Sleep Disorders in Child Neurology

Mandeep Rana

Umakanth Khatwa

Sanjeev V. Kothare

NORMAL SLEEP IN CHILDREN

DEFINITION: Reversible behavioral state of perceptual disengagement and unresponsiveness to and from the environment.

PHYSIOLOGY: Complex amalgam of physiologic and behavioral processes.¹ Two separate states are defined on the basis of physiologic parameters: rapid eye movement (REM) sleep and non-REM sleep (Table 20.1).

MATURATIONAL CHANGES: Sleep architecture changes occur across entire life span (Figs. 20.1 and 20.2), but most significant changes occur within the 1st few years of life. For the 1st 3 mo of life, transition from wake to sleep is through REM sleep (called active sleep in newborns). Cyclic alternation of REM and NREM sleep occurs every 50 to 60 min at birth transitioning to every 90 min in adults. REM sleep decreases from birth (50% of sleep) through early childhood into adulthood (20%-25%). Slow-wave sleep peaks in early childhood and starts reducing at puberty, continuing to reduce through adulthood.

MECHANISM OF WAKE SLEEP REGULATION: “Two-process model” (Fig. 20.3): interaction between homeostatic sleep drive (“process S”) and endogenous circadian timing (“process C”).²^,³ S accrues during wakefulness and is dissipated during sleep; C oscillates with near perfect 24-h periodicity.⁴^,⁵

EVALUATION OF CHILDHOOD SLEEP DISORDERS⁶³

HISTORY:(1) Bedtime routine: Sleep associations and behaviors, sleep environment and sleep schedules, including that on weekdays and weekends, late evening activities such as watching TV, internet access, texting, emailing. (2) Nighttime Sx: Snoring, arousals, restlessness, leg movements, pauses in breathing, sweating, dry mouth, mouth breathing; (3) Daytime Sx: Sleepiness, fatigue, naps. (4) Medical and psychiatric history: Asthma, GERD, allergies, chronic lung disease, sickle cell disease, pain, neurologic problems such as epilepsy, HA, CP, DD, ADHD, ASD, depression, anxiety, and bipolar disorder. (5) FHx: Sleep apnea, narcolepsy, restless leg syndrome (RLS), long sleep requirements. (6) Meds: Caffeine, alcohol, sedatives, and stimulants.

PHYSICAL EXAMINATION: (1) Growth parameters: Height, weight, BMI, neck circumference. (2) ENT exam: Deviated nasal septum, turbinate hypertrophy, adenotonsillar hypertrophy, oropharyngeal crowding, large tongue. (3) Craniofacial features: Adenoid facies, high arched palate, midfacial hypoplasia, retrognathia, crossbite. (4) Neurologic exam: Especially in children with restless leg Sx, EDS, atypical parasomnias, and seizures.

TABLE 20.1 Sleep Staging: Classic vs. Updated Stage Definitions

Sleep Type	Describe Type	Classic Stage Definition	Updated Stage Definition
NREM	“Light sleep”	1, 2	N1, N2
	“Deep sleep” or SWS	3, 4	N3
REM	Dreaming sleep, Paradoxical sleep	REM	R

TOOLS

Polysomnography (PSG)

Continuous recording of several physiologic parameters during sleep, including electroencephalogram (EEG), electrocardiogram (EKG), electro-oculogram (EOG), respiratory effort using chest and abdominal belts, airflow, gas exchange using pulse oximetry and end tidal CO₂, EMG for legs and chin activity, snore, and microphone. PSG is indicated to evaluate: (1) Sleep-disordered breathing (SDB): OSA, central sleep apnea, and hypoventilation. (2) Nocturnal events: Parasomnia vs. nocturnal seizure (see also Tables 3.2 and 6.16, and note parasomnias by themselves are not an indication for performing a PSG), REM behavior disorder, periodic limb movements disorder (PLMD). (3) Unexplained hypersomnia; (4) Narcolepsy: Usually PSG is done prior to multiple sleep latency test (MSLT) to rule out OSA and assess adequate duration of sleep. (5) Sleep state misperception (6) CPAP/Bilevel positive airway pressure titration. (7) SDB in special populations:

