COGNITIVE FUNCTION AND ASSESSMENT OF LUNG-FUNCTION IN THE ELDERLY

The feasibility of spirometry or respiratory impedance measurements fo r assessing lung function in the elderly was compared in 208 instituti onalized patients with various degrees of cognitive function impairmen t. Respiratory impedance was determined by the forced oscillation tech nique. Cognitive function was assessed by the score for the mini-menta l state (MMS) examination. Of the 208 patients, 126 had severe cogniti ve impairment (MMS less than or equal to 17), 36 had mild impairment ( 18 less than or equal to MMS less than or equal to 23), and 46 had no impairment (MMS greater than or equal to 24). Of the 208 patients, res piratory impedance measurements were possible in 159, whereas in only 85 was spirometry possible. The overall difference between the feasibi lity rates for the spirometric and respiratory impedance measurements was highly significant (chi(2) = 71.4; p < 10(-6)). The difference bet ween the feasibility rates for the two techniques was higher in the gr oup of subjects with severe cognitive impairment than in the groups wi th mild impairment and no impairment, respectively. Among the 84 patie nts able to complete both tests, significant correlations were found b etween the spirometric and respiratory impedance measurements. These r esults indicate that respiratory impedance measurement seems a more us eful tool than spirometry for assessing lung function in elderly patie nts whenever cognitive function is impaired.