A 34-year-old man presented with a history of snoring for more than 1 year, progressive daytime sleepiness over 6 months, and recurrent nocturnal fall-related injuries during the preceding 2 weeks. The clinical picture combined excessive daytime sleepiness with abnormal nocturnal behaviors, prompting comprehensive sleep evaluation.
Video-polysomnography (vPSG) was performed and captured a classical episode of somnambulism arising during non-rapid eye movement (NREM) sleep. The same vPSG established the presence of severe obstructive sleep apnea (OSA). The simultaneous documentation of a somnambulism event on vPSG and diagnostic criteria consistent with severe OSA produced a unifying diagnosis linking parasomnia behavior to underlying sleep-disordered breathing.
The patient also underwent a multiple sleep latency test (MSLT) prior to treatment; that test produced a positive result consistent with objective sleepiness. Specific numeric values for vPSG indices, apnea-hypopnea index, MSLT mean latencies, or oxygenation metrics are not reported in the abstract.
The patient received continuous positive airway pressure (CPAP) therapy for the documented severe OSA. Following initiation of CPAP, the somnambulism episodes ceased and the patient's sleep architecture returned to a normal pattern as assessed by follow-up observation or testing. The previously positive MSLT normalized after adequate CPAP treatment.
The temporal relationship — disappearance of somnambulism and normalization of sleep structure after CPAP — supports a causal or precipitating role of untreated severe OSA in this patient’s parasomnia and daytime sleepiness.
The authors highlight that severe OSA can lead to false-positive MSLT results. The proposed mechanism described in the report is that marked sleep fragmentation from recurrent respiratory events and subsequent REM sleep rebound can produce abnormal daytime sleepiness measurements on MSLT that may not reflect primary hypersomnia disorders.
In this case, the MSLT was positive before OSA treatment but returned to normal after CPAP, implying that the untreated OSA — through fragmented sleep and altered REM dynamics — produced an MSLT result that could be misinterpreted if OSA is not first addressed.
Based on this case, the authors recommend the following clinical approach for patients who present with daytime sleepiness accompanied by abnormal nocturnal behaviors:
Perform video-polysomnography (vPSG) as the initial diagnostic test to evaluate both nocturnal behavior and for evidence of obstructive sleep apnea.
If OSA is identified, institute adequate therapy (for example, CPAP) and reassess symptoms and objective measures after treatment rather than proceeding immediately to tests for primary hypersomnia.
Defer the MSLT until OSA has been adequately treated, because untreated severe OSA may produce misleading positive MSLT findings due to sleep fragmentation and REM rebound.
These recommendations emphasize treating potentially reversible contributors to daytime sleepiness and parasomnia before labeling a patient with a primary hypersomnia disorder or attributing abnormal MSLT results to intrinsic sleepiness.
This report is a single-patient case. The abstract does not provide detailed numeric results for vPSG parameters, the apnea-hypopnea index, CPAP pressures or adherence data, or exact MSLT latency values before and after treatment. Those details were not reported in the abstract and would be required to quantify effect size or generalize more broadly.
Nevertheless, the documented resolution of somnambulism and normalization of sleep architecture and MSLT after CPAP in this patient support the clinical lesson: in patients with daytime sleepiness and abnormal nocturnal behaviors, clinicians should screen for and treat obstructive sleep apnea first using vPSG, and postpone MSLT until OSA has been adequately managed.
This case illustrates that severe obstructive sleep apnea can trigger parasomnia (somnambulism), cause significant sleep fragmentation and REM rebound, and lead to a positive MSLT that may not reflect a primary hypersomnia disorder. Adequate CPAP treatment eliminated the somnambulism and normalized objective sleepiness testing, supporting an evaluation strategy that prioritizes identifying and treating OSA before proceeding to MSLT-based assessments for primary sleep disorders.
Conflict of interest statement: all authors declared no conflicts of interest, as reported in the source abstract.