Study designs of evaluations included in the review
Randomised controlled trials (RCTs) and meta-analyses were eligible for inclusion in the review. All the included RCTs were of a crossover design.
Specific interventions included in the review
Treatments with melatonin were eligible. The doses of melatonin ranged from 0.5 to 6 mg, with most doses given in a single dose 30 to 120 minutes before bedtime. Slow-release preparations and transbuccal preparations were included. The duration of treatment ranged from 4 days to 2 months.
Participants included in the review
Elderly insomniacs were eligible. The mean age of patients across the studies ranged from 65 to 79 years. The included patients were a highly selected group; the inclusion criteria varied considerably between studies, ranging from elderly people with a variety of chronic diseases to elderly patients without any co-morbidity, who fulfilled certain sleep disorder criteria.
Outcomes assessed in the review
The inclusion criteria were not defined a priori in terms of the outcomes. The following measures of sleep quality were assessed:
sleep onset latency, i.e. the time elapsed between the participant's self-selected sleep time and sleep onset; wake after sleep onset, i.e. a summation of all the time awake during the sleep period; sleep efficiency, i.e. the percentage of time the participant was in bed following sleep onset, which was spent asleep; and total sleep time, i.e. the amount of sleep between sleep onset and sleep termination.
Actigraphy and polysomnography (consisting of electroencephalography, electromyogram, and electro-oculography) were used to measure the objective outcomes. Subjective sleep quality was assessed using visual analogue scales and sleep diaries.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.