Nonspecific effects of gap paradigm on swallowing

Abstract Objective Analogous to the gap paradigm in experiments for saccadic eye movements with very short reaction times, we hypothesized that the initiation of oropharyngeal swallowing movements guided by visual cues are encouraged under experimental conditions using a similar gap paradigm. Methods A red visual cue indicating to hold a bolus in the mouth and a blue one indicating to swallow the bolus were sequentially provided on a computer display to 11 healthy participants. The gap period between these cues varied from 0 to 800 ms. Swallowing kinetics and kinematics were recorded using surface electromyography and a laser displacement sensor, respectively. Results In comparison with the no-gap paradigm, the delay from the onset of muscle activities to initiation of movement significantly decreased with a 100- ( p < 0.01) and 200-ms ( p < 0.005) gap period. With other gap periods, no significant change was detected in the delay. Conclusions Initiation of visually guided swallowing was enhanced by a gap paradigm of 100–200 ms. Wrist flexion was boosted in a similar manner. Thus, the gap effect may be a generalized warning effect. Significance Our findings might provide insights into the contribution of the basal ganglia to volitional swallowing.