© Springer-Verlag Italia 2015
Angelo Sghirlanzoni, Giuseppe Lauria and Luisa Chiapparini (eds.)Prognosis of Neurological Diseases10.1007/978-88-470-5755-5_66. Sleep Disorders
(1)
Clinical Epileptology & Experimental Neurophysiology Unit, Fondazione Istituto Neurologico C. Besta, Via Celoria 11, Milan, 20133, Italy
Keywords
Sleep Disorders –OSASInsomniaNarcolepsyParasomniaREM Behavior DisorderAbbreviations
AD, Alzheimer’s disease; AHI, Apnea-hypopnea index; BMI, body mass index; CPAP, continuous positive airway pressure; CSA, central sleep apnea; CT, computed tomography; EDS, Excessive daytime sleepiness; ESS, Epworth Sleepiness Scale; LBD, Lewy body dementia; MAD, maxillary advancement device; MSLT, Multiple Sleep Latency Test; MR, magnetic resonance imaging; NFLE, nocturnal frontal lobe epilepsy; NIH, National Institutes of Health; NREM, non REM; OSAS, obstructive sleep apnea syndrome; PD, Parkinson disease; PLM, periodic leg movements during sleep; PSG, polysomnography; RBD, REM behavior disorder; REM, rapid eye movement; RLS, Restless leg syndrome; SOREMP, sleep onset REM period; SWS, slow-wave sleep; UARS, Upper airways resistance syndrome.
6.1 Introduction
The most relevant sleep disorders for the neurologist are (1) sleep-related breathing disorders, (2) parasomnias, (3) insomnias, (4) hypersomnias, and (5) restless leg syndrome.
6.1.1 Sleep-Related Breathing Disorders
Sleep-related breathing disorders include a variety of disorders, the most common and most relevant in the clinical practice being obstructive sleep apnea syndrome (OSAS). This condition is caused by a mechanical obstruction of the upper airways during sleep. Central sleep apnea (CSA), due to a loss of sensitivity of the chemoreceptors and neural activity in the brainstem, is another important disorder [1].
Key Facts
Definitions and terminology – OSAS: repetitive episodes of mechanical upper airway obstruction that occur during sleep.
OSAS severity: based on polysomnographic AHI (apnea-hypopnea index). Mild: AHI 5–15; moderate: AHI 16–30; severe: AHI >30.
Clinical features – Snoring apneic episodes; excessive daytime sleepiness (EDS); unrestorative sleep; nocturia.
Diagnostic markers
Imaging (CT/MR) – Abnormalities of the upper airways and/or mandibular-pharyngeal.
Neurophysiology – Sleep hypopneas-apneas and sleep fragmentation (EEG arousals) at nocturnal polysomnography.
Top differential diagnoses
Central sleep apnea syndrome, primary snoring, upper airways resistance syndrome (UARS), periodic limb movement disorder, narcolepsy, idiopathic hypersomnia, insufficient sleep syndrome.
Principles of treatment
Diet, continuous positive airways pressure (CPAP), mandibular advancement devices (MAD), nasal, palato-pharingeal, and maxillo-facial surgery. OSAS is an independent risk for cardiovascular diseases and stroke in adults, and for behavioral disturbance in children.
Prognosis –Risk factor of hypertension, cardiovacular diseases, methabolic dysregulation and stroke.
6.1.2 Definition
Obstructive sleep apnea syndrome (OSAS) (also known as sleep apnea, obstructive apnea, upper airway apnea, hypersomnia sleep apnea syndrome) is a sleep breathing disorder characterized by repetitive episodes of upper airway obstruction that occur during sleep. OSAS is graded on a scale based on the apnea-hypopnea index (AHI). It is defined by the mean number of apneas and hypopneas per hour of sleep. An AHI of 5–15 is considered a mild disturbance, 16–30 is considered moderate, and >30 is considered severe.
6.1.3 Clinical Features and Epidemiology
OSAS prevalence is variable depending on sex and age: male 4 %, female 2 %, children 2 %. Childhood form: from 0 to 10. Adult form: from 40 to 60 (women are more likely to develop OSAS after menopause).
A long history of snoring generally precedes the onset of OSAS, with snoring a most typical OSAS symptom.
Bed-partners may also report apneic episodes, often associated with arousal to restart breathing (choking or suffocation may be reported). Excessive daytime sleepiness (EDS) is the most typical presenting complaint. Driving accidents are frequently related to EDS.
Patients typically feel unrestored by nocturnal sleep, and may describe mouth dryness upon awakening and/or morning headaches that may last from one to several hours.
Nocturia (1–5 times per night) is frequently reported and it is related to the severity of the syndrome. Gastroesophageal reflux can occur in association with the effort to re-establish breathing. Secondary symptoms include psychiatric disturbances such as mood disorder, anxiety, and irritability. A loss of libido and erectile ability may also be reported.
