Neuropsychological outcomes after thalamic deep brain stimulation for essential tremor.

INTRODUCTION: Non-motor DBS outcomes have received little attention in ET relative to PD. This study examines neuropsychological outcomes in ET following thalamic VIM DBS. METHODS: Fifty patients completed neuropsychological evaluations preoperatively and approximately seven months postoperatively. Cognition and mood changes were analyzed at the group level and individual level. Additional associations with treatment, disease, and demographic characteristics were assessed. RESULTS: Significant cognitive decline was not observed at the group level. At the individual level, 46% of patients demonstrated at least subtle overall cognitive decline (≥1SD on at least one test within at least two domains). Mild decline (≥1SD) was seen in 10%-29.17% of patients on individual tests across all cognitive domains, with highest rates in verbal memory. Substantial cognitive decline (≥2SD) occurred in less than 9% of the sample across all tests. Factors related to cognitive decline included higher DBS parameter settings, older age of ET onset, intracranial complications, and inability to reduce ET medications postoperatively. Depression and anxiety did not change when accounting for questionnaire items that could be falsely elevated by tremor. CONCLUSION: Substantial cognitive decline after VIM DBS is rare in patients with ET. However, subtle decrements can occur across cognitive domains and particularly in verbal memory. DBS parameter settings may relate to cognitive decline. Further research is needed to better understand possible associations with electrode lateralization and other variables that could also relate to disease progression and test-retest effects. Symptoms of depression and anxiety remain stable.

Iowa Gambling Task Performance in Parkinson Disease Patients with Impulse Control Disorders.

OBJECTIVE: A subgroup of patients with Parkinson disease (PD) develops impulse control disorders (ICD) associated with their dopamine replacement therapy. Patients and their families may be reluctant to report ICD symptoms or unaware these symptoms are related to PD medication, which can make detecting an ICD difficult for clinicians. Ideally, a behavioral measure that is sensitive to ICD could be employed to ensure that patients with these behaviors are identified and treated. The Iowa Gambling Task (IGT), a standardized decision-making task, has proven sensitive in other populations with impulse control problems. We hypothesized that the IGT would differentiate between PD patients with and without ICD. METHODS: We compared IGT performance and disease variables in 24 PD patients with ICD and 24 PD patients without ICD. Patient groups were matched in terms of age, sex, and duration of PD. RESULTS: There were no significant differences in IGT scores between PD groups. IGT performance declined with increasing age, but the majority of patients performed within normal limits based on published age- and education-corrected normative data. CONCLUSIONS: The IGT did not distinguish between PD patients with and without ICD. Increasing age negatively impacted performance in both groups. Other studies have found that IGT performance may decline in normal aging. Our results suggest that the IGT lacks the sensitivity and specificity needed to differentiate between age-related deficits and disruption in frontal-subcortical circuits underlying ICD associated with PD medications. Therefore, the IGT is not an appropriate behavioral measure for ICD in PD patients.

Toward a firmer foundation for DSM-5.1: domains of impairment in DSM-IV/DSM-5 personality disorders.

In recent editions of the Diagnostic and Statistical Manual of Mental Disorders, personality disorders (PDs) have been conceptualized as reflecting impairments in four areas: cognition, affectivity, interpersonal functioning, and impulse control. However, there have been no systematic surveys of PD symptoms to assess the degree to which these four domains of impairment are actually represented in the DSM-IV/DSM-5 PD symptom criteria. Results of such a survey indicated that the most common domain of impairment for DSM-IV/DSM-5 PDs is interpersonal functioning (41% of all PD symptoms), followed by cognition (30%), and affectivity (18%), with relatively few PD symptoms reflecting difficulties in impulse control (6%). Comparison of the proportions of symptoms in different impairment domains in DSM-III, DSM-III-R, and DSM-IV/DSM-5 confirmed that these symptom distributions have been stable across revisions of the diagnostic manual. Implications of these results for the conceptualization of PDs in DSM-5.1 and beyond are discussed.