Many people who suffer strokes will subsequently experience spasticity, where the arm and leg muscles cramp or spasm as a result of message between the brain and muscle being blocked. This can cause long periods of contraction in major muscles resulting in bent elbows, pointed feet, arms pressed against the chest, or the distinctive curled hand common to many stroke survivors.
Neuroscientists at Newcastle University have developed a new device which aims to help stroke patients by strengthening a spinal connection known as the reticulospinal tract that can take over some of the function of more major neural pathways connecting the brain to spinal cord when they are damaged following a stroke. This strengthening can alleviate the symptoms of spasticity in the hand and arm of patients, allowing them additional control that can help them regain an important degree of independence in their life.
An article published in the Journal of Neuroscience reports on the early success of this device, which is about the size of a mobile phone and can deliver an audible click followed by a small electric shock to the arm of patients. Electrical stimulation has previously been used to improve nerve function in other types of injury, but the combination with an auditory signal is new. The study shows that the device is able to strengthen the connections in the reticulospinal tract – the nerve tract in the spine which passes messages from the brain to the limb muscles. After a stroke, the body tends to recover the strength of connections to flexor muscles (which allow you to close your hand) more than extensor muscles (which allow you to open your hand). This is why many stroke patients suffer from a curled (semi-closed) hand.
Stuart Baker, Professor of Movement Neuroscience at Newcastle University who has led the work said: “We were astonished to find that a small electric shock and the sound of a click had the potential to change the brain’s connections. However, our previous research in primates changed our thinking about how we could activate these pathways, leading to our study in humans.”
You can read more in “K.M. RIASHAD FOYSAL, FELIPE DE CARVALHO, STUART N. BAKEr. Spike-timing Dependent Plasticity in the Long Latency Stretch Reflex Following Paired Stimulation from a Wearable Electronic Device. Journal of Neuroscience, October 2016, 36 (42).” Or in www.jneurosci.org/content/36/42/10823.