Functional connectivity in the basal ganglia network differentiates PD patients from controls.

Journal article

OBJECTIVE: To examine functional connectivity within the basal ganglia network (BGN) in a group of cognitively normal patients with early Parkinson disease (PD) on and off medication compared to age- and sex-matched healthy controls (HC), and to validate the findings in a separate cohort of participants with PD. METHODS: Participants were scanned with resting-state fMRI (RS-fMRI) at 3T field strength. Resting-state networks were isolated using independent component analysis. A BGN template was derived from 80 elderly HC participants. BGN maps were compared between 19 patients with PD on and off medication in the discovery group and 19 age- and sex-matched controls to identify a threshold for optimal group separation. The threshold was applied to 13 patients with PD (including 5 drug-naive) in the validation group to establish reproducibility of findings. RESULTS: Participants with PD showed reduced functional connectivity with the BGN in a wide range of areas. Administration of medication significantly improved connectivity. Average BGN connectivity differentiated participants with PD from controls with 100% sensitivity and 89.5% specificity. The connectivity threshold was tested on the validation cohort and achieved 85% accuracy. CONCLUSIONS: We demonstrate that resting functional connectivity, measured with MRI using an observer-independent method, is reproducibly reduced in the BGN in cognitively intact patients with PD, and increases upon administration of dopaminergic medication. Our results hold promise for RS-fMRI connectivity as a biomarker in early PD. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that average connectivity in the BGN as measured by RS-fMRI distinguishes patients with PD from age- and sex-matched controls.

Authors: Szewczyk-Krolikowski, K; Menke, R; Rolinski, M; Duff, E; Salimi-Khorshidi, G

• Publication status: Published
• Journal: Neurology
• Volume: 83
• Issue: 3
• Pages: 208-214
• Publication date: 2014-07-01
• DOI: 10.1212/WNL.0000000000000592
• EISSN: 1526-632X
• ISSN: 0028-3878
• Language: English
• Keywords: Nerve Net; Cohort Studies; Parkinson Disease; Basal Ganglia; Aged; Humans; Aged, 80 and over; Magnetic Resonance Imaging; Female; Middle Aged; Diagnosis, Differential; Functional Neuroimaging; Male