Deep brain stimulation (DBS) is a well-established therapy for treating motor symptoms of movement disorders. However, little is known about the impact of patient-perceived symptom severity on quality of life (QoL). Additionally, conflicting data exist regarding the effects of DBS on QoL measures, including depression. We analyzed the change in measures of tremor and QoL in DBS patients at our institution.
A retrospective chart review was performed including patients with Parkinson’s disease and essential tremor. We analyzed data from pre-operative, post-operative and one-year follow-up visits including: the Patient-Health Questionnaire (PHQ-9, a standardized depression scale), UPDRS, and clinician-reported and self-reported tremor scores. Repeated measures ANOVA was used to examine changes in PHQ-9 and self-reported tremor from pre-operative to post-operative visits. Relationships between PHQ-9, UPDRS, clinician-reported and self-reported tremor scores were analyzed using linear regressions.
Eighty-one patients who underwent unilateral or bilateral DBS at Cleveland Clinic from 2011-2013 completed PHQ-9 assessments. PHQ-9 scores significantly decreased from pre-operative (8.3±.66) to post-operative (6.7±.62) and one-year follow-up visits (5.8±.54)[F(2, 159.7)=8.89, p=.0002]. Self-reported tremor scores, completed by 34 patients, significantly decreased from pre-operative (12.4±.79) to one-year follow-up (6.6±.82)[F(1.6, 53.2)=23.9, p< .0001]. Prior to DBS surgery, there was no relationship between PHQ-9 and self-reported tremor. However, at post-operative and one-year follow–up visits, higher self-reported tremor scores were predictive of higher PHQ-9 scores [(ß=.28, p=.043) and (ß=.45, p=.007) respectively]. Interestingly, UPDRS and clinician-reported tremor scores were not predictive of PHQ-9 scores.
We observed long-term improvement in patient-perceived depression following DBS, accompanied by a reduction in self-reported tremor scores. More severe tremors were predictive of higher depression ratings post-operatively. These data suggest that patient-perceived DBS efficacy is critical to patient quality of life. Further investigation is warranted to understand the relationship between factors that influence how patients experience illness and outcomes after DBS.
Deep brain stimulation is an invasive therapy that is frequently used to treat medically refractory movement disorders. As such, there is value in examining how perception of DBS efficacy affects long-term quality of life. Knowledge of these effects will help target pre-operative selection strategies and post-operative follow-up care to improve management of patients suffering from prolonged, incurable illnesses.
1 – Identify at least one scale to measure quality of life in patients with movement disorders 2 – Describe the impact of DBS on depression in patients with Parkinson’s disease and essential tremor 3 – Discuss the relationship between patient perception of outcomes after DBS and quality of life measures, including depression.