title: The clinical significance of neuropsychological changes following bilateral subthalamic nucleus deep brain stimulation for Parkinson's disease.
abstract: Despite the clinical importance of the question, a number of methodological issues have limited firm conclusions regarding the cognitive safety of deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson's disease (PD). Amongst these issues, studies have generally failed to consider the postoperative changes that occur within individual patients. This study utilized reliable change indices (RCIs) derived from a PD sample to determine the frequency of clinically significant postoperative decline on a battery of neuropsychological measures. This approach addresses measurement reliability, potential practice effects, and disease progression. The proportion of patients experiencing clinically significant postoperative decline on measures of list learning and verbal fluency was greater than expected based on disease progression; however, the majority of patients (55%) did not experience a significant decline in performance on any of the cognitive tests administered, and only one experienced decline on more than one test. Therefore, the statistically significant declines on measures of list learning and verbal fluency observed in the sample as a whole were the result of clinically significant declines experienced by a minority of participants.
authors.affiliation: Loyola College in Maryland, Department of Psychology, Baltimore, MD 21210-2699, USA. cihigginson@loyola.edu
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Higginson
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Wheelock
authors.forename: Dawn
authors.initials: D
authors.lastname: Levine
authors.forename: David S
authors.initials: DS
authors.lastname: King
authors.forename: Conrad T E
authors.initials: CT
authors.lastname: Pappas
authors.forename: Karen A
authors.initials: KA
authors.lastname: Sigvardt
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D003071:Cognition / Q000502:physiology*; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D013238:Stereotaxic Techniques; D020531:Subthalamic Nucleus / Q000502:physiology*