The relation of testosterone levels with fatigue and apathy in Parkinson's disease

Abstract Objective Fatigue and apathy are frequent in patients with Parkinson's disease (PD). Testosterone deficiency in male patients may contribute in development of fatigue and apathy as well. We investigated whether a possible relation exists between serum testosterone levels, fatigue and apathy in male PD patients. Materials and methods We included 29 non-demented and non-depressed PD patients and 30 age- and sex-matched healthy subjects. Fatigue Severity Scale (FSS) and Apathy Evaluation Scale (AES-C) were used for the evaluations. In PD patients and healthy subjects, a relationship between FSS, AES-C scores and plasma testosterone levels were assessed. In addition, a correlation between FSS, AES-C and Unified Parkinson's Disease Rating Scale was investigated in PD group. Results The mean scores of FSS and AES-C were significantly higher in PD patients than those of the control group. The Unified Parkinson's Disease Rating Scale (UPDRS) scores were significantly correlated with FSS and AES-C scores. Mean free testosterone level was significantly lower in PD patients than controls ( p  = 0.008). f-Testosterone levels of PD patients were not correlated with FSS or AES-C scores. Conclusion Apathy and fatigue are frequent in PD and show significant correlation with the severity of the disease. f-Testosterone levels are not related with apathy or fatigue in male PD patients and the role of testosterone in the pathophysiology of these non-motor symptoms is still controversial.