Comprehensive, Multidisciplinary Deep Brain Stimulation Screening for Parkinson Patients: No Room for “Short Cuts”

Abstract

Careful, often cumbersome, screening is a fundamental part of DBS evaluation in Parkinson's disease (PD). It often involves a brain MRI, neuropsychological testing, neurological, surgical, and psychiatric evaluation, and "ON/OFF" motor testing. Given that DBS has now been a standard treatment for advanced PD, with clinicians' improved comfort and confidence in screening and referring patients for DBS, we wondered whether we can now streamline our lengthy evaluation process. We reviewed all PD patients evaluated for DBS at our center between 2006 and 2011 and analyzed the reasons for exclusion and for dropping out despite passing the screening process. A total of 223 PD patients who underwent DBS evaluation had complete charting. Only 131 (58.7%) patients were successfully implanted. Sixty-one (27.3%) patients were excluded after screening because of significant cognitive decline (32.7%), early disease with room for medication adjustment (29.5%), behavioral dysfunction (21.3%), suspected secondary parkinsonism or atypical parkinsonism syndrome (13.1%), PD, but with poor levodopa response (11.4%), unrealistic goals (9.8%), PD with predominant axial symptoms (6.5%), significant comorbidities (6.5%), or abnormal brain imaging (3.2%). In addition, 31 (13.9%) patients were cleared for surgery, but either chose not have it (18 patients), were lost to follow-up (12 patients), or were denied by medical insurance (1 patient). Through careful screening, a significant percentage of surgical candidates continue to be identified as less suitable because of a variety of reasons. This underscores the continued need for a comprehensive, multidisciplinary screening process.

Are non-demented patients with Parkinson's disease able to decide about their own treatment?

“…The present patient sample might therefore been characterized by a better overall health and better cognitive functioning than patients of previous studies. As such, the sample included in the present study might be a better representation of the group of patients undergoing DBS, as PD patients with profound cognitive impairment and high scores on the Hoehn & Yahr scale due to gait and balance dysfunction are excluded from surgical candidacy in most centers [23].…”

Global cognitive scores do not predict outcome after subthalamic nucleus deep brain stimulation

“…Our decision-making procedure for DBS candidacy and surgical plan has been described elsewhere. 3– 5 Forty-four patients underwent bilateral STN-DBS implantations and 62 patients had unilateral procedures (20 right [7 left-handed]; 42 left [38 right-handed]).…”

Insights gleaned by measuring patients' stated goals for DBS

“…Other contraindications included atypical parkinsonism, poor levodopa response, predominant axial symptoms, medical comorbidities, abnormal brain imaging, and, rarely, lack of family support. 14 Measures. The study employed a mixed methodology including quantitative scales and qualitative methods.…”

“…For example, patients who pursue DBS may have a stronger family support system and advocacy, which might affect the patients' stated goals (e.g., it is possible that due to the strong social support to pursue DBS, our sample may not have rated social activities as highly as another sample with PD). In addition, as part of the selection process, we screen out patients with clinically meaningful cognitive symptoms and ensure that any psychiatric symptoms are wellcontrolled prior to moving forward 14 ; thus, these nonmotor symptom goals may be relatively minimized in our sample and potentially even more prominent in other PD groups. Our team also is attentive to patients' stated goals for DBS and, in some cases, patients have not been offered surgery due to unrealistic expectations 14 ; thus, our sample may not be representative of other DBS patients.…”

“…In addition, as part of the selection process, we screen out patients with clinically meaningful cognitive symptoms and ensure that any psychiatric symptoms are wellcontrolled prior to moving forward 14 ; thus, these nonmotor symptom goals may be relatively minimized in our sample and potentially even more prominent in other PD groups. Our team also is attentive to patients' stated goals for DBS and, in some cases, patients have not been offered surgery due to unrealistic expectations 14 ; thus, our sample may not be representative of other DBS patients. Our small sample size precluded our ability to examine the potential effect of PD phenotype or site of surgery, which are potentially important considerations.…”