SUBSTANTIAL sleep disruption was observed in people with amyotrophic lateral sclerosis (ALS), with reduced sleep efficiency, shorter total sleep time, increased wake after sleep onset, and diminished rapid eye movement sleep reported across a large retrospective cohort.
The study analyzed 240 people with ALS who underwent polysomnography after diagnosis. Most had spinal onset disease, and the cohort largely represented advanced ALS, with 83% classified as King stage 4 at the time of polysomnography. Median age at onset was 59.3 years, 63% were male, and median time from symptom onset to polysomnography was 27.5 months.
Respiratory dysfunction was common. Median forced vital capacity was reduced at 58%, and forced vital capacity declined by a median 3.9 percentage points per month in the months before polysomnography. Sleep quality was also markedly impaired, with median total sleep time of 339 minutes, sleep efficiency of 62.8%, and wake after sleep onset of 172 minutes.
Forced Vital Capacity Linked to Sleep Efficiency
Forced vital capacity emerged as a significant predictor of sleep efficiency after adjustment for age and sex. People with forced vital capacity of 70% or lower had significantly higher wake after sleep onset, while trends toward lower sleep efficiency and less rapid eye movement sleep were also observed.
The findings reinforce the clinical relevance of ALS sleep disturbances, particularly because respiratory symptoms can be subtle before respiratory insufficiency becomes advanced. Morning headache, unrefreshing sleep, daytime sleepiness, and fragmented sleep may provide earlier clues than dyspnea or orthopnea alone.
Site of onset also appeared to influence sleep architecture. People with spinal onset ALS had a significantly higher number of arousals than those with bulbar onset disease. The authors suggested that reduced ability to reposition during sleep, muscle cramps, discomfort, or a higher incidence of sleep apnea may contribute to this pattern.
Earlier Sleep Assessment May Support ALS Care
Survival analyses showed that spinal onset, slower forced vital capacity decline before polysomnography, and preserved forced vital capacity of at least 70% at polysomnography were associated with improved survival. Preserved sleep efficiency showed a trend toward better survival.
The results support continued vigilance for nocturnal respiratory dysfunction in ALS, as breathing impairment may emerge first during sleep. Earlier referral for polysomnography may help identify hypoventilation and guide timely consideration of noninvasive ventilation, although the optimal timing of initiation remains under debate.
Reference
Bracaval K et al. Sleep disturbances and respiratory dysfunction in amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener. 2026;1-7.
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