Performing slow vital capacity in older people with and without cognitive impairment — is it useful?

Background: most patients with moderate cognitive impairment are unable to perform forced spirometry. It has been suggested that slow vital capacity (SVC) is easier to perform than forced vital capacity (FVC) because it requires less understanding and co-ordination. We conducted a study to determine whether that assertion is correct. Methods: we studied 83 inpatients, mean age 83 years (range 67–95, 51 female). They had measurements made of FVC, SVC and the Mini-Mental State Examination (MMSE). The spirometry was conducted using the European Respiratory Society/American Thoracic Society standards. Results: of the 83 subjects, 38 were able to do both FVC and SVC and 32 were unable to do either. The overall concordance was 84%. Twelve were able to do SVC but not FVC (eight due to excessive cough, two due to weakness and two had an MMSE