Long-term benefits in quality of life provided by bilateral subthalamic stimulation in patients with Parkinson disease

OBJECT: The goals of this study were to evaluate long-term benefits in quality of life in patients with Parkinson disease (PD) after bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) and to evaluate the relationship between improvements in motor function and quality of life. METHODS: Seventy-one patients who received bilateral STN stimulation implants and participated in follow-up review for at least 12 months were included in the study. Fifty-nine patients participated in a 12-month follow-up review and 43 patients in a follow-up review lasting at least 24 months. Patients' symptoms were assessed preoperatively by using the Unified PD Rating Scale (UPDRS) in the "medication-on" and "medication-off' conditions and quality of life was examined using the 39-item PD Questionnaire (PDQ-39). Patient evaluations were repeated postoperatively during periods of stimulation. The UPDRS activities of daily living (ADL) and motor scores as well as the PDQ-39 total, mobility, ADL, emotional well-being, stigma, and bodily discomfort scores were significantly improved at 12 months compared with baseline scores; the UPDRS ADL and motor scores as well as the PDQ-39 total, mobility, ADL, stigma, and bodily discomfort scores were significantly improved at the longest follow-up examination compared with baseline scores. There was a strong correlation between UPDRS motor and ADL scores and the PDQ-39 total, mobility, and ADL scores. Further analyses indicated that improvements in tremor were only correlated with PDQ-39 ADL subscale scores and rigidity was not correlated with any aspect of quality of life. Nevertheless, bradykinesia was strongly correlated with improvements in the PDQ-39 total, mobility, and ADL scores. CONCLUSIONS: Improvements in quality of life following bilateral DBS of the STN are maintained in the long term. These improvements are strongly correlated with improvements in motor function, primarily with regard to bradykinesia.