No gender differences in neural gating of respiratory sensations in COPD patients – preliminary findings

Abstract

<b>Background:</b> Recent studies suggested that female COPD patients show greater perception of dyspnea compared to male patients. According to the neural gating model of respiratory sensations (NGRS), dyspnea results from reduced neural gating of respiratory afferent signals into the cerebral cortex, but potential gender differences in NGRS in COPD remain untested. <b>Aims and objectives:</b> This electroencephalography (EEG)-study compared the NGRS mechanism between female and male COPD patients. We hypothesized that female patients would show reduced NGRS. <b>Methods:</b> During EEG measurements, 11 female (mean age=63.5 years; mean FEV1%pred=55.2) and 15 male COPD patients (mean age=64.1 years; mean FEV1%pred=48.6) underwent three experimental blocks during which paired inspiratory occlusions were repeatedly presented (S1 and S2; each: 150 ms, ITI: 500ms). NGRS is characterized by reduced amplitudes of the respiratory-related evoked potential component N1 (~100 ms post-occlusion) evoked by the second occlusion (S2) compared to the N1 evoked by the first occlusion (S1). NGRS is quantified as the ratio of N1 peak amplitudes (S2/S1) with higher ratios reflecting reduced NGRS. <b>Results:</b> An independent-samples t-test did not reveal significant differences in the N1 S2/S1 ratios between female (M=0.68, SD=0.20) and male COPD patients (M=0.78, SD=0.41); t (24)=1.67, p=0.208. These results suggest that neural gating is not reduced in female compared to male COPD patients. <b>Conclusions:</b> These preliminary findings suggest no gender differences in the neural gating of respiratory sensations in COPD. However, these findings need to be confirmed in larger samples in order to draw definite conclusions.