Elisabeth graduated from the University College London combined MB/PhD Programme in 2007. Her PhD was funded by a Brain Research Trust Prize studentship and was based at the Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, UCL. She completed her general medical training starting as an Academic Foundation Trainee in the North Central Thames Deanery, and completed her Core Medical Training in the Oxford Deanery. She was appointed as a Clinical Lecturer in Neurology at Oxford University in 2011.
Dr Elisabeth Rounis
MB PhD, MRCP (UK)
Clinical Lecturer in Neurology
My research background lies in the fields of systems neuroscience, cognitive motor control and neuroplasticity. During my PhD I studied motor recovery using repetitive transcranial magnetic stimulation (rTMS) and functional neuroimaging. This led me to become interested in neurological conditions associated with deficits in the cognitive control of action.
I was awarded the 2013 Helen Lawson grant from the British Medical Association to study mechanisms underlying limb apraxia in stroke.
Limb apraxia is often observed after a stroke but has also been described in neurodegenerative conditions and movement disorders. It is a higher order motor disorder leading to an inability to perform skillful and/or previously learnt actions. Patients with this condition are typically very clumsy despite the primary motor and sensory apparatus being intact. For example stroke patients with this condition often display deficits in their unaffected hand. Recent evidence has shown that this condition leads to poorer recovery from stroke indexed by worse clinical outcomes in these patients.
My working hypothesis is that limb apraxia represents a deficit in the representation and selection of affordances to guide action. This is mostly based on a theoretical framework termed the 'affordance competition' hypothesis (Cisek, 2007).
Affordances are defined as features of objects which trigger specific actions - for example a knob affords pushing or twisting actions, a handle affords holding. The brain regions responsible for storing features of an object as visuomotor associations (ie. 'affordances'), and trigger movement representations upon viewing them comprise inferior parietal and ventral premotor cortices respectively. They interact with dorsal stream and subcortical action selection networks during visually-guided action performance (Fagg and Arbib 1998). These areas and their interconnections are likely to be involved in causing the deficits observed in limb apraxia.
We are developing new paradigms to study patients with limb apraxia caused by lesions in the aforementioned networks. We are interested in how these patients may be unable to use affordances to guide action. We are using neuroimaging (lesion mapping, BOLD fMRI and diffusion tractography) as well as TMS-perturbation techniques to explore the functional architecture of this disorder.
Though it is a rare complication of stroke, understanding the mechanisms underling limb apraxia may shed light into motor recovery in general and help develop new treatments.
This work is being carried out at the Cognitive Neuropsychology Centre, Department of Experimental Psychology and at the Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, in Oxford.
Limb apraxia and the "affordance competition hypothesis".
Rounis E. and Humphreys G., (2015), Front Hum Neurosci, 9
Acute neurological presentation due to copper deficiency in a hemodialysis patient following gastric bypass surgery.
Rounis E. et al, (2010), Clin Nephrol, 74, 389 - 392
Theta-burst transcranial magnetic stimulation to the prefrontal cortex impairs metacognitive visual awareness.
Rounis E. et al, (2010), Cogn Neurosci, 1, 165 - 175
Altered dorsal premotor-motor interhemispheric pathway activity in focal arm dystonia.
Koch G. et al, (2008), Mov Disord, 23, 660 - 668
Wallerian degeneration of the corticofugal tracts in chronic stroke: a pilot study relating diffusion tensor imaging, transcranial magnetic stimulation, and hand function.
Lindberg PG. et al, (2007), Neurorehabil Neural Repair, 21, 551 - 560