Understanding the Impact of Hair and Skin on fNIRS Technology
Study reveals how physical traits affect brain activity monitoring using fNIRS.
Meryem A Yücel, M. A. Yücel, J. E. Anderson, D. Rogers, P. Hajirahimi, P. Farzam, Y. Gao, R. I. Kaplan, E. J. Braun, N. Muqadam, S. Duwadi, L. Carlton, D. Beeler, L. Butler, E. Carpenter, J. Girnis, J. Wilson, V. Tripathi, Y. Zhang, B. Sorger, A. von Lühmann, D. Somers, A. Cronin-Golomb, S. Kiran, T. D. Ellis, D. A. Boas
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Table of Contents
Wearable technologies are becoming common in our daily lives, helping us track our health and habits. Devices like fitness trackers and sleep monitors give us ongoing, real-time information about how our bodies work. One interesting advancement is Functional Near-Infrared Spectroscopy (FNIRS), a safe way to look at brain activity by measuring blood flow in the brain. As this technology moves from labs into everyday use, it offers big potential for personal health care, rehabilitation, and studying the brain’s function in different fields, such as sports and social behavior. To fully benefit from fNIRS, it’s crucial that this technology is available and suitable for everyone. Making it accessible will help gather better data and include a wide range of people in research.
fNIRS and Its Challenges
fNIRS uses light to gather data about brain activity, but factors like hair and skin can affect the quality of these Signals. For example, thick or dark hair can absorb more light, which means less light gets through to the brain. Similarly, darker skin also absorbs more light, making it hard to collect accurate readings. Different hair types and thicknesses can also affect how well the sensors stick to the scalp, leading to poorer quality signals. This is a significant issue when trying to include all types of people in research.
To improve the quality of fNIRS Measurements, experts need to think about how different hair and skin types can affect data collection. Advancing the design of the sensors and creating standardized guidelines can help improve the quality of fNIRS readings, making them more useful for a diverse group of people.
Study Overview
In a recent study, researchers looked at how participant-level traits like hair and skin types, head size, sex, and age influenced the quality of fNIRS signals. They worked with 115 Participants, measuring brain activity while participants completed resting and movement tasks. The researchers used specific procedures to check and adjust hair and skin features to get the best signal quality.
By analyzing this data, the researchers were able to provide recommendations for future fNIRS studies, aiming for a more inclusive approach to research and applications. They also suggested a way for researchers to share relevant data, which can help future studies look at how different factors affect fNIRS readings.
Participants and Measurements
The study involved 115 participants, including more females than males, with ages ranging from 18 to 89. The researchers used specific criteria to select participants, ensuring they did not have any history of neurological disorders or were taking medications that could affect the study. Participants came from varied backgrounds, reflecting different races and ethnicities.
The researchers used a special 3D-printed cap with sensors placed on specific areas of the head where brain activity is vital. They collected data from different parts of the brain, focusing particularly on areas related to movement. To ensure accurate results, they carefully measured hair and skin Characteristics using precise tools. Participants were asked to complete tasks while their brain activity was recorded.
Hair and Skin Measurements
Researchers assessed hair and skin characteristics in detail. For skin, they measured pigmentation using a special device and visually categorized skin types based on how sensitive they were to sunlight. For hair, they used high-resolution images to analyze thickness, color, and other properties. They categorized hair based on its color, curl pattern, and thickness, as these qualities can significantly affect the quality of data collected.
Results: Impact of Hair and Skin Characteristics
The analysis showed that hair characteristics strongly affected the quality of fNIRS signals. For instance, darker hair types or thicker hair corresponded with lower signal quality. Likewise, higher levels of skin pigmentation also led to poorer signal quality. These findings highlight how physical traits can impact the performance of brain monitoring technology.
The researchers also found that sex and age played a role in signal quality. For example, females generally showed different signal qualities compared to males, potentially due to differences in hair and scalp characteristics. As participants aged, some showed improvements in signal quality, which could relate to changes in hair density and other factors.
Recommendations for Future Research
The researchers emphasized the importance of documenting participant characteristics in fNIRS studies to avoid bias and ensure inclusivity. They suggested that researchers should consider hair and skin measurements as important factors when collecting and analyzing data. By recognizing how these factors influence signal quality, researchers can improve the accuracy and reliability of their findings.
In addition, adapting the design of caps and sensors to better accommodate various hair textures and styles can lead to better data collection. This includes using materials that are comfortable for participants and help keep the sensors in place, as well as exploring new technologies that enhance signal acquisition.
Addressing Inclusivity in fNIRS Studies
The goal of this research is to make fNIRS technology more inclusive and reflective of diverse populations. To achieve this, researchers must continuously evaluate how participant characteristics influence measurements. They should implement standardized methods for assessing hair and skin traits and ensure that their findings represent a wide range of individuals.
By collecting detailed metadata about participants, researchers can help others understand how these physical attributes may affect the results. This can lead to more accurate studies and a better understanding of brain function in different groups of people.
Conclusion
In conclusion, the study highlights the significant impact of hair characteristics, skin pigmentation, sex, and age on the quality of fNIRS signals. To enhance the inclusivity and accuracy of future fNIRS research, it is crucial to document participant-level factors thoroughly. Adjusting cap designs and exploring new technologies can help researchers gather better data and broaden the scope of brain monitoring studies.
By moving toward more inclusive practices, fNIRS can pave the way for more effective applications in neuroscience and clinical care, ultimately benefiting a greater variety of individuals.
Title: Inclusivity in fNIRS Studies: Quantifying the Impact of Hair and Skin Characteristics on Signal Quality with Practical Recommendations for Improvement
Abstract: Functional Near-Infrared Spectroscopy (fNIRS) holds transformative potential for research and clinical applications in neuroscience due to its non-invasive nature and adaptability to real-world settings. However, despite its promise, fNIRS signal quality is sensitive to individual differences in biophysical factors such as hair and skin characteristics, which can significantly impact the absorption and scattering of near-infrared light. If not properly addressed, these factors risk biasing fNIRS research by disproportionately affecting signal quality across diverse populations. Our results quantify the impact of various hair properties, skin pigmentation as well as head size, sex and age on signal quality, providing quantitative guidance for future hardware advances and methodological standards to help overcome these critical barriers to inclusivity in fNIRS studies. We provide actionable guidelines for fNIRS researchers, including a suggested metadata table and recommendations for cap and optode configurations, hair management techniques, and strategies to optimize data collection across varied participants. This research paves the way for the development of more inclusive fNIRS technologies, fostering broader applicability and improved interpretability of neuroimaging data in diverse populations.
Authors: Meryem A Yücel, M. A. Yücel, J. E. Anderson, D. Rogers, P. Hajirahimi, P. Farzam, Y. Gao, R. I. Kaplan, E. J. Braun, N. Muqadam, S. Duwadi, L. Carlton, D. Beeler, L. Butler, E. Carpenter, J. Girnis, J. Wilson, V. Tripathi, Y. Zhang, B. Sorger, A. von Lühmann, D. Somers, A. Cronin-Golomb, S. Kiran, T. D. Ellis, D. A. Boas
Last Update: 2024-10-28 00:00:00
Language: English
Source URL: https://www.biorxiv.org/content/10.1101/2024.10.28.620644
Source PDF: https://www.biorxiv.org/content/10.1101/2024.10.28.620644.full.pdf
Licence: https://creativecommons.org/licenses/by/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
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