Neuromuscular weakness: hypoventilation and OSA
Chiari 1 and 2 malformation: central sleep apnea, OSA, and hypoventilation
Chronic respiratory disease: gas exchange abnormalities
Sickle cell disease: OSA
Down syndrome, Prader-Willi syndrome: OSA

FIGURE 20.1 Changes in Total Daily Sleep Time, and REM and NREM Distribution over Ages. Note the large amount of REM in neonates and infants.⁶¹ Total sleep time decreases with age. (From Roffwarg HP, Muzio JN, Dement WC. Ontogenetic development of the human sleep-dream cycle. Science. 1966;152(3722):604-619, with permission.)

FIGURE 20.2 NREM and REM Sleep Cycles through Age: Sleep Maturation from Childhood to the Adult Period. Slow-wave sleep is maximal in childhood and decreases with age. REM sleep gradually decreases from childhood to adulthood. The first NREM cycle in children is over 90 min, unlike in adults where it is around 60 min. Also note REM sleep increases in the latter half of the night. These may be physiological mechanisms why night terrors occur in the first half of the night and nightmares in the second half.⁶² (From Mindell JA, Owens JA. Biology of Sleep. In: Clinical Guide to Pediatric Sleep: Diagnosis and Management of Sleep Problems. Philadelphia, PA: LWW; 2003, with permission.)

FIGURE 20.3 The Two-Process Model (Homeostatic and Circadian Drive) for Control of Sleep and Arousal. Homeostatic drive accumulates during wake period and dissipates in sleep, whereas the circadian drive oscillates with a 24-h periodicity. The forbidden zone is the period where these drives are maximal and is a poor time to expect a child to sleep.³ (From Ferber R. How to Solve Your Child’s Sleep Problems. New York, NY: Simon and Schuster; 2009, with permission.)

Multiple Sleep Latency Test (MSLT)

Validated measure to assess the tendency to fall asleep during daytime.

CSF Studies

CSF hypocretin/orexin levels are occasionally used to confirm the diagnosis of narcolepsy/cataplexy. Levels <110 pg/mL have >95% specificity in diagnosing narcolepsy with cataplexy and >50% specificity in diagnosing narcolepsy without cataplexy.⁶^,⁷

Miscellaneous

(a) Pediatric sleep questionnaires such as “BEARS” algorithm (Table 20.2).⁸ Sleep Logs assess sleep-wake behaviors over 24-h period. Actigraphy is a viable tool for assessing insomnia/circadian rhythm disorders. It is based on the premise that presence of movements indicates wakefulness and absence of movements indicates sleep.⁹

INSOMNIA IN CHILDHOOD

Behavioral Insomnia of Childhood (Table 20.3)

DEFINITION: Difficulty falling asleep, staying asleep, or both, related to an identified behavioral etiology.¹⁰^,⁶⁴

PATHOPHYSIOLOGY: (1) Limit-setting type is characterized by bedtime stalling or refusal that is the result of inadequate limit setting by the caregiver. (2) Sleep onset association type is characterized by the child’s dependency on specific stimulation, objects, or settings for initiating sleep or returning to sleep following awakening. In the absence of these conditions, sleep onset is significantly delayed. Nighttime awakenings are actually the norm in early childhood (Table 20.4). They occur in between normal sleep cycle, so that brief awakenings occur every 90 to 120 min. The response to this waking is variable: Self-soothers go back to sleep without parental intervention, signalers alert their parents with crying or getting out of bed and typically have developed this pattern as a result of reinforcement by the caregiver.

TREATMENT: (1) Promoting good night sleep with good sleep hygiene, regular bedtimes and nap times, and positive reinforcement. (2) Putting the child into the bed drowsy but still while awake is helpful. (3) Pharmacotherapy (Table 20.5) not typically for mild behavioral insomnia. No FDA-approved medications for pediatric insomnia exist.¹¹^,¹² Indications: failure of behavioral interventions, medical illness, neurodevelopmental disabilities, and psychiatric and genetic disorders. Contraindications: substance abuse, drug-drug interactions, associated OSA.

