Sleep disorders have an adverse impact on daily living for both children and their caregivers.1 Sleep disturbance and lack of restful sleep can masquerade as a myriad of clinical problems, including inattention, depression, headache, and seizures. While most neurological disorders are well characterized during the waking state, descriptions of pathophysiology, signs and comorbidities are frequently poorly described during sleep. Physiologic changes associated with sleep can cause an alteration of signs and function during both REM (rapid eye movement) and non-REM (NREM) sleep. These changes may include alterations in muscle tone, central control of autonomic functions, and changes in cortical neurotransmitter system interaction and balance.
Epilepsy is also a disorder that affects every aspect of a child's cognitive, social, and emotional well-being. When these disorders coexist, they can be both challenging to identify and differentiate, and a burden to the young patient and their families.
This review is devoted to the relationships between epilepsy, sleep and its disorders. The effects of epilepsy on sleep architecture and the quality of children's sleep are reviewed. How sleep may affect epilepsy and the role of circadian rhythms is discussed next. Evidence regarding the relation between epilepsy and both childhood sleep breathing disorders and restless legs syndrome (RLS) is summarized. Finally, a discussion highlighting differences between epilepsy and the most common sleep disorders during childhood is provided. An outline of evaluation and treatment of the epileptic child with a sleep disorder ends this review.
PATHOPHYSIOLOGY OF SLEEP DISORDERS IN CHILDREN WITH EPILEPSY
Epilepsy and Sleep Architecture
Epilepsy has important effects on sleep and the sleep–wake cycle.2 Alterations in total sleep, time sleep latency, and spontaneous awakenings have been demonstrated in epileptic children.3 Epilepsy may affect both the quantity and the architecture of sleep. The effects of epilepsy on sleep vary depending on seizure type. In patients with primary generalized tonic–clonic seizures, the amount of REM sleep is decreased by 50%, while in those suffering from secondarily generalized seizures, it may be as low as 41%.4,5 Infants with epileptic encephalopathies (hypsarrhythmia and Lennox–Gastaut syndrome)6 also have decreased REM sleep as well as a decrease in total sleep time in a 24-hour period.6,7,8 Prolonged sleep latency, an increase in the proportion of stages 1 and 2 NREM sleep, a decrease in the proportion of stages 3 and 4 NREM sleep, and an increase in the shifting between sleep stages have also been described.
Patients affected with childhood absence epilepsy and epilepsy with myoclonic absences do not show sleep disturbances.9 Among patients with complex partial seizures, only in those suffering from multiple nocturnal seizures, as in nocturnal frontal lobe epilepsy (NFLE), the proportion of REM sleep significantly lowered.10 Children with focal drug-resistant epilepsy studied with all-night polysomnography evidence a reduction of total sleep time, reduction of ...