Table 5.
Summary measures of continuous Neck Disability Index.
| Variable | Follow-up time | N | Mean (SD) | Min, Max |
|---|---|---|---|---|
| NDI | Baseline | 33 | 9.4 (3.9) | 2, 19 |
| 1-month | 30 | 4.3 (3.3) | 0, 12 | |
| 3-month | 28 | 3.4 (3.0) | 0, 13 | |
| 6-month | 26 | 4.0 (2.6) | 0, 9 | |
| 12-month | 25 | 2.7 (2.5) | 0, 9 | |
| Change in NDIa | 1-month | 30 | 4.9 (4.6) | −2, 19 |
| 3-month | 28 | 5.8 (4.4) | −4, 15 | |
| 6-month | 26 | 5.2 (4.8) | −3, 16 | |
| 12-month | 25 | 6.6 (4.0) | 0, 16 | |
| % change in NDIa | 1-month | 30 | 49.2 (36.0) | −33.3, 100.0 |
| 3-month | 28 | 56.9 (43.1) | −100.0, 100.0 | |
| 6-month | 26 | 43.5 (55.0) | −150.0, 100.0 | |
| 12-month | 25 | 69.6 (29.4) | 0.0, 100.0 |
NDI = Neck Disability Index; SD = standard deviation; Min = minimum value; Max = maximum value.
a
From baseline to each follow-up time point (i.e., value at baseline minus value at each follow-up time point).