The effect of anxiety on respiratory sensory gating measured by the respiratory related evoked potential (RREP)

Abstract

Respiratory sensory gating is evidenced by decreased amplitude of the respiratory-related evoked potentials (RREP) N1 peak for the second occlusion (S2) when two 200-millisecond (msec) occlusions are presented with a 500-msec interval during inspiration. The N1 peak amplitude ratio of the S2 and first occlusion (S1), S2/S1, is less than 0.5 due to central neural sensory gating. We hypothesized that anxiety can modulate individuals' respiratory neural gating. We tested this hypothesis with the paired inspiratory occlusion protocol in 11 low and 10 high anxious individuals. Individuals were divided into the two groups based on their state anxiety scores obtained by the State-Trait Anxiety Inventory. The results showed a significant difference of the N1 peak gating S2/S1 ratio between the low anxious and high anxious group (0.28 ± 0.13 and 0.42 ± 0.16, respectively, p<0.05). A two-way ANOVA confirmed that this ratio difference was due to significantly lower S2 amplitudes in the low anxious group compared to the high anxious group (−1.31 ± 0.6 μV and −1.83 ± 0.59 μV, respectively). The results demonstrated that the respiratory sensory gating function was decreased in high anxious individuals. This suggests that anxiety was associated with increased neural throughput of redundant respiratory sensory information which might underlie altered respiratory symptom perception in anxious individuals.