Adding continuous infusion therapies after bilateral subthalamic deep brain stimulation in advanced Parkinson’s disease: clinical outcomes and quality of life assessment in a case series

Parkinson's disease (PD) is a progressive neurodegenerative disorder that primarily presents with motor and non-motor symptoms and significantly affects patients' quality of life (QoL). Although bilateral subthalamic nucleus deep brain stimulation (STN DBS) is recognized as an effective advanced treatment (AT), disease progression may lead to diminished therapeutic outcomes, with recurrence of motor complications, including dyskinesia and fluctuations. This study evaluates the clinical effectiveness and QoL outcomes associated with adding a second advanced therapy (either levodopa-carbidopa intestinal gel [LCIG] or continuous subcutaneous apomorphine infusion [CSAI]) to bilateral STN DBS in six patients experiencing symptom recurrence despite optimized stimulation settings and oral pharmacotherapy. Clinical assessments included motor performance (UPDRS part III), medication dosage (LEDD), electrode positioning using Lead-DBS software, and patient-reported QoL outcomes (EQ- -5D, PDQ-39, PDSS-1, and VAS scales). Four patients demonstrated motor improvement following the introduction of dual therapy. Combined therapies effectively managed refractory symptoms, reduced medication dosages, and significantly enhanced patients' quality of life. This study highlights the clinical potential of integrating multiple advanced therapeutic approaches in managing complex cases of advanced Parkinson's disease.