SLEEP-RELATED BREATHING DISORDERS IN CHILDREN

Obstructive Sleep Apnea (OSA)

PATHOPHYSIOLOGY: OSA results from increased upper airway resistance during sleep, resulting in intermittent partial or complete airway closure, a/w snoring, increased respiratory effort, resulting in sleep fragmentation and/or gas exchange abnormalities.¹³

EPIDEMIOLOGY: OSA occurs in children of all ages, from neonate to adolescents, but peaks between ages of 2 and 6 y, which coincides with the peak age of lymphoid hyperplasia and adenotonsillar hypertrophy. Second peak occurs in adolescence and is most likely secondary to obesity. Overall prevalence is 2.2% to 3.8%¹⁴^,¹⁵ and up to 36% in obese children.¹⁶

TABLE 20.2 BEARS Sleep Screening Algorithm

@@	Toddlers/Preschool (2-5 y)	School-aged (6-12 y)	Adolescents (13-18 y)
Bedtime problems	Does your child have any problems going to bed? falling asleep?	Does your child have any problems at bedtime? (P) Do you have any problems going to bed? (C)	Do you have any problems falling asleep at bedtime? (C)
Excessive daytime sleepiness	Does your child seem overtired or sleep a lot during the day? Does he or she still take naps?	Does your child have difficulty waking in the morning, seem sleepy during the day, or take naps? (P) Do you feel tired a lot? (C)	Do you feel sleepy a lot during the day? In school? While driving? (C)
Awakenings during the night	Does your child wake up a lot at night?	Does your child seem to wake up a lot at night? Any sleepwalking or nightmares? (P) Do you wake up a lot at night? Have trouble getting back to sleep? (C)	Do you wake up a lot at night? Have trouble getting back to sleep? (C)
Regularity and duration of sleep	Does your child have a regular bedtime and wake time? What are they?	What time does your child go to bed and get up on schooldays? Weekends? Do you think he or she is getting enough sleep? (P)	What time do you usually go to bed on school nights? Weekends? How much sleep do you usually get? (C)
Snoring	Does your child snore a lot or have difficulty breathing at night?	Does your child have loud or nightly snoring or any breathing difficulties at night? (P)	Does your teenager snore loudly or nightly?
Owens JA, Dalzell V. Use of ‘BEARS’ sleep screening tool in a pediatric residents’ continuity clinic: a pilot study. Sleep Med. 2005;6(1):63-69.
Note: For school-aged children and adolescents: (P) Parent-directed question, (C) child-directed question. The BEARS is designed to provide practical guidance of how to incorporate a pediatric sleep history into the standard history. Each sleep domain has a set of age-appropriate “trigger questions” for use in the clinical interview.

TABLE 20.3 Behavioral Insomnia of Childhood

A child’s Sx meet the criteria for insomnia based upon reports of parents or other adult caregivers.
The child shows a pattern consistent with either the sleep-onset association or limit-setting type of insomnia described below.
1. Sleep-onset association type includes each of the following:
  1. Falling asleep is an extended process that requires special conditions.
  2. Sleep-onset associations are highly problematic or demanding.
  3. In the absence of the associated conditions, sleep onset is significantly delayed or sleep is otherwise disrupted.
  4. Nighttime awakenings require caregiver intervention for the child to return to sleep.
2. Limit-setting type includes each of the following:
  1. The individual has difficulty initiating or maintaining sleep.
  2. The individual stalls or refuses to go to bed at an appropriate time or refuses to return to bed following a nighttime awakening.
  3. The caregiver demonstrates insufficient or inappropriate limit setting to establish appropriate sleeping behavior in the child.
The sleep disturbance is not better explained by another sleep disorder, medical or neurological disorder, or medication use.

ICSD: Diagnostic and Coding Manual. 2nd ed.; 2005:23.

Risk factors: African Americans, male gender after puberty, obesity, prematurity, hypotonia, craniofacial syndromes, laryngomalacia, cerebral palsy, GE reflux, hypothyroidism, sickle cell disease, Prader-Willi, Down syndrome (most common, OSA from macroglossia, midfacial hypoplasia, micrognathia, and hypotonia).

