Abstract
Whilst the diagnosis of Parkinson's disease (PD) relies on the motor triad of bradykinesia, rigidity and tremor, the underlying pathological process starts many years before these signs are overt. In this prodromal phase of PD, a diverse range of non‐motor and motor features can occur. Individually they do not allow a diagnosis of PD, but when considered together, they reflect the gradual development of the clinical syndrome. Different subgroups within the prodromal phase may exist and reflect different underlying pathology. Here, we summarise the evidence on the prodromal phase of PD in patient groups at increased risk of PD with well described prodromal features: patients with idiopathic rapid eye movement sleep behaviour disorder, patients with idiopathic anosmia and families with monogenic mutations that are closely linked to PD pathology. In addition, we discuss the information on prodromal features from ongoing studies aimed at detecting prodromal PD in the general population. It is likely that better delineation of the clinical prodromes of PD and their progression in these high‐risk groups will improve understanding of the underlying pathophysiology.
Highlights
Parkinson’s disease (PD) is diagnosed when bradykinesia occurs along with rigidity or tremor, with consideration of additional supporting and exclusionary features (Hughes, Daniel, Kilford, & Lees, 1992; Postuma, Berg, et al, 2015)
We summarise the evidence on the prodromal phase of PD in patient groups at increased of PD with well described prodromal features: patients with idiopathic rapid eye movement (REM) sleep behaviour disorder (RBD), patients with idiopathic anosmia and families with monogenic mutations that are closely linked to PD pathology, in particular the Leucine-rich repeat kinase 2 gene (LRRK2) and glucocerebrosidase gene (GBA)
The sensitivity, fell to 14.6% without REM sleep behavioural disorder (RBD) (Fereshtehnejad et al, 2017). Together these findings suggest that patients with RBD develop a variety of other prodromal features before converting to clinical PD
Summary
Parkinson’s disease (PD) is diagnosed when bradykinesia occurs along with rigidity or tremor, with consideration of additional supporting and exclusionary features (Hughes, Daniel, Kilford, & Lees, 1992; Postuma, Berg, et al, 2015). In another study using olfaction as one key identifier, the Tübingen Evaluation of Risk Factors for Early Detection of Neurodegeneration (TREND) study has followed nearly 700 “healthy” older adults (50–85 years) with prodromal markers (impaired olfaction, depression or RBD) with biannual assessments. Those with anosmia had significantly fewer other prodromal features than the other two groups at baseline. In patients with established PD who are heterozygous for GBA mutations the clinical features are similar to those with idiopathic PD, but a slightly earlier onset has been reported, and non-motor symptoms including RBD and cognitive impairment occur more commonly and earlier than in idiopathic PD (Balestrino & Schapira, 2018). Ongoing follow-u p of this cohort will be essential to examine progression rates from the onset of the prodromal phase through to established PD
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
