Is excessive daytime sleepiness characteristic of Prader-Willi syndrome? The effects of weight change
J. C. Harris and R. P. Allen
Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Md, USA.
OBJECTIVES: To assess nighttime and daytime sleep patterns in patients with
Prader-Willi syndrome and to examine the effects of weight change on
excessive daytime sleepiness in patients with this disorder. DESIGN: Case
series (within-subject design). SETTING: A university sleep disorders
center. PATIENTS: Eight patients (5 males and 3 females), ranging in age
from 5.5 to 21 years, who met the diagnostic criteria for Prader-Willi
syndrome. INTERVENTIONS: Overnight sleep polysomnographic recording and
daytime Multiple Sleep Latency Test. Four of the 8 patients were restudied
after their weight had changed. MAIN OUTCOME MEASURES: Changes in the sleep
disordered breathing rate and Multiple Sleep Latency Test measures.
RESULTS: Sleep-disordered breathing occurred in all patients and was
principally characterized by obstructive hypoventilation or episodes of
apnea that occurred primarily during rapid eye movement sleep. After weight
reduction, 3 patients had respiratory values that were within the broad
normal range (disordered breathing rate, < 15 breaths per hour).
Statistically significant (P < .05) weight loss effects occurred during
nonrapid eye movement sleep (decrease with weight loss, F = 6.243).
Excessive daytime sleepiness was documented in 6 of 7 patients who
completed the Multiple Sleep Latency Test. Excessive daytime sleepiness was
not consistently correlated with body weight or any of the nocturnal sleep
variables. CONCLUSIONS: A sleep-related breathing disorder occurred during
rapid eye movement and nonrapid eye movement sleep and improved with weight
change in patients with Prader-Willi syndrome, emphasizing the importance
of weight reduction in clinical management. However, excessive daytime
sleepiness persisted despite a reduction in sleep-disordered breathing
after weight loss, suggesting a primary disturbance of sleep. Our findings
provide additional support for the view that primary hypersomnia is a
characteristic feature of the Prader-Willi syndrome.
