Polysomnography and the multiple sleep latency test are considered the gold standard methods for the diagnosis of most sleep disorders and of narcolepsy, respectively. Criteria for these disorders are reported herein.
To facilitate the diagnosis and treatment of sleep disorders, this review provides a framework using the International Classification of Sleep Disorders, Primary. Diagnosis and treatment of sleep disorders: a brief review for clinicians. Abad VC (1), Guilleminault C. Author information: (1)Stanford University Sleep Disorders.
The diagnostic methods utilized in the investigation of sleep disorders range from subjective assessment, through the application of specific questionnaires, to daytime or nighttime actigraphic or polysomnographic recordings. Various questionnaires can be used for routine clinical diagnosis, for monitoring the response to the treatments initiated, for epidemiological studies and for clinical research. Most are international and few have been validated for use in Portuguese, which leads us to believe that misinterpretations, as well as cultural differences, may influence the specificity and sensitivity of these methods.
In view of this, if validated for the population in question, such questionnaires can be used to predict and estimate the severity of sleep disorders, serving as screening for the objective diagnoses Table 1. There are questionnaires that assess sleep in its general aspects, focusing on the time required for sleep initiation sleep latency , sleep quality, behavioral aspects, nighttime awakenings and daytime sleepiness.
Notable among such questionnaires are the Sleep Disorders Questionnaire 1 featuring quantitative and qualitative evaluation questions , the Pittsburgh Sleep Quality Index 1 evaluating the quality of sleep in the preceding month, providing an index of severity and nature of the disorder , the Mini-sleep Questionnaire 1 assessing the frequency of complaints , the Basic Nordic Sleep Questionnaire 2 analyzing the most common complaints in terms of frequency and intensity in the last three months, with quantitative specification and the self-reporting sleep questionnaire 1 utilized in psychopharmacological research.
Some questionnaires are more focused on specific disorders, the most well-known and utilized of which are the Epworth Sleepiness Scale 3 - with scores ranging from 0 to 24, values higher than 10 indicating excessive sleepiness Table 2 - and the Stanford Sleepiness Scale, 1 which describes the feeling of sleepiness at a given moment. There are also questionnaires used to assess the sleep-wake cycle, whereas still others are specific to pediatric use.
Actigraphy is technique for evaluating the sleep-wake cycle that allows the recording of motor activity through determining limb movements over a hour period. It involves the use of an actometer, which is a motion-sensing device worn around the wrist like a wrist watch , producing digitalized data that can be transferred to a computer, thus providing information on parameters such as total time asleep, total time awake, number of awakenings and sleep latency. It is particularly useful in the study of individuals such as small children, insomniacs and elderly people, who do not tolerate sleeping in laboratories.
All-night polysomnography carried out in the laboratory is the gold standard method for the diagnosis of sleep disorders, and there is an increasing diversity of systems on the market. The polysomnographic setting 9 makes it possible to use a polygraph to record results of electroencephalograms EEGs , electro-oculograms EOGs and electromyograms EMGs of the mentalis and limbs, as well as electrocardiogram ECG results and measurements of oronasal flow, thoracoabdominal movement and pulse oximetry Figures 1 and 2.
Additional channels may be available for the recording of other parameters, such as body position, esophageal pressure, snoring and supplementary derivations of EEG. Sleep staging is based on the brain wave patterns, mentalis activity and EOGs analyzed every 20 to 30 seconds, periods known as "epochs". Stage 1 sleep is characterized by a predominance of low-frequency, low-amplitude brain waves theta waves , lower muscle activity than during waking, and slow eye movements.
Stage 2 is characterized by the presence of K-complex and sleep spindles and by the absence of eye movements. Stages 3 and 4 slow-wave sleep present high-amplitude, low-frequency waves delta waves. In REM sleep, there is a significant reduction in or absence of muscle tone, rapid eye movements and sawtooth waves Figure 3. Other parameters, such as respiration, oxyhemoglobin saturation and heart rate, are also routinely analyzed. Although most polysomnographic systems are digital and their software analyzes these parameters automatically, it is mandatory that they be checked by a professional, certified in polysomnography.
Polysomnographic parameters. The main data presented in polysomnography are:. The distribution and proportion of the stages of sleep can be represented in a graphic known as a hypnogram Figure 4. The normality values for the above-mentioned parameters are shown in Tables 3 and 4. Polysomnographic findings.
The clinical and polysomnographic characteristics of sleep disorders are cataloged in the International Classification of Sleep Disorders. There is a reduction of total sleep time in insomnias and, if secondary to depression, it is possible to detect reduced latency for REM sleep, an increase in spontaneous micro-arousals, a reduction of slow-wave sleep and an increase in rapid eye movements. Narcolepsy presents significantly reduced latency for REM sleep, as well as a fragmented sleep pattern.
