Tech Report: Cambridge brain waves open communication for the severely paralysed
An exciting breakthrough in a brain-computer interface (BCI) system that translates brain waves into computer commands – without the need for implanted electrodes - might soon be assisting paralyzed people in their daily activities.
The novel BCI system is being developed by the Wadsworth Center, a public health laboratory for the New York State Department of Health, with help from Silicon Fen icon Cambridge Consultants who are transforming a brilliantly engineered and technically complex research system into an easy-to-use solution at a fraction of the cost.
"Our device requires neither implanted electrodes nor eye movement to help severely paralyzed individuals to communicate," said Dr. Jonathan Wolpaw, director of the BCI unit of the Wadsworth Center. "We’re trying to take a solution that might cost tens of thousands of dollars and make it work better at a price of around $5000."
The Cambridge Consultants' team led by vice president Andrew Diston (pictured) was, he said, "helping us to make our technology more easily usable by non-technical caregivers outside a lab setting, with readily accessible PCs and components".
Field testing began last month, with up to ten people due to get the system for use at home or in hospitals by June.
The Wadsworth system matches the capabilities of costly invasive systems that need surgery to implant electrodes in the brain – and should be able to help individuals who have lost all muscular control, unlike other augmentative or assistive communications approaches such as eyeball-tracking.
Brain waves make words
For years BCI technology has been seen as a way to harness the brain for controlling the body and the devices we manipulate. In the near term, this technology can enable individuals suffering from conditions such as Lou Gehrig’s disease or brainstem strokes to communicate with the world. These individuals face huge challenges in communicating and may even be entirely "locked in" to their bodies, possessing no muscle control at all.
Future iterations of the technology may well enable control of a range of devices including wheelchairs, prosthetic limbs, light switches or TV controls. There is also great interest in applications where streamlined communications are essential such as military pilots activating jet defensive mechanisms. The challenge has remained to deliver BCI systems that are accurate yet affordable and easy to use.
The Wadsworth system consists of three main hardware components and several pieces of specialized software. A mesh cap holds small sensor electrodes firmly against the user’s head. An amplifier is connected to the electrodes to boost the minute analog signals received from the surface of the scalp. These then are converted to digital and analyzed by software running on a PC. Two monitors are connected to the PC, one for the caregiver and one for the user.
Patient concentrates on an icon
Cambridge Consultants helped Dr. Wolpaw’s BCI Group transform its research-based system, with its technically demanding interface, into one capable of daily use by people who aren't necessarily technically savvy. They needed to develop a sensor cap that was comfortable enough to wear for some time yet also allowed a caregiver to position the sensors accurately on the head. Changing positions from session to session by more than a few millimetres dramatically affects accuracy.
The team is pursuing several sensor cap designs to make them more ergonomically comfortable for extended wear and to make them less obtrusive, without sacrificing precision. The firm provided electronics hardware and software device drivers to link the BCI software with the hardware from several different manufacturers.
They also helped create a graphical software interface with icons and sound to make it easier for users to communicate with their caregivers. For example, they can now access icons for "water" and "food," and traverse a menu with various choices using their brain waves to go beyond the language barrier.
Users make selections in either of two ways. In one, they pay attention to one icon displayed among many in a grid on the computer screen. As the icons flash in succession, a distinct electrical response is evoked in the brain by the icon being focussed on. The system tracks the timing of the flashes and the evoked response, identifies the attended icon and outputs the appropriate sound, text, and/or environmental control signal.
In the second method, the user imagines particular movements. Even if the user is totally paralyzed, the imagined action generates a localized electrical stimulus in the brain that can be detected. The system then maps that action to moving the computer cursor in a particular direction. Thus, the user can navigate menu structures to select actions and/or perform word processing activities, similar to the way people normally use a computer mouse. The system can also generate speech from those words created on computer, enabling users to communicate audibly with a caregiver if they choose.
3rd April, 2006
