Effect of Gum Chewing Frequency on Oxygenation of the Prefrontal Cortex.

Since increased cerebral oxygenation reflects cerebral activation, this study investigated the effect of mastication frequency on prefrontal cortex oxygenation. Eleven young volunteers (nine women, two men; M age = 20.9 years, SD = 0.9) carried out three trials in which they were asked to chew a tasteless gum for 3 min at varying (rates of mastication frequency: 30, 70, and 110). Breaks of 2 min each were interleaved between trials. The oxygenation of the left prefrontal cortex was monitored by near-infrared spectroscopy. We found a significant increase in cortical oxygenation during gum chewing in all three conditions ( p < .05), compared with a resting level; we also found a significant difference between the Fast and Slow chewing conditions, and between the Fast and Normal (70 rpm) conditions, both findings seemingly related to activation of a motor command in frontal brain regions. To our knowledge, this is the first report on the effect of mastication frequency on cerebral oxygenation. Possible implications of this finding are discussed.