A small device that transmits signals directly from the brain to a computer wirelessly has been demonstrated with human patients for the first time, giving hope to millions of paralyzed people worldwide. The breakthrough marks an important step towards giving paralyzed people their autonomy back through controlling electrical devices using just their thoughts – a goal researchers have been striving towards for decades.
Technology similar to this has broken ground in recent times, with a paralyzed man doing his shopping and controlling a computer using a wired electrode array. However, these devices require a wired tether to be attached to the user. This device, which was created as part of the initiative BrainGate, works wirelessly to transmit data directly from the brain’s motor cortex to a receiver with high fidelity (meaning it matches closely with the signals that were sent) and with "single-neuron resolution".
“We’ve demonstrated that this wireless system is functionally equivalent to the wired systems that have been the gold standard in BCI performance for years,” said John Simeral, an assistant professor of engineering at Brown University and lead author, in a statement.
“The signals are recorded and transmitted with appropriately similar fidelity, which means we can use the same decoding algorithms we used with wired equipment. The only difference is that people no longer need to be physically tethered to our equipment, which opens up new possibilities in terms of how the system can be used.”
Their findings were published in the journal IEEE Transactions on Biomedical Engineering.
The study involved a clinical trial of two participants with tetraplegia, which is the paralysis of all four limbs and the torso. Individuals with tetraplegia often lose both sensation and control of the majority of their body, and it typically occurs after damage to the spinal cord or brain from either neurological disease or injury. Despite many promising research avenues, paralysis remains one of the most challenging medical conditions, and despite treatments that can improve motor function there is currently no complete cure.
The two participants have an electrode array that was previously implanted into their motor cortex – the region of the brain involved in voluntary movement – but these usually involve an expert to oversee their use, as well as a large wiring system that connects the user to the receiver. These are impractical for daily use, limiting their movement and needing a helper to attach and remove the system.
In the BrainGate trial, the researchers replaced the wiring rig with a wireless transmitter. The device is relatively small and allows the user freedom of movement without a tether.
When asked to perform tasks on the computer, such as point-and-click and typing, the wireless system achieved comparable results to wired systems, which have been utilized by brain-computer interfacing (BCI) for years.
Even more exciting for the users, the wireless device was able to continuously monitor brain signals throughout a period of 24 hours in their own home, suggesting a wireless device could work in practice as a continuous addition to their daily routine.
The researchers do explain there are some trade-offs in having a small, wireless device as compared to a connected rig. As research is progressing in BCI technology, higher electrode counts within the brain are being utilized for more precise measurements – however, this requires far more bandwidth to transmit this data. As such, the researchers are considering alternative approaches that require less bandwidth but maintain the accuracy needed, which will likely be one of the challenges of wireless BCI devices in the future.
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