Attention deficit hyperactivity disorder and poor school performance are associated with sleep disorders in pediatrics such as frequent arousals and sleep onset and maintenance problems
Attention deficit hyperactivity disorder (ADHD) is estimated to affect 3% to 5% of school age children in the United States.1 ADHD is a group of symptoms rather than a disease. It is characterized by a persistent pattern of inattention and hyperactive impulsive behaviors that are more frequent and severe than typically observed in children of the same age.2 There is no single test to diagnose ADHD. An extensive evaluation that includes behavior rating scales completed by parents and teachers, physical examination, and psychometric testing is required to diagnose ADHD and also to rule out other disorders and identify co-morbidities. Indeed, comorbidities such as learning disorders, mood disorders, oppositional defiant and conduct disorders, Tourette’s syndrome, seizure disorders, and fragile X syndrome are just a few of the many problems that can complicate the diagnosis even further.3,4
Daytime symptoms of poor or insufficient sleep in children overlap considerably with those of ADHD.5-7 This is in contrast to the typical sleep-deprived adult who is obviously excessively sleepy during the day. Parents of children with ADHD and other disorders that affect behavior and school performance frequently describe problems relating to sleep. These include sleep onset and maintenance problems, frequent arousals, and increased tiredness on awakening compared to controls.8,9 Researchers in many centers are studying these relationships more specifically; however, there is enough evidence at this time to assist the clinician who is in the position to identify and manage sleep problems in the child with attention deficit, hyperactivity, and academic performance problems.
Sleep deprivation may be the most common sleep disorder that affects daytime function in children.10,11 Children with ADHD and children suffering from sleep deprivation share a similar cognitive, behavioral, and emotional profile.12-14 Randazzo et al studied 16 children (7 males, 9 females) between the ages of 10 and 14 years.15 One group was assigned to 11 hours in bed, and the other restricted to 5 hours in bed on a single night in the sleep laboratory. The following day, a battery of performance and sleepiness measures were given. Sleep latencies on the multiple sleep latency test (MSLT) were significantly shorter in the sleep restriction group, by about 10 minutes on each nap. Although routine performance was maintained, psychomotor and cognitive performance of higher functions (verbal creativity and abstract thinking) were impaired.
Parents of children with ADHD report significantly more sleep problems than parents of normally developing children. Corkum et al9 compared questionnaire results with sleep diaries and actigraphy in 25 children with ADHD and 25 normal controls. Responses on the questionnaire revealed a significant difference between the two groups in sleep duration, difficulty with sleep onset, difficulty awakening in the morning, restless sleep, and bedtime resistance; however, none of the reported sleep problems could be verified by actigraphy (bedtime resistance and difficulty arising could not be assessed by actigraphy). Sleep diary results were similar to the objective actigraphy data, confirming the usefulness of the sleep diary in the evaluation of sleep disorders. Specific historical questions and studies to determine if the individual child is receiving the appropriate duration and timing of sleep are a mandatory component of the evaluation of the child with symptoms suggestive of ADHD.
Sleep Disordered Breathing
Daytime somnolence, declining school performance, mood, and personality changes were among the problems first reported as part of the obstructive sleep apnea (OSA) syndrome in children in 1976.16 Other studies have confirmed and expanded on these findings, documenting attention disorders, memory and learning disabilities, school failure, developmental delay, hyperactivity, aggressiveness, and withdrawn behavior.17,18 Chervin et al19 surveyed 143 parents of children attending one of two clinics, selected consecutively without regard to diagnosis or reason for the clinic visit. The sample included children ages 2 to 18 years—half from a child psychiatry clinic and half from a general pediatric clinic. Parents completed validated questionnaires for pediatric sleep and for inattention/hyperactivity. Three groups were analyzed including ADHD subjects from the psychiatric clinic, other children from the psychiatric clinic, and the general pediatric clinic subjects. Habitual snoring was present in 33% of those with ADHD, compared with 9% to 11% of other children. The higher the sleep disordered breathing (SDB) score, the higher was the hyperactivity/inattention score. The authors suggest that 81% of habitually snoring children who have ADHD (25% of all children with ADHD) could have their ADHD eliminated if their habitual snoring and any associated sleep-related breathing disorder were effectively treated. More recently, Chervin et al20 studied an even larger sample of 866 consecutive children from general pediatric clinics, again recruited without regard to diagnosis or presenting complaint. Parents completed pediatric sleep and hyperactivity/inattention questionnaires. Habitual snoring increased the chance of hyperactivity from 12% to 22% among all the children (odds ratio 2.2), and from 9% to 30% among young boys (odds ratio 4.3). On the other hand, this association is not so clear when the polysomnogram is used as the standard for diagnosis of SDB. Chervin and Archbold21 studied 113 children ages 2-18 years referred to the sleep disorders laboratory for suspected SDB. Parents completed a Connors’ Parental Rating Scale. The scores were high in both the SDB and non-SDB groups and there was no association between the hyperactivity score and the rate of apneas and hypopneas, desaturation, and the most negative esophageal pressure. This may demonstrate that we are not using the polysomnogram properly in identifying these children. We may need to incorporate more sensitive means to identify hypopnea, changes in upper airway resistance, hypoventilation, or arousals than are commonly used in routine studies.22
Improvement after treatment (generally adenotonsillectomy) provides further evidence that sleep-related breathing disorders can cause or at least contribute to ADHD symptoms.23,24 Gozal25 studied 297 first graders in the lowest tenth percentile of the class academically. Of these children, 18% demonstrated sleep associated gas exchange abnormalities. This is significantly higher than the generally accepted estimates of a 1% to 2% prevalence of SDB in all children of that age group.18 Academic performance in second grade improved significantly in those children whose parents chose treatment (adenotonsillectomy). Certainly the recognition and treatment of SDB are critical in the management of the child presenting with ADHD symptoms.
