Does fatigue in Parkinson's disease correlate with autonomic nervous system dysfunction?

BackgroundDespite its negative impact on quality of life, fatigue in Parkinson's disease (PD) remains an under-recognized issue and the underlying pathology is undetermined.ObjectiveTo contribute at understanding the pathogenesis of fatigue in a naturalistic cohort of cognitively intact PD patients.MethodsIn a Caucasian population of PD patients (n=27), we evaluated to what extent fatigue (quantified as PFS-16 score) is associated with PD duration and with autonomic dysfunction, studied by both MIBG scintigraphy and autonomic nervous system testing. The latter included the head-up tilt test, Valsalva maneuver, deep breathing, and handgrip tests.ResultsPFS-16 score correlated with disease duration (R=0.57, p=0.002). Fatigue showed a clear correlation with deep breathing test (R=-0.53, p=0.004) but not with the MIBG H/M ratios.ConclusionsOur data are consistent with a multifactorial pathogenesis of fatigue and with effects of dopamine depletion in PD-related fatigue; on the other hand, our findings do not support a role for sympathetic denervation in PD-related fatigue.