Sleep Apnea | Periodic Limb Movement Disorder and Restless Legs Syndrome
In patients with sleep apnea, breathing ceases for periods
of 10 seconds or more (Aldrich 2000), either because
no effort is made to breathe (central sleep apnea) or because the
oropharynx collapses during attempts to breathe (obstructive sleep
apnea). The predominant type of sleep apnea seen in elderly individuals
is obstructive sleep apnea (Ancoli-Israel et al. 1987).
A number of studies suggest that the frequency of obstructive sleep
apnea increases with age (Ancoli-Israel 1989; Ancoli-Israel et al. 1991; Dickel and Mosko 1990; Roehrs et al. 1983). Apnea generally causes excessive sleepiness,
although mild to moderate apnea can be associated with insomnia.
Referral to a sleep disorders specialist is required for diagnosis
and treatment. The treatment of choice for obstructive sleep apnea
is continuous positive airway pressure (CPAP). This treatment involves
blowing air through the nose at night to increase pressure within
the upper airway, thereby preventing the collapse that leads to
apnea. Some individuals (particularly those with anatomical anomalies
predisposing them to apnea) are treated with upper airway surgery.
Central sleep apnea is relatively rare, constituting 4%–10% of
patients with apnea (White 2000). This disorder can
be caused by a number of different pathophysiologies, including
any cause of waking alveolar hypoventilation, congestive heart failure,
neurological disorders, and nasal and upper airway obstruction.
Therapy should be targeted to the particular underlying process,
although in many cases no such problem can be identified, and CPAP
is usually the first treatment attempted (White 2000).