Response of non-motor symptoms to levodopa in late-stage Parkinson's disease: results of a levodopa challenge test

"BACKGROUND: Non-motor symptoms (NMS) are extremely common among late-stage Parkinson's disease (LSPD) patients. Levodopa (L-dopa) responsiveness seems to decrease with disease progression but its effect on NMS in LSPD still needs to be investigated. OBJECTIVE: To assess the response of blood pressure (BP), pain, fatigue and anxiety to L-dopa in LSPD patients. METHODS: 20 LSPD patients, defined as Schwab and England ADL Scale <50 or Hoehn Yahr Stage >3 (MED ON) and 22 PD patients treated with subthalamic deep brain stimulation (advanced PD group) underwent an L-dopa challenge. BP and orthostatic hypotension (OH) assessment, a visual analogue scale (VAS) for pain and fatigue and the Strait Trait Anxiety (STAI) were evaluated before and after the L-dopa challenge. RESULTS: Systolic BP dropped significantly after L-dopa intake (p < 0.05) in LSPD patients, while there was no change in pain, fatigue or anxiety. L-dopa significantly improved (p < 0.05) pain and anxiety in the advanced PD group, whereas it had no effect on BP or fatigue. L-dopa-related adverse effects (AEs), namely OH and sleepiness, were more common among LSPD patients. 40% and 65% of LSPD patients were not able to fill out the VAS and the STAI, respectively, while measurement of orthostatic BP was not possible in four LSPD patients. CONCLUSIONS: This exploratory study concludes that some non-motor variables in LSPD do not benefit from the acute action of L-dopa while it can still induce disabling AEs. There is a need for assessment tools of NMS adapted to these disabled LSPD patients."