A stair-climbing test for ambulatory assessment of children with cerebral palsy

The purpose of this study was to develop a stair-climbing test to measure energy cost (EC) and mechanical efficiency (ME) in children with cerebral palsy (CP) to evaluate ambulation-related motor function and its changes after intervention or maturation. Five normally developed (ND) and 10 children with CP were tested. The gross ME (MEg) was calculated from the work done (W) and the total energy cost (oxygen consumption) measured while repeatedly ascending and descending four steps for ≈5 min without subtracting the resting metabolic rate. The MEg was significantly lower in CP than ND (3% versus 20%, P<0.001). The test was repeated in the 10 children with CP after a 4-month therapy recess. The MEg values correlated with the initial tests, with a small, significant increase of 2%. When calculating net ME (MEn) from W and the energy cost above resting, the correlation of MEn values before and after therapy was inferior to that using MEg values. Similarly, individual ME values obtained by estimating energy cost from the increase in heart rate (HR) during stair-climbing also correlated poorly, with large variability. These results show that MEg may be used to evaluate changes in motor function resulting from age-related development or therapy. MEg is as good or superior to MEn; the extra time required to obtain resting energy cost and heart rate values is not necessary when measurements are desired within the same individual.