BACKGROUND:
Chronic cough is common, and
medical treatment can be ineffective. Mindfulness is a
psychological intervention that aims to teach moment-to-moment non-judgemental
awareness of thoughts, feelings and
sensations. METHOD: 30 healthy subjects and 30 patients with
chronic cough were studied in two sequential trials. For both studies,
cough reflex sensitivity to
citric acid (C5) was measured on two occasions, with urge to
cough rated following each
inhalation; between challenges subjects were randomised to (1) no intervention, (2) mindfulness or (3) no intervention but modified
cough challenge (subjects suppress
coughing). For the healthy volunteers, measures were 1 h apart and mindfulness was practised for 15 min. For the patients with
chronic cough measures were 1 week apart and mindfulness was practised daily for 30 min. RESULTS: In healthy volunteers,
median change (
interquartile range (
IQR)) in
cough reflex sensitivity (logC5) for no intervention, mindfulness and suppression was +1.0 (0.0 to +1.3), +2.0 (+1.0 to +3.0) and +3.0 (+2.8 to +3.0) doubling concentrations (p = 0.003); there were
significant reductions for both mindfulness (p = 0.043) and suppression (p = 0.002) over no intervention. In patients with
cough,
median change (
IQR) in logC5 for no intervention, mindfulness training and voluntary suppression was 0.0 (-1.0 to +1.0), +1.0 (-0.3 to +1.0) and +1.0 (+1.0 to +2.0) doubling concentrations (p = 0.046); there was a
significant reduction for suppression (p = 0.02) but not mindfulness (p = 0.35). Urge to
cough did not change after mindfulness compared with control in either healthy subjects (p = 0.33) or those with
chronic cough (p = 0.47). CONCLUSION: Compared with control, mindfulness decreased
cough reflex sensitivity in healthy volunteers, but did not alter
cough threshold in patients with
chronic cough. Both groups were able to suppress
cough responses to
citric acid inhalation.
