Preoperative Visual Memory Performance as a Predictive Factor of Cognitive Changes after Deep Brain Stimulation of Subthalamic Nucleus in Parkinson‘s Disease

Abstract

Aim: Deep brain stimulation of subthalamic nucleus (DBS STN) is considered to be a clinically established treatment method to manage the symptoms of advanced stage Parkinson’s disease. Despite the strict inclusion criteria, it may have negative impact on the quality of cognitive functions. Our research aimed to identify predictive neuropsychological factors that signal risk of postoperative deterioration of cognitive functions before the DBS STN. Patients and methods: Forty-six patients with idiopathic Parkinson’s disease were included in the study (mean age at the time of operation 59.61 years; SD = 7.06). The patients were examined by a neuropsychologist before and after the DBS STN implantation. The neuropsychological test battery included Wechsler Adult Intelligence Scale short form, Mattis Dementia Rating Scale, Word list, Rey-Osterrieth Complex Figure Test, Stroop Colour Word Test and verbal fluency tests. Results: The quality of visual memory proved to be a sensitive predictive factor related to risk of cognitive changes after DBS STN implantation, as before the implantation the level of visual memory statistically negatively corresponded to impairment of cognitive performance in neuropsychological tests after the implantation. Conclusion: Low performance in the area of visual memory before the implantation may predict an increased risk of cognitive deterioration after the implantation of DBS STN in Parkinson’s disease. We assume that the changes in visual memory reflect progression of degenerative process in Parkinson’s disease into other brain areas away from the frontostriatal circuit, mainly to posterior temporoparietal areas.