A program for neuropsychological investigation of deep brain stimulation (PNIDBS) in movement disorder patients: development, feasibility, and preliminary data.

Objective: This technical report and feasibility study propose a standardized method for collecting neuropsychological data in patients undergoing the deep brain stimulation (DBS) procedure.

Background: Programs for standardizing motor data collected in studies investigating surgical therapies for Parkinson disease are already widely used (e.g., Core Assessment Program for Intracerebral Transplantations). The development and rationale for the proposed Program for Neuropsychological Investigation of Deep Brain Stimulation (PNIDBS) are outlined, and support for the feasibility of these methodologies is provided via preliminary data.

Method: The PNIDBS includes a core battery of neuropsychological tests that assesses a wide range of cognitive functions (attention, language, visuospatial, memory, and executive) as well as depression. Using the PNIDBS, three Parkinson disease and two dystonia patients were evaluated at baseline and after surgery, once with stimulation off and once with stimulation on.

Results: Patients with severe motor disabilities were able to complete the PNIDBS. These preliminary data suggest that the DBS procedure as a whole had a minimal impact on cognitive functioning in most patients studied. There was also some evidence that the one patient who showed cognitive decline after the DBS procedure had demographic and clinical characteristics that may have put him at risk for this decline.

Conclusions: The procedures in the PNIDBS were systematically developed and are feasible to execute. The relatively brief core battery has multiple versions and can be supplemented to meet individual investigator needs. By evaluating the components of the DBS procedure (electrode placement and stimulation), the PNIDBS can address clinical questions regarding the cognitive effects of the DBS procedure as well as investigate basic scientific issues regarding how different cognitive functions are affected when subcortical-prefrontal circuits are manipulated by the DBS procedure.