Q.1 How much sleep does an average individual need?
Ans.The criteria for adequate sleep are arbitrary. Most adults sleep for six to ten hours per night, with an average of eight hours. Six and a half hours of sleep time with cut off points of 15 to 20 minutes of latency is suggested by the International Classification of Sleep Disorders (ICSD). A sleep of less than four hours or more than ten hours is generally associated with sleep disorders. The need for sleep changes with increase in age and varies with each person. Regardless of where the exact line is drawn, patients with the diagnosis of sleep state misperception will gradually shade into the category of psychophysiological insomnia.
Q.2 What is normal sleep? Ans. Within sleep two separate states – nonrapid eye movement (NREM) and rapid eye movement (REM) have been defined on the basis of a constellation of physiological parameters. The EEG pattern in NREM sleep is synchronous with characteristic waveforms as sleep spindles, K complexes and high-voltage slow waves. NREM sleep is usually associated with fragmented mental activity. REM sleep, is defined by EEG activation, muscle atonia and episodic bursts of rapid eye movements. The onset of sleep under normal circumstances in normal adult humans is through NREM sleep. This fundamental principle is important in considering normal versus pathological sleep. e.g. the abnormal entry into sleep via REM is a diagnostic sign in adult patients with nacrolepsy.
Q.3 Do older people need less sleep? Ans. The strongest and most consistent factor affecting the pattern of sleep stages across the night is age. The changes in sleep patterns common in older people include:
- Going to bed earlier and waking up earlier
- Spending less time in deep sleep
- Waking up frequently at night
- Spending more time awake at night
This may be caused due to changes in lifestyle, such as napping more often during the day, discomfort from physical and physiological conditions such as arthritis and back pain, and also from emotional problems such as stress and depression.
Q.4 Which are the main symptoms of sleep disorder? Ans. The inability to fall or stay asleep at night (insomia) and the inability function well during the day due to sleepiness are the two most common symptoms of sleep disorder. Accurate differential diagnosis of sleep disorder is important to determine specific appropriate treatment.
Q.5 How are sleep disorders diagnosed? Ans. Sleep disorders can generally be diagnosed in a laboratory If a physician finds an evidence of a sleep disorder such as apnea, nacrolepsy, restless leg syndrome then polysomography may be recommended. These studies is conducted generally in a sleep laboratory within a medical center. These studies can be helpful only in some cases of insomnia, as in most of the cases the patient’s history taken by the physician can determine the cause or causes of insomnia.
Q.6 What are “circardian sleep disorders”?
Ans. “Circardian sleep disorders” also referred to as “Delayed sleep phase syndrome” is characterized by sleep onset and wake times which are delayed 3 to 6 hours relative to conventional sleep wake times. The clinical picture may be that of sleep-onset insomnia. The patients are unable to sleep at normal times and may report use of sedative-hypnotic drugs, bedtime use of alcohol or even psychtherapy. Sleepiness in such persons is greatest in the mornings and lessens as the circardian drive for wakefulness peaks in the late afternoon and they often feel alert in the late evenings. The syndrome may be associated with daytime irritability and poor performance in school or at work place. This syndrome may be mistaken for depression in, in which the sleep wake cycle may also be delayed or advanced.
Q.7 What is “Advanced sleep phase syndrome”? Ans.Advanced sleep phase syndrome (ASPS) is characterized by habitual and involuntary sleep and wake times that are at least several hours earlier than normal. In such cases sleep itself is normal but the individuals often complain of persistent and irresistible sleepiness in the late afternoon or towards early evening. They may complain of involuntary early morning awakening (2 to 5 AM), which occurs even if the sleep onset is voluntarily delayed. In such cases diagnosis of depression can erroneously be made.
Q.8 Which are the main screening questions required for complete sleep evaluation? Ans. TFor complete sleep evaluation the first and the foremost is recording the careful sleep history of the patient. The other essential questions which need to be asked are:
- What is the nature and duration of the complaint?
- Does the complaint vary with time?
- Is it cyclic or periodic?
- Does it increase with stress or other symptoms?
- Is there a family history of similar sleep problems?
It can also be helpful if a patient keeps a sleep diary or a detailed record of daily sleep patterns and symptoms to help to determine the periodicity and relationship to stressful events and other related issues.
Q.9 What are the main causes of insomnia? Ans.Insomnia is basically not a disorder but is a complaint, and hence requires systemic evaluation and exclusion of several etiological factors. The most common causes of insomnia could be:
- Medical disorders especially those associated with pain. Also medication prescribed for certain medical problems may result in side effects of insomnia.
- Psychiatric disorders especially anxiety and depression are associated with insomnia. The complaint may include difficulty in getting sleep (common in anxiety), difficulty in staying asleep or early morning awakening (common in depression).
- Chronic sedative-hypnotic abuse e.g. medications started for transient or short-term insomnia but not stopped and patients self-medicating with alcohol because of difficulty in getting to sleep.
- Nocturnal myoclonus (periodic movements in sleep) may cause insomnia in some patients.
- Psychophysiologic insomnia – This condition occurs mostly in people with fragile sleep (sleep easily disturbed by mild stress). In such cases a stress-related insomnia results, in patients worrying about going to bed (and therefore becoming aroused) because they fear that once again they will not be able to sleep.
Q.10 Is behavioral therapy useful for treating insomnia? Ans. Behavioral therapy is the treatment of choice for psychphysiologic insomnia, idiopatic insomnia and patients with inadequate sleep hygiene. It serves as an adjunctive therapy in insomnias secondary to psychiatric or medical illness. Behavioral techniques include, sleep hygiene, exposure to bright light and relaxation.
Q.11 How is bright light used in the treatment of sleep disorders? Ans.Bright light can shift circardian rhythms. It acts on the superchiasmatic nucleus of the hypothalmus via the retinohypothalmic tract to alter the phase or timing of the circardian system. Hence exposure to bright light in the late evening i.e. at the beginning of the sleep cycle promotes sleep.
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