Psychological Construct
Concepts that are believed to exist, but are intangible and difficult to measure.
Sleep
a regular and naturally occurring altered state of consciousness that involves a loss of awareness and disengagement from internal and external stimuli.
Consciousness
the level of awareness an individual has over their thoughts, feelings, perceptions and existence. occurs on a continuum
Normal Waking Consciousness
the states of consciousness associated with being awake and aware of thoughts, memories, feelings and the experiencing of external sensations.
Altered States of Consciousness
Any state of consciousness that is distinctly different from normal waking consciousness, characterised by lower levels of awareness.
Sleep Episode/Sleep Cycle
the full duration of time spent asleep, made up of repeated cycles of REM and non-REM, which last approximately 90 minutes.
REM:NREM
REM makes up 20-25% of a sleep episode. Non-REM makes up 75-80% of a sleep episode, and becomes shorter with each sleep cycle.
REM Sleep
characterised by rapid eye movement, high levels of brain activity and low levels of physical activity.
non-REM Sleep
characterised by a lack of rapid eye movement, and low levels of brain activity, subdivided into three substages.
DARE
detects, amplifies and records (for sleep measurement)
EEG
a device that indicates changes in brainwave activity. Low levels of activity relates to NREM sleep, while high levels relate to REM.
EOG
indicates changes in electrical activity in the muscles around the eye. Low levels of activity relate to NREM, while high levels relate to REM.
EMG
indicates changes in electrical activity in muscles. Low levels of activity relate to REM, while high levels relate to NREM.
Video Monitoring
The use of camera and audio technologies to record an individual as they sleep
Sleep Diaries
self-reported descriptions from an individual about their sleep experience, including estimations of time sleeping and judgements about the quality and nature of sleep.
Circadian Rhythm
A biological process following a 24-hour cycle, e.g. the sleep-wake cycle.
Ultradian Rhythm
Biological processes that occur more than once in a 24-hour period, e.g. individual sleep cycles.
Superchiasmatic Nucleus
An area of the hypothalamus responsible for regulating sleep-wake patterns. Located above the optic chiasm.
Zeitbegers
Environmental cues, such as light, temperature, eating patterns, exercise, and social activity which help regulate the body’s circadian rhythms.
Partial Sleep Deprivation
a state caused by having less quality or quantity of sleep than what is normally required.
Total Sleep Deprivation
a state caused by not having any sleep at all over an at least 24-hour period.
BAC, 0.05
equivalent affective, behavioural and psychological effects to 17 hours of sleep deprivation
BAC, 0.10
equivalent affective, behavioural and psychological effects to 24 hours of sleep deprivation
Delayed Sleep Phase Syndrome (DSPS)
sleep and waking occur later than usual for the individual.
Advanced Sleep Phase Disorder (ASPD)
sleep and waking occur earlier than usual for the individual.
Sleep Disorders
Caused by a misalignment between external and internal cues that regulate the circadian rhythm. External cues are received at the appropriate time, but internal cues are not - therefore, melatonin secretion is disordered.
Shift-Work Related Sleep Disorder
Circadian rhythm is disrupted by inconsistency in sleeping, due to an occupation that involves irregular hours that may be unusual.
Bright Light Therapy
A method used to adjust a person’s circadian rhythm through exposure to a high-intensity light source, causing the inhibition of melatonin.
Sleep Hygiene
the practices and habits that promote an individual’s sleeping patterns, including light, temperature, and eating and drinking patterns.