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Clearing the fog

June 4, 2015

By Betty Zou

Imagine being in the prime of your life and receiving a diagnosis for which there is no cure. That is the reality for the estimated 1,000 Canadians diagnosed with multiple sclerosis (MS) each year, most of them between 15 and 40 years of age. Multiple sclerosis is thought to be an autoimmune disease in which the body’s immune system attacks its own nervous system. Over time, these inflammatory attacks damage the fatty layer of insulation around nerves in the central nervous system. This protective covering, called the myelin sheath, helps to transmit nerve signals quickly between the brain and the rest of the body, and prevents the nerve fibres from being harmed. When the myelin sheath is damaged, communication between nerve cells slows down and in severe cases, is blocked altogether. This leads to a multitude of symptoms, depending on where the damage is.

Patients with MS are at an increased risk for psychiatric disorders and cognitive dysfunction. Dr. Anthony Feinstein, an associate scientist in the Hurvitz Brain Sciences Research Program at Sunnybrook Research Institute and director of the neuropsychiatry program at Sunnybrook, sees many of these patients in his practice. Feinstein has spent the last 25 years studying the psychiatric and cognitive disorders that frequently accompany MS and devising ways to improve diagnosis and care.

Roughly 40% to 60% of MS patients suffer from cognitive impairment. Identifying these patients remains a major obstacle due to the lack of qualified neuropsychologists who can perform the one-on-one cognitive testing. “Canada does not have a large number of neuropsychologists, which means that there are a lot of MS patients who are not receiving cognitive testing,” says Feinstein, who is also a professor at the University of Toronto. At Sunnybrook, he notes, there is only one neuropsychologist to look after a growing patient population with cognitive disorders related to aging and disease.

To address this deficit, Feinstein developed a computer-based test specifically designed to identify and assess the unique cognitive difficulties seen in MS patients. The Sunnybrook Cognitive Computerized Screen, or SunScreen for short, is available to researchers and clinicians for free. “By bringing computers into the clinic, we actually make available to patients testing that they wouldn’t normally get,” says Feinstein. SunScreen has been sent to doctors all over the country and has, so far, received good reviews.

Feinstein is also interested in the effects of cannabis on cognition in patients with MS. About 16% of MS patients use cannabis on a regular basis, either recreationally or to help manage pain. “Patients come to me and they say, ‘I’m smoking cannabis. Is that good or bad for me?’ I don’t know,” he says. “There are no studies on the effects of smoked cannabis on cognitive or behavioural difficulties in MS.”

In a study published last year in the journal Neurology, Feinstein and colleagues found that smoking cannabis worsened cognitive impairment in patients with MS. “We showed that cannabis brings about a fair bit of deterioration in memory and information processing,” he says. These findings will help clinicians provide more informed advice to their patients. “Like any drug, you have to weigh out the pros and cons,” says Feinstein. “If it helps your pain, that’s great. [But] potentially, it might worsen your cognition.”

For Feinstein, who is also the chair of the medical advisory committee for the Multiple Sclerosis Society of Canada, his work is far from over. “How do we better detect cognitive function in MS? How do we better treat mood disorders in MS?” he says. “Canada has the highest rate of MS in the world. It’s a big health care issue and there’s a lot of work to be done.”

Read more about Feinstein’s research in the 2013 SRI Magazine.

Feinstein’s research is supported by the Canadian Institutes of Health Research and Multiple Sclerosis Society of Canada.

Dr. Anthony Feinstein