Table 5

Trouble concentrating or thinking clearly at baseline, week 7 and week 14 by group. Mean score derived from the Columbia Scale according to response to the second question, "Over the last 3 days how much have you been bothered by trouble concentrating or thinking clearly? Possible answers and scoring: 1 = not at all, 2 = a little bit, 3 = moderately, 4 = quite a bit, 5 = extremely.

Time point

Control (n = 23)

Intervention (n = 46)

mean score (SD)

mean score (SD)

Baseline

2.5 (1.1)

2.9 (1.2)

Week 7

2.6 (1.1)

1.9 (0.9)

Study end (Week 14)

2.5 (0.9)

1.8 (0.9)

Mills et al. Journal of Circadian Rhythms 2007 5:2   doi:10.1186/1740-3391-5-2