Cases of Alzheimer’s disease (AD) and other forms of dementia are reaching epidemic scale these days, with over one millon Canadians expected to be suffering from the ailments within 25 years. Yet scientists still know relatively little about how the conditions develop, how to treat them or how to prevent them. A new study by Toronto’s Baycrest neurological research centre offers an intriguing clue about one, devastating form of dementia, finding a link between the patients’ career choice and how the disease attacks their brains.
The researchers compared each patient’s occupation with the location of brain-tissue loss from frontotemporal dementia (FTD), which affects 25,000 Canadians a year, many under 65. They found that patients with professions rated highly for verbal skills, such as school principals, had greater tissue loss on the right side of the brain, while those rated low for verbal skills, such as flight engineers, had more tissue loss on the left side of the brain. Said Dr. Nathan Spreng, who did the study as a graduate student at Baycrest and is now a post-doctoral fellow at Harvard:
The disease appeared to attack the side of the brain that was the least used in the patient’s professional life.
The brain’s left hemisphere, particularly the temporal lobe, specializes in language and verbal skills. In occupations dependent on verbal ability, tens of thousands of hours of applying those skills may build reserve capacity, making it more resistant to damage due to FTD, suggested Dr. Spreng in a statement. This process may also make the right hemisphere, which is less concerned with verbal tasks, more vulnerable to dementia through disuse.
But researchers say another, equally fascinating explanation is also possible: that some impairment related to the disease biases patients toward a certain career path, decades before they get sick.