Neurology Reviews - June 2014

PHILADELPHIA—The midportion of the nigra may be significantly different on fractional anisotropic analysis in patients with Parkinson’s disease, compared with controls, according to research presented at the

66th Annual Meeting of the American Academy of Neurology. Fractional anisotropic analysis may also reveal differences between controls and patients with REM sleep behavior disorder, who are at increased risk of developing Parkinson’s disease.

Investigators are seeking a biomarker for the early detection of Parkinson’s disease because diagnosis occurs too late for neurologists to intervene effectively with neuroprotective or neurorestorative strategies, said Matthew Brodsky, MD, Associate Professor of Neurology at Oregon Health and Science University in Portland.

Patients with REM sleep behavior disorder are a valuable cohort to consider because the onset of this disorder typically predates the onset of motor symptoms in Parkinson’s disease by a decade or more, he added.

“Our hypothesis was that fractional anisotropic analysis of the posterior lateral portion of the nigra pars compacta would be reduced in patients with Parkinson’s disease, and that a smell identification test and this imaging finding might be reduced in a subset of patients with REM sleep behavior disorder who ultimately develop Parkinson’s disease,” said Dr. Brodsky.

Comparing Three Patient Groups

To test their hypothesis, Dr. Brodsky and colleagues recruited patients with REM sleep behavior disorder and age-matched healthy controls from the community. The researchers also enrolled patients with Parkinson’s disease who presented to their clinic in Portland. REM sleep