Professor, Department of Neurology & Neurosurgery, McGill University
Director, Comprehensive Stroke Centre, Jewish General Hospital
Dr. Thiel is a neurologist and neuroscientist, who does translational research in post-stroke recovery using brain imaging and non-invasive brain stimulation methods. His neuroplasticity research program was established around the stroke unit at the Jewish General Hospital. This combination of an acute stroke unit with a non-invasive brain stimulation and imaging laboratory is the first of its kind in Canada, constituting a research facility at the patient’s bedside. It was awarded the HSFQ Stroke Excellence Award. This clinical research environment was further strengthened in January 2016 through the creation of a clinical trial platform on the new integrated neuroscience unit at the Jewish General Hospital that facilitates the systematic evaluation of different stimulation modalities and imaging methods in a clinical context.
His research program follows three major strands:
(i) the translational program for in vivo molecular imaging of post-stroke recovery with MRI and PET studies processes like neruoinflammation as well neurodegeneration and regeneration in patients in vivo:
(ii) the clinical program for non-invasive brain-stimulation as adjuvant therapy in early post-stroke rehabilitation; and
(iii) the brain connectivity program which aims to determine whether network specific inter-hemispheric connectivity can identify patients which will respond better to inhibitory brain stimulation treatment or robot assisted training and may be useful in individualizing therapeutic brain stimulation.
Dr. Thiel’s lab is cooperating with national and international researchers in the context of the international multicenter brain stimulation trial, for which Dr. Thiel’s lab is the lead study center. On a national level his lab collaborates with Drs. Haschinski, Cechetto and Whithead (University of Western Onatrio) on brain imaging of post-stroke cognitive recovery, in addition to the ongoing fruitful collaboration with Dr. Schirrmacher (University of Alberta), and Dr. Pike from the University of Calgary.
Major Research Activities
The overall goal of the neuroplasticity research program is to develop imaging predictors and new therapeutic strategies for post-stroke recovery. Although initial stroke severity is correlated with outcome, it is a poor predictor for the extent of recovery. Contrary to widely held beliefs, severely affected stroke patients may have the greatest benefit from early and intensive treatment. Identifying such patients soon after a stroke is, thus, of clinical importance for planning treatment. Using functional, morphological, and molecular imaging, Dr. Thiel's research has indentified three key parameters and pathophysiological mechanisms which determine the outcome and recovery from motor and language deficits following a stroke:
1) Using diffusion tensor imaging (DTI), a new MRI technique, he was the first to reconstruct the entire motor fibre tracts in the brain of patients with subcortical stroke. Such measurements represent the severity of ischemic tract damage and, as such, are highly correlated with clinical deficit and outcome.
2) Imaging activated microglia, the main cellular component of post-stroke neuroinflammation. With PK11195-PET, he was able to predict secondary (Wallerian) degeneration of fibre tracts. Patients exhibiting high levels of persisting microglia activation around the infarct and along the affected tract, exhibited accelerated degeneration and worse clinical outcomes.
3) Using transcranial magnetic stimulation (TMS), an electrophysiological method to modulate electrical brain activity, he performed the first prospective, controlled pilot studies on non-invasive brain stimulation for improving recovery from aphasia after stroke. This new technique may be used as adjuvant therapy to conventional speech and language therapy in patients with post-stroke aphasia to normalize brain activation patterns and improve recovery. TMS promises to become the first effective supplementary therapy for treatment of post-stroke deficits and is currently being evaluated also for motor deficits in larger patient samples.
Schirrmacher R, Dea M, Heiss WD, Kostikov A, *Funck T, Quessy S, Bedell B, Dancause N, § Thiel A. Which aspects of stroke do animal models capture? A multitracer micro-PET study of focal ischemia. Cerebrovascular Disease 2016 41(3-4):139-47.
Thiel A, Vahdat S. Structural and Resting-State Brain Connectivity of Motor Networks After Stroke. Stroke. 2015;46(1):296-301.
Thiel A, Cechetto D, Heiss WD, Hachinski V, Whitehead S (2014) Amyloid burden, neuro-inflammation and links to cognitive decline after ischemic stroke. Stroke;45(9):2825-9.
Thiel, A, Hartmann A, Rubi-Fessen, I, Anglade, C, Kracht L, Weiduschat, N, Kessler, J, Rommel T and Heiss, WD (2013) Effects of non-invasive brain stimulation on language networks and recovery in early poststroke aphasia. Stroke 44.
*Radlinska, B., *Ghinani, S., Leppert, I., Minuk, J., Pike, B., Thiel, A., 2010. Diffusion Tensor Imaging, Pyramidal Tract Damage and Clinical Outcome in Sub-cortical Stroke. Neurology 75, 1048-1054.
*Radlinska, B., *Ghinani, S., Lyon, P., Jolly, D., Soucy J.P., Minuk, J., Schirrmacher, R., Thiel, A., 2009. Multi-modal microglia imaging of fiber tracts in acute sub-cortical stroke. Annals of Neurology 66 , 825-832.