Circadian Rhythm Phase Shift
Conditions
Brief summary
Effects of Smartphone Use at Night with Light Emitting Diode Display With and Without Blue Light in Healthy Adults: A Randomized, Double-blind, Cross-over, Placebo-controlled Comparison
Interventions
DEVICEsmartphone display
Sponsors
Samsung Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
SCREENING
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
20 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
(1) Healthy males 20-40 years of age who understood the study procedure and agreed to participate after being fully informed about the study were included.
Exclusion criteria
1. psychiatric diseases according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria;15 2. cognitive or neurological disorders; 3. alcohol or substance abuse; 4. unstable or serious medical illness; 5. current use of psychoactive mediations including antidepressants, anxiolytics, neuroleptics, anticonvulsants, hypnotics, or stimulant medications; 6. primary sleep disorder; 7. habitual sleep onset earlier than 21:00 or later than 24:00; 8. shift worker; 9. travel across more than two time zones within 90 days of the study; and 10. ophthalmologic disease during the study period.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Changes of serum melatonin | serum melatonin levels were measured every 60 min from 7:00 PM on day 1 to 8:00 AM on day 2, from 7:00 PM on day 2 to 8:00 AM on day 3, and from 7:00 PM to 11:00 PM on day 3 for 3 days. |
| Changes of serum cortisol | cortisol levels were measured every 120 min from 7:00 PM on day 1 to 8:00 AM on day 2, from 7:00 PM on day 2 to 8:00 AM on day 3, and from 7:00 PM to 11:00 PM on day 3 for 3 days. |
| Changes of body temperature | body temperature was measured every 120 min from 7:00 PM on day 1 to 8:00 AM on day 2, from 7:00 PM on day 2 to 8:00 AM on day 3, and from 7:00 PM to 11:00 PM on day 3 for 3days. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| profile of mood states(POMS) | day 1,3 | Mood was measured using the POMS,17 a well-validated self-report measure of mood states. |
| continuous performance test(CPT) | day1,3 | Integrated visual-auditory CPTs were performed at days 1 and 3 by a psychologist who was an expert on cognitive tests |
| Epworth Sleepiness Scale(ESS) | day 1,3 | ESS18 is comprised of eight questions that query the subject's likelihood of dozing off or falling asleep in a particular situation that is commonly met in daily life. |
| Fatigue severity scale(FSS) | day 1,3 | The FSS20 is composed of 9 statements (items) that describe fatigue symptoms. Respondents select the most relevant level of agreement over the last week on a 7-point scale (1 strongly disagree; 7 strongly agree). |
Outcome results
None listed