Non-dopaminergic symptoms in Parkinson’s disease

Parkinson’s disease (PD) is well known for the dopaminergic symptoms: tremor, rigidity and bradykinesia. PD patients can also suffer from various non-dopaminergic symptoms like: postural instability, cognitive dysfunction and autonomic symptoms. The impact of these non-dopaminergic symptoms on overall disease burden and prognosis is not well known. In addition proper research on diagnosis and treatment of specific non-dopaminergic symptoms is lacking. In this thesis we show that prognosis in PD in terms of disability is mainly determined by the early presence of non-dopaminergic symptoms. In addition we present a prognostic model which allows individual patient prognostication with variables that can easily be obtained at the moment of diagnosis.
In this thesis we also focus on one specific part of the autonomic symptoms in PD: orthostatic hypotension (OH). We show that a substantial proportion of PD patients have OH, but that the scientific literature concerning this symptom is biased by studies performed in tertiary care populations. In addition, we show that the results of orthostatic blood pressure measurements have no clear association with the orthostatic symptoms that PD patients experience in daily life. Additional autonomic function tests show a better association with daily experienced orthostatic symptoms, but these tests are difficult to perform and their test characteristics remained relatively poor. The search for better diagnostic tests for this specific problem needs to continue.