The Eeg Pattern Associated With Normal Waking Alert States Is

[Xena Donovan]

Theaverage newborn sleeps much of the day and night, waking only for feedings every few hours. It is often hard for new parents to know how long and how often a newborn should sleep. Unfortunately, there is no set schedule at first and many newborns have their days and nights confused?they think they are supposed to be awake at night and sleep during the day.

Generally, newborns sleep about 8 to 9 hours in the daytime and about 8 hours at night. Most babies do not begin sleeping through the night (6 to 8 hours) without waking until at least 3 months of age, or until they weigh 12 to 13 pounds. However, this varies considerably and some babies do not sleep through the night until closer to 1 year. Newborns and young infants have a small stomach and must wake every few hours to eat. In most cases, your baby will awaken and be ready to eat about every 3 hours. How often your baby will eat depends on what he or she is being fed and his or her age. Make sure you talk with your doctor to determine if it is necessary to wake a baby for feedings.

Watch for changes in your baby's sleep pattern. If your baby has been sleeping consistently, and suddenly is waking, there may be a problem such as an ear infection. Some sleep disturbances are simply due to changes in development or because of overstimulation.

Babies, like adults, have various stages and depths of sleep. Depending on the stage, the baby may actively move or lie very still. Infant sleep patterns begin forming during the last months of pregnancy?active sleep first, then quiet sleep by about the eighth month. There are two types of sleep:

REM (rapid eye movement sleep). This is a light sleep when dreams occur and the eyes move rapidly back and forth. Although babies spend about 16 hours each day sleeping, about half of this is in REM sleep. Older children and adults sleep fewer hours and spend much less time in REM sleep.

A baby enters stage 1 at the beginning of the sleep cycle, then moves into stage 2, then 3, then 4, then back to 3, then 2, then to REM. These cycles may occur several times during sleep. Babies may awaken as they pass from deep sleep to light sleep and may have difficulty going back to sleep in the first few months.

Babies also have differences in how alert they are during the time they are awake. When a newborn awakens at the end of the sleep cycles, there is typically a quiet alert phase. This is a time when the baby is very still, but awake and taking in the environment. During the quiet alert time, babies may look or stare at objects, and respond to sounds and motion. This phase usually progresses to the active alert phase in which the baby is attentive to sounds and sights, and moves actively. After this phase is a crying phase. The baby's body moves erratically, and he or she may cry loudly. Babies can easily be overstimulated during the crying phase. It is usually best to find a way of calming the baby and the environment. Holding a baby close or swaddling (wrapping snugly in a blanket) may help calm a crying baby.

It is usually best to feed babies before they reach the crying phase. During the crying phase, they can be so upset that they may refuse the breast or bottle. In newborns, crying is a late sign of hunger.

Babies may not be able to establish their own sleeping and waking patterns, especially in going to sleep. You can help your baby sleep by recognizing signs of sleep readiness, teaching him/her to fall asleep on his or her own, and providing the right environment for comfortable and safe sleep.

Not all babies know how to put themselves to sleep. When it is time for bed, many parents want to rock or breastfeed a baby to sleep. Establishing a routine at bedtime is a good idea. However, be sure that the baby does not fall asleep while eating or in your arms. This may become a pattern and the baby may begin to expect to be in your arms in order to fall asleep. When the baby briefly awakens during a sleep cycle, he or she may not be able to go back to sleep on his or her own.

Most experts recommend allowing a baby to become sleepy in your arms, then placing him or her in the bed while still awake. This way the baby learns how to go to sleep on his own. Playing soft music while your baby is getting sleepy is also a good way to help establish a bedtime routine.

Experts now agree that putting a baby to sleep or down for a nap on his or her back is the safest position. Side-sleeping has a higher risk for SIDS than back sleeping. Other reports have found soft surfaces, loose bedding, and overheating with too many blankets also increase the risk for SIDS. When infants are put to sleep on their stomach and they also sleep on soft bedding, the risk for SIDS is even higher. Smoking by the mother is also a risk for SIDS, as are poor prenatal care and prematurity. Since the American Academy of Pediatrics (AAP) made the "back-to-sleep" recommendation in 1992, the SIDS rate has dropped more than 50%.

