Non-motor symptoms and quality of life in tremor dominant vs postural instability gait disorder Parkinson's disease patients

To explore the differences in the features and impact on quality of life (QOL) of non-motor symptoms (NMS) of tremor dominant (TD) and postural instability gait disorder (PIGD) phenotypes early Parkinson's disease (PD), as well as the determinants of poor QOL for TD and PIGD phenotypes. This cross-sectional study recruited 301 patients with early PD and 101 healthy controls. Specific assessments used for NMS included NMS scale (NMSS), the Hamilton Rating Scale for Depression (HRSD-24), the Hamilton Anxiety Scale (HAMA), the Mini-Mental state examination (MMSE), and Addenbrooke's Cognitive Exam-Revised (ACE-R). QOL was evaluated with the PD Quality of Life Questionnaire (PDQ-39). Tremor dominant phenotype patients were 117 (38.9%), and PIGD were 155 (51.5%). Compared with TD patients, patients with PIGD had higher frequency of NMS (9.0 ± 5.3 vs 6.7 ± 4.6, P < 0.001), NMSS total scores (39.6 ± 34.5 vs 24.4 ± 22.7, P < 0.001) and more poorly for PDQ-39 summary index (19.2 ± 14.0 vs 13.8 ± 11.5, P = 0.001). There was no difference in the impact of NMS measured with NMSS on QOL between PIGD and TD phenotypes. PIGD phenotype had little impact on poor QOL once the effect of depression was taken into account. Depression was a primary negative predictor for QOL in both TD and PIGD patients (Beta: 0.697 and 0.619, respectively, P < 0.001). PIGD phenotype had a higher prevalence of NMS and worse QOL than TD phenotype. Depression is related to a dramatic decline in QOL in both TD and PIGD phenotype patients with PD.