Motor and non-motor symptoms of Parkinson's disease and their impact on quality of life and on different clinical subgroups

Abstract

IntroductionThe aim of the present study is to analyse the influence that motor and non-motor symptoms have on the quality of life (QoL) of patients with Parkinson's disease (PD), and to study the relationship between the two types of symptoms. Material and methodsThis cross-sectional study included 103 patients with PD (55 men and 48 women). Quality of life was measured on the PDQ-39 scale. The UPDRS scale (I-IV) was also used, and different items were grouped to analyse the presence of tremor, rigidity, bradykinesia, and axial symptoms. The non-motor symptoms scale (NMSS) was administered to assess non-motor symptoms. We performed correlation analyses between different scales to analyse the influence of motor and non-motor symptoms on QoL. ResultsCorrelations were observed between the PDQ-39 summary index (PDQ39 SI) and the NMSS (correlation coefficient [cc], 0.56; P<.001), UPDRS III (cc, 0.44; P<.001) and UPDRS IV (cc, 0.37; P<.001) scores. The strongest correlation was between cognitive symptoms and mood. The analysis pointed to a direct relationship between the NMSS score and axial symptoms (cc, 0.384; P<.01), bradykinesia (cc, 0.299; P<.01), and to a lesser extent, rigidity (cc, 0.194; P<.05). No relationship was observed between presence of tremor and the NMSS score. ConclusionCognitive symptoms and mood exert the most influence on QoL of patients with PD. We found at least two phenotypes; one with predominantly axial symptoms, with significant involvement of non-motor symptoms, and a tremor-associated phenotype in which these symptoms are less prevalent.