Objectives: The aim of this study was to compare subjective measures (overall health assessment both by the study physician and the child's mother) with objective measurements of forced expiratory volumes (FEVt) and maximal flow at functional residual capacity (V)over dot(max)FRC) in recurrently wheezy infants. Methods: Sixteen wheezy infants (12 boys) aged 8-26 months were studied. A clinical assessment at visit 1 was followed by the run-in period during which day- and nighttime asthma symptom scores were obtained. The actual study period consisted of 2 visits when patient's lung function was assessed. The first of which was during an acute exacerbation (visit 2), while the second was when the infant was asymptomatic (visit 3). FEVt were obtained by the raised volume rapid thoracic compression technique (RVRTC) and (V)over dot(max)FRC by the tidal volume rapid thoracic compression technique (TVRTC). Results: Mean FEVt but not mean (V)over dot(max)FRC were significantly lower at visit 2 compared to visit 3 (FEV0.5: p = 0.005, and FEV0.75: p = 0.002; (V)over dot(max)FRC: p = 0.15) and correlated well with overall health assessment by the study physician (FEV0.5: r = 0.82, and FEV0.75: r = 0.84), but not with the overall health assessment by the mother. Conclusions: We have shown in the present study that objective measurements of FEVt from a raised lung volume correlate well with the overall health assessment by the study physician; this was in contrast to measurements Of (V)over dot(max)FRC in the tidal volume range. We therefore conclude that the RVRTC technique is a feasible method to assess and monitor obstructive lung disease in infancy. Copyright (C) 2002 S Karger AG, Basel.