The validity and reliability of an open source biosensing board to quantify heart rate variability

Area of Science:

• Biomedical Engineering
• Physiological Monitoring
• Wearable Technology

Background:

• Heart rate variability (HRV) quantifies autonomic function but typically requires costly electrocardiogram (ECG) equipment.
• Existing HRV measurement systems are often expensive and inaccessible for widespread research or clinical use.

Purpose of the Study:

• To determine the validity and reliability of an open-source OpenBCI cyton biosensing board for accurate HRV quantification.
• To assess the feasibility of using a low-cost, open-source system for autonomic function assessment.

Main Methods:

• A 3-lead ECG configuration using the OpenBCI cyton board was utilized to record heart rate waveform data.
• Concurrent validity was assessed by comparing the cyton board's HRV metrics against an industry-standard ADInstruments ECG (n=15).
• Between-day reliability was evaluated over a 7-day period (n=10), with HRV metrics analyzed in time- and frequency-domains.

Main Results:

• The OpenBCI cyton board demonstrated excellent agreement and high association (r² > 0.98) with the industry-standard ECG.
• No significant differences in time- or frequency-domain HRV metrics were found between the two devices.
• The cyton board exhibited excellent between-day reliability (Cronbach's Alpha ≥ 0.916, ICC ≥ 0.930) and low measurement error.

Conclusions:

• The open-source OpenBCI cyton board is a valid and reliable tool for multimodal HRV assessments.
• This system offers a significantly more affordable alternative (~4% of standard ECG setup cost) for quantifying autonomic function.
• The cyton board's reliability supports its application in longitudinal studies and broader research settings.