Sleep and dementia: an algorithm trained on nine measures

A study in Scientific Reports (2024) trained a four-class machine learning algorithm on age and nine sleep biomarkers. The classes were Alzheimer's disease dementia, Lewy body dementia, prodromal synucleinopathy (people with isolated REM sleep behaviour disorder) and controls without neurodegenerative disease. The algorithm was then tested on 381 recordings, which also included people with Parkinson's disease without dementia and with mild cognitive impairment.

The nine sleep biomarkers used

The nine biomarkers are REM sleep time, sleep spindle duration, atypical N3 sleep, non-REM hypertonia, autonomic activation, non-REM relative theta, non-REM theta/alpha ratio, sleep efficiency and supine sleep. They were recorded at home with a dedicated device that picks up frontal EEG, eye movements, pulse, head position and snoring: these are not measures an ordinary ring or watch can provide.

Lewy body dementia can be hard to tell apart from Alzheimer's and Parkinson's. In the study, the sleep profile matched the clinical diagnosis in over 75% of cases for Alzheimer's, Lewy body dementia and controls. On a repeat recording, the profile was the same or similar in 88% of people with Lewy body dementia, 86% of those with Alzheimer's and 98% of controls.

The neuroprotective intervention window

According to the authors, biomarkers for early detection of neurodegeneration are needed to treat symptoms earlier and to identify people who may benefit from neuroprotective interventions. They also write that the method still needs development and validation in larger groups.

The study used a dedicated device and a clinical diagnosis: this is not what an app does. The Digital Twin lines up the data your devices write to your phone, such as steps, heart rate and sleep, and shows you how they change over time. It does not compare your sleep with this algorithm's profiles, it does not flag disease and it does not diagnose: this research describes groups of people, not you. A neurological assessment is for your doctor to decide.