Transcranial direct current stimulation associated with physical exercise can help smokers to quit smoking: a randomized controlled trial

Abstract

Chronic exposure to nicotine is related to low activity in the prefrontal cortex and insular hyperactivity in smokers. Therefore, addiction has been the target of experimental studies in aerobic exercise (AE) and transcranial direct current stimulation (tDCS). Thus, the objective of this study was to verify the effect of AE and anodal tDCS at F4 and cathodal at T3 on craving, motivation to change smoking behaviour (MCSB) and brain reactivity (BR) in smokers. The sample consisted of 41 chronic smokers distributed into four groups: tDCS (G1), AE (G2), tDCS combined with AE (G3) and sham tDCS combined with AE (G4). All volunteers underwent 5 consecutive sessions of the intended intervention. Before starting the intervention protocol and after the last intervention session, the volunteers answered questionnaires and underwent an electroencephalogram exam, to evaluate the variables investigated. The results demonstrated that AE, when associated with active tDCS, was effective in promoting a reduction in craving (p < 0,05), cigarette consumption (p < 0,05), and BR (p < 0,05) during exposure to smoking cues, in addition to increasing MCSB (p < 0,05). Therefore, only when associated with AE, tDCS was able to modulate positive effects on smoking.

Fig. 1

Carbon monoxide (CO) levels (mean ± standard error). *p < 0.05, **p < 0.01. There was no significant difference between the groups.

Fig. 2

Cigarette consumption in the groups. ***p < 0.001 and *p < 0.05.

Fig. 3

MMCF level (mean ± standard error) **p < 0.01.

Fig. 4

Craving level (mean ± standard error) ***p < 0.001.

Fig. 5

Gamma rhythm of the left anterior region (LA) (mean ± standard error) *p < 0.05.

Fig. 6

Gamma rhythm of the left posterior region (LP) (mean ± standard error) *p < 0.05.

Fig. 7

Gamma rhythm of the right anterior region (RA) (mean ± standard error) *p < 0.05.

Fig. 8

Gamma rhythm of the left anterior region (LA) (Mean ± standard error) *p < 0.05.

Fig. 9

Gamma rhythm of the right posterior region (RP) (mean ± standard error) *p < 0.05.

Fig. 10

Gamma rhythm of the right anterior region (RA) during the post-test of task 2 (mean ± standard error) *p < 0.05.

Fig. 11

Recording of increased gamma activity during task 1, in group G1 (tDCS), in the left anterior (a,b) and posterior (c,d) regions pre and post test. Color scale bar represents brain waves frequency (Hz). The colors of the spectrum are distinguished by the different frequency ranges from low (red) to high (blue) : delta (δ), theta (θ), alpha (α), beta (β), and gamma (γ). Dark blue shows an increase in gamma activity.

Fig. 12

Recording of increased gamma activity during task 2, in group G1 (tDCS), in the right anterior region pre (a) and post test (b). Color scale bar represents brain waves frequency (Hz). The colors of the spectrum are distinguished by the different frequency ranges from low (red) to high (blue) : delta (δ), theta (θ), alpha (α), beta (β), and gamma (γ). Dark blue shows an increase in gamma activity.

Fig. 13

Recording of decreased gamma activity in G3 (tDCS + AE) group (b) in the right anterior region during task 2 compared to G1 (tDCS) group (a). Color scale bar represents brain waves frequency (Hz). The colors of the spectrum are distinguished by the different frequency ranges from low (red) to high (blue): delta (δ), theta (θ), alpha (α), beta (β), and gamma (γ). Dark blue shows an increase in gamma activity.

Fig. 14

Recording of increased gamma activity during task 1, in group G4 (sham), in the left anterior (a,b) and right posterior (c,d) regions pre and post test. Color scale bar represents brain waves frequency (Hz). The colors of the spectrum are distinguished by the different frequency ranges from low (red) to high (blue) : delta (δ), theta (θ), alpha (α), beta (β), and gamma (γ). Dark blue shows an increase in gamma activity.