Table 1. The exercise modifiers to control the difficulty vestibular rehabilitation exercises (Alsalaheen, Whitney et al. (2013))

Modifier	Choices
Posture	1: Sitting, 2: Standing, 3: Walking, Not applicable/Not specified (NA/NS)
Surface	1: Level, 2: Foam, 3: Uneven, 4: Obstacle, 5: Stairs, 6: Ramps, NA/NS
Base of support	1: Feet-apart, 2: Feet-together, 3: Semi-tandem, 4: Tandem, NA/NS
Trunk position	1: Upright, 2: Leaning, 3: Rotated, NA/NS
Arm position	1: Weight bearing, 2: Close to body, 3: Away from body, 4: Reaching, 5: Carrying, 6: Picking up objects, 7: Juggling, NA/NS
Head movement direction	1: Still, 2: Yaw, 3: Pitch, 4: Roll, NA/NS
Direction of whole-body movements	1: Anterior–posterior, 2: Medial–lateral, 3: Multi-directional, NA/NS
Visual input	1: Eyes closed, 2: Eyes open, 3: Complex patterns, NA/NS
Cognitive dual task	1: Yes, 2: No
Special circumstances	For example, note if the VORx1 exercise was performed with a near or far target