The pathophysiology of the postural instability gait difficulty (PIGD) subtype of Parkinson's disease (PD) is unclear. Information on the spectrum of non-motor symptoms (NMS) in PIGD phenotype is limited. Our objective is to compare the spectrum of NMS in PIGD subtype compared to non-PIGD subgroup in PD patients and to determine predictive factors that are associated with PIGD phenotype. A total of 432 PD patients comprising 158 PIGD and 274 non-PIGD patients were recruited. NMS burden (frequency and severity) was assessed using non-motor symptom scale (NMSS). In the univariable analysis, NMSS total score (P = 0.0132), NMSS domain 3 (mood/apathy) score (P = 0.0108), NMSS domain 5 (attention/memory) score (P = 0.0048) and NMSS domain 8 (sexual function) score (P = 0.0052) were significantly higher in the PIGD group than in the non-PIGD group. Using multivariable logistic regression, UPDRS tremor score, UPDRS PIGD score, H&Y staging score and NMSS domain 8 (sexual function) score were found to be significantly different in the PIGD group compared to the non-PIGD group. We disclosed for the first time that PIGD patients demonstrated a greater overall NMS burden and sexual dysfunction and was an independent predictor of PIGD phenotype. Early intervention of sexual dysfunction symptoms in PIGD patients may improve their clinical management.
Keywords: Non-motor symptoms; Parkinson’s disease; Postural instability gait difficulty.