# Detecting the fractal physical activity pattern in aged adults with cerebral small vessel disease

## TL;DR

This study shows that physical activity patterns in older adults with brain vessel disease become more random as the disease worsens.

## Contribution

The study identifies fractal physical activity disturbances as a novel marker for cerebral small vessel disease severity.

## Key findings

- Low severity cSVD is linked to more random fractal physical activity patterns.
- Fractal disturbances correlate with physical activity levels, not sleep quality.
- Lacune presence is associated with altered fractal activity patterns.

## Abstract

Actigraphy is widely used to detect a decline in physical activity in aged individuals with cerebral small vessel disease (cSVD). Disturbed fractal physical activity has been reported in aged adults with Alzheimer’s disease (AD), mild cognitive impairment (MCI), and other neuropsychiatric disorders.

To analyze the fractal physical activity pattern in elderly patients with cSVD.

From May 2021 to August 2023, 55 patients with cSVD aged 60–80 years admitted to the seventh medical center of PLA General Hospital were included. The presence of lacunes, white matter hyperintensities, cerebral microbleeds, and perivascular spaces on magnetic resonance images (MRI) were rated independently. Furthermore, these MRI markers were summed in a score of 0–4, representing all cSVD features combined. Detrended fluctuation analysis (DFA) was used to evaluate the fractal physical activity fluctuations at multiple time scales. The relationship between the fractal physical activity pattern and physical activity and sleep quality was analyzed with partial Pearson correlation analysis.

Individuals with a low severity cSVD burden showed a significant tendency toward a random fractal pattern relative to those with a higher severity cSVD burden. Similar results were obtained when comparing the lacune positive and negative groups. In aged adults with cSVD, fractal disturbance was associated with an average level of physical activity and not sleep quality.

These findings demonstrate the presence of obvious fractal physical activity complexity in aged adults with cSVD.