Chapter 028. Sleep Disorders (Part 14)

Shift-Work Disorder: TreatmentCaffeine is frequently used to promote wakefulness. However, it cannot forestall sleep indefinitely, and it does not shield users from sleep-related performance lapses. Postural changes, exercise, and strategic placement of nap opportunities can sometimes temporarily reduce the risk of fatigue-related performance lapses. Properly timed exposure to bright light can facilitate rapid adaptation to night-shift work.While many techniques (e.g., light treatment) used to facilitate adaptation to night shift work may help patients with this disorder, modafinil is the only therapeutic intervention that has ever been evaluated as a treatment for this specific patient population. Modafinil (200 mg, taken...
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Chapter 028. Sleep Disorders (Part 14) Chapter 028. Sleep Disorders (Part 14) Shift-Work Disorder: Treatment Caffeine is frequently used to promote wakefulness. However, it cannotforestall sleep indefinitely, and it does not shield users from sleep-relatedperformance lapses. Postural changes, exercise, and strategic placement of napopportunities can sometimes temporarily reduce the risk of fatigue-relatedperformance lapses. Properly timed exposure to bright light can facilitate rapidadaptation to night-shift work. While many techniques (e.g., light treatment) used to facilitate adaptationto night shift work may help patients with this disorder, modafinil is the onlytherapeutic intervention that has ever been evaluated as a treatment for thisspecific patient population. Modafinil (200 mg, taken 30–60 min before the startof each night shift) is approved by the U.S. Food and Drug Administration as atreatment for the excessive sleepiness during night work in patients with SWD.Although treatment with modafinil significantly increases sleep latency andreduces the risk of lapses of attention during night work, SWD patients remainexcessively sleepy at night, even while being treated with modafinil. Safety programs should promote education about sleep and increaseawareness of the hazards associated with night work. The goal should be tominimize both sleep deprivation and circadian disruption. Work schedules shouldbe designed to minimize: (1) exposure to night work, (2) the frequency of shiftrotation so that shifts do not rotate more than once every 2–3 weeks, (3) thenumber of consecutive night shifts, and (4) the duration of night shifts. Shiftdurations of >16 h should be universally recognized as increasing the risk of sleep-related errors and performance lapses to a level that is unacceptable innonemergency circumstances. Delayed Sleep Phase Disorder Delayed sleep phase disorder is characterized by: (1) reported sleep onsetand wake times intractably later than desired, (2) actual sleep times at nearly thesame clock hours daily, and (3) essentially normal all-night polysomnographyexcept for delayed sleep onset. Patients exhibit an abnormally delayed endogenouscircadian phase, with the temperature minimum during the constant routineoccurring later than normal. This delayed phase could be due to: (1) an abnormallylong, genetically determined intrinsic period of the endogenous circadianpacemaker; (2) an abnormally reduced phase-advancing capacity of thepacemaker; or (3) an irregular prior sleep-wake schedule, characterized byfrequent nights when the patient chooses to remain awake well past midnight (forsocial, school, or work reasons). In most cases, it is difficult to distinguish amongthese factors, since patients with an abnormally long intrinsic period are morelikely to choose such late-night activities because they are unable to sleep at thattime. Patients tend to be young adults. This self-perpetuating condition can persistfor years and does not usually respond to attempts to reestablish normal bedtimehours. Treatment methods involving bright-light phototherapy during the morninghours or melatonin administration in the evening hours show promise in thesepatients, although the relapse rate is high. Advanced Sleep Phase Disorder Advanced sleep phase disorder (ASPD) is the converse of the delayed sleepphase syndrome. Most commonly, this syndrome occurs in older people, 15% ofwhom report that they cannot sleep past 5 A.M., with twice that numbercomplaining that they wake up too early at least several times per week. Patientswith ASPD experience excessive daytime sleepiness during the evening hours,when they have great difficulty remaining awake, even in social settings.Typically, patients awaken from 3–5 A.M. each day, often several hours beforetheir desired wake times. In addition to age-related ASPD, an early-onset familialvariant of this condition has also been reported. In one such family, autosomaldominant ASPD was due to a missense mutation in a circadian clock component(PER2, as shown in Fig. 28-2) that altered the circadian period. Patients withASPD may benefit from bright-light phototherapy during the evening hours,designed to reset the circadian pacemaker to a later hour. Non-24-Hour Sleep-Wake Disorder This condition can occur when the maximal phase-advancing capacity ofthe circadian pacemaker is not adequate to accommodate the difference betweenthe 24-h geophysical day and the intrinsic period of the pacemaker in the patient.Alternatively, patients self-selected exposure to artificial light may drive thecircadian pacemaker to a >24-h schedule. Affected patients are not able tomaintain a stable phase relationship betwee ...