Cardiac arrhythmias may occur during sleep in patients with OSAS; and hypertension with an elevated diastolic pressure values is commonly observed.
6.1.4 Diagnostic Markers
Blood, CSF, Genetics: n.s.
Imaging
Cephalometric radiographs, magnetic resonance imaging (MR), computed tomography (CT) scanning, fiberoptic endoscopy, and drug-induced sleep endoscopy can all show abnormal anatomy or obstruction of the upper airways and/or mandibular-pharyngeal abnormalities. In childhood, tonsillar and/or adenoids enlargement is typically observed.
Neurophysiology
The gold standard for OSAS diagnosis is the all-night polysomnography (PSG). In adult patients PSG must document >5 obstructive apneas/hypopneas of more than of 10 s per hour of sleep, associated with significant arterial oxygen desaturation. EEG arousals related to apneas/hypopneas and bradytachycardia runs are part of the typical polysomnographic presentation.
The Multiple Sleep Latency Test (MSLT) may be used to objectively measure EDS. The Epworth Sleepiness Scale (ESS) is routinely used to assess subjective sleepiness.
6.1.5 Differential Diagnoses
Common differential diagnoses include narcolepsy, idiopathic hypersomnia, insufficient sleep syndrome, and periodic limb movement disorder.
Other sleep breathing disorders (central alveolar hypoventilation, central sleep apnea syndrome, Cheyne-Stokes respiration, primary snoring. Upper airways resistance syndrome (UARS), paroxysmal nocturnal dyspnea) can be differentiated by OSAS by performing a PSG study.
Panic attacks, sleep choking syndrome, and sleep-related laryngospasm can occasionally be misdiagnosed as OSAS. Sleep-related gastroesophageal reflux and sleep-related abnormal swallowing syndrome can also produce choking episodes.
6.1.6 Principles of Treatment
Obesity is a major risk factor for OSAS. Reduction of excessive weight is an important therapeutic goal in almost all OSAS patients. Continuous positive airway pressure (CPAP) is the recommended treatment for sleep apnea.
Generally, severely symptomatic patients (severe EDS with AHI >30 events/h) readily improve with CPAP therapy. Conversely, in asymptomatic patients (no or mild EDS present), even with a markedly elevated apnea/hypopnea index, the clinical therapeutic CPAP effect may be difficult to appreciate by the patient. In mild OSAS, oral appliances (mandibular advancement devices) can be considered as a valid alternative to CPAP.
Various techniques of soft tissue surgery for treatment of OSAS have been proposed but their efficacy still remains controversial. An exception is adeno-tonsillectomy: it is almost always successful in children, but also in adult patients with well-documented tonsillar hypertrophy.
Facial-maxillary surgery can be very effective in selected patients.
6.1.7 Prognosis
OSAS in adult patients is a well-recognized independent risk factor and National Institutes of Health (NIH) guidelines include OSAS as an identifiable cause of hypertension. An apnea-hypopnea index of 15 events/h or more was independently associated with a threefold increased risk of developing hypertension.
Cardiovascular diseases associated with OSA include heart failure, stroke, cardiac arrhythmias, myocardial ischemia, and pulmonary arterial hypertension [2–4].
In addition, OSAS may be associated with metabolic dysregulation (insulin resistance and lipid disorders), which in turn is a risk factor for cardiovascular diseases.
Strong evidence indicates that OSAS is an independent risk factor for stroke [2]. Moreover, OSAS exacerbates damage produced by a stroke and increases the risk for a subsequent stroke.
In children, the most relevant long-term consequences of OSAS are behavioral and neurocognitive morbidities. Behavioral dysregulation is commonly considered as a comorbidity of OSAS, but several authors report some association between OSAS and hyperactivity, attention deficits, impulsivity, and attention deficit hyperactivity disorder-like symptoms. Last but not least, EDS related to OSAS is a risk factor for motor vehicle accidents (estimated OR = 6.3) [5].
6.2 Parasomnias
Parasomnias are undesirable motor and behavioral phenomena occurring during sleep, at sleep-onset, or during sleep-arousals [1]. The type and complexity of movements and behaviors observed can vary according to the sleep stage (NREM or REM) and to the form of parasomnia. The patient is usually unaware of the parasomnic episode, which can be characterized by finalistic actions. The subject may awake during or at the end of the paroxysmal episode; a dreamlike memory can sometimes be reported after awakening, above all in REM parasomnias.
Key Facts
Definitions and terminology – NREM parasomnias: undesirable physical, behavioral, or experiential events occurring during NREM sleep; NREM parasomnias are subclassified in several different disorders including confusional arousal, somnambulism or sleep-walking, sleep terrors or pavor nocturnus.
Diagnostic markers
Neurophysiology – Diffuse hypersynchronous high voltage EEG delta activity during episodes; episodes occurring during slow-wave NREM sleep.
