ORIGAMI INSPIRES NOVEL BRAIN SURGERY

A research team led by the University of Oxford and the University of Cambridge have created new ‘origami-inspired’ brain electrodes that can fold up to a fraction of their full size. This advance could significantly reduce the amount of surgery needed to treat conditions such as epilepsy, or to install brain-computer interfaces.

Measuring brain electrical activity is essential to accurately diagnose and treat conditions such as epilepsy. However, this often requires surgeons to cut out a large window in the skull (a craniotomy) to place electrodes directly onto the brain surface. This highly invasive procedure typically entails a prolonged recovery period, and poses severe infection risks.

The new study, published in Nature Communications, demonstrated that using a folding design for brain electrodes could reduce the incision area needed by about five times, without affecting functionality.

Senior author Associate Professor Christopher Proctor (Department of Engineering Science, University of Oxford) said: ‘This study presents a new approach to directly interfacing with large areas of the brain through a key-hole like surgery. The potential significance of this work is two-fold. First, there is the promise of a less invasive diagnostic tool for epilepsy patients. Second, we envision the minimally invasive nature will enable new applications in brain machine interfaces.’

When fully expanded, the device resembles a flat, rectangular silicone wafer with 32 embedded electrodes, attached to a cable. The wafer – around 70 microns thick (about the width of a human hair)- is then folded up, accordion-like, enabling it to fit through a slit just 6mm across. Once in position on the brain surface, a pressurised fluid-filled chamber in the wafer inflates and unfolds the device to cover an area five times larger, up to 600 mm².

In comparison, applying a non-folding device of the same size would typically require cutting out an area of at least 600mm² from the skull.

According to the team, the device could potentially start to be used to treat human patients within a few years. Around 50 million people worldwide have epilepsy, which carries a risk of premature death up to three times higher than for the general population (World Health Organization).

Lead-author Dr Lawrence Coles (Department of Engineering, University of Cambridge) said: ‘We are now working with clinical partners to refine the design with the aim of starting trials in human patients within two years. Besides epilepsy, this approach could be used to diagnose and treat other conditions that result in brain seizures, such as certain brain tumours.’

‘Brain-computer interfaces are an incredibly fast-moving and promising area of development’ Dr Coles added. ‘A particularly exciting area is direct speech decoding, where electrodes measure signals directly off the brain surface itself to translate what the person is trying to say.’