Frequency domain analysis of electrooculogram and its correlation with cardiac sympathetic function

Area of Science:

• Physiology
• Neuroscience
• Biomedical Engineering

Background:

• Autonomic functions are crucial for maintaining homeostasis.
• Heart rate variability (HRV) is a well-established indicator of autonomic nervous system activity.
• The electrooculogram (EOG) is typically used to study eye movements, but its potential role in reflecting autonomic function is less explored.

Purpose of the Study:

• To investigate whether electrooculogram (EOG) signals contain information related to autonomic functions.
• To explore the correlation between EOG parameters and heart rate variability (HRV) during sleep and over a 24-hour period.

Main Methods:

• Correlation analyses were performed between EOG and HRV parameters in 24 healthy young volunteers.
• Continuous frequency-domain analysis was used to assess EOG low-frequency power (PEOG).
• Data were collected during night sleep and over 24-hour recordings.

Main Results:

• EOG low-frequency power (PEOG) emerged during night sleep and showed a graded change.
• PEOG significantly correlated with R-R interval and the low-frequency to high-frequency ratio (LF/HF) of HRV.
• These correlations strengthened during 24-hour recordings, indicating sustained autonomic information within EOG signals.

Conclusions:

• The electrooculogram, analyzed in the frequency domain, contains information on sympathetic activity.
• This information is present not only during night sleep but also throughout the day and night in healthy young people.
• EOG analysis offers a potential non-invasive method for assessing autonomic nervous system status.