The effects of light therapy on well-being among university students was investigated. A three-week intervention study examined whether the use of light glasses improved sleep quality and concentration and reduced symptoms of depression and anxiety among university students. First, a questionnaire was administered to about 130 students to screen for sleep problems. Based on the responses, those with the most sleep problems were invited to participate in the intervention study, which resulted in 39 participants in total. Although studies of light therapy for sleep problems and depression among patients have yielded positive results, the use of light has not been studied much among healthy individuals. The intervention study used glasses that project light in two intensities and participants were randomized into two groups with different intensities of light. The aim of the study was to: a) compare the effects of different light intensities on sleep and concentration and b) investigate whether light therapy influences symptoms of depression and anxiety among university students. The study is expected to increase knowledge of light therapy among healthy individuals, and if the treatment proves successful, it is an easy and inexpensive way to increase well-being among university students.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
39
The circadian-effective light glasses used by the experimental group (BL) emitted narrowband (peak lambda = 470 nm) blue light with an irradiance of 250 μW/cm2 (120 lux). The light glasses emit light from LEDs at a distance of 15 millimeters (15mm, 0.015.) from the eye. The device is classified as safe for the eyes in accordance with the international standard IEC 62471 and complies with the United States of America's FCC marking, and is designed to be worn on the participant's head, similar to a pair of regular glasses. For safety purposes, the light glasses do not contain UV or infra-red light. Brand: AYO glasses.
The circadian-ineffective sham glasses (DL) emitted blue light with an irradiance of 2.5 μW/cm2 (1.16 lux). The light glasses emit light from LEDs at a distance of 15 millimeters (15mm, 0.015.) from the eye. The device is classified as safe for the eyes in accordance with the international standard IEC 62471 and complies with the United States of America's FCC marking, and is designed to be worn on the participant's head, similar to a pair of regular glasses. For safety purposes, the light glasses do not contain UV or infra-red light. Brand: AYO glasses.
Department of Psychology, Reykjavík University
Reykjavik, Iceland
The Bergen Insomnia Scale (BIS)
The Bergen Insomnia Scale (BIS) is a short scale on sleep habits consisting of six items pertaining to sleep onset, maintenance, early morning wakening, restorative sleep, daytime functioning, and sleep satisfaction. Responses indicate how often sleep problems, according to the six items, are experienced during the last month on an 8-point scale (0-7 days per week) with a range between 0 and 42, where a higher score suggests more sleep problems.
Time frame: BIS was used to screen for sleep-related problems, prior to the intervention, at baseline (day 1), at the middle of intervention (FU1, day 11) and at the of intervention (FU2, day 21).
The Pittsburgh Sleep Quality Index (PSQI)
The Pittsburgh Sleep Quality Index (PSQI) consists of 19 self-rated items about sleep habits during the last month. The questions are categorised into seven components, rated from 0 to 3, evaluating sleep duration, quality, and latency as well as habitual sleep efficiency, sleep disturbances, usage of sleep medication, and daytime dysfunction. A global PSQI score, ranging from 0 to 21, is calculated by summarising the seven components' scores, where a higher global score indicates worse sleep quality and a score above five suggests poor sleep quality.
Time frame: PSQI was administered at baseline (day 1), FU1 (day 11), and FU2 (day 21).
Objective sleep measure by actigraphy: Total time in bed
Wrist-worn actigraphy devices (model GT3X+ ActiSleep) were used to objectively measure sleep. Sleep parameters were calculated using the Cole-Kripke sleep algorithm in the ActiLife 6 data analysis software. Parameter measured: Total time in bed, measured as minutes.
Time frame: Participants were asked to wear the devices on their non-dominant arm for four consecutive days, both at baseline (day 1-4) and at FU2 (day 18-21).
Objective sleep measure by actigraphy: Total sleep time
Wrist-worn actigraphy devices (model GT3X+ ActiSleep) were used to objectively measure sleep. Sleep parameters were calculated using the Cole-Kripke sleep algorithm in the ActiLife 6 data analysis software. Parameter measured: Total sleep time, measured as minutes.
Time frame: Participants were asked to wear the devices on their non-dominant arm for four consecutive days, both at baseline (day 1-4) and at FU2 (day 18-21).
Objective sleep measure by actigraphy: Sleep latency
Wrist-worn actigraphy devices (model GT3X+ ActiSleep) were used to objectively measure sleep. Sleep parameters were calculated using the Cole-Kripke sleep algorithm in the ActiLife 6 data analysis software. Parameter measured: Sleep latency, measured as minutes.
Time frame: Participants were asked to wear the devices on their non-dominant arm for four consecutive days, both at baseline (day 1-4) and at FU2 (day 18-21).
Objective sleep measure by actigraphy: Wake after sleep onset
Wrist-worn actigraphy devices (model GT3X+ ActiSleep) were used to objectively measure sleep. Sleep parameters were calculated using the Cole-Kripke sleep algorithm in the ActiLife 6 data analysis software. Parameter measured: Wake after sleep onset, measured as minutes.
Time frame: Participants were asked to wear the devices on their non-dominant arm for four consecutive days, both at baseline (day 1-4) and at FU2 (day 18-21).
Objective sleep measure by actigraphy: Number of awakenings
Wrist-worn actigraphy devices (model GT3X+ ActiSleep) were used to objectively measure sleep. Sleep parameters were calculated using the Cole-Kripke sleep algorithm in the ActiLife 6 data analysis software. Parameter measured: Number of awakenings, measured as number of awakenings per sleep period.
