Introduction: Stroke is a major cause of acquired cerebral disability among adults, frequently accompanied by depression. New ways of intervention to prevent post stroke depression is therefore needed. The blue light spectrum is the strongest zeitgeber (time-giver) and is known to stabilize the circadian rhythm. Patients admitted for rehabilitation are often lacking the blue light in daytime due to the long indoor admission; furthermore, they are often exposed to blue light in the evenings, as blue light is contained in standard lightning.
Hypothesis: Circadian light will reduce depressive mood in stroke patients admitted for rehabilitation.
Methods: The study is a prospective parallel longitudinal randomized controlled study (quasi randomization). Stroke patients in need of rehabilitation were included at the acute stroke unit and randomized to either the intervention unit (IU)(circadian lighting) or the control unit (CU)(standard lighting). The circadian light was installed in the entire IU (Cromaviso, Denmark). Examination was done in the acute unit and at discharge after at least 2 weeks in the IU/CU. Change in depressive mood was measured by the Hamilton Rating Scale for Depression (HAM-D6) and The Major Depression Inventory scale (MDI).
Results: Patients were included over a year (N=90), 6 did not reach randomization, 45 were randomized to the IU, and 39 to the CU. A sample of 59 and 62 patients were able to answer the HAM-D6(N=30IU;N=29CU) and MDI (N=30IU;N=29CU) score, respectively. Both scores were significantly lower in the intervention group at discharged compared with the control group (ANCOVA, antidepressants medicine was included as a confounder, HAM-D6, P=0.018, Estimate=-2.25;SEM=0.92, MDI, P=0.009, Estimate=-4.72;SEM=1.74).
Conclusion: Our findings show for the first time circadian light as a beneficial intervention on depressive mood on long-term hospitalized patients in a real hospital setting. The circadian lightning should be considered as an integrated segment in the environment of rehabilitation units.