Neuropsychological consequences of pallidal deep brain stimulation altering brain networks

The purpose of this study was to evaluate postoperative changes in the neuropsychological function of cervical dystonia patients who had undergone deep brain stimulation (DBS) of the internal segment of the globus pallidus (GPi) and to investigate how DBS affects neuropsychological function by altering the neural networks of the brain. In 12 cervical dystonia patients, the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) was used to measure the preoperative and postoperative status of cervical dystonia, and the Seoul Neuropsychological Screening Battery was used to gather neuropsychological data. The data were analyzed using a Wilcoxon signed-rank test. The average improvement in the TWSTRS score at the time of the postoperative neuropsychological battery was 56.1 ± 26.8%. In the neuropsychological battery, inhibitory control, as evaluated by the Stroop test, was significantly decreased after GPi DBS. The average pre-/postoperative Stroop test word and color reading correct response score were 107.9/99.2 (P = 0.043) and 85.3/75.8 (P = 0.032), respectively. The observed neuropsychological consequence of GPi DBS in this study, i.e., decreased inhibitory control, implies that electrical stimulation of the GPi may alter brain networks via the centromedian-parafascicular nuclear complex, suppressing the inhibitory control function of the prefrontal cortex.