location of one of the words (i.e., O or Q). This probe will appear on the screen until the participant presses one of two response buttons to indicate the identity of the probe. The presentation of the probe will be staggered to maximize attention for the neutral stimulus. Latency and accuracy of the button press responses are recorded by the computer.
Administration of right LLLT consists of applying light of a specific wavelength (1064 nanometers) using a laser diode, the CG-5000 high density laser (Cell Gen Therapeutics, LLC). Right LLLT will target the right forehead. The diameter parameters of stimulation are the same that showed psychologically beneficial effects in Schiffer et al. (2009). At the power level described, the energy emitted by the CG-5000 at this setting is one quarter of the skin MPE (0.250 W/cm2), exposure to it is not deemed harmful to tissue, and it causes no detectable physical damage and negligible heat.
Administration of sham LLLT is designed to resemble active LLLT from the participant's perspective, but uses a dosage markedly below the minimal necessary threshold to elicit a response.