Brain-Computer Interfaces: What They Are and Why They Matter

By Matthew AdamsReviewed by Danielle Ellis, B.Sc.

What are brain-computer interfaces?
How do BCIs work?
Current applications of BCIs and their transformative potential across industries
Key players and innovations in the BCI space
Challenges and ethical considerations
The future of brain-computer interfaces
What decision-makers should know about BCIs
References
Further reading

What are brain-computer interfaces?

Brain-computer interfaces (BCIs) are devices that allow for the action or control of an external device from brain signals. These technologies have a broad range of applications, from advances in healthcare and research to leisure and industry. BCIs work by leveraging the intrinsic electrical activity of the brain, detecting and analyzing brain signals to render them into an actionable output.

The history of BCIs can be tied directly to the development and implementation of electroencephalogram (EEG) systems. The use of this to generate recordings of brain signals could then be translated into an output. For example, in 1965, Alvin Lucier's Music for Solo Performer used EEG data to stimulate percussion instruments.¹

The first peer-reviewed research on BCI was from Jacques Vidal, published in 1973, coining the term BCI. ² Vidal's further research in 1977 demonstrated this idea, using an EEG system to move a graphic through a maze. ³

How do BCIs work?

The core components of BCI systems are a sensor that can detect neural signals, a computer that runs an algorithm to decode the incoming signals from the sensor, and some form of output device, which will vary depending on the application the BCI is being used for. ⁴

BCIs can be broadly categorized by their invasiveness of implementation, typically judged by how close the recording electrodes are to the brain. EEG systems are a popular non-invasive device that can read brain activity. Scalp EEGs are an attractive approach in BCI technology due to their simplicity of use and lower cost. ⁵

Electrocorticography is an example of an invasive sensor technique that attaches the sensors to the surface of the brain. As electrocorticography can capture activity with a large area of the brain's surface, it is ideal for implementation in areas where the desired outcome requires input from various areas of the brain, such as speech. ⁶

Endovascular recording techniques fall centrally in the invasive-to-non-invasive dichotomy. This recording technique utilizes a minimally invasive approach by situating a passive stent-electrode recording array within a vein within the brain. ⁷ This approach may reduce the risk of complications of invasive surgery, such as infection or hematoma, posing a desirable option. ⁸

Current applications of BCIs and their transformative potential 

BCIs have huge implications across the healthcare field. Research has demonstrated the application of BCIs in prosthesis control, allowing individuals to control a robotic arm to perform tasks accurately. ⁹

 BCIs also allow for increased communication through the integration of word processors or access to digital spaces. This research has massive implications for patients who are paralyzed, allowing them to complete tasks previously unattainable or challenging. This presents huge potential for increasing the quality of life in such conditions. ¹⁰

Neurorehabilitation is also a key area on which BCI research and implementation has focused. Strokes, for example, have a huge global disease burden, often resulting in the loss of the ability to move limbs.^11,12

BCIs in this application record the brain activity of the patient during motor attempts, which triggers electrical stimulation of the normally activated peripheral pathways.^13,14 This methodology induces neuroplasticity in the brain, reinforcing movement pathways and enhancing recovery. ^15,16

However, BCIs have further potential in stroke rehabilitation, especially in emotion. Depression is a major psych-emotional deficit faced by stroke patients, reducing engagement with rehabilitation. This has led some groups to speculate the role BCIs may also play in alleviating these deficits, as BCI performance has been seen to correlate with motivation in stroke patients. ¹⁷

As low-cost systems perform incredibly similarly compared to more conventional units, these low-cost systems seem a very real possibility for the consumer market.¹⁸ With the opportunity to combine BCIs with virtual reality (VR), the opportunity to create a virtual environment that can be interacted with purely through thought alone has huge potential for immersive engagement. ¹⁹

Key players and innovations in the BCI space

Unsurprisingly, given the widespread application of BCIs, many companies and research teams around the world are spearheading the drive for further development.

One leading company in the development of BCIs is Neuralink. Neuralink is primarily known for its implant, which is aimed to "restore autonomy to those with unmet medical needs today and unlock human potential tomorrow." ¹⁹

Neuralink's PRIME Study is focussed on a targeted trial of implantation and testing of their implant in individuals with disabilities limiting the use of their limbs. In a blog update in August 2024, one participant with a spinal cord injury was described as having gained the ability to use 3D design software, which had been previously challenging. ²¹

Challenges and ethical considerations

Despite the large strides made in the development of BCIs, critical challenges remain before their mass implementation. One question raised by researchers is the long-term safety and dependability of implanted devices. ²² Given the localization of electrodes in invasive BCIs, potential toxicity represents a huge risk to patients.

Privacy is another large ethical concern surrounding BCIs. As BCIs have unrestricted access to an individual's brain signals, this may lead to the drawing of sensitive information. ²³

Exacerbating this concern further is potential security threats posed by BCI-internet communications. These may allow cyber attackers to intercept communications and alter normal operations of the BCI implementation, posing huge risks to individuals with implants. ²⁴

Finally, the cost of BCIs is a huge consideration when discussing the ethical implications of such a technology. The cost of such technology will greatly define who has access, potentially leading to large healthcare or social inequalities where cost accessibility is not considered. ²⁵

The future of brain-computer interfaces

AI integration has marked a further leap in the power and potential of BCIs. AI offers the opportunity to decode the incoming neural signals at increased speeds and accuracy, increasing the quality of output.¹² This may allow for more finely tuned movements in prosthetics, for example

AI integration further offers the opportunity to enrich stimulation during bi-directional communication with the brain. This bi-directional BCI sends signals back to the brain, such as adding the feeling of touch from prosthetic limbs.²⁶

A further long-term possibility powered by the bi-directional ability of BCIs is direct brain-brain communication. Limited brain-brain communication has already been achieved one way through the stimulation of visual stimuli.²⁷ This possibility of communication completely circumventing the peripheral nervous system has captivated many, potentially offering both healthcare and social benefits. ²⁸

What decision-makers should know about BCIs

The vast applications and future potential of BCIs in healthcare, research, and industry have many adopters and investors interested in their long-term use. Practical considerations for such groups should include a clearly targeted use case to procure the most appropriate devices (such as low-cost, non-invasive BCIs for gaming).

Currently, only BCIs that are invasive or used in healthcare settings are regulated, such as by the EU Medical Devices Regulation or the United States Food and Drug Administration. ^29,30

The consumer market is essentially unregulated in most of the globe. Therefore, the pathway to commercialization (especially in mass-market designs) may first take the form of leisure/entertainment devices such as gaming accessories.

It is likely that in healthcare, commercialization will focus on the communicative/rehabilitation aspects of BCIs, with a special focus on disability conditions such as paralysis, locked-in syndrome, or amyotrophic lateral sclerosis.

References

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2. Vidal' JJ. TOWARD DIRECT BRAIN-COMPUTER COMMUNICATION. Annu Rev Biophys Bioeng. 1973;2(1). www.annualreviews.org/aronline

3. Vidal JJ. Real-time detection of brain events in EEG. Proceedings of the IEEE. 1977;65(5):633-641. doi:10.1109/PROC.1977.10542 https://ieeexplore.ieee.org/document/1454811

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Further Reading

• All Brain Content
• Human Brain Structure
• The Impact of Climate Change on Brain Health
• Language and the Human Brain
• An Overview of Brain Development