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 600ml), after 8h of fasting. On each assessment day, eye blink responses (EMG) to 10 acoustic startle stimuli (105dB) were assessed at 4 measurement points (before, 0, 7, 14min. 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 600ml 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.