Axial signs and magnetic resonance imaging correlates in Parkinson's disease

BACKGROUND: Age-related brain changes may contribute to axial features in Parkinson's disease (PD). OBJECTIVES: To determine if ventricular volume and white matter high signal changes (WMC) are related to motor signs in PD and controls independent of age. METHODS: Patients were rated with the Unified Parkinson's Disease Rating Scale (subscore A: tremor, rigidity, bradykinesia, and facial expression; subscore B: speech and axial impairment). Steps and time taken to walk 9.144 meters were measured. Total ventricular volume (TVV) and intracranial volume (ICV) were measured on T1-weighted MRI using manual tracing software. WMC were rated on axial T2-weighted, dual-echo or FLAIR MR images using a visual scale. RESULTS: TVV (cm3) (PD: 36.48 +/- 15.93; controls: 32.16 +/- 14.20, p = 0.21) and WMC did not differ between groups (PD: 3.7 +/- 4.2; controls: 3.2 +/- 3.1, p = 0.55). Age correlated positively with ICV-corrected TVV and WMC in PD (cTVV: r = 0.48, p = 0.003; WMC: r = 0.42, p = 0.01) and controls (cTVV: r = 0.31, p = 0.04; WMC: r = 0.44, p = 0.003). Subscore B (r = 0.42, p = 0.01) but not subscore A (r = 0.25, p = 0.14) correlated with cTVV in PD. Steps and walking time correlated with cTVV and WMC in PD; cadence correlated with cTVV and steps with WMC in controls. Age-adjustment eliminated correlations. CONCLUSION: Subscore B, but not subscore A correlated positively with ventricular volume in PD, though this association was accounted for by age. Age-related brain change super-imposed on PD may contribute to axial features.