Gastric modulation of startle eye blink

Previous assessment methods of gastric interoception either rely on self-reports, or imply invasive procedures. We investigated the reliability of startle methodology as a non-invasive alternative for the assessment of afferent gastric signals. Twenty-four participants were tested on three separate days, on which they were requested to ingest water (either 0, 300 or 600 ml), after 8 h of fasting. On each assessment day, eye blink responses (EMG) to 10 acoustic startle stimuli (105 dB) were assessed at 4 measurement points (before, 0, 7, 14 min. after ingestion). Increased normogastric responses (EGG), ratings of satiety and fullness, and higher heart rate variability (RMSSD) suggested effective non-invasive induction of gastric distention. Startle responses were lower directly after ingestion of 600 ml as compared to earlier and later measurements. These results suggest that startle methodology provides a reliable method to investigate afferent gastric signals. It could be useful to study possible dissociations between subjective reports and objective afferent gastric signals in eating or somatoform disorders.