Sleep & Alertness Clinic

Chronic Insomnia Disorder is present in about one in seven to one in ten adults with symptoms of difficulty initiating sleep, maintaining sleep or waking up earlier than desired despite adequate opportunity for sleep. International criteria require that these symptoms interfere with daily life and must be present for more than three times a week for more than three months. This way, brief episodes of insomnia most people naturally experience across the lifespan are not misdiagnosed as chronic insomnia. In children, symptoms can also relate to either resistance to sleeping or needing rituals to sleep. In adults, it is associated with other medical conditions, including cognitive impairment, cardiovascular and metabolic disorders, chronic pain and depression. In such conditions, detailed evaluation with neuropsychological and laboratory tests may clarify an underlying cause to the insomnia and direct a combined treatment that improves quality of life. First line treatment for almost all people is Cognitive Behavioral Therapy for Insomnia (CBTi), whereas medications are considered for a period of time for certain people.

ISS refers to inadequate sleep amount for a period of 3 months and is often misinterpreted as insomnia by patients due to the common feature of not falling asleep when desired. However, in contrast to insomnia syndromes where people have the opportunity to sleep, people with ISS are usually not given the opportunity to sleep or do not pursue sleep and, if sleep is pursued, they tend to fall asleep within minutes. ISS is usually accompanied by excessive daytime somnolence, a sense of fatigue, and inability to focus and perform tasks effectively in the daytime, which are the main symptoms people visit their clinician. People with ISS are at increased risk of neurological (e.g., dementia, stroke), cardiovascular (e.g., heart attack, hypertension), and metabolic-endocrine (hypothyroidism, diabetes, hyperlipidemia) problems. It is driven by social causes that lead to sleep deprivation, such as extended work hours or being a caregiver to others. The detrimental effects of ISS worsen as sleep deprivation accumulates over time, whereas weekend catch-up sleep, although helpful, is not sufficient to fully replenish the body’s lost rest. As a syndrome caused by social factors, treatment is achieved by changes in social habits, which also avoids unnecessary use of medications or coffee that people tend to take to remain awake.

Sleep apnea is the most commonly diagnosed syndrome of sleep disordered breathing (SDB) and refers to shallower breathing or breathing arrests during sleep that lead to either a decrease in the body’s oxygen or awakenings from sleep. About a third of adult men and post-menopausal women, and 9% of pre-menopausal women have sleep apnea. It is classified generally into Obstructive Sleep Apnea (OSA) and Central Sleep Apnea (CSA), depending on whether the disordered breathing is caused by narrowing or collapsing of the upper airway (OSA), or by a decreased or non-existent respiratory effort (CSA). The main risk factors for OSA are male sex, narrow upper airway anatomy, and age. CSA is observed in people with certain neurological or cardiac diseases (e.g., heart failure), although brief central apnea events are normally observed in people the first seconds of entering sleep and in pre-kindergarten children during REM sleep. The vast majority of people with sleep apnea have or are at risk of cardiac (e.g., arrhythmias), metabolic (e.g., hyperlipidemia, diabetes), neurological (e.g., stroke, dementia) and psychiatric (e.g., depression and anxiety) disorders. Of the cognitive deficits associated with sleep apnea, vigilance is the most affected, but improves with treatment of sleep apnea as deep sleep is achieved.

SDB also explains why many people use the bathroom in the middle of the night (nocturia) even though they don’t have prostate or cardiac problems, because certain hormones that regulate urine production are poorly regulated due to decreased oxygen. It is not uncommon for men to receive surgical prostate procedures for nocturia, even though the cause to their symptoms is sleep apnea. In children that remain asleep throughout the night, SDB can present as enuresis into later childhood. Children with sleep apnea may also not seem sleepy in the daytime, and are often given a diagnosis of Attention Deficit Hyperactivity Disorder that is treated with stimulants, which could otherwise improve by treating the underlying sleep apnea.

The view that only obese older men who are sleepy in the daytime and snore loudly have SDB is incorrect, and instead even young thin women and children have SDB. Very thin younger people with SDB may not have the typical sleep apnea described above, and instead have the, often undiagnosed, syndrome Upper Airway Resistance Syndrome (UARS). People with UARS take progressively more effortful breaths during sleep because their body tries push air through the bottleneck caused by a long and thin upper airway, which in turn leads to brief arousals. Sleep becomes fragmented and unrefreshing, leading to trouble focusing in the daytime, but not necessarily daytime somnolence.

