title: Reliability analysis of the resting state can sensitively and specifically identify the presence of Parkinson disease.
abstract: Parkinson disease (PD) is characterized by a number of motor and behavioral abnormalities that could be considered deficits of a "no task" or "resting" state, including resting motor findings and defects in emerging from a resting state (e.g., resting tremor, elevated resting tone, abulia, akinesia, apathy). PET imaging, and recently, the MRI technique of continuous arterial spin labeling (CASL) have shown evidence of changes in metabolic patterns in individuals with PD. The purpose of this study was to learn if the presence of PD could be "predicted" based on resting fluctuations of the BOLD signal. Participants were 15 healthy controls, 14 subjects with PD, and 1 subject who presented as a control but later developed PD. The amplitude of the low frequency fluctuation (ALFF) was used as an index of brain activity level in the resting state. Participants with PD using this index showed a reliable decrease in activity in a number of regions, including the supplementary motor cortex, the mesial prefrontal cortex, the right middle frontal gyrus, and the left cerebellum (lobule VII/VIII) as well as increased activity in the right cerebellum (lobule IV/V). Using a cross validation approach we term "Reliability Mapping of Regional Differences" (RMRD) to analyze our sample, we were able to reliably distinguish participants with PD from controls with 92% sensitivity and 87% specificity. Our "pre-diagnostic" subject segregated in our analysis with the PD group. These results suggest that resting fMRI should be considered for development as a biomarker and analytical tool for evaluation of PD.
authors.affiliation: North Florida/South Georgia Veterans Health System, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA. Electronic address: fskidmore@ufl.edu.
authors.forename: F M
authors.initials: FM
authors.lastname: Skidmore
authors.affiliation: Department of Statistics, University of Florida, Gainesville, FL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Psychiatry, University of Florida, Gainesville, FL, USA.
authors.forename: L
authors.initials: L
authors.lastname: Baxter
authors.affiliation: Department of Psychiatry, University of Florida, Gainesville, FL, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: von Deneen
authors.affiliation: Department of Engineering, Warwick University, Warwick, UK.
authors.forename: J
authors.initials: J
authors.lastname: Collingwood
authors.affiliation: North Florida/South Georgia Veterans Health System, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA.
authors.forename: G
authors.initials: G
authors.lastname: He
authors.affiliation: Department of Psychology, University of Florida, Gainesville, FL, USA.
authors.forename: K
authors.initials: K
authors.lastname: White
authors.affiliation: Department of Systems and Industrial Engineering, University of Florida, Gainesville, FL, USA.
authors.forename: D
authors.initials: D
authors.lastname: Korenkevych
authors.affiliation: Department of Statistics, University of Florida, Gainesville, FL, USA.
authors.forename: A
authors.initials: A
authors.lastname: Savenkov
authors.affiliation: North Florida/South Georgia Veterans Health System, Gainesville, FL, USA; Department of Neurology, University of Florida, Gainesville, FL, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Heilman
authors.affiliation: Department of Psychiatry, University of Florida, Gainesville, FL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Gold
authors.affiliation: Department of Psychiatry, University of Florida, Gainesville, FL, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000368:Aged; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis*; D015203:Reproducibility of Results; D012146:Rest; D012680:Sensitivity and Specificity