Lung Foundation Australia/Boehringer Ingelheim COPD Research Fellow
Conjoint Senior Lecturer, UNSW
+612 9399 1827
Anna Hudson completed her doctorate at NeuRA and UNSW in 2010, investigating the neural control of the human inspiratory muscles using single motor unit electromyography (EMG) recordings. With the support of an NHMRC Early Career Fellowship she conducted postdoctoral studies at Hôpital Pitié-Salpêtrière, Paris using electroencephalography (EEG) and signal processing techniques to investigate how breathing is controlled in healthy subjects and patient groups. She has also made contributions in the broader discipline of motor control, including the descending control of limb muscles.
Anna returned to NeuRA in 2014. Current studies include investigation of the relationship between the mechanics and neural control in respiratory and limb muscles using ultrasound and EMG and of sensorimotor cortical control of the respiratory muscles in healthy subjects and in patients with respiratory disorders such as chronic obstructive pulmonary disease, obstructive sleep apnoea and asthma using EEG.
Anna is looking for Honours and PhD students for the broad range of current studies listed above. Contact her for more details.
Approximately 33% of critically ill patients require mechanical ventilation to support respiration. During this time the major respiratory muscles, namely the diaphragm, abdominal and intercostal muscles, weaken. This vicious cycle leads to difficulty in separating patients from mechanical ventilation, increased mortality, and more readmissions to intensive care. Interventions that maintain respiratory muscle strength and reduce atrophy during mechanical ventilation are likely to reduce ventilation duration, complications and costs, and improve quality of life.
The abdominal muscles are the primary muscle group used during forced exhalation. We have shown that surface Functional Electrical Stimulation (FES) of the abdominal muscles, termed Abdominal FES, can improve respiratory function and assist weaning from mechanical ventilation in spinal cord injury. We hypothesise that Abdominal FES in critically ill patients will reduce diaphragm and abdominal muscle atrophy, with the long term goal of this project to demonstrate reduced mechanical ventilation duration.
We are currently conducting a pilot study at the Prince of Wales Hospital, Sydney, to investigate whether Abdominal FES is a feasible technique for reducing mechanical ventilation duration in critical illness. This work is being supported by our American project partners, Liberate Medical.
While tetraplegia is often characterized by paralysis of all four limbs, paralysis also affects the major respiratory muscles, namely the diaphragm and abdominal and intercostal muscles. This reduces respiratory function, with associated respiratory complications, such as pneumonia and atelectasis. Such complications are a leading cause of illness and death for the tetraplegic population. Up to 68% of patients with tetraplegia have a respiratory complication in the first 6 weeks (i.e. the acute stage) of injury. A reduction in respiratory complications in acute tetraplegia would decrease illness and death, reduce rehabilitation time, improve quality of life, and result in a large cost saving for global health systems.
Surface electrical stimulation of the abdominal muscles, termed Abdominal Functional Electrical Stimulation (FES), can contract the abdominal muscles, even when paralysed. We have shown that the repeated application of Abdominal FES improves the respiratory function of people with tetraplegia. However, while respiratory function is a predictor of respiratory complications in tetraplegia, evidence that Abdominal FES reduces respiratory complications is only anecdotal. We will undertake the first prospective, multi-centre, randomised placebo controlled trial, to determine whether Abdominal FES reduces respiratory complications in acute tetraplegia.
Definitive evidence of the effectiveness of Abdominal FES to reduce respiratory complications in tetraplegia will drive the rapid worldwide translation of this low cost and easily applied technology for this vulnerable patient group. This will decrease illness and death, reduce rehabilitation time, improve quality of life, and result in a large cost saving for global health systems.
This international collaboration brings together leading research and medical teams from: Neuroscience Research Australia, the Prince of Wales Hospital, and the Royal North Shore Hospital in Australia; The Indian Spinal Cord Injury Centre; Chang Mai University Hospital in Thailand and The Queen Elizabeth National Spinal Injuries Unit and the University of Glasgow in Scotland.
Not only are the breathing muscles controlled automatically from the brainstem and motor cortex, but they can be activated in response to emotion, e.g. during laughing and crying. We plan to investigate the neural pathways involved in emotional breathing in healthy volunteers.
This basic science project aims to examine the behaviour of human motoneurones during sustained activation to reveal their mechanisms of recovery after activation. We will take the fundamental findings from this study and compare the behaviour of motoneurones innervating muscles affected by neurological injury such as spinal cord injury and stroke.
Breathing is a complex motor task that needs to be coordinated at all times while we eat, speak, exercise and even during sleep. The breathing muscles are controlled automatically from the brainstem during normal breathing but can also be controlled voluntarily from the motor cortex. The way these two drives to the breathing muscles interact is still not well understood. While there is some evidence that there are at least two independent pathways, and that integration of the pathways occurs at the spinal cord, there is some uncertainty about whether these pathways may have some interaction in the brainstem. Our current experiments are looking at voluntary and involuntary drive to the breathing muscles to try to answer this fundamental question about the neural control of breathing. In addition we are looking at the potential cortical contributions to resting breathing in respiratory disorders.
Our recent studies of the control of breathing muscles have shown a strong link between neural drive and mechanical action of the muscle. We showed that for a number of breathing muscles, the neural drive is directed to the muscles with the best mechanical effect for breathing. We termed this link between mechanics and neural drive ‘neuromechanical matching’. It is a new principle of muscle activation that allows for metabolically efficient activation of the muscles. This basic research finding is now leading to further studies in patients with respiratory disorders where muscle mechanics have changed. Chronic obstructive pulmonary disease is one such disease, where muscle mechanics are known to change. Our new studies will look at whether these patients have “adapted” to the changed muscle mechanics or whether their muscles may be activated inefficiently.
DR CLAIRE BOSWELL-RUYS Postdoctoral fellow
DR RACHEL MCBAIN Postdoctoral fellow
DR CHAMINDA LEWIS PhD student