Affordable Near-Infrared Open-Source Wearable Brain-Monitoring Device Revolutionizes Neuroscience

Artist’s depiction of fNIRS data and AI study of brain health © chaisiri - stock.adobe.com

Functional neuroimaging technology has made significant strides in understanding brain activity. However, most traditional devices are bulky and expensive, limiting use to laboratory environments. Addressing this gap, researchers from Vanderbilt University and Stanford University School of Medicine have unveiled a leading-edge low-cost, wearable fNIRS headband system that is fully integrated and wireless, allowing for brain monitoring in everyday settings (1).

Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures brain activity by detecting changes in blood oxygenation. Unlike other neuroimaging methods such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), which are restricted to laboratory use due to their large size and high cost, fNIRS offers a more portable and affordable alternative. This new headband system, previously detailed in the journal HardwareX, has marked a significant advancement by being both cost-effective and user-friendly (1).

Read More: Wearable Near-Infrared Technology

Design and Features

The headband features a single LED-pair light source and four detectors, encased in a soft, lightweight cloth and silicone enclosure. This design prioritizes comfort and ease of use, making it suitable for continuous wear during various activities. The accompanying software supports both computer and smartphone data collection, enhancing its versatility (1). "Our goal was to create a system that is not only affordable but also easy to use and capable of delivering reliable data in real-world settings," said Francis Tsow, lead author of the study (1).

Technical Specifications

The device operates with two LEDs at the near-infrared wavelengths of 740 nm and 850 nm and is designed for scalability. Future iterations could include up to 10 detectors and multiple light sources, broadening its application scope. The current prototype, weighing only 142 grams, can transmit data at 10 Hz with a battery life of up to five hours, making it ideal for extended use (1).

Validation and Performance

The headband was validated through several tests, including a breath-holding test, which is known to influence cortical hemodynamics. Results showed clear, reproducible patterns in oxyhemoglobin concentrations, demonstrating the system's capability to accurately monitor brain activity (1).

Implications and Future Directions

This development opens new avenues for research in sports medicine, athletic training, psychology, physiology, behavior science, economics, and productivity by enabling brain monitoring in naturalistic environments (1,2). "The ability to monitor brain activity outside of the laboratory has tremendous potential to advance our understanding of human behavior and cognition," said co-author SM Hadi Hosseini (1).

Neurological Applications of fNIRS

Other recent research utilizing fNIRS hyperscanning techniques has investigated how brains interact during various human activities, leading to the discovery of a phenomenon known as interpersonal neural synchronization (INS). Despite these advancements, there has been limited research on INS within close relationships. To bridge this gap, a meta-analysis was conducted on 17 functional near-infrared spectroscopy (fNIRS) hyperscanning studies involving 1,149 dyads, including romantic couples and parent-child pairs. The analysis revealed consistent and robust INS in the frontal, temporal, and parietal brain regions, with similar patterns observed in both couples and parent-child studies. These findings support attachment theory, highlighting the scientific and neural basis of close human relationships (2).

By making neuroimaging technology more accessible and adaptable to various settings, this innovative fNIRS headband technology could revolutionize research and clinical applications. The team anticipates further development and mass production, which could lower costs and broaden its impact.

References

(1) Tsow, F.; Kumar, A.; Hosseini, S. H.; Bowden, A. A Low-Cost, Wearable, Do-It-Yourself Functional Near-Infrared Spectroscopy (DIY-fNIRS) Headband. HardwareX 2021, 10, e00204. https://doi.org/10.1016/j.ohx.2021.e00204.

(2) Zhao, Q.; Zhao, W.; Lu, C.; Du, H.; Chi, P. Interpersonal Neural Synchronization during Social Interactions in Close Relationships: A Systematic Review and Meta-Analysis of fNIRS Hyperscanning Studies. Neurosci. Biobehav. Rev. 2024, 105565. https://doi.org/10.1016/j.neubiorev.2024.105565. ​