Sleep

What is it?

Sleep is critical for our bodies to function — we die without it!  Sleep is important for how we learn and remember new information, for keeping our immune systems strong, and even for how our bodies use the energy from the food we eat.

How is it measured?

Participants complete a short series of validated, computerized, self-report questionnaires:

Sleep Quality refers to how long and how well a person is sleeping during the night.  Questions ask about bedtime and wake time, how long it takes to fall asleep, difficulty sleeping (bathroom, breathing issues, snoring, bad dreams), use of medication and how they feel overall.  For adults, we use the Pittsburgh Sleep Quality Index which has 18 questions (Buysse et al., 1989).  Kid sleep duration is estimated using questions that assess the usual time at which they fall asleep and wake up on weekdays and weekends.

Chronotype (also known as “diurnal preference”) refers to the time of day or night that a person feels at their best.  Questions ask a person when they feel their best, how they feel when they first wake up, and when they would wake up and go to bed if they could plan their own day.  There are two different surveys to measure chronotype:  Horne Ostberg Scale (for adults) and Morningness Eveningness Scale for Children (kids).

Daytime Sleepiness asks about how often a person feels tired during the day doing routine activities, like after eating a meal, riding in a car, or watching television.  There are two different surveys to measure daytime sleepiness:  the Epworth Scale (for adults) and Pediatric Daytime Sleepiness Scale (PDSS; for children). Both have 8 questions.  Items on the child version include “How often do you fall asleep or feel drowsy in class?” and “How often do you have trouble getting out of bed in the morning?”.  Higher scores on both versions indicate higher levels of daytime sleepiness. High daytime sleepiness scores have been associated with  PDSS scores were associated with narcolepsy, idiopathic hypersomnia or obstructive sleep apnea syndrome in adults (Johns 1991) and worse school achievement, absenteeism, more illness, and worse mood in children(Drake et al., 2003).

This station is available for the following audience and takes approximately:

• Adults (English, Spanish, Chinese, Vietnamese and Korean) – Each of the three surveys take about 2-5 minutes
• Kids (English, Spanish, Chinese, Vietnamese and Korean) – Each of the three surveys take about 2-5 minutes

How we determined the categories?

Sleep Quality

For adults, the Pittsburgh Sleep Quality Index (PSQI) assigns 0-3 points for each of the 18 questions.  These 18 questions are converted to seven component scores that are then summed to give a Global PSQI score.

Chronotype

For adults, the Horne Ostberg scale assigns 0-6 points for each of the 5 questions.  These points are then tallied to give an overall chronotype score (Adan & Almirall, 1991).

* These chronotype scores were used to calculate the “recommendation” graphics.  See below for a note about adjusted chronotype scoring on SeeIt

For kids, the Morningness-Eveningness Scale for Children has 10 questions and assigns 1-5 points for 7  of the questions.  These points are then tallied to give an overall chronotype score (Diaz-Morales et al., 2007).

* These chronotype scores were used to calculate the “recommendation” graphics.  See below for a note about adjusted chronotype scoring on SeeIt

 * A note about chronotype scoring on SeeIt – As you may have noticed, chronotype scores differ for adults and kids because they use different surveys.  To make these scores able to be graphed together, we created a new calculated column that adjusts chronotype scores for SeeIt.  You can see that while they don’t line up perfectly, they provide a better approximation for comparing these two surveys.

Daytime Sleepiness

For adults, the Epworth Sleepiness Scale assigns 0-3 points for each of the 8 questions.  Total scores could range from 0-24.  These points are then tallied to give an overall daytime sleepiness score (Johns & Hocking, 1990).  According to Johns (1991), Epworth Sleepiness Scores greater than 16 were found only in patients with narcolepsy, idiopathic hypersomnia or obstructive sleep apnea syndrome (OSAS) of at least moderate severity.

For kids, the Pediatric Daytime Sleepiness Scale assigns 0-4 points for each of the 8 questions. Total scores could range from 0 to 32, with higher scores indicating higher levels of sleepiness. The PDSS was developed and validated on a sample of 450 children and adolescents, aged 11–15 years. Higher PDSS scores were associated with worse school achievement, absenteeism, more illness, and worse mood (Drake et al., 2003). 

