Our protocol uses a noninvasive brain modulation technique called transcranial direct current stimulation, or tDCS, to reduce online gaming use. tDCS is simple, safe and inexpensive to administer, compared to other brain stimulation techniques. We also use neuroimaging to assess brain changes related to stimulation.
After recruiting both online game playing and non-online game playing individuals, explain to each participant the aim of the study, the main experimental procedures, and any potential risks associated with participating in the study. After answering any questions, obtain written consent. Have each participant fill out questionnaires, such as the Internet Addiction Test and Brief Self Control Scale;and ask the participants to report the average weekly hours spent playing games.
To perform an FDG PET scan, inject each participant with 185 to 222 megabecquerels of FDG;and have the participants rest for 45 minutes, in a supine position, in a dark and quiet room, with their eyes closed, to allow FDG uptake. At the end of the uptake period, use a PET/CT scanner to acquire transaxial emission images and CT images in about 15 minutes, applying standard attenuation correction, filtering, and reconstruction techniques. Within a week after the baseline assessment, seat the participant in a chair in the exam room, and set the parameters of the tDCS device to ramp up to 2 milliamps over 30 seconds.
Remain at this current for 29 minutes before returning to zero milliamps over the last 30 seconds. Place a head cap, constructed in accordance with the International 10-20 system, on the participant's head, and mark the left dorsolateral prefrontal cortex at F3, and the right dorsolateral prefrontal cortex at F4.After removing the head cap, place two sponge electrodes in the rubber holders of the tDCS headband, and soak the electrodes with saline solution. Remove any makeup, dirt, or sweat from the scalp where the electrodes will be applied, and place the headband on the participant's head, with the anodal electrode over F3, and the cathodal electrode over F4.Then use the cable to connect the electrodes to the tDCS device.
Turn on the device and ask the participant to report any adverse effects during or after the tDCS session. At the end of the 30 minute stimulation, turn off the device and remove the electrodes from the participant. Within a week after the last session, administer the same questionnaires, and acquire a post treatment FDG-PET scan.
For preprocessing of the imaging data, use an appropriate software package to convert the DICOM files to NIfTI files, and spatially normalize all of the PET images to the standard PET template. After creating binary masks for the left and right dorsolateral prefrontal cortices, use the masks to extract the Regional Cerebral Metabolic Rate of Glucose of the left and right dorsolateral prefrontal cortices. Then calculate the Asymmetry Index of the Regional Cerebral Metabolic Rate of Glucose in the dorsolateral prefrontal cortex.
A positive index indicates a right greater than left asymmetry of glucose metabolism. In this representative analysis, a total of 15 gamers and 10 non-gamers were recruited. The tDCS sessions successfully lowered the Internet Addiction Test score and weekly hours spent playing games, and improved the Brief Self Control Scale score in gamers.
A significant negative correlation was also found between the changes in the Internet Addiction Test score and the changes observed in the Brief Self Control Scale score in gamers. PET analysis revealed that the Asymmetry Index of the Dorsolateral prefrontal cortex was significantly different between the gamer group and the non-gamer group at baseline. Notably, following the tDCS sessions, the Asymmetry Index of the Dorsolateral prefrontal cortex in the gamer group was significantly decreased.
While performing this procedure, it is important to ensure that the parameters are set correctly, and the electrodes are positioned accurately over the stimulation site. Active tDCS can be compared to Sham tDCS to validate its efficacy. Also, other neuroimaging methods, such as fMRI, can be used to assess the brain changes.
These protocols can be adapted to explore new treatment options, or other psychiatric or neurological disorders.