TABLE 20.4 Causes of Night-Wakings

Inadequate sleep hygiene	Parasomnias
Inappropriate napping	NREM parasomnias
Inconsistent sleep schedule	Confusional arousals
Excess caffeine	Sleepwalking
Environmental factors	Sleep terrors
Child behavior/parent-child interaction	REM parasomnias
Sleep-onset association disorder	REM behavior disorder
Limit-setting sleep disorder	Nightmares
Nighttime fears	Medical or psychiatric conditions
Primary insomnia	Anxiety/depression
Fragmented sleep secondary to arousals	Pain
OSA	Substance abuse
PLMS	Psychoses
Narcolepsy	Epilepsy
Bruxism	HAs
Others	Asthma
Nocturnal seizures	GERD
	Medications

TABLE 20.5 Pharmacotherapy of Insomnia in Children

Drug	Dose	Half-life (h)	Side Effects	Tolerance/Withdrawal	Safety Profile
Clonazepam	0.01 mg/kg	19-60	Daytime sedation, cognitive changes, anterograde amnesia	Yes	Abuse, respiratory depression
Flurazepam	15-30 mg	48-120
Quazepam	7.5-30 mg	48-120
Temazepam	15-30 mg	3-25
Estazolam	1-2 mg	8-24
Triazolam	0.125-0.25 mg	8-24
Chloral Hydrate	50 mg/kg	10	Gastrointestinal, dizziness	Yes	Liver toxicity, respiratory depression
Clonidine	0.05-0.3 mg	6-24	Fluctuation with blood pressure
Guanfacine	0.5-2 mg	24			Little experience in children
Zolpidem	5-10 mg	2-4		Ususally no
Zaleplon	5-10 mg	1-2
Eszopiclone	1-3 mg	4-6
Trazodone	25-50 mg	30-120	Anticholinergic		Priapism
Amitryptiline	0.5 mg-2 mg/kg	4-8	Decreased REM		Cardiac
Melatonin	3-9 mg	3-9	Daytime sedation	No	Worsens seizures
Diphenhydramine	1 mg/kg	4-6	Daytime sedation	Possible	Anticholinergic
Hydoxyzine	0.6 mg/kg	6-24
Selected herbal preprations used for insomnia in children
Name	Mechanism of action	Dosage	Sleep effect	Comments
Valerian	Binds BDZ receptors	2-3 g t.i.d.	Decreases sleep-onset latency SWS, improves sleep efficiency	Toxicity rare
Chamomile	Binds BDZ receptors	1-3 g t.i.d.	Decreases sleep-onset latency	Hypertensive effect
Kava	CNS depressant	60-120 mg/d	Improves SE	Weak anxiolytic
Lavender	CNS depressant	Oil inhalation	Improves SE	Potentiates effects of alcohol
Van der Heijden KB, Smits MG, Van Someren EJ, et al. Idiopathic chronic sleep onset insomnia in attention-deficit/hyperactivity disorder: a circadian rhythm sleep disorder. Chronobiol Int. 2005;22(3):559-570.

SYMPTOMS: Daytime Sx include mouth breathing, morning headaches (HAs), behavioral and mood changes, learning difficulties, poor attention span, hyperactivity, and EDS.¹⁷^,¹⁸^,¹⁹ Nocturnal Sx include snoring, mouth breathing, apneic pauses, gasping, paradoxical breathing, sweating, labored breathing, enuresis, abnormal sleeping position (e.g., hyperextended neck).

DIAGNOSIS: PSG helps in confirming the diagnosis and assessing the severity of OSA. It is also an important baseline measure for children with OSA who may need additional PSGs after treatment to assess residual deficit.

TREATMENT: (1) Adenotonsillectomy: Recommended first-line therapy. Residual OSA may be present in PSG in up to 40% of cases postoperatively,²⁰ especially in obese children. (2) Continuous positive air pressure (CPAP) therapy: For children with moderate to severe OSA without surgically correctable obstruction. (3) Leukotriene antagonists, nasal steroids

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