Gain values were independent of stimulus frequencies within the range that we presented, as was also described in Kelders et al.
11 Therefore, data were pooled over all frequencies.
The three reflex-gain values of the age-matched subjects at all frequencies are plotted in
Figure 1(controls A, C, E; patients B, D, F). Recently, Kelders et al.
11 found an increased COR gain in elderly patients (older than 60 years) and in patients with whiplash injury.
6 In addition, in this study, a higher COR gain was found in WAD patients than in healthy controls (
Figs. 1A 1B ; Kolmogorov-Smirnov test,
P = 2.9 × 10
−6). OKR and VOR gains do not show a significant change (VOR gain,
P = 0.27; OKR gain,
P = 0.25). Gain values of patients remained consistent with those of healthy controls
(Figs. 1C 1D 1E 1F) . Previously, Kelders et al.
11 also found a negative correlation between COR gain and VOR gain in healthy controls.
Figure 2Ashows a similar correlation for healthy participants (
r = −0.38,
P = 0.01), but not for patients (
r = 0.01,
P = 0.95). Furthermore neither reflex was significantly correlated with the OKR in controls (
r = 0.26,
P = 0.08;
r = −0.02,
P = 0.9 respectively,
Fig. 2B ), or patients (
r = 0.09,
P = 0.05,
r = 0.16,
P = 0.31 respectively,
Fig. 2C ). Although the COR gain increases with age in controls (
r = 0.32,
P < 0.02), such a difference does not appear in patients (
r = −0.05,
P > 0.7;
Fig. 3 ).