From a motor point of view, Parkinson's disease has traditionally been classified into different clinical phenotypes, which may be associated with a different prognosis of the disease. Tremor-predominant subtypes have been associated with more favourable prognoses than non-tremor subtypes.
IDIVAL's neurodegenerative diseases group has been participating in the COPPADIS study since 2016. This study consists of a multicentre project involving 35 Spanish centres, based on the prospective follow-up of a large cohort of patients with Parkinson's disease for 5 years. The aim of this study is to deepen the knowledge of the different clinical, molecular, genetic and neuroimaging aspects that characterise Parkinson's disease, and to identify those factors that may influence clinical progression or the appearance of complications.
A study has recently been published in the Journal of Parkinson's Disease in which changes in motor phenotype over the course of disease progression were analysed. Patients were classified into 3 groups based on motor phenotype at baseline and 2-year follow-up: tremor-dominant (TD), postural instability and gait difficulty (PIGD) and indeterminate. A total of 511 patients with Parkinson's disease were included. At initial assessment, 47.4% corresponded to the tremor phenotype, 36.6% to PIGD, and 16% had an indeterminate phenotype. Up to 38% of patients changed their phenotype between baseline and 2-year assessment, most frequently from a tremor to an indeterminate phenotype (8.4%), and from tremor to PIGD (6.7%). Factors associated with a change from a tremorphic phenotype to another motor subtype were A worse cognitive status (OR = 0.966) and less autonomy for activities of daily living (OR = 0.937) at V0 and a greater increase in the globalNMS burden (OR = 1.011) from V0 to V2 were associated with changing from TD to another phenotype after 2-year follow-up.
This paper concludes that the motor phenotype of Parkinson's disease changes with disease progression, increasing the percentage of cases with non-tremorphic subtypes. In addition, patients who switched from the tremor subtype to the PIGD phenotype had significantly increased non-motor symptom burden.
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