Validity and Efficacy of Screening Algorithms for Assessing Deep Brain Stimulation Candidacy in Parkinson's Disease

Abstract

Background Deep Brain Stimulation (DBS) for Parkinson disease (PD) may be underutilized because of limited access to care (most DBS surgeries are performed at specialized centers) or over-referral of poor candidates, leading to inequitable utilization of limited evaluative resources. There is a pressing need for a widely employable screening algorithm to aid in the evaluation of PD candidates for DBS. Objective To compare the validity and efficacy of two published screening algorithms, the Florida Surgical Questionnaire for PD and Stimulus, to predict candidacy for DBS. Methods We reviewed the clinical data at our DBS center for 147 consecutive PD DBS referrals between 9/1/2007 and 12/31/2011. Florida Surgical Questionnaire and Stimulus scores were applied retrospectively through a chart review of the Movement Disorder neurologist's initial clinical evaluation. The validity and accuracy of these two algorithms in predicting candidacy for DBS was compared to the decision to offer DBS surgery by our multidisciplinary DBS team. Results Of the 130 consecutive PD referrals who presented for initial evaluation, 50 were offered DBS after a standardized multidisciplinary evaluation. The Stimulus scale was a superior screening tool for predicting PD DBS candidacy in these referrals [Area under the Receiver operating curve = 0.8088] compared to the Florida Surgical Questionnaire for PD [Area under the Receiver operating curve = 0.6285]. Conclusion In this single center study, Stimulus was a more appropriate screening measure than the Florida Surgical Questionnaire for PD to assess DBS candidacy for PD.

Deep-brain stimulation for Parkinson's disease: current perspectives on patient selection with an emphasis on neuropsychology

“…33 Another center reported that despite passing screening, about 9% of those on the DBS-evaluation pathway were excluded for dementia and about 4% for depression on the basis of neuropsychological evaluation. 35 These findings again highlight the importance of neuropsychological evaluation. It appears rare that persons identified as having normal or only very mildly impaired cognition by full neuropsychological evaluation go on to develop disabling cognitive deficits soon after DBS, although such cases have been reported.…”

“…Both the referral of persons for whom DBS is inappropriate and nonreferral of those for whom DBS is appropriate diminish the efficiency of the presurgical patient-selection process. 23,28 At least two standardized questionnaires have been developed for use by referring primary-care physicians and non-subspecialists in movement disorders to enhance referral of those persons for whom DBS has a high likelihood of being an appropriate treatment. The Florida Surgical Questionnaire for Parkinson Disease (FLASQ-PD) was developed at one US movement-disorder surgery center (University of Florida) to improve surgical referral patterns.…”

“…It was found that when compared to the center's questionnaire-independent, multidisciplinary decision to offer DBS to 50 of 130 consecutive persons referred and presenting for evaluation (82 were placed on the DBS-evaluation pathway), Stimulus-DBS was superior (positive predictive value [PPV] about 60%, negative predictive value [NPV] 93%) to FLASQ-PD (PPV 50%, NPV 69%) in predicting from suggested cutoff scores (Stimulus-DBS ≥7, FLASQ-PD ≥25) which patients were ultimately offered DBS. 23 A subsequent multicenter study in Europe found the Stimulus-DBS tool to have PPV of 79% and NPV of 75%, 30 and that 77% of those screened (and in whom DBS was appropriate according to the tool) were accepted for DBS, as opposed to 48% of an unscreened group.…”

“…21,22 Given the complexity of presurgical evaluation and the time and cost involved, some proposed a screening process (that can especially be used by primary-care physicians and general neurologists) to ensure adequate and efficient access of patients to a limited number of specialty centers. 23 Additionally, structured, standardized prescreening questionnaires have been developed to aid in efficient patient evaluation and determination of the potential appropriateness of DBS.…”

Referring Parkinson’s disease patients for deep brain stimulation: a RAND/UCLA appropriateness study

“…An observational study in Germany and Spain showed that the selection rate for DBS was significantly higher for patients in which the Stimulus tool had been used compared to the unscreened population (77 versus 48 %, respectively) [ 8 ]. A recent single-centre study in the USA showed that Stimulus was superior to another tool in predicting DBS candidacy in patients with PD [ 9 ].…”