FROM THE EDITORS

A closer look at brain function

Mary M. Machulda, Ph.D., L.P.
Psychiatry & Psychology

With more and more people living longer, dementia has become a leading major public health concern worldwide. Alzheimer's disease is the most common cause of dementia in the elderly. However, other neurodegenerative disorders leading to dementia are also becoming more prevalent. It is becoming increasingly apparent that by the time dementia is clinically detectable, it may be too late for effective treatment.
 
In the best of all worlds, the most effective treatment may be prevention. But prevention requires detection of cognitive changes before an individual meets diagnostic criteria for dementia. That's why it's crucial to develop new diagnostic tools for early diagnosis.
 
In my work as a neuropsychologist at Mayo Clinic in Rochester, I'm conducting research using functional magnetic resonance imaging (fMRI) to help us better understand and detect changes in brain function in individuals with mild cognitive impairment. The term mild cognitive impairment is used to describe an intermediate stage of cognitive performance that falls between how the normal-aging brain functions and dementia. The concept of mild cognitive impairment has arisen in the context of a shift in focus to early detection and prevention of Alzheimer's disease. Individuals with mild cognitive impairment have significantly increased risk of developing dementia compared to people without MCI, and represent a population who would benefit from early intervention.
 
The diagnostic tool I'm working with — fMRI — is a non-invasive technology that measures very small changes in blood flow as individuals complete cognitive tasks while in the MRI scanner. This technology shows promise for detecting changes in brain function very early in the course of the disease. Because fMRI assesses brain function associated with cognitive tasks, it may have an advantage over other imaging techniques that focus only on structural changes in the brain.

Among individuals with MCI, there is variability in terms of the type and degree of cognitive difficulties experienced. For example, some may experience more difficulty with memory or language skills. Others may encounter challenges related to concentration and attention span. Adding to the complexity of this disorder is the fact that some individuals with MCI progress to dementia while others remain cognitively stable.

With the help of fMRI, a number of researchers and clinicians around the country — myself included — are engaged in trying to better understand MCI and detect it earlier. It's challenging and very exciting work in which to be involved. The use of fMRI as a diagnostic tool holds great promise in the field of neurosciences. Eventually, it may help us identify brain changes associated with neurodegenerative disorders that will lead to dementias other than Alzheimer's disease. Once we can do that, it's hoped that treatment might be more specifically tailored to the neurodegenerative disorder affecting any given individual.