Comparison of horizontal head drifts under different conditions in healthy individuals
| Experimental condition | Gaze-evoked horizontal drifts | Rebound drifts | ||
|---|---|---|---|---|
| Amplitude slope | Velocity slope (s−1) | Null position (degrees) | Velocity slope (s−1) | |
| LED target plus laser | −0.0001 ± 0.0001 | 0.0003 ± 0.001 | N/A | 0.001 ± 0.002 |
| LED target only | −0.03 ± 0.01 | −0.008 ± 0.003 | 0.001 ± 0.09 | 0.08 ± 0.01 |
| LED target and neck vibration | −0.22 ± 0.02 | −0.015 ± 0.003 | −0.130 ± 0.16 | 0.12 ± 0.2 |
| LED target, laser, and neck vibration | −0.02 ± 0.008 | −0.010 ± 0.002 | 0.02 ± 0.1 | 0.1 ± 0.02 |
Results for each of the four conditions and four measured variables were compared separately by t test. There were no significant differences among the null positions for any of the conditions. The slopes of amplitudes were significantly different among all conditions (p < 0.001), except for conditions of LED target only versus LED target plus laser and neck vibration (p < 0.5). The slopes of velocities were also significantly different among all conditions (p < 0.001), again except for conditions of LED target only versus laser, LED target and neck vibration (p < 0.5).