Trinity research on the effect of polio on the nervous system has unearthed newly found changes to the brain caused by the disease.
Polio, now a rare condition in most parts of the world thanks to a highly effective vaccine, was once a huge cause for concern in public health.
Though most people who contract the viral disease show no symptoms or mild symptoms such as vomiting, fever, or muscle stiffness, it can cause paralysis in 1 in every 100 infections, and 1 in 10 of those paralysed will die as a result. Though the last recorded case of polio in Ireland was in 1984, there are still many living with the effects of previous infection from the disease.
Polio affects muscle movement by damaging neurons in the spinal cord. Neurons stimulate movement by taking up and transmitting electrical and chemical signals around the body, including to and from muscles. If these are damaged by the poliovirus in extreme cases, mobility and even breathing can be seriously impaired.
Until now research had suggested that polio affected only the spinal cord and not the brain. But recent research from clinical medicine researchers from Trinity has shown that polio does in fact create changes in brain networks. In essence, the brain has been “rewired” by the neurological disease.
The research was carried out by taking neuro-electric measurements of brain activity and muscle activity in 25 adult survivors of infant/childhood polio and a control group of 11 individuals who had never contracted the virus.
“Our research findings show for the first time that the brain “rewires” in those who suffered from polio in childhood. This has implications for our understanding of brain plasticity, and in the longer term for rehabilitation and new biomarker development,“ says Prof Orla Hardiman, team leader and co-author of the study.
The research gives important insight into the effect neurological and neurodegenerative diseases have on the nervous system and how the brain compensates for these changes. The new information may not only be helpful in the diagnosis and treatment of polio caused neurological disorders but could also shed light on Motor Neuron disease and childhood-onset Spinal Muscular Atrophy which affect the same neurons.
The first author of the study and Clinical Medicine PhD researcher, Dr. Amina Coffey said “This study shows that neurophysiological markers can pick up changes in brain connectivity patterns that have implications in our understanding of other similar neurological conditions like Spinal Muscular Atrophy.”
The findings of the study could impact drug development and patient rehabilitation for these neurological conditions. It supports current precision medicine approaches where a patient’s diagnosis and treatment could be based on how their specific neural network has been affected.
“These types of inexpensive non-invasive methods can be further developed for probing the different “neural networks” in humans that are responsible for different day-to-day movements and different diseases that affect them,” says Dr Bahman Nasseroleslami, Assistant professor of Clinical Medicine, and co-author of the paper.