Hallucinations and cognitive impairment are associated with blood pressure fluctuations in Parkinson's disease

Patients with Parkinson's disease (PD) frequently develop cardiovascular autonomic dysfunctions, including blood pressure (BP) fluctuations and orthostatic hypotension (OH) in the early stage, and hallucinations or cognitive impairment in the middle stage to late stage. The current study aimed to determine whether OH, BP fluctuations and cerebral white matter hyperintensities (WMHs) on MRI are associated with the development of hallucinations and cognitive impairment.

In this joint cross-sectional case-control study conducted across two institutions, we analysed the systolic BP coefficient of variation (SBP-CV) and nocturnal BP dipping using ambulatory BP monitoring and OH prevalence in 121 patients with PD and 21 hospital controls. The association between these factors and hallucinations/psychosis or cognitive impairment was analysed using multivariable logistic regression models. Then, we conducted mediation analyses of the relationship between abnormal BP fluctuations and cognitive impairment in PD, with WMHs evaluated using the Fazekas scale as the intermediate factor.

Patients with PD were characterised by large SBP-CV without pulse rate-CV elevation, neurogenic OH and riser pattern of nocturnal BP dipping. Neurogenic OH was significantly associated with hallucinations/psychosis (adjusted OR: 6.22; 95% CI 2.47 to 15.64; p<0.001), and large SBP-CV was significantly associated with hallucinations/psychosis (adjusted OR: 2.15; 95% CI 1.32 to 3.53/5 points; p=0.002) and cognitive impairment (adjusted OR: 1.79; 95% CI 1.15 to 2.78/5 points; p=0.010). Periventricular hyperintensity (PVH) was associated with cognitive impairment (adjusted OR: 5.80; 95% CI 1.81 to 18.61; p=0.003), but not with BP fluctuations. The ORs for SBP-CV in cognitive impairment in PD were very similar across multivariable analyses that included PVH or deep WMH as mediator variables.

Large BP fluctuations in PD were associated with hallucinations and cognitive impairment, but WMHs did not mediate this relationship.