Important note for SeeIt:  SeeIt is currently graphing these scales together.  Please proceed with caution until an adapted scale is created for the data.

Where to get more information…

About Sleep, Sleep Disorders and Biological Rhythms from the National Institutes of Health

About Sleep Disorders from the National Institutes of Health

Research Bibliography

Adults

Sleep Quality

Pittsburgh Sleep Quality Index (PSQI)  (http://www.sleep.pitt.edu/content.asp?id=1484&subid=2316)

Morningness Eveningness

Currently used cutpoints based on Adan and Almirall (1991): Adan & Almirall (1991). Horne & Östberg morningness-eveningness questionnaire: A reduced scale. Personality & Individual Differences, 12(3), 241-253. http://www.sciencedirect.com/science/article/pii/019188699190110W#

Epworth Sleepiness Scale

 Johns, M. and B. Hocking (1990). Excessive daytime sleepiness: Daytime sleepiness and sleep habits of Australian workers. Sleep, 20(10, 844-849  http://epworthsleepinessscale.com/wp-content/uploads/2009/09/daytime_sleepiness_and_sleep_habits_of_australian_workers.pdf

For outcomes of daytime sleepiness, see Johns, M.W. (1991). A new method for measuring daytime sleepiness: The Epworth Sleepiness Scale. Sleep, 14(6), 540-545.  http://epworthsleepinessscale.com/wp-content/uploads/2008/12/a-new-method-for-measuring-daytime-sleepiness-the-epworth-sleepiness-scale2.pdf

Kids

Morningness Eveningness Scale for Children (MESC)

Carskadon M, Vieira C, and C. Acebo (1993). Association between puberty and delayed phase preference. Sleep, 16, 258–262.

We currently use the 20th/80th percentile cutoffs.

Juan Francisco Dıaz-Morales, Celeste Davila de Leon, and Marıa Gutierrez Sorroche. Validity of the morningness-eveningness scale for children among spanish adolescents. Chronobiology International, 24(3): 435–447, (2007). http://informahealthcare.com/doi/pdf/10.1080/07420520701420659

For stricter cutoffs(10th/90th percentile cutoffs of 18 and 30), please see Diaz-Morales et al., 2008.

Other applicable MESC references:

Duffy JF, Dijk DJ, Hall EF, et al. (1999) Relationship of endogenous circadian melatonin and temperature rhythms to self-reported preference for morning or evening activity in young and older people J Investig Med 47, 141-50.

Duffy JF, Rimmer DW, Czeisler CA (2001) Association of intrinsic circadian period with morningness-eveningness, usual wake time, and circadian phase Behav Neurosci 115, 895-9.

Bailey SL, Heitkemper MM (2001) Circadian rhythmicity of cortisol and body temperature: morningness-eveningness effects Chronobiol Int 18, 249-61.

Natale V, Esposito MJ, Martoni M, et al. (2006) Validity of the reduced version of the Morningness–Eveningness Questionnaire Sleep and Biological Rhythyms 4, 72-4.PDSS

Pediatric Daytime Sleepiness Scale (PDSS)

We use 25^th/75^th percentile cutoffs based on:   

Drake C, Nickel C, Burduvali E et al. The pediatric daytime sleepiness scale (PDSS): sleep habits and school outcomes in middle school children. SLEEP 2003;26(4):455-458. http://psycnet.apa.org/psycinfo/2004-17237-008.

Perez-Chada D; Perez-Lloret S; Videla AJ; Cardinali D; Bergna MA; Fernández-Acquier M; Larrateguy L; Zabert GE; Drake C. Sleep disordered breathing and daytime sleepiness are associated with poor academic performance in teenagers. A study using the pediatric daytime sleepiness scale (PDSS). SLEEP 2007;30(12):1698-1703

Other applicable PDSS references: 

Iowa Sleep Disorders Center’s  “Pediatric Daytime Sleepiness Scale