Making EEG Testing More Inclusive for All Hair Types
By Ariqa Everett. Ariqa has degrees in biological sciences and African American studies and currently works as a program assistant for a Global Health organization.
Medical review by Diane B. Francis, PhD
Has your hair ever been labeled as a cause for your EEG appointment being canceled? People with coarse, curly hair are often denied opportunities to participate in neuroscience research that uses electroencephalogram (EEG) testing due to standard electrodes being unable to reach the scalp.
Over 7 million Americans require accurate yearly EEG recordings to monitor and diagnose common brain disorders such as epilepsy, stroke, mental health diseases, and brain injuries. However, the current EEG system is incompatible with natural hair for Black patients leading to poor quality data, an uncomfortable patient experience, and denied access to participate in research studies. Recently, scientists have started looking at the issue's roots, researching how to make EEG testing accessible to everyone.
The Important Role of Electrodes in EEG Testing
EEG is a noninvasive and affordable brain imaging tool. Yet, many Black people lack access. EEG testing relies on secure contact between the patient's scalp and the electrodes of the EEG machine to monitor activity in the brain. Despite widespread use since 1929, the current method for recording EEG signals excludes coarse, curly hair. Typical electrodes are circular or rectangular with a preferred diameter of 10 mm.
Depending on the condition being examined, EEG technicians will apply 8 to 23 electrodes flat to the scalp, using a gel when needed for better reading. Patients are asked to arrive with freshly washed and dried hair with zero hair products in preparation for this test. Patients with coarse, curly hair are often requested to remove hair extensions, straighten, and, in some cases, shave areas of their heads for a more accurate reading. Curly hair is also sensitive to moisture, sweat, and humidity, or the EEG gel can cause the straightened hair to revert to its natural state during the procedure, impacting data quality.
A good EEG reading is defined by the impedance level or electrical resistance, which should be less than 50 Kilo-ohms. Using standard electrodes on curly or coarse hair can yield levels of 615 Kilo-ohms or higher. Poor contact with just one electrode can weaken the signal, leading to inaccurate readings and misdiagnosis.
Oona Tempest/ KFF Health News Illustration
The Intersection of Hair Type Bias and EEG
African hair comes in beautiful textures, ranging from looser, bouncier curls to coarse, tightly coiled, kinky curls. Our hair is unique because of the shape of the hair follicles. Caucasian or Asian hair is large and round at the strand, while those of African descent have a small and elliptical shape. The difference in follicle shape creates hair that is straight or curly at the roots. While straight hair can be easily adjusted, curly hair acts as a spring pushing the electrodes away from the scalp.
Researchers often apply standard screening criteria that have excluded people with coarse, curly hair. As a result, Black people are less likely to participate in research that involves EEG technology and are underrepresented in neuroscience research. In 2019, researchers compared 81 peer-reviewed articles on EEG testing. They found that only five articles included Black participants, and none of the papers stated that the data from these participants were included in the final results. There are several reasons why people of African descent are excluded from this research, such as :
● Lack of cultural understanding when working with people of color
● Poor knowledge of curly hair
● The assumption that coarse, curly hair automatically yields poorer results
Hair discrimination impacts a significant amount of patients, as there are people of African descent in all parts of the world. Understanding the unique structure of African hair can create innovative solutions that improve signal quality and better patient experiences.
Next Steps in Making Neuroscience More Inclusive
Neuroscience must become more inclusive to everyone, starting with its tools. EEG's lack of accessibility for Black people with coarse, curly hair creates a limited understanding of brain diseases. Attempts to adjust EEG protocols to be more compatible with Black hair have been virtually nonexistent until 2020.
In 2020, researchers at Carnegie Mellon University's Grover Lab began working on methods to expand EEG research in two ways. First, the team redesigned the shape of the electrode from its standard circle to the form of a dragonfly, which caters to patients with coarse, curly hair. The dragonfly shape allows the electrodes to be freely clipped into position onto the scalp rather than the current limited approach of using an EEG cap. Second, the team aims to develop braiding techniques that could result in a higher quality of data and better patient comfort. The study suggests that thin cornrows could anchor the dragonfly electrode clip. Modifications to traditional cornrowing create exposed sections of the scalp for the required electrode positioning. The dragonfly clip, known as the Sevo, is not currently a clinical option as it is in the prototype stage. One of the most innovative aspects of this idea is that it requires the clinical tool to adapt to us. This novel approach is rewriting the narrative: Black hair is a strength rather than a hindrance.
Although innovative solutions are being developed, there are considerable gaps. More research needs to be done before products like the Sevo clip are widely used in clinical spaces. Still, a commitment to human-centered care and research can move us toward making neuroscience more inclusive.
Call to Action
DHH is expanding and amplifying research on inequities in diagnostic testing. We believe this topic impacts EVERYONE, as tests are the baseline for care and treatment of any health issue or disease. Stay tuned to learn with us, as we continue to report on what you need to know to advocate for yourself and others. Subscribe for the latest.
Sources
Choy, T., Baker, E., & Stavropoulos, K. (2021). Systemic Racism in EEG Research: Considerations and Potential Solutions. Affective Science, 3(1), 14–20. Accessed June 23, 2023. https://doi.org/10.1007/s42761-021-00050-0
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Webb, E., Etter, J., Kwasa, J. (2022). Addressing racial and phenotypic bias in human neuroscience methods. Nature Neuroscience. Accessed June 23, 2023. https://doi.org/10.1038/s41593-022-01046-0
A. Etienne et al. Novel electrodes for reliable EEG recordings on coarse and curly hair. BioRxiv.org. February 27, 2020. doi: 10.1101/2020.02.26.965202
Tudor, Mario et al. “Hans Berger (1873-1941)--povijest elektroencefalografije” [Hans Berger (1873-1941)--the history of electroencephalography]. Acta medica Croatica : casopis Hravatske akademije medicinskih znanosti vol. 59,4 (2005): 307-13.
Tarena Lofton, How a Black patient’s textured hair nearly kept her from a needed medical procedure, (KFF, May 17, 2023). Accessed June 28, 2023. https://inquirer.com.
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