Perfil clínico-neurofisiológico da dor em pessoas com doença de Parkinson: estudo observacional transversal

Abstract

Introduction: Parkinson's disease (PD) is a chronic, progressive neurodegenerative condition characterized by the degeneration of dopaminergic neurons in the nigrostriatal pathway and the presence of Lewy bodies, which result from misfolded α-synuclein proteins located in the dopaminergic presynaptic membrane within basal ganglia. The role of pain in PD is debated, as it may be a precursor, concurrent, or secondary symptom. Pain, whether acute or chronic, is complex and challenging in clinical management. Objective: To identify the characteristics of pain in PD and to explore its physiological mechanisms through qualitative sensory tests (QSTs). Materials and Methods: This cross-sectional epidemiological study (CAAE: 64807417.6.0000.5546) involved 33 volunteers with clinically diagnosed PD (20 men, age 58.75 ± 5.16 years; 13 women, age 65.92 ± 7.70 years). Variables analyzed included pain intensity, incidence, and impact, alongside peripheral sensory thresholds, primary and secondary hyperalgesia, ascending and descending nerve function, and thermal latency. Statistical analyses were conducted using SPSS 30.0 and GraphPad Prism 8.0, with significance set at p≤0.05. Tests included Shapiro-Wilk for normality, Mann-Whitney U, Wilcoxon, and one-way repeated measures ANOVA with Bonferroni post-hoc corrections. Results: Most participants reported moderate to severe pain in the last week, with a maximum pain intensity of 6.15 and an average of 3.61. Men reported higher average and minimum pain intensity compared to women, and pain during crises was significantly higher than at rest (p<0.001). Thermal and pain sensitivity testing revealed potential deficits in sensory accommodation, with only six volunteers enduring the maximum time for thermal stimulus, showing an average tolerance of 46.06 seconds. A total of 88 distinct pain sites were identified, highlighting pain’s significant impact on PD and suggesting sensory modulation deficits related to the condition. Conclusion: People with PD have associated chronic pain, with deficits in the excitatory and inhibitory pain pathways. In addition, pain perception is increased, corroborating the findings of chronification.