Daijiworld Media Network – Mumbai
Mumbai, May 29: A new study has found that sleep apnea and sleep-related oxygen deprivation may slow down the brain’s ability to recognise facial emotions, highlighting the wider impact of disrupted sleep on cognitive and emotional functioning.
Researchers from Iceland observed that sleep-related oxygen desaturation and poor sleep architecture could affect how quickly and accurately adults identify emotional expressions on faces.
The findings add to growing evidence that obstructive sleep apnea (OSA) may influence neurocognitive health beyond breathing-related complications.
The study involved 55 adults who completed the Penn Emotion Recognition Task, a psychological assessment designed to measure responses to facial expressions displayed at varying emotional intensities.
Participants then underwent three consecutive nights of self-administered polysomnography, a comprehensive sleep study used to monitor breathing, oxygen levels and sleep patterns.
Researchers averaged the sleep data across all three nights.
Among the participants, 47.3 per cent were male, with an average age of 46.4 years and an average body mass index (BMI) of 27.9 kg/m².
The study found that around 65 per cent of participants had an apnea-hypopnea index (AHI) of at least five events per hour, meeting the criteria for obstructive sleep apnea.
Researchers observed that reaction times were slower when participants attempted to recognise emotions, particularly subtle or low-intensity emotional expressions.
Average reaction times recorded were 2,746 milliseconds for high-intensity emotions, 2,786 milliseconds for low-intensity emotions and 3,308 milliseconds for neutral facial expressions.
Recognition accuracy was highest for strong emotional expressions at 88.8 per cent, while low-intensity emotions were correctly identified only 73.3 per cent of the time.
After adjusting for age, gender and depressive symptoms, researchers found that higher hypoxic burden — the severity and duration of oxygen desaturation during sleep — was significantly associated with delayed recognition of low-intensity emotions.
Lower sleep efficiency and reduced REM sleep percentage were also linked to slower emotional recognition responses.
The study suggests that disrupted sleep structure and repeated oxygen deprivation during sleep may contribute to broader cognitive vulnerability and social processing difficulties.
Researchers noted that conducting polysomnography over multiple nights improved the reliability of the findings compared to single-night sleep assessments.
The findings reinforce the growing understanding that sleep quality and breathing disorders can significantly affect emotional processing, cognitive performance and overall brain health.