Time frame: Participants were asked to wear the devices on their non-dominant arm for four consecutive days, both at baseline (day 1-4) and at FU2 (day 18-21).
Objective sleep measure by actigraphy: Sleep fragmentation index
Wrist-worn actigraphy devices (model GT3X+ ActiSleep) were used to objectively measure sleep. Sleep parameters were calculated using the Cole-Kripke sleep algorithm in the ActiLife 6 data analysis software. Parameter measured: Sleep fragmentation index, measured as percentage.
Time frame: Participants were asked to wear the devices on their non-dominant arm for four consecutive days, both at baseline (day 1-4) and at FU2 (day 18-21).
Objective sleep measure by actigraphy: Sleep movement index
Wrist-worn actigraphy devices (model GT3X+ ActiSleep) were used to objectively measure sleep. Sleep parameters were calculated using the Cole-Kripke sleep algorithm in the ActiLife 6 data analysis software. Parameter measured: Sleep movement index, measured as events per hour.
Time frame: Participants were asked to wear the devices on their non-dominant arm for four consecutive days, both at baseline (day 1-4) and at FU2 (day 18-21).
Objective sleep measure by actigraphy: Sleep efficiency
Wrist-worn actigraphy devices (model GT3X+ ActiSleep) were used to objectively measure sleep. Sleep parameters were calculated using the Cole-Kripke sleep algorithm in the ActiLife 6 data analysis software. Parameter measured: Sleep efficiency, measured as percentage.
Time frame: Participants were asked to wear the devices on their non-dominant arm for four consecutive days, both at baseline (day 1-4) and at FU2 (day 18-21).
The Center for Epidemiological Studies Depression Scale (CES-D)
The Center for Epidemiological Studies Depression Scale (CES-D) is a 20 item self-report instrument, designed to measure common symptoms of depression that have occurred over the past week such as poor appetite, hopelessness, pessimism, and fatigue. Response options range from 0 to 3 for each item. Scores range from 0 to 60, with high scores indicating greater depressive symptoms.
Time frame: CES-D was administered at baseline (day 1), FU1 (day 11) and FU2 (day 21).
General Anxiety Disorder (GAD-7)
General Anxiety Disorder (GAD-7) is a shorter version of the original GAD-13 item scale designed to measure anxiety. Each of the seven questions is rated on a 4-point Likert scale based on symptom frequency. The total score is calculated by summing the scores for all seven items, thus scores range from 0 to 21, with higer score meaning more anxiety. Cut-points are as follows: 0-4: Minimal anxiety, 5-9: Mild anxiety, 10-14: Moderate anxiety, and 15-21: Severe anxiety. A score of 10 or greater is often used as a clinical cut-off point.
Time frame: GAD-7 was administered at baseline (day 1), FU1 (day 11) and FU2 (day 21).
The reduced Horne & Östberg Morningness-Eveningness Questionnaire (rMEQ)
The reduced Horne \& Östberg Morningness-Eveningness Questionnaire (rMEQ) is a self-report questionnaire is one of the most widely used questionnaire to measure chronotype. The rMEQ consists of 5 questions that assess an individual's preference for morning or evening activities. Based on results from the scoring, individuals can be categorized as: Morning Types: Prefer morning activities; Evening Types: Prefer evening activities or Intermediate Types: Have no strong preference.
Time frame: rMEQ was administered at baseline (day 1).
The Epworth Sleepiness Scale (ESS)
The Epworth Sleepiness Scale (ESS) is widely used in sleep research and clinical settings and consists of 8 questions (each with 4 answering possibilities) about sleepiness. measure a person's likelihood of dozing off during various daily activities. ESS provides a score ranging from 0 to 24, with higher scores indicating excessive daytime sleepiness. In general ESS scores can be interpreted as follows: 0-5 Lower Normal Daytime Sleepiness; 6-10 Higher Normal Daytime Sleepiness; 11-12 Mild Excessive Daytime Sleepiness; 13-15 Moderate Excessive Daytime Sleepiness; and 16-24 Severe Excessive Daytime Sleepiness.
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Time frame: ESS was administered at baseline (day 1), FU1 (day 11) and FU2 (day 21).
Objective measures of cognitive performance: Operation Span (Ospan)
Three neuropsychological tests were used to measure cognitive performance: Operation Span (Ospan) is a cognitive task designed to measure working memory capacity by requiring participants to remember sequences of letters while simultaneously solving simple math problems. This dual-task approach assesses how well individuals can manage their memory resources under distraction.
Time frame: Ospan was administered at baseline (day 1) and FU2 (day 21).
Objective measures of cognitive performance: Digit span forward
Three neuropsychological tests were used to measure cognitive performance: Digit span forward is a cognitive task where a person listens to a sequence of numbers and then repeats them back in the same order. This task primarily measures short-term auditory memory and is commonly used in psychological assessments to evaluate working memory capacity.
Time frame: Digit span forward was administered at baseline (day 1) and FU2 (day 21).
Objective measures of cognitive performance: Digit span backward
Three neuropsychological tests were used to measure cognitive performance: Digit span backward is a cognitive task that measures short-term memory by requiring participants to recall a sequence of numbers in reverse order. This task is more challenging than recalling the numbers in the original order, as it involves both storage and manipulation of the information.
Time frame: Digit span backward was administered at baseline (day 1) and FU2 (day 21).