Chronic pain profiles, use of benzodiazepines, and fibromyalgia may intrude on rapid electroencephalographic rhythms, mainly during slow-wave sleep. Regarding REM sleep behavioral disorders, it can be observed that muscle tone is maintained during this sleep stage.
Concerning sleepwalking, such abnormal behavior occurs during slow-wave sleep. Polysomnographic systems. Portable systems for home sleep monitoring are quickly becoming widely available on the market and are principally being used for the diagnosis of obstructive sleep apnea and hypopnea. The American Sleep Disorders Association recommends that this monitoring be restricted to patients with acute clinical symptoms or when classic polysomnography is not available. It is also acceptable in the treatment of patients who have already been diagnosed through conventional means.
An American Sleep Disorders Association Committee published a review of the polysomnographic systems currently available, classifying them into several levels according to their respective resolution levels: Studies in literature validate these systems in the diagnosis of obstructive sleep apnea and hypopnea syndrome, using different cutoff points of breathing event indices, but the system is not efficient with regard to other sleep disorders.
Orr et al. When comparing conventional polysomnography with Level II polysomnography, the former showed more accuracy in the assessment of the stages of sleep. In this system, only the cardiorespiratory variables are assessed, not enabling the analysis of sleep parameters. The system presents high sensitivity and specificity for sleep apnea when applied to a symptomatic population.
This system includes devices ranging from a simple oximeter to the most sophisticated devices with algorithm analysis. The available studies indicate that the continuous recording of one or two of these parameters for the diagnosis of obstructive sleep apnea varies considerably in terms of precision.
Pulse oximetry, combined with a clinical score, has proven useful as a triage test in the selection of patients for standard polysomnography. This system consists of equipment which records oximetry and one more respiratory channel airway flow, snoring. Recently, interest in the use of the Auto-set continuous positive airway pressure for the diagnosis of sleep apnea has increased.
Classically, this system is used as a means of treating obstructive sleep apnea, for which the pressure adjustment of the nasal continuous positive airway pressure is obtained automatically. The system also has a diagnosis mode which estimates the nasal airway flow semiquantitatively by assessing the variation of the pressure obtained with the nasal catheters, which are connected to a pressure transducer, thereby detecting apneas, respiratory irregularities, snoring and airway flow limitation flattening index. This is considered the method of choice for the assessment and monitoring of excessive daytime sleepiness, quantifying this symptom and making it possible to identify REM sleep, which makes it extremely useful in the diagnosis of narcolepsy.
It is the only scientifically validated test for the objective assessment of sleepiness. This test is carried out in the sleep laboratory, beginning at 1. The patient remains in the laboratory for practically the entire day. The MSLT should ideally follow a night of polysomnography. Roughly half of all adults report occasional bouts of insomnia, which are stretches of poor sleep lasting anywhere from one night to several weeks.
Roughly 10 percent of adults experience chronic insomnia.
Sleep apnea is a condition in which a person repeatedly stops breathing during the night, which harms the depth and quality of his or her sleep. In some cases, these breathing stoppages can occur hundreds of times each night. There are two types:. Obstructive sleep apnea: This is caused by the partial or total blockage of breathing airways during sleep.
More on those below. Type 2 narcolepsy : Patients with this condition do not have low levels of hypocretin, but experience other narcolepsy symptoms. For some, RLS can be so severe that it becomes difficult to fall or stay asleep. This can lead to excessive daytime drowsiness and insomnia. This biological clock determines the release of neurochemicals that either initiate sleep or chase it away. Delayed sleep phase disorder: This could be thought of as "night owlism. Advanced sleep phase disorders: This is basically the opposite of delayed sleep phase disorder.
This type, which is most common among the elderly, typically involves going to bed at a very early hour—sometime between 6 and 9 p. There are many other types of sleep disorders, but the above are the most common. While some sleep disorders have a clearly identifiable cause, others emerge from a combination of factors. Often, sleep disorders are the unwelcome side effect of some other mental or physical medical condition. For example, narcolepsy can stem from a specific kind of autoimmune disorder or, in rare cases, from a brain injury.
For these reasons, the many causes or risk factors for a sleep disorder are too numerous to lay out here, but here are the most common:. The symptoms of a sleep disorder differ depending on its type and underlying cause.
Your doctor will almost always start by conducting a thorough in-person interview and taking your medical history. This is usually coupled with a physical exam. These initial tests can help your doctor zero in on the specific type of sleep disorder you may be dealing with, as well as any underlying medical issues that may cause or contribute to your sleeping issues.
If your doctor suspects insomnia or one of several other sleep disorders, he or she may ask you to keep a detailed sleep journal for a week or two.