A new method combining a pulse oximeter with an artificial intelligence algorithm could simplify the diagnosis of sleep disorders, according to a study published in Pulmonology on 12 June 2026. The research, led by Jean-Louis Pépin of Grenoble Alpes university and Matias Rusanen, a postdoctoral researcher in deep learning, shows that a simple device placed on the fingertip can accurately track a night's sleep down to the second. This performance is comparable to the electroencephalogram (EEG), a key tool used in polysomnography, the standard test for diagnosing sleep disorders. Polysomnography involves recording brain activity (EEG), muscle activity (electromyogram), and eye movement (electrooculogram) during sleep. This data is used to create a detailed sleep-wake pattern known as a hypnogram. However, sleep disorders are becoming more common in France, and specialized clinics are overwhelmed, leading to longer wait times for diagnosis. The study found that the pulse oximeter, which measures blood flow changes through a process called photoplethysmography, can indirectly track blood pressure and heart rate. These metrics vary depending on whether a person is awake or asleep. The researchers used artificial intelligence to combine this data with EEG recordings, second by second, to determine the likelihood of a person being in a specific sleep stage at each moment. This produces colored diagrams called hypnodensity, which are more closely linked to the fatigue and daytime sleepiness reported by patients than traditional EEG analysis, which typically looks at 30-second intervals. This method offers several advantages, including its ease of use, which allows for home monitoring over multiple nights, providing a more accurate picture of sleep patterns. It can also detect small events that might be overlooked when analyzing sleep in 30-second segments. The algorithm has been tested primarily on people with sleep apnea, and the Grenoble team is now verifying these results in healthy individuals. They plan to apply the same approach to other patient groups to create distinct diagrams for different types of sleep disorders.