Sleep Disorders in Older People (Part III)

Narcolepsy and cataplexy

It is a chronic neurologic disorder of unclear origin that results in excessive daytime somnolence and fatigue. The main symptoms are sleep attacks (an irresistible urge to sleep for a few minutes or up to an hour), hypnogogic hallucinations while falling asleep or when waking up, sleep paralysis (a temporary inability to move upon wakening or before falling asleep), and cataplexy (a sudden, temporary, often unpredictable loss of muscle tone, which leads frequently to complete collapse).

Cataplexy can occur in the absence of other features of narcolepsy and sometimes triggered by intense emotion, during which patient is awake but unable to move or experience focal muscle weakness.



Sleep-related movement disorders

Periodic leg movements occur specifically during sleep. The abnormal movements range from subtle contraction of the muscles of the ankles and toes to impressive flailing of the arms and legs. The syndrome can be asymptomatic and require no intervention.

People with restless legs syndrome complain of a crawling feeling under the skin, tingling, and unpleasant, crampy or even very painful sensations, usually in their limbs. This condition is characterized by an intense urge to move or massage the legs, which offer some relief. The syndrome appears to involve abnormalities in dopaminergic neural transmission or iron metabolism. It can be associated with iron deficiency, rheumatoid arthritis, renal failure, and a variety of neurologic lesions, especially peripheral neuropathy.

Unlike periodic leg movements, which awaken people from sleep, the symptoms of restless legs syndrome usually occur when patients get into bed, and thereby cause sleep-onset insomnia.



Sleep-related respiratory disorders

These disorders range from snoring to hypopnea and apnea during sleep.

With aging, the weakening and loss of tone of upper airway muscles during sleep predisposes to airway obstruction which leads to snoring.

In obstructive sleep apnea, the upper airway is obstructed repeatedly during sleep that reduces air flow (hypopnea) or stops the air flow (apnea). This condition leads to interrupted, poor-quality sleep, and nocturnal oxygen desaturation. Obstructive sleep apnea is related to daytime sleepiness, hypertension, stroke, ischemic heart disease and cognitive impairment.

Older patients who have had ischemic events involving the central nervous system may display frequent central sleep apnea with clinically significant nighttime oxygen desaturation. This disorder is characterized by a periodic cessation of respiratory drive in the absence of airway obstruction.