The first line treatment for sleep apnea is Positive Airway Pressure (PAP) therapy during sleep where ambient air is pushed into the airway through the nose (or nose and mouth in some cases). This air works like a wedge that stabilizes the airway and prevents its collapse. For people who also have problems exhaling enough CO2 during sleep or have CSA (e.g., morbid obesity, neuromuscular disorders, cardiac

Hypersomnia syndromes refer to excessive sleepiness in the daytime even though people have had adequate and fair quality sleep the previous nights. Distinct from hypersomnia is hypersomnolence, a symptom referring to sleepiness in the daytime that does not necessarily lead to sleep. There are three main hypersomnia syndromes: narcolepsy type 1 (NT1), narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH).

NT1 is the best described hypersomnia and it is caused by decreased levels of a chemical produced at the hypothalamus of the brain called hypocretin or orexin (Hcrt/Orx). Hcrt/Orx helps people consolidate sleep periods, preventing the brain from going in and out of sleep randomly. As a result, people with NT1 report excessive daytime somnolence with sudden sleep attacks and fragmented unrefreshing sleep at night. Because sleep and wake are poorly dissociated, people have experiences as if being simultaneously in both states, such as having dream-like hallucinations around sleep periods, and sleep paralysis with inability to move for several seconds upon awakening. Almost unique to NT1 is the symptom of cataplexy, where people report sudden loss of muscle tone where their jaw drops or their knees buckle with strong emotional reactions such as laughter. Diagnosis of NT1 is based on sleep studies both at night (overnight polysomnography [PSG]) and in the daytime (multiple sleep latency test [MSLT]) that reveal fast onset of sleep and especially REM sleep. To the extent available, Hcrt/Orx levels in the cerebrospinal fluid that is obtained through a lumbar puncture is also helpful in making a diagnosis.

NT2 is similar to NT1 with excessive sleepiness in the daytime and rapid onset of REM sleep on PSG and MSLT, but it is not accompanied by low Hcrt/Orx levels or by cataplexy symptoms. People with IH, instead, do not have rapid onset of REM sleep on PSG or MSLT even though they fall asleep within minutes during testing. They also don’t have cataplexy symptoms or low orexin levels, and their main complaint is long sleep duration throughout a 24-hour period that usually lasts 12-14 hours.

For a group of people with excessive daytime sleepiness, especially when this first presents above age 55, there is frequently co-existing cognitive impairment, which justifies a clinician’s decision to pursue multidisciplinary evaluation with neuropsychological testing and brain imaging to examine if the hypersomnolence symptoms hint to a comorbid neurocognitive disorder such as Lewy Body Dementia or Alzheimer’s dementia.

Overall, people with hypersomnia syndromes usually benefit by pharmacological therapies that consolidate sleep and wake periods, and by establishing daily habits, such as scheduling naps in the daytime and being exposed to sunlight in the morning, that decrease the chance of a sudden urge to sleep.

CRSD are syndromes where the timing of sleep throughout the day, the so-called circadian rhythm, is out of synchrony to the established societal norms. People whose natural sleep-wake cycle is much later than most, falling asleep in the early morning hours and waking up very late in the day, are typical “night owls” and have a Delayed Sleep Phase Chronotype, whereas people who are “morning larks,” going to bed early in the evening and waking up very early in the morning have an Advanced Sleep Phase Chronotype. These chronotypes have a strong genetic background, are regulated by the body’s response to sunlight and a hormone secreted in the evening called melatonin, but are only considered disorders if they interfere with people’s lives. People with Delayed Sleep Phase Disorder (DSPD) often misinterpret their delayed sleep-wake cycle as insomnia and may pursue inappropriate pharmacological or other treatments, because the symptom recognized is an inability to fall asleep at a socially expected time. It is not uncommon for people with DSPD to become sleep deprived during workdays and have catch-up sleep on weekends. Advanced Sleep Phase Chronotypes are extremely common in teenagers as their body changes, justifying later school start times and their association to better student academic performance. Advanced Sleep Phase Chronotypes also become more common with aging, which may indicate less sunlight passing through eyes with cataracts or early neurodegenerative changes in sleep-wake regulating brain centers.

