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.