Top differential diagnoses
Sleep-related epilepsy, nocturnal frontal lobe epilepsy, REM parasomnias (REM behavior disorder), nocturnal psychogenic nonepileptic seizures, nocturnal panic attacks, sudden awakenings in OSAS.
Principles of treatment and prognosis
Treatment not necessary in sporadic episodes; 5-OH-tryptophane, clonazepam, antiepileptic drugs (severe cases). NREM arousal disorders usually have onset during childhood and a spontaneous disappearance within adolescence. Occasionally, they persist later on, during adolescence and adulthood.
6.2.1 NREM Parasomnias
6.2.1.1 Definition
NREM parasomnias (arousal disorders, somnambulism) [common definition] are undesirable physical, behavioral, or experiential events occurring during NREM sleep.
6.2.1.2 Clinical Features and Demographics
The prevalence of NREM parasomnias or NREM arousal disorders in the general population is around 1–6 % without significant gender differences [6, 7].
Age: prevailing in childhood, possible persistence, or onset in adolescence and adulthood.
6.2.1.3 Clinical Presentation
NREM arousal disorders occur during slow-wave sleep (SWS) and are divided into three forms: confusional arousals, sleep-walking (somnambulism), and sleep terrors (pavor nocturnus). The clinical manifestations of the three main types of arousal parasomnias can coexist in the same individual and sometimes also in the same episode. Episodes are typically sporadic, occurring during the initial third or first half of the night. Some authors have emphasized the frequent comorbidity between nocturnal frontal lobe epilepsy (NFLE) and arousal disorders [7, 8]. In some groups of NFLE patients, the prevalence of parasomnias can reach percentages (34 %) much higher than the prevalence of arousal disorders in the general population (1–6 %). It could be hypothesized that these two disorders, even if etiologically different, could share a common pathophysiological mechanism, acting through an alteration of the arousal regulatory system.
6.2.1.4 Diagnosis
Genetics
A family history of NREM parasomnias is a major risk factor. Specific genetic alterations have not been identified yet.
Imaging (CT/MR) – ns
SPECT Scan
Regional activation during episodes (i.e., hyperperfusion) of cingulate and motor areas, with frontal deactivation has been described [9].
Neurophysiology
Video-polysomnography is the gold standard for the diagnosis of NREM parasomnias [10]. During the episodes, the EEG is characterized by a diffuse hypersynchronous high voltage delta activity typical of the SWS. Episodes occur during slow-wave NREM sleep.
6.2.1.5 Differential Diagnoses
6.2.1.6 Principles of Treatment
Treatment is not usually necessary if episodes are sporadic. When necessary, benzodiazepine (first choice: clonazepam 0.5-2 mg at night), 5-OH-tryptophane, antiepileptic drugs (i.e., carbamazepine, topiramate) can be used in selected cases.
6.2.1.7 Prognosis
NREM arousal disorders usually show onset during childhood and then a spontaneous disappearance within adolescence. Occasionally, they persist later on, during adolescence and adulthood. When episodes are frequent and especially if they are drug resistant, sleep disruption and social disability can occur. In severe cases, injuries (to the patient or to the bed-partner) may be a consequence of violent, nocturnal behaviors.
Key Facts
Terminology and definitions – REM parasomnias are undesirable physical, behavioral, or experiential events occurring during REM sleep. REM parasomnia are subclassified in several different disorders including REM behavior disorder (RBD), recurrent isolated sleep paralysis, nightmare disorder.
Clinical features – Motor and behavioral phenomena during REM sleep.
Diagnostic markers
Blood, CSF, Genetics, Imaging (CT/MR) – ns.
Neurophysiology – Video-PSG: loss or reduction of physiological muscular atonia on EMG channels during REM sleep.
Top differential diagnoses – Sleep-related epilepsy, nocturnal frontal lobe epilepsy, NREM parasomnias, nocturnal psychogenic non epileptic seizures, nocturnal panic attacks, sleep-related movement disorders, sudden awakenings related to OSAS.
Principles of treatment and prognosis – Low-dose clonazepam, melatonin, antiepileptic drugs (severe cases).
RBD is a chronic disorder, with onset during adulthood at around 50 years and persisting through senescence.
6.2.2 REM Sleep Behavior Disorder (RBD)
6.2.2.1 Terminology and Definitions
Synonyms
Oneirism, idiopathic RBD, symptomatic RBD, REM sleep without atonia, REM sleep motor Parasomnia
6.2.2.2 Definition and Clinical Features
RBD is characterized by the intermittent loss of REM sleep atonia and by the appearance of elaborate motor activity associated with dream mentation. The dreams often involve kicking, screaming, punching, grabbing, and even jumping out of bed. When awoken, the patient may recall the dream matching the actions he was performing [1].
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