Back sleeping also appears to be safer for other reasons. There is no evidence that babies are more likely to vomit or spit up while sleeping on their back. In fact, choking may be more likely in the prone position.

Offer your baby a pacifier at sleep times, but don't force the baby to take it. Some studies have shown a lower rate of SIDS among babies who use pacifiers. (Breastfeeding mothers should wait until the baby is 1 month old or is used to breastfeeding before offering a pacifier.)

To prevent overheating, the report recommends that the infant should be lightly clothed for sleep and the room temperature kept comfortable for a lightly clothed adult. Avoid overbundling, and check the baby's skin to make sure it is not hot to the touch.

While babies should sleep on their back, other positions can be used during the time babies are awake. Babies can be placed on their stomachs while awake and under supervision to help develop the muscles of the eyes, stomach, and neck.

Avoid using home cardiorespiratory monitors and commercial devices?wedges, positioners, and special mattresses?to help decrease the risk for SIDS and sleep-related infant deaths. These devices have not been shown to decrease the risk of SIDS. In rare cases, they have resulted in an infant's death.

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The sleep of college students is often variable in both duration and timing, with many students suffering from considerable sleep deficiency1,2,3,4,5. In adults, short sleep duration has been associated with cognitive impairments, including increased reaction time and reduced cognitive throughput6; motor vehicle accidents and early mortality7; elevated risk for metabolic disorders, including obesity8, type 2 diabetes9, and cardiovascular disease10; and psychiatric disorders11. Sleep is multidimensional, however, and its importance to health and performance may not be purely dependent upon its daily duration. The composition of sleep varies depending on circadian phase and the time of day at which sleep occurs12, 13. Circadian phase is affected by light exposure; even room light shifts circadian phase significantly in humans14. Individuals who frequently change their sleep timing, and consequently their pattern of light/dark exposure, may experience misalignment between the circadian system and the sleep/wake cycle, since the circadian clock takes time to adjust to schedule changes15. Such misalignment may have an adverse effect on both cognitive function and health7, 16.

Using the SRI, we assessed real-world sleep patterns in college undergraduates and classified individuals as Regular (top quintile) or Irregular (bottom quintile). We examined the relationships among SRI, sleep duration, distribution of sleep across the day, and academic performance during one semester. In addition, we measured the phase of the endogenous circadian melatonin rhythm and light exposure patterns in participants classified as Regular or Irregular. Differences in circadian timing of endogenous melatonin secretion and sleep propensity between Regular and Irregular sleepers could potentially be due to systematic differences in circadian physiology. For example, Irregular sleepers could have longer intrinsic circadian periods, leading to delayed circadian rhythms28 and increased overlap of sleep with morning classes, leading to irregular sleep schedules. Alternatively, the difference in circadian timing could be due to different patterns of light exposure associated with Regular vs. Irregular sleepers, because light exposure during the early biological night delays the circadian clock29. We tested these mechanistic hypotheses using a previously-validated mathematical model of the human circadian clock and its response to light.

As a group, Regular sleepers expressed a robust daily rhythm in the percentage of time they spent asleep averaged across the day in 1-h time bins (Fig. 2A). As summarized in Table 1, Regular sleepers obtained significantly more sleep during the clock night (defined as 22:00 to 10:00) and significantly less sleep during the clock day (defined as 10:00 to 22:00) than Irregular sleepers. Regular sleepers were asleep 55% of the clock night and only 1% of the clock day. By contrast, Irregular sleepers were asleep for 42% of the clock night and 11% of the clock day.

Correlations between sleep regularity index (SRI), grade point average (GPA), and timing of melatonin secretion. Panels (A, B and C) show the relationships between the variables: SRI, GPA, and salivary DLMO. Dashed lines show the linear fits, with r-values and p-values shown for each linear (Pearson) correlation. Each data point represents an individual, with colors indicating whether the individual was a member of the Regular (blue), Irregular (red), or neither group (black). Note that DLMO was only assessed in the Irregular and Regular participants.

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