Background of the study

Visual hallucinations (VH) are the most common non-motor symptoms in Parkinson’s disease (PD). As an independent predictor for cognitive decline and nursing home placement they form an important disability milestone in the course of PD. According to current clinical guidelines minor VH do not require treatment per se. But as minor VH precede the stage of major VH without insight and PD associated psychosis (PDP) they offer an opportunity for early intervention. Neuroleptic drugs delay the transition into PDP but are unsuitable for early treatment of VH due to their side effects. We hypothesize that cholinesterase inhibitors (ChEI) are a well-tolerated alternative for the early treatment of minor VH to delay the progression to PDP.

Objective of the study 

Investigate whether early treatment with ChEI delays the progression of minor VH to major VH without insight or PDP. In addition, we will measure motor control, psychotic symptoms, cognitive impairment, mood disorders, adverse events and compliance, disability, caregiver burden and care use. We assess the cost-effectiveness of early chronic treatment of VH with ChEI.

Study design

A randomized, double blind, placebo-controlled, multi-center trial with an economic evaluation.

Study population

168 patients with PD and VH after fulfilling the in-and exclusion criteria.


Rivastigmine capsule 6 mg BID or placebo BID for 24 months.

Primary study parameters/outcome of the study

The primary outcome measure is the median time until PD patients with minor VH progress to major VH without insight. The clinical endpoint is defined as the start with antipsychotic treatment.

Secundary study parameters/outcome of the study

Secondary outcome measures are changes in motor control, psychotic symptoms, cognitive impairment, mood disturbance, cholinergic deficiency, the number of adverse events, compliance, disability, caregiver burden, and care use. All relevant costs will be measured and valued.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness

The burden of participation consists of a total of 5 clinical visits (every 6 months), 4 telephone interviews on adverse events during the escalation phase and 9 internet questionnaires (every 3 months). There is a risk for adverse reactions with rivastigmine treatment; the most common are nausea and vomiting.