Melatonin and bright-light treatment for rest-activity disruption in institutionalized patients with Alzheimer's disease.
OBJECTIVE
To test whether the addition of melatonin to bright-light therapy enhances the efficacy in treating rest-activity (circadian) disruption in institutionalized patients with Alzheimer's disease (AD).


METHODS
Randomized, controlled trial.


METHODS
Two nursing homes in San Francisco, California.


METHODS
Fifty subjects (mean age 86) with AD.


METHODS
Experimental subjects received 1 hour of morning light exposure (> or = 2,500 lux in gaze direction) Monday to Friday for 10 weeks and 5 mg melatonin (LM, n=16) or placebo (LP, n=17) in the evening. Control subjects (n=17) received usual indoor light (150-200 lux).


METHODS
Nighttime sleep variables, day sleep time, day activity, day:night sleep ratio, and rest-activity parameters were determined using actigraphy.


RESULTS
Linear mixed models were employed to test the primary study hypotheses. No significant differences in nighttime sleep variables were found between groups. At the end of the intervention, the LM group showed significant improvement in daytime somnolence as indicated by a reduction in the duration of daytime sleep, an increase in daytime activity, and an improvement in day:night sleep ratio. The LM group also evidenced a significant increase in rest-activity rhythm amplitude and goodness of fit to the cosinor model.


CONCLUSIONS
Light treatment alone did not improve nighttime sleep, daytime wake, or rest-activity rhythm. Light treatment plus melatonin increased daytime wake time and activity levels and strengthened the rest-activity rhythm. Future studies should resolve the question of whether these improvements can be attributed to melatonin or whether the two zeitgebers interact to amplify efficacy.
Dowling
Glenna A
GA
Department of Physiological Nursing, University of California at San Francisco, San Francisco, California 94143, USA. glenna.dowling@nursing.ucsf.edu
Burr
Robert L
RL
Van Someren
Eus J W
EJ
Hubbard
Erin M
EM
Luxenberg
Jay S
JS
Mastick
Judy
J
Cooper
Bruce A
BA
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications*; D000975:Antioxidants / Q000627:therapeutic use*; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008550:Melatonin / Q000627:therapeutic use*; D008875:Middle Aged; D010789:Phototherapy / Q000379:methods*; D012112:Residential Facilities; D012495:San Francisco; D012720:Severity of Illness Index; D020178:Sleep Disorders, Circadian Rhythm / Q000209:etiology / Q000628:therapy*; D016896:Treatment Outcome
D000975:Antioxidants; D008550:Melatonin