Table 2 Standard deviations of head motion in each of the 6 axes for Healthy controls as well as Preoperative and Postoperative VS subjects (Mean ± SD)

Fore-aft

Lateral

Vertical

Roll

Pitch

Yaw

Tasks

Healthy control

Tandem walk forward (FGA)

95 ± 40

69 ± 29

63 ± 21

7.0 ± 2.5

10 ± 6.4

6.7 ± 1.9

Tandem walk forward

106 ± 87

68 ± 38

72 ± 44

6.9 ± 3.3

9.0 ± 5.6

6.4 ± 2.4

Tandem walk backward

83 ± 22

77 ± 42

62 ± 24

7.4 ± 3.6

8.2 ± 1.7

6.9 ± 2.3

Tandem stance eyes open

30 ± 12

22 ± 6.9

18 ± 9.7

1.5 ± 0.9

2.3 ± 1.4

1.8 ± 0.6

Tandem stance eyes closed

28 ± 9.9

33 ± 16

21 ± 8.6

2.2 ± 1.1

2.3 ± 1.0

3.0 ± 1.5

Standing on firm eyes closed

23 ± 6.5

18 ± 3.9

14 ± 5.5

0.9 ± 0.2

1.4 ± 0.6

1.2 ± 0.2

Standing on foam eyes closed

27 ± 5.9

23 ± 4.0

18 ± 4.1

1.5 ± 0.4

1.9 ± 0.5

2.0 ± 0.6

Standing on foam eyes open

28 ± 14

20 ± 3.4

15 ± 6.7

1.0 ± 0.3

1.7 ± 1.0

1.7 ± 0.8

Foam cup balance 1 foot

139 ± 72

52 ± 29

54 ± 45

3.6 ± 1.9

8.8 ± 4.5

4.9 ± 2.0

Foam cup alternatively foot

90 ± 38

100 ± 46

59 ± 22

7.6 ± 3.2

8.7 ± 3.2

7.8 ± 3.1

Preoperative

Tandem walk forward (FGA)

104 ± 57

106 ± 48

68 ± 34

9.6 ± 4.4

9.7 ± 5.6

8.2 ± 4.2

Tandem walk forward

91 ± 43

93 ± 46

74 ± 41

8.7 ± 4.1

8.8 ± 3.9

7.7 ± 3.7

Tandem walk backward

101 ± 52

107 ± 54

62 ± 31

10 ± 4.9

9.4 ± 5.1

8.2 ± 3.9

Tandem stance eyes open

50 ± 24

40 ± 28

22 ± 12

3.5 ± 2.3

3.9 ± 2.0

3.8 ± 1.9

Tandem stance eyes closed

63 ± 29

94 ± 56

41 ± 20

8.4 ± 4.7

7.2 ± 4.8

7.6 ± 3.4

Standing on firm eyes closed

41 ± 23

27 ± 23

15 ± 9.6

2.1 ± 2.0

2.8 ± 2.4

2.1 ± 1.6

Standing on foam eyes closed

55 ± 34

42 ± 21

34 ± 27

3.8 ± 1.7

4.4 ± 2.4

3.7 ± 1.4

Standing on foam eyes open

32 ± 12

25 ± 15

15 ± 6.6

2.2 ± 1.3

2.4 ± 1.1

2.1 ± 0.8

Foam cup balance 1 foot

93 ± 73

86 ± 53

46 ± 28

7.0 ± 4.2

7.0 ± 3.6

6.1 ± 2.6

Foam cup alternatively foot

74 ± 29

111 ± 28

53 ± 11

9.6 ± 2.7

7.7 ± 2.3

8.5 ± 2.7

Postoperative

Tandem walk forward (FGA)

81 ± 48

95 ± 63

66 ± 44

8.7 ± 6.1

6.8 ± 4.2

6.5 ± 4.3

Tandem walk forward

94 ± 64

84 ± 53

67 ± 45

7.6 ± 4.9

7.3 ± 5.0

6.5 ± 4.0

Tandem walk backward

86 ± 51

89 ± 59

65 ± 44

8.2 ± 5.3

7.1 ± 4.3

6.8 ± 4.3

Tandem stance eyes open

67 ± 54

40 ± 24

23 ± 12

3.5 ± 2.3

3.0 ± 1.8

3.5 ± 1.7

Tandem stance eyes closed

73 ± 44

66 ± 39

46 ± 29

5.9 ± 2.4

6.4 ± 2.8

6.3 ± 2.5

Standing on firm eyes closed

39 ± 15

26 ± 9.4

16 ± 7.6

1.8 ± 0.7

2.6 ± 1.3

2.2 ± 0.7

Standing on foam eyes closed

65 ± 42

56 ± 23

38 ± 22

4.8 ± 2.8

6.2 ± 3.3

6.0 ± 3.3

Standing on foam eyes open

59 ± 50

23 ± 9.2

25 ± 23

1.9 ± 0.8

3.1 ± 2.2

2.6 ± 1.4

Foam cup balance 1 foot

92 ± 55

74 ± 42

48 ± 22

6.2 ± 3.8

6.7 ± 3.3

5.8 ± 2.3

Foam cup alternatively foot

65 ± 14

112 ± 39

56 ± 13

8.4 ± 2.9

6.3 ± 0.9

8.4 ± 1.9