In older people with neurocognitive disorders due to advanced neurodegeneration it is common to observe Irregular Sleep-Wake Rhythm Disorder, during which circadian rhythms become fragmented even though total sleep time remains normal. As a result, people go in and out of sleep throughout the 24-hour cycle.

A rare but well-described CRSD is the non-24-hour CRSD, where some people who are blind or lack specific light receptors in the eye have a gradual delay of their circadian rhythm, progressing their sleep-wake times over the 24-hour cycle. Not all people who are blind will have non-24-hour CRSD, because the specific light receptors can be intact, even though visual stimuli are not perceived in the brain.

In addition to intrinsic causes leading to CRSD, there are two extrinsic mechanisms that can lead to difficulties in daily life. The first, called Shift Work Rhythm Disorder, presents in people who are forced to have a work schedule that interferes with their natural sleep times. Similar to people with DSPD, they may become sleep deprived and, because their circadian rhythms are poorly consolidated, also exhibit features of insomnia or excessive daytime somnolence depending on the time of day. The second extrinsic mechanism of CRSD is jet lag, observed in people traveling across multiple time zones by plane, where their internal circadian rhythm is misaligned to their new environment.

Therapies for CRSD include pharmacological and non-pharmacological approaches that an expert can recommend.

Parasomnia syndromes refer to abnormal complex behaviors during sleep. Parasomnias are divided in NREM and REM sleep parasomnias, depending on the sleep stage that they occur in.

NREM parasomnias are complex behaviors during deep NREM sleep (slow-wave sleep) and are divided into confusional arousals, sleep related sex behaviors (sexsomnia), sleep walking, and sleep eating. Because they occur at a stage of sleep that the cortex is inactive, people waking up from NREM parasomnias are confused and have no recollection of their actions. Being a variation to an underlying sleep stage where NREM sleep and wakefulness are not fully dissociated, people with one NREM parasomnia may exhibit other NREM parasomnias at different times. They are usually associated with sleep deprivation, alcohol consumption or certain medications. A NREM parasomnia specific to children is night terrors, where children wake up frightened and crying inconsolably during sleep with no recollection of a bad dream. If the diagnosis of a NREM parasomnia is not clear from the history or videos provided, an overnight sleep study is required to distinguish it from other neurological disorders that can occur during sleep (e.g., seizures), or from other parasomnias that may have a different underlying cause and prognosis (e.g., RBD vs. NREM parasomnias).

REM parasomnias are complex behaviors that occur during REM sleep (dream sleep) with the main culprit being REM Behavior Disorder (RBD). RBD refers to acting out of dreams, where people move violently as if fighting off someone in 80% of cases, or perform complex movements as if playing a musical instrument or a sport. People are able to recall elements of a dream in most cases upon awakening, because RBD reflects a overlapping state between REM sleep and wakefulness. This dissociated state is caused by dysfunction of a part of the brain called the brainstem. In contrast to NREM parasomnias, however, RBD is almost always associated with an underlying brain disease, which in most cases is a synucleinopathy, such as Parkinson’s disease or Lewy Body Dementia. RBD symptoms is often the first symptom of synucleinopathy, preceding other symptoms by an average of eight years, with some people having had RBD symptoms for up to 50 years before motor symptoms. RBD is also observed in other conditions where REM sleep and wakefulness are poorly dissociated that affect the brainstem, such as narcolepsy type 1, spinocerebellar ataxia type 3, and certain rare immune-mediated encephalopathies (e.g., IgLON5). A sleep study with video monitoring is almost always indicated for its diagnosis, because of its clinical association to an underlying brain disease that can be managed with pharmacological or non-pharmacological therapies.

Sleep talking without any other abnormal sleep behaviors is not considered a parasomnia and can present at any stage of normal sleep in healthy people.

People with RLS report an irresistible urge to move their legs, or other limbs, while awake and not moving, especially at night. This is very uncomfortable and often noted when entering the bed to sleep or taking a long ride in a vehicle. The experience improves by massaging the limbs or getting up and walking, but will get worse again when getting into a resting position. It is often present in people who have iron deficiency and is even present in children. It is not uncommon for people to become sleep deprived or to report insomnia symptoms. Iron supplementation or medications that reduce the uncomfortable feeling are helpful, depending on the cause of RLS. Although older studies suggested an association of RLS to leg movements during sleep, this is not supported by the recent literature.