It is my pleasure and privilege to present one of my novel project
for this IAP year – The Pediatric Sleep Project. Sleep is a
physiological state of unconsciousness from which a person can be
aroused fully, compared to coma where arousal is either not there or
is partial. Sleep is now considered to be an active process by the
inhibition of the arousal system. In children especially growth
hormone production is augmented during sleep. Increased production
and decreased catabolism of protein occurs during sleep. Sleep
disorders can lead to neurocognitive impairment, behavioral
disorders like attention deficit and substance abuse in addition to
the burden on the care givers.
Stages of Sleep
Sleep is divided into non rapid eye movement
sleep(NREM) and rapid eye movement sleep (REM). Wakefulness is
characterized by alpha rhythm (8-13 Hz). NREM is divided into 3
stages. N1 (stage 1, light sleep) is low voltage 4-8 Hz (theta) and
constitute only 2-5% of sleep cycle. N2 (stage 2) is 10-25 minutes
duration and occupies 45-55%of the sleep time. N3 is stage 3 and 4
(deep sleep)occupies 15-20% of sleep time. This is characterized by
high frequency low voltage theta waves (2 Hz). REM is divided into
tonic and phasic cycles. Tonic REM is characterized by high arousal
threshold and penile erection in men. In REM there is rise in heart
rate, BP, dreaming, paralysis of the muscles and increase in the
brain metabolism. The usual progression of sleep in first cycle is
from N1 to N3 to REM and usually complete in 70 to 100 minutes (mean
90 minutes) compared to 90-120 minutes of subsequent cycles. In the
first one third of the sleep cycle N3 is usually seen while in the
rest of the sleep REM is predominant.
Physiology of Sleep
Sleep center is situated at ventrolateral
preoptic nucleus. GABA and galanin initiate sleep by inhibiting
arousal neurons. Arousal centers are tuberomammillary nucleus,
lateral hypothalamus, locus coeruleus, dorsal raphe, laterodorsal
tegmental (LDT) nucleus, and pedunculopontine tegmental (PPT)
nucleus. The excitatory neurotransmitters from this centers are
orexin, histamine and acetylcholine. Adenosine is the hormone that
help transmission to sleep state. Initial NREM sleep is due to the
inhibition by GABA on excitatory centers. Later the cholinergic REM
is due to the activation of PPT, LDT and basal forebrain. REM has
parasympathetically mediated tonic component and sympathetically
mediated phasic component. Pupillary dilatation, increased heart
rate, respiratory rate are due to this phasic component. Muscle
atonia and rapid eye movements are important features of REM sleep.
Sleep Wake Cycles
This is dependent on intrinsic circadian
pacemaker, a homeostatic process. Sleep drive is dependent on the
duration of wakefulness. As duration of wakefulness increase the
homeostatic process also increase till sleep is established. The
circadian process act independently of wakefulness, sometimes a dip
in the circadian process occurs in the afternoon and is the reason
for the afternoon lunch dip.
Duration of Sleep
Exact Indian data is not available regarding the
duration of sleep in Indian children. Various studies show that our
children sleep less than their counterparts in developed nations by
2-3 hours.
Newborns sleep for 14-16 hours a day. This
gradually decreases around 4-5 months. Subsequently they become
nocturnal sleepers. Initially sleep cycle routine like night or day
is not seen in new born. On an average they used to wake up 3-4
times during night. By 3 months most of the newborns night sleep
increase in duration. This is important in mothers point of view as
they need to be fed by 2-3 hrs only. Inadequate sleep decrease
prolactin secretion in mother, which is important in breast milk
production. Newborn sleep is REM sleep, at the expense of NREM
especially N3 sleep. As the infant becomes older slow wave sleep
evolves.
Infants sleep for 12 to 14 hours. Preschool
children may have day time snap and they avoid that when they reach
the school. Children aged 6-12 years requires 10-11 hours of sleep
in a 24- hour period while adolescents generally require about
9-9.30 hours of sleep per night and adults on an average about 7-8
hours of sleep per day.
Sleep Disorders
Dyssomnias are the disorders that produce
either difficulty initiating or maintaining sleep or excessive
sleepiness. These can be intrinsic or extrinsic.
Parasomnias are manifestations of central
nervous system activation through the skeletal muscle; and include
arousal disorders, sleep-wake transition disorders; those usually
associated with REM sleep; and others.
Sleep disorders can also be associated with
mental, neurologic, or other medical disorders.
Proposed sleep disorders Obstructive sleep
apnea syndrome (OSAS), restless leg syndrome, sleep walking, sleep
paralysis, sleep terror, narcolepsy, sleep talking.
Co-Sleeping
Keeping the child in close proximity to the
parents is known as co-sleeping. Bed sharing is one in which
children sleep in the same bed as that of the parents and co-bedding
is one in which the children share the same bed of sibs. There are
advantages as well as disadvantages in co-sleeping. Indian cultures
favor co sleeping. There is more chance for bonding, breastfeeding
and prevention of SIDS by this method. But if any of the parents are
smokers or alcoholics or if the parents has to wake up at night
frequently for any reason, co-sleeping is not advisable. It is not a
bad idea to encourage children to sleep alone in another room by 3
years without locking up either the children’s or the parent’s room.
All pediatricians have to address the sleep history also in the
interview with the parents and adolescents. Practicing sleep
rituals, maintaining sleep diary are important steps to have a good
sleep hygiene to improve the cognitive ability of our children.
Facility for sleep studies has to be given momentum in the coming
years.
Sleep Rituals
1. Start the rituals before you plan sleep,
that has a relaxing experience like a warm bath, reading,
drinking a glass of milk, brushing or flossing your teeth.
2. Go to bed only when you are really
sleepy. In practical terms most of the children, men and women
have a set time and it is better to adhere to this set time.
3. It is important to make it a practice to
wake up at the same time always either by an alarm or
entrusting somebody for the same.
4. Avoiding snaps after 3 pm is good to
have a proper sleep at night.
5. If not able to fall into sleep by 20
minutes it is better to move out of bed and to do some kind of
relaxing things.
6. Avoid alcohol, nicotine, heavy dinner,
all kind of caffeinated items, severe exercises at least 6 hrs
before bed time.
7. Always try to get a full night sleep.
8. Don‘t use the bed for planning next
day’s activities.
9. Don’t go to bed if you are hungry.
10. Avoid sleeping pill. |
We had a successful TOT in Mumbai, 3rd September
2011 led by national trainers Dr Rajeshwar Dayal, Dr Yamuna, Dr C
Jayakumar. We are planning to conduct twenty five district workshops
soon. I thank Dr Rajeshwar Dayal, National Chairperson, Dr H
Paramesh, National Co-ordinators, Dr Yamuna and Dr C Jayakumar for
preparing the module. I acknowledge the help of Dr C Jayakumar for
preparing this article.