# High Frequency Oscillations During Sleep in Down Syndrome

## TL;DR

This study finds high frequency brain waves during sleep in people with Down syndrome, which may predict Alzheimer's and epilepsy later in life.

## Contribution

The first study to detect high frequency oscillations in Down syndrome using wideband sleep monitoring.

## Key findings

- HFOs were detected in all Down syndrome participants but not in controls.
- HFOs appeared before Alzheimer's and epilepsy diagnoses in DS individuals.
- HFO rates increased with age in Down syndrome cases.

## Abstract

Alzheimer's disease (AD) dementia has near full penetrance in adults with Down syndrome (DS) and is strongly linked to late‐onset myoclonic epilepsy syndrome (LOMEDS). However, promising biomarkers of epileptogenicity, such as high frequency oscillations (HFOs>250Hz), have not been studied. This study is the first to use wideband polysomnography in DS to investigate if HFOs occurred and preceded AD dementia and LOMEDS.

Wideband (0.1‐500Hz, 2048Hz) polysomnography was performed using the international 10‐20 system. HFOs were automatically detected during slow‐wave sleep, followed by manual review.

Eleven individuals with DS and five age‐matched euploid controls were studied. HFOs were detected in all DS cases but not controls, with a mean rate of 7.4±2.0HFOs/min. HFOs emerged before AD dementia and LOMEDS diagnoses. A trend toward increased HFO rates with age in DS cases warrants further confirmation.

HFOs are promising biomarkers that may predict symptomatic AD dementia in adults with DS.