Anticipated adaptation or scale recalibration?

BACKGROUND The aim of our study was to investigate anticipated adaptation among patients in the subacute phase of Spinal Cord Injury (SCI). METHODS We used an observational longitudinal design. Patients with SCI (N = 44) rated their actual, previous and expected future Quality of Life (QoL) at three time points: within two weeks of admission to the rehabilitation center (RC), a few weeks before discharge from the RC, and at least three months after discharge. We compared the expected future rating at the second time point with the actual ratings at the third time point, using student's t-tests. To gain insight into scale recalibration we also compared actual and previous ratings. RESULTS At the group level, patients overpredicted their improvement on the VAS. Actual health at T3(M = 0.65, sd =0.20)) was significantly lower than the predicted health at T1 of T3 (M = 0.76, sd = 0.1; t(43) = 3.24, p < 0.01), and at T2 of T3(M = 0.75,sd = 0.13; t(43) = 3.44, p < 0.001). Similarly the recalled health at T3 of T2 (M = 0.59, sd = 0.18) was significantly lower than the actual health at T2 (M = 0.67, sd = 0.15; t(43) = 3.26, p <0.01). Patients rated their future and past health inaccurately compared to their actual ratings on the VAS. In contrast, on the TTO patients gave accurate estimates of their future and previous health, and they also accurately valued their previous health. Looking at individual ratings, the number of respondents with accurate estimates of their future and previous health were similar between the VAS and TTO. However, the Bland-Altman plots show that the deviation of the accuracy is larger for the TTO then the VAS. That is the accuracy of 95% of the respondents was lower in the TTO then in the VAS. CONCLUSIONS Patients at the onset of a disability were able to anticipate adaptation. Valuations given on the VAS seem to be biased by scale recalibration.