Snoring prevalence in hospitalized ischemic stroke patients under adaptive versus standard ward lighting: a sequential two-cohort observational study

AIM OF THE STUDY: To examine whether snoring, an objective marker of upper-airway instability, differs between acute ischemic stroke patients hospitalized under standard fluorescent ward lighting and those hospitalized after installation of an adaptive, time-of-day-varying LED system. CLINICAL RATIONALE FOR THE STUDY: Sleep-disordered breathing affects most patients in the acute stroke period and is independently associated with worse neurological outcomes, recurrence, and mortality. Ward lighting is a modifiable environmental factor, but its relationship to objectively recorded snoring, an acoustic marker of upper-airway instability, has not previously been examined in stroke. MATERIAL AND METHODS: In this single-center, sequential two-cohort observational study, two non-overlapping groups of acute ischemic stroke patients were compared: one admitted under standard lighting (n = 47) and one admitted after installation of adaptive lighting (n = 46). No patient was studied under both conditions. Snoring was recorded with the WatchPAT 300 (ZOLL Itamar Medical, Caesarea, Israel), and the analysis was performed at the patient level. The primary comparison was the prevalence of snoring above 45 dB (Fisher's exact test); secondary comparisons were the proportion of sleep time and the duration spent snoring above threshold (Mann-Whitney U test). Respiratory indices and sleep architecture were compared to assess group balance. RESULTS: Snoring above threshold was observed in 47 of 47 patients (100%) in the standard-lighting group and 37 of 46 patients (80%) in the adaptive-lighting group (p = 1.1 × 10-3). Both the proportion of sleep time spent snoring (p = 7.8 × 10-4) and the duration of snoring (p = 1.1 × 10-3) were lower in the adaptive-lighting group. Among patients who snored, mean snoring intensity did not differ between groups (p = 0.09). The two groups were comparable on all measured respiratory indices and on sleep architecture (all p > 0.05). CONCLUSIONS AND CLINICAL IMPLICATIONS: Snoring prevalence and burden were lower in the cohort hospitalized under adaptive ward lighting, in the context of two groups well matched on respiratory severity and sleep architecture. The non-randomized design precludes causal inference, but the association supports adaptive lighting as a low-risk, non-pharmacological candidate intervention worth testing in a randomized trial with polysomnographic endpoints.