Neuropsychological Profiles of Older Adults with Superior versus Average Episodic Memory: The Northwestern "SuperAger" Cohort.

OBJECTIVE: SuperAgers are adults over the age of 80 with superior episodic memory performance and at least average-for-age performance in non-episodic memory domains. This study further characterized the neuropsychological profile of SuperAgers compared to average-for-age episodic memory peers to determine potential cognitive mechanisms contributing to their superior episodic memory performance. METHOD: Retrospective analysis of neuropsychological test data from 56 SuperAgers and 23 similar-age peers with average episodic memory was conducted. Independent sample t-tests evaluated between-group differences in neuropsychological scores. Multiple linear regression determined the influence of non-episodic memory function on episodic memory scores across participants. RESULTS: As a group, SuperAgers had better scores than their average memory peers on measures of attention, working memory, naming, and speeded set shifting. Scores on tests of processing speed, visuospatial function, verbal fluency, response inhibition, and abstract reasoning did not differ. On an individual level, there was variability among SuperAgers with regard to non-episodic memory performance, with some performing above average-for-age across cognitive domains while others performed in the average-for-age range on non-memory tests. Across all participants, attention and executive function scores explained 20.4% of the variance in episodic memory scores. CONCLUSIONS: As a group, SuperAgers outperformed their average memory peers in multiple cognitive domains, however, there was considerable intragroup variability suggesting that SuperAgers' episodic memory strength is not simply related to globally superior cognitive functioning. Attention and executive function performance explained approximately one-fifth of the variance in episodic memory and maybe areas to target with cognitive interventions.

Anterior lead location predicts verbal fluency decline following STN-DBS in Parkinson's disease.

INTRODUCTION: Verbal fluency (VF) decline is a well-documented cognitive effect of Deep Brain Stimulation of the subthalamic nucleus (STN-DBS) in patients with Parkinson's disease (PD). This decline may be associated with disruption to left-sided frontostriatal circuitry involving the anteroventral non-motor area of the STN. While recent studies have examined the impact of lead location in relation to functional STN subdivisions on VF outcomes, results have been mixed and methods have been limited by atlas-based location mapping. METHODS: Participants included 59 individuals with PD who underwent bilateral STN-DBS. Each participant's active contact location was determined in an atlas-independent fashion, relative to their individual MR-visualized STN midpoint. Multiple linear regression was used to examine lead location in each direction as a predictor of phonemic and semantic VF decline, controlling for demographic and disease variables. RESULTS: More anterior lead locations relative to the STN midpoint in the left hemisphere predicted greater phonemic VF decline (B = -2.34, B SE = 1.08, ß = -0.29, sr2 = 0.08). Lead location was not a significant predictor of semantic VF decline. CONCLUSION: Using an individualized atlas-independent approach, present findings suggest that more anterior stimulation of the left STN may uniquely contribute to post-DBS VF decline. This is consistent with models in which the anterior STN represents a "non-motor" functional subdivision with connections to frontal regions, e.g., the left dorsal prefrontal cortex. Future studies should investigate the effect of DBS lead trajectory on VF outcomes.

The impact of dispositional optimism and depression on post-operative motor functioning following deep brain stimulation surgery for Parkinson's disease.

INTRODUCTION: The primary goal of subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson's disease (PD) is to improve motor function. Dispositional optimism has been associated with better physical outcomes following a rehabilitation program in PD but has not been investigated in relation to STN-DBS. This study investigated the influence of dispositional optimism on motor outcomes following STN-DBS in individuals with PD. METHODS: A retrospective data analysis of 33 individuals with PD who underwent STN-DBS was conducted. Linear regression was used to determine whether dispositional optimism, measured by the Life Orientation Test-Revised questionnaire, predicted change in motor symptoms following DBS surgery, as assessed by the Movement Disorder Society-sponsored revision of the Unified PD Rating Scale, Part III. Self-reported levels of depressive and anxiety symptoms were included as co-variates. RESULTS: Higher pre-operative dispositional optimism combined with less self-reported depressive symptoms predicted greater post-operative improvement in motor symptoms from the baseline OFF-medication to post-operative ON-medication/ON-stimulation state, accounting for 38.8% of the variance in post-operative change. CONCLUSION: The large percentage of variance in post-STN-DBS motor change predicted by pre-operative dispositional optimism and depressive symptoms suggests that assessment of these variables prior to surgery may provide valuable information for clinicians regarding the surgery's ultimate initial motor benefit for individuals with PD. If modifiable, these variables may provide cost-effective targets to improve motor outcomes of STN-DBS in PD.

Psychological well-being in elderly adults with extraordinary episodic memory.

OBJECTIVES: The Northwestern University SuperAging Program studies a rare cohort of individuals over age 80 with episodic memory ability at least as good as middle-age adults to determine what factors contribute to their elite memory performance. As psychological well-being is positively correlated with cognitive performance in older adults, the present study examined whether aspects of psychological well-being distinguish cognitive SuperAgers from their cognitively average-for-age, same-age peers. METHOD: Thirty-one SuperAgers and 19 cognitively average-for-age peers completed the Ryff 42-item Psychological Well-Being questionnaire, comprised of 6 subscales: Autonomy, Positive Relations with Others, Environmental Mastery, Personal Growth, Purpose in Life, and Self-Acceptance. RESULTS: The groups did not differ on demographic factors, including estimated premorbid intelligence. Consistent with inclusion criteria, SuperAgers had better episodic memory scores. Compared to cognitively average-for-age peers, SuperAgers endorsed greater levels of Positive Relations with Others. The groups did not differ on other PWB-42 subscales. DISCUSSION: While SuperAgers and their cognitively average-for-age peers reported similarly high levels of psychological well-being across multiple dimensions, SuperAgers endorsed greater levels of positive social relationships. This psychological feature could conceivably have a biological relationship to the greater thickness of the anterior cingulate gyrus and higher density of von Economo neurons previously reported in SuperAgers.