In The Field

Sfn: hope in stroke

Amid the dazzling high-tech displays of new-generation brain-machine interfaces (including brain implants with which monkeys can operate robotic arms) was a less glamorous but elegantly simple study which promises to improve quality of life for stroke victims, or victims of traumatic brain injury, whose ability to balance has been obliterated.

Monica Metea of the company Wicab in Wisconsin displayed her company’s new balancing device BrainPort which has been through a pilot study of 17 patients, allowing them to stand, walk, dance without falling over.

It works on the principle of brain plasticity. It’s a slim 2 cm square grid of 100 electrodes connected to a head position-detecting sensor which sits directly above them. The patients sticks the device in their mouths, and quickly learns from the pattern of the pinprick sensations delivered by the electrodes which way is up and which way is down. The brain also learns this in a physical sense. Somehow certain circuits get reconfigured such that even after the device is removed – after 20 minutes or so – the patient maintains his or her sense of balance, for hours, sometimes for days. No need to open up the skull and implant the device directly into delicate brain tissue like the more dramatic stories which will eventually help the paralysed. But applicable to probably millions of people who can’t stand up without falling over.

Another rather astonishing glimmer of hope for stroke victims was the report from neurosurgeon Eric Leuthard from the Washington University School of Medicine. One hemisphere of the brain controls arm and leg movement on the other side – but Leutard’s team has shown that the apparently embryonic signals in a ‘same side’ hemisphere are small but unique. They could theoretically be tapped to replace signals from the ‘opposite side’, if that opposite side has been disabled by the stroke. There’s more to come from this direction.

Leuthard did his work on six epilepsy patients whose skulls he had opened to pinpoint the source of their epilepsy. He took the opportunity (with their permission and cooperation) to do the tests recording on the surface of the brain – not in the service of epilepsy but in the service of stroke patients. He told me he thought that there was almost a moral obligation to do research on human brains in this way while you have the opportunity. I couldn’t agree more.

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