Parkinson’s disease (PD) is a neurodegenerative disease characterised by different stages, which are frequently established by the age of onset.
The team around Prof Rejko Krüger from the Luxembourg Centre for Systems Biomedicine of the University of Luxembourg have published a review paper on the classification of advanced Parkinson’s disease. Neurologists and physicians distinguish juvenile PD (develops until 20 years of age), early PD (until 40 years) and normal PD (after 40 years of age). However, disease stages can also be classified regarding motor and non-motor symptoms, disease severity or even neuropathological alterations.
Despite all these classifications, the diagnosis of advanced PD (advPD), disease form in which the symptom patterns become not only more complex, but also more individualized, remains uncertain. Indeed, previous concepts that define advPD by certain milestones of motor disability apparently fall short in addressing the increasingly recognized complexity of motor and non-motor symptoms and do not allow accounting for the individual symptom patterns of each patient. In addition, it is very complicated to differentiate advPD from atypical parkinsonism (AP) with the actual clinical diagnosis, as they share a majority of characteristics, but require different care and medication approaches.
In order to offer better care to patients in the progression of their disease, researchers have recently investigated all the existent types of Parkinson’s disease classifications used to establish a diagnosis, as well as a suitable therapy, and have then discussed their efficiency. So far, there is no test available that possesses sufficient sensitivity and specificity for the accurate clinical diagnostic differentiation between advPD and AP, when it is used exclusively as an isolated procedure. Indeed, the non-motor symptoms, the patient’s quality of life, psychological burden and stigma have to be taken into account, as recent studies, based on clinical trials, point out their importance in the progression of the PD.
Therefore, the scientists underline the need to implement new complementary approaches to the classical clinical trials in order to characterize the broad-scaled, continuous and multidimensional spectrum of disease-related motor and non-motor symptoms and their progression under real-life conditions. One suggestion would be the deep phenotyping approaches that represent precise researches on all the characteristics of the disease for an individual at different scales. It could focus on genetics technologies (e.g. identify gene profiles that could be implicated), device-based assessment (e.g. smartphone app used by the patient to inform about their symptom patterns in real-life scenarios) and, biological mechanisms. Thus, personalised approaches from clinical trials to individual patient’s response to therapy appear to be the key word, but to succeed in this new trial designs, patient’s help is needed.