Effects of Glucose Tablet Candy Ingestion on Attention Following Smartphone Use in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Crossover Trial

<b>Background/Objectives</b>: Excessive smartphone use may negatively affect cognitive functions, including attention. While sensorimotor rhythm, beta, and theta waves have been linked to concentration, the electroencephalography (EEG) frequency band that most reliably serves as a neurophysiological marker of concentration is unclear. Therefore, we aimed to evaluate the effects of glucose tablet candy ingestion on attention following smartphone use in healthy adults. <b>Methods</b>: A randomized, double-blind, placebo-controlled crossover trial was conducted in 16 healthy adults aged 18-39 years. Participants performed a 30 min smartphone-based information search task. Attention was assessed before and after the task using the Cognitrax test battery, and participants ingested either a glucose tablet candy (containing 26 g of glucose) or a placebo (no glucose) between tests. EEG was performed during attention tests using a patch-type device. Subjective sensations, including attention, fatigue, and mental clarity (clear-headedness), were evaluated using a visual analog scale (VAS). The primary outcome was attention test scores, and secondary outcomes included EEG power and VAS ratings. <b>Results</b>: Glucose tablet candy ingestion after smartphone use significantly improved mean correct response time and error response scores in part 2 of the four-part continuous performance test, a subtest within Cognitrax, compared to that with the placebo. Additionally, glucose intake significantly attenuated the decrease in right prefrontal beta EEG power observed with the placebo. Improvements were also observed in self-reported physical fatigue and mental clarity on the VAS following glucose ingestion. <b>Conclusions</b>: The ingestion of the glucose (26 g) tablet candy improved sustained attention after smartphone use in healthy adults aged 18-39 years and was associated with changes in brain activity. These results suggest that the glucose tablet candy may help counteract the decline in concentration following cognitively demanding smartphone use.