Longitudinal changes in free-water within the substantia nigra of Parkinson's disease

Edward Ofori, Ofer Pasternak, Peggy J. Planetta, Hong Li, Roxana G. Burciu, Amy F. Snyder, Song Lai, Michael S. Okun, David E. Vaillancourt

Research output: Contribution to journalArticle

84 Scopus citations

Abstract

There is a clear need to develop non-invasive markers of substantia nigra progression in Parkinson's disease. We previously found elevated free-water levels in the substantia nigra for patients with Parkinson's disease compared with controls in single-site and multi-site cohorts. Here, we test the hypotheses that free-water levels in the substantia nigra of Parkinson's disease increase following 1 year of progression, and that baseline free-water levels in the substantia nigra predict the change in bradykinesia following 1 year. We conducted a longitudinal study in controls (n = 19) and patients with Parkinson's disease (n = 25). Diffusion imaging and clinical data were collected at baseline and after 1 year. Free-water analyses were performed on diffusion imaging data using blinded, hand-drawn regions of interest in the posterior substantia nigra. A group effect indicated free-water values were increased in the posterior substantia nigra of patients with Parkinson's disease compared with controls (P = 0.003) and we observed a significant group x time interaction (P < 0.05). Free-water values increased for the Parkinson's disease group after 1 year (P = 0.006), whereas control free-water values did not change. Baseline free-water values predicted the 1 year change in bradykinesia scores (r = 0.74, P < 0.001) and 1 year change in Montreal Cognitive Assessment scores (r = -0.44, P = 0.03). Free-water in the posterior substantia nigra is elevated in Parkinson's disease, increases with progression of Parkinson's disease, and predicts subsequent changes in bradykinesia and cognitive status over 1 year. These findings demonstrate that free-water provides a potential non-invasive progression marker of the substantia nigra.

Original languageEnglish (US)
Pages (from-to)2322-2331
Number of pages10
JournalBrain
Volume138
Issue number8
DOIs
StatePublished - Aug 1 2015

Keywords

  • Parkinson's disease
  • diffusion MRI
  • extracellular space
  • longitudinal
  • substantia nigra

ASJC Scopus subject areas

  • Clinical Neurology

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    Ofori, E., Pasternak, O., Planetta, P. J., Li, H., Burciu, R. G., Snyder, A. F., Lai, S., Okun, M. S., & Vaillancourt, D. E. (2015). Longitudinal changes in free-water within the substantia nigra of Parkinson's disease. Brain, 138(8), 2322-2331. https://doi.org/10.1093/brain/awv136