Global improvement after deep brain stimulation in Parkinson's disease: Comparison between patient and clinician perspectives

Background: The definition of improvement after Deep Brain Stimulation (DBS) in Parkinson's Disease (PD) remains unclear. The neurologist's perspective, based on measurable parameters, may differ from the patient's perception, and both are crucial for therapeutic success. Whether clinical variables influence these differences is unknown. Objective: To compare the correlation between clinician-assessed (Clinical Global Impression of Improvement, CGI) and patient-reported (Patient Global Impression of Change, PGIC) improvement after DBS and identify factors affecting variability. Methods: We included DBS patients treated at Ferrara Hospital (2006–2022) with ≥ 1-year follow-up. CGI and PGIC were collected at that time, and their correlation analyzed across clinical and demographic subgroups. Results: Among 51 PD patients, CGI rated 21 as “very much improved,” 21 “much improved,” and 9 “minimally improved,” primarily based on MDS-UPDRS III reduction. Agreement with PGIC was 0.65 (p < 0.001), unaffected by age, gender, disease duration, IPG type, LEDD, medication count, MDS-UPDRS III improvement, or stimulation-induced complications. Concordance was weaker (k < 0.60) in patients with higher baseline MDS-UPDRS III, lower MDS-UPDRS IV, less MDS-UPDRS IV improvement, greater tablet reduction, and fewer outpatient visits. It was stronger (k > 0.70) with more follow-ups in the first year. Conclusion: Clinician-patient agreement on DBS improvement is moderate, with motor symptom amelioration only partially reflecting patients’ overall perceived improvement. Various factors widen the gap of concordance, particularly in patients with subtle improvement according to clinicians, while more follow-ups due to stimulation management enhance it. Clinicians must consider that their perspectives may only partially mirror those of the patient during DBS treatment.