Brainwave that caps it all

UK Engineers have helped slash the cost of a brainwave reading computer system that enables severely paralysed people to communicate. The researchers, from Cambridge Consultants, gave their time and expertise free to develop the technology so it can be used in patients’ homes.

The initial brain-computer interface (BCI) had been developed by the Wadsworth Centre, a public health laboratory in New York.

It did away with the need for patients to undergo invasive surgery for implanting electrodes in the brain. Instead, it has external sensors to detect brainwaves which can be controlled even by people who have lost all muscular control.

But only a few could benefit from BCI because the equipment was awkward, expensive and limited. The cap containing the sensors became uncomfortable, the 64-channel amplifier for boosting the detected microvolt signals cost $13,000 (£7,500) and the user software offered few choices.

Since last September a team from Cambridge Consultants has been working to make the system cheaper and easier to use.

’The magnitude of BCI’s impact is far beyond that of most other medical devices,’ said Mark Manasas, Cambridge project manager. ’It is the difference between people being able to communicate or not.’

The goal was to design a robust, easy to use and accurate system that would qualify for financial support under US medical insurance rules so there would be little cost to the patients. This meant the price — including a speech assistance system — had to be under $5,000.

’Clearly we had to do something about the expensive amplifier,’ said Manasas. ’We designed hardware and software so the centre could evaluate whether other amplifiers would do the job. They then found that eight channels are sufficient in nearly all cases.’

The next item for improvement was the headgear. Cambridge Consultants pursued several alternative sensor cap designs to make them more ergonomically comfortable for extended wear. ’The original cap was only comfortable for a couple of hours at most,’ said Manasas.

’So we took design cues from the headgear worn by surgeons, who may have to wear lamps and other equipment for long periods. The new caps are being made now and people will be able to wear them comfortably all day.’

The amplified signals from the sensor cap are fed into a standard PC where bespoke software interprets the data. ’We knew we had to include a speech assistance system and fortunately we found software within Windows XP that offered that functionality,’ said Manasas. ’That was some very simple work for us, but it means medical insurers are now able to pay for the device to go into people’s homes.’

Cambridge Consultants also helped create a graphical software interface with icons and sound so that patients can more readily communicate with their carers. ’We also added the functionality for nested matrixes,’ said Manasas.

Future versions will provide the ability to interface with environmental control systems to turn lights on and off or change a television channel as well as to communicate remotely with carers. The team is also developing software that will allow BCI to retrieve system-use data from users around the world.

The first system is in use in Delaware, and a batch of new amplifiers is due in mid-April so the user group will be able to rise to five patients. Dr Jonathan Wolpaw, director of the BCI unit at the Wadsworth Centre, said that the collaboration with the UK team had been vital to making the technology usable by non-technical carers outside a lab setting.

Andrew Diston of Cambridge Consultants said: ’Breakthrough technologies are created every day in labs. The art is to make innovations usable and affordable on a larger scale.’

The same technology has the potential to control medical devices such as wheelchairs and prosthetic limbs. Elsewhere, researchers are designing powered exo-skeletons (The Engineer, 30 January) to prevent the development of secondary conditions in people unable to move their limbs. An affordable BCI could give such patients the ability to control the exo-skeleton.

BCI has also been assessed by the military, for applications where streamlined communications are essential such as pilots activating jet defensive mechanisms.