Restless legs syndrome (RLS) is a disorder of uncomfortable leg sensations (dysesthesias) with an irresistible urge to move the legs. It is worse when sitting or lying down and at least partially relieved by movement. Most individuals with RLS have periodic limb movements during sleep (PLMS). When these movements result in arousals and fragment sleep to a degree that daytime sleepiness occurs or performance is affected, then it is termed periodic limb movement disorder (PLMD). RLS exists to varying degrees of severity in 10% to 15% of the adult population. Surveys of adults reveal that 18% recall onset before 10 years of age, and 25% recall onset between 11 and 20 years of age.26 There is growing evidence that RLS and/or PLMD may aggravate or cause daytime symptoms in a subgroup of children with ADHD.4 Picchietti and Walters27 reviewed 3 years of polysomnographic studies in a pediatric sleep laboratory. Of the 129 children with a PLMS index greater than 5, 117 had ADHD via DSM-IV criteria; 16 of the children had PLMS indices greater than 25. Of this subgroup, many exhibited school problems, sleep onset problems, and restless sleep, and had a positive family history of RLS. The severity of the PLMS was not related to the use of stimulant medication.
Parents are more likely to bring their child to their primary care provider for evaluation of daytime behavior/school problems than for problems related to sleep; therefore, the astute clinician should recognize that sleep problems may be contributing to the presenting symptom complex. This is particularly important to investigate in children previously “diagnosed” with ADHD. The evaluation begins with a detailed sleep history. A validated pediatric sleep questionnaire9,20 completed by the parent can be used to define problems that require more thorough discussion. Reviewing a typical 24-hour day, starting with the bedtime routine, can provide some structure to the interview. Bedtime resistance, sleep onset and maintenance, snoring and obstructive pauses, restless sleep, and difficulties with waking on school days should be identified and detailed. Daytime behavior and school performance, sleepiness, and naps (at any age) should be queried. Remember to ask specifically about the duration/severity of these problems. The family may neglect to admit months of absence from school unless asked directly. By determining what is most disruptive to the child and family, priorities can be determined. It is also helpful to discuss intervention the family has attempted to date, such as behavioral strategies and medications they have tried. You may be able to determine why they were not effective.
Reviewing a completed sleep diary is a very useful tool in this interview. We send a sleep diary with instructions to the family at the time the appointment is scheduled, generally 2 weeks before the appointment. This data guides the discussion and may elucidate patterns the parent had not noticed. Family history is helpful, particularly for circadian rhythm disorders, insomnia, parasomnias, and RLS. The environmental history, particularly with regard to the sleep situation (location and distractions), may provide clues for intervention. The physical examination may reveal risk factors such as obesity, poor growth, or sites of upper airway obstruction (most commonly rhinitis and adenoid/tonsillar hypertrophy). Secondary signs of OSA such as a loud second heart sound, heart murmurs, or edema may be present in extreme cases. A thorough neuropsychiatric evaluation is essential. This may include referral for neurological or psychiatric consultation as well as psychological testing depending on your own area of expertise.
History and questionnaire responses cannot reliably distinguish between primary snoring and OSA.28 The polysomnogram remains the most useful diagnostic tool; however, other problems such as bedtime resistance, scheduling, inappropriate use of medications, rhinitis, and asthma should be evaluated and treated before scheduling the sleep study. With this approach, the family will experience immediate success and the stress surrounding the behavioral situation is diminished. The polysomnogram should be performed and interpreted using accepted standards for children.29 End tidal CO2 monitoring and anterior tibialis electromyography should be included.
The treatment plan must be individualized based on findings from the evaluation and the degree of symptoms that disrupt the child’s school performance and social interaction.30 Some points to consider include:
• Behavioral interventions should be implemented if there is any suggestion of inadequate sleep or inappropriate timing of sleep. Common problems include bedtime resistance and delayed sleep phase syndrome. For example, adolescents frequently overextend themselves with advanced placement or honors classes, extracurricular sports and clubs, part-time employment, and obligatory social time with friends, which insidiously intrude into sleep time. These can be often be diagnosed and managed by history alone without a sleep study.
• Specific sleep disorders diagnosed by the patient’s history and polysomnogram should receive optimal treatment. This may include adenotonsillectomy for OSA, medications for RLS or PLMD, or a comprehensive management program for narcolepsy.
• If stimulant medication is used for ADHD, the dose and schedule will need to be determined on a case by case basis. For example, stimulant medications interfere with sleep onset in some individuals, while in others, a low dose in the evening may help organize behavior resulting in less conflict at bedtime.
Children with ADHD are most often evaluated and treated by their primary care provider; therefore, professionals in sleep medicine need to educate their medical community regarding the importance of a detailed sleep history and focused evaluation, particularly for these children who are struggling in so many ways every day. What is the primary problem? Does ADHD result in behavioral and other sleep disorders, or do primary sleep disorders result in ADHD? It is likely a combination of the two, which requires a thorough evaluation and specific management plan for each child.
Gary L. Montgomery, MD, is the medical director of the Sleep Disorders Center at Children’s Healthcare of Atlanta at Scottish Rite in Atlanta.
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