Long-term anodal tDCS eases hunger, food intake in obese individuals
Short-term anodal transcranial direct current stimulation (tDCS), a noninvasive technique used to modulate brain activity, appears to confer no immediate effect on ad libitum food intake or weight change compared with sham tDCS, according to a study. However, a longer period of anodal tDCS reduces hunger and snack food intake in obese individuals.
Findings showed that short-term anodal tDCS had no effect on ad libitum food intake from the vending machines relative to sham tDCS. Consequently, there was no effect seen on short-term or 4-week weight change.
Visual analogue scale (VAS) ratings for hunger and the urge to eat significantly decreased more in the anodal tDCS group (p=0.01) vs the sham group (p=0.05). Total energy intake during a snack food taste test (SFTT) was relatively lower in satiated individuals (p=0.01) after long-term tDCS.
Researchers conducted a randomized parallel-design study combining inpatient and outpatient assessments over 31 days. Twenty-three obese individuals (mean body mass index, 39.3 kg/m2; 12 men) received 15 sessions of anodal or sham tDCS aimed at the left dorsolateral prefrontal cortex (DLPFC), a region of the brain that plays a key role in the support of self-regulatory aspects of eating behaviour and inhibitory control.
A vending machine paradigm and SFTTs were used to assess ad libitum food intake. Appetite was estimated using a VAS, and body weight was measured. Researchers then examined the effect of short-term (ie, three sessions) and long-term (ie, 15 sessions) tDCS on these variables.
“Obesity is associated with reduced activation in the left DLPFC,” according to researchers.