Spotlight on a Dementia and Movement Disorders Expert: Dr. Mario Masellis

Spotlight on a Dementia and Movement Disorders Expert: Dr. Mario Masellis

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Dr. Mario Masellis MSc (Pharm), MD, PhD, FRCPC

Associate Scientist, Evaluative Clinical Sciences, Hurvitz Brain Sciences Research Program Co-Director, Cognitive Neurology Research Unit, Sunnybrook Health Sciences Centre Assistant Professor, Neurology, University of Toronto Associate Member, Institute of Medical Science


By: Usman Saeed

With expertise in four principle research disciplines: Neurology, Neuroimaging, Genetics, and Pharmacology, Dr. Mario Masellis is a remarkable individual who is at the forefront of global research on dementia. Recently, he was part of an international multi-centered study published in The Lancet Neurology,1 which identified some of the earliest structural neuroimaging and cognitive markers in individuals at risk of frontotemporal dementia. Dr. Masellis serves as the co-director of one of the most productive laboratories, L.C. Campbell Cognitive Neurology Research Unit, at the Sunnybrook Health Sciences Centre. His clinical expertise are in the diagnosis and treatment of early-onset and other dementias associated with movement disorders. Needless to say, he cherishes both of these roles–those of an avid investigator and a skillful clinician.

Not long ago in 1997, Dr. Masellis completed his MSc degree in Pharmacology under the supervision of Dr. James Kennedy and Dr. Werner Kalow at the University of Toronto. He explains, “I didn’t think I would be interested in clinical research, but I had some great opportunities offered to me by my supervisors.” Dr. Masellis, following the footsteps of his own father, completed an MD degree at the University of Toronto and pursued a fellowship in cognitive neurology. “I was always intrigued by hearing some of the cases my father had dealt with in his practice,” he adds, “I became interested in brain disorders, initially from a research perspective and then medicine allowed me to integrate my investigative curiosities with clinical knowledge.” Masellis defended his PhD thesis in Clinical Neurosciences studying a rare progressive neurological disorder known as Corticobasal Syndrome (CBS), under the supervision of Dr. Sandra Black.

Dr. Masellis considers research a valuable aspect of a clinician’s role and important for the advancement of scientific knowledge. He expressively states, “In many regards, clinicians have studied the human condition and dealt with the patients’ suffering on a personal level. The hypotheses I investigate in studies are often generated from observations made from individual or groups of patients that I see in my clinic. As a Clinician-Scientist, I am not only able to understand the disease from a textbook reading, but also able to appreciate its consequences directly on the patient and develop studies to improve upon the current treatments.”

The most rewarding part of the job, according to Dr. Masellis, is helping his patients by using standard of care therapies and offering them the opportunity to participate in research studies and clinical trials. He comments, “Although neurodegenerative dementias remain incurable, standard of care therapies are available and clinical trials have the potential to help these and other patients with similar problems in the future.” Further elaborating on his patient interactions, he enthusiastically comments, “I try to learn from my patients. Every patient has a slightly different presentation of the same disease and understanding this person-to-person heterogeneity is of great interest to me.”

Talking about his most significant works, Dr. Masellis points out that every article he has written is an accomplishment for him in its own right, irrespective of the publishing journal. He describes two of his current projects as groundbreaking, “We are participating in a large international cohort study in patients at genetic risk of developing frontotemporal dementia, which is a terrible neurodegenerative disease that causes huge functional decline in very young working families. Using a multi-centered consortium approach, we have amassed large brain imaging and fluid biomarker data in a short period of time. Having access to this cohort and engaging in some of the neuroimaging works with my team will help improve our understanding of this devastating disease.” His second recent contribution has been a study where he examined pharmacogenetic responses to anti-parkinsonian drugs. He explains, “We have recently tapped into a very large clinical trial of a drug called ‘Rasagiline’ used to treat Parkinson’s disease and have identified biomarkers that determine the clinical response to this drug”

When asked about the future of research in dementia, Dr. Masellis believes that it involves integration of different techniques and disciplines to answer some of the toughest questions. He elaborates, “For example, combining neuroimaging with genomics to identify mechanisms that influence the brain functions.” He also foresees a greater emphasis on finding treatments in asymptomatic at-risk individuals in order to stop or delay the dementia onset.

I couldn’t help but ask: what advice would you give to a graduate or medical student starting off in your field? He answers, “It is a huge commitment and it is important to be sure that one enjoys all aspects of it.” He adds, “In addition to mastering the relevant knowledge and skills, one should also be prepared to develop new and better studies to assist in the understanding of complex diseases that we see as neurologists.” Outside of the professional setting, Dr. Masellis enjoys road and trail cycling. Even as he travels to out-of-city meetings, he takes the opportunity to embark on an exploratory ride around the city on a bike. In the winter, Nordic skiing is his favourite activity.

Dr. Masellis has been a recipient of several major awards that include the Maud Menten New Principal Investigator Finalist Prize from the CIHR, the early researcher award from the Ministry of Economic Development and Innovation, and in his earlier training he was honoured with a young delegate award by the International College of Neuropsychopharmacology.

Upon request, Dr. Masellis offers two articles that can be of great interest to our IMS Magazine community in understanding the research field of dementia. The first article is a review paper that discusses the differences between the late and early-onset dementias including diagnostic strategies and potential mechanisms.2 The second paper examines two neurodegenerative dementias that have parkinsonism as an associated feature.3 Dr. Masellis explains, “Sometimes, dementia with Lewy bodies presents itself without visual hallucinations which makes it difficult to differentiate from Corticobasal Syndrome. This study presents neuroimaging and neuropsychological features that can help distinguish between the two.”



  1. Rohrer JD, Nicholas JM, Cash DM, et al. Presymptomatic cognitive and neuroanatomical changes in genetic frontotemporal dementia in the Genetic Frontotemporal dementia Initiative (GENFI) study: a cross-sectional analysis. Lancet Neurol. 2015; 14(3):253-62
  1. Masellis M, Sherborn K, Neto P, et al. Early-onset dementias: diagnostic and etiological considerations. Alzheimers Res Ther. 2013;5(Suppl 1):S7.
  1. Misch MR, Mitchell S, Francis PL, et al. Differentiating between visual hallucination-free dementia with Lewy bodies and corticobasal syndrome on the basis of neuropsychology and perfusion single-photon emission computed tomography. Alzheimers Res Ther. 2014; 6(9):71.