Performance Validity in Deep Brain Stimulation Candidates.

Objective: Effort and motivation are important factors that influence performance on neuropsychological tests. Performance validity tests (PVT) have not been investigated in a sample of individuals who are at risk for cognitive decline and are presumably highly motivated to do well. The aim of the current study is to investigate performance validity in individuals with Parkinson's disease and essential tremor who are being considered for deep brain stimulation (DBS) surgery.

Methods: Thirty DBS surgical candidates underwent neuropsychological evaluation including completion of the Word Memory Test (WMT) as well as embedded PVTs.

Results: Sixteen DBS candidates (53.3%) obtained a passing WMT score, 11 patients (36.6%) obtained scores in the "caution" range, and three patients (10%) produced failing scores. None of the patients scored below an 82.5% on the first three WMT subtests.

Conclusions: This pilot study is the first to describe PVT in DBS candidates and in a presumed highly motivated, older, and cognitively at-risk sample.