Changes in Self- and Informant-Reported Frontal Behaviors in Parkinson's Disease: A Longitudinal Study.

OBJECTIVE: Frontal behaviors (i.e., executive dysfunction, disinhibition, apathy) are common in Parkinson's disease (PD). However, it is unclear if patient and informant reports of patient frontal behaviors are in agreement over time. METHOD: Sixty-two PD patients without dementia and their informants (87% spouses/partners) completed the self- and informant-versions of the Frontal Systems Behavior Scale at baseline and 2-year follow-up. Dyad ratings were compared and predictors of behavior ratings were examined. RESULTS: Patient and informant reports at baseline and follow-up were in agreement, with significant increases in overall frontal behaviors, executive dysfunction, and apathy. Higher levels of baseline patient depression and caregiver burden predicted decrements in patient-reported executive function; worse patient cognition at baseline predicted worsening apathy as rated by informants. CONCLUSIONS: PD patients and their informants are concordant in their ratings of worsening frontal behaviors over time. Targeting patient depression, cognition, and caregiver burden may improve decrements in frontal behaviors (executive dysfunction and apathy) in PD.

Prospective predictors of care partner burden and depression in Parkinson's disease.

OBJECTIVES: Care partners who provide informal care to individuals with Parkinson's disease (PD) report higher levels of burden and depression; however, longitudinal research on these symptoms is scarce. The current study assessed changes in care partner burden and depression, and patient and care partner predictors of these symptoms over time. Such knowledge may provide important information for assessment and treatment of depression and burden in care partners of individuals with PD. RESEARCH DESIGN AND METHODS: Participants were 88 PD patients without dementia and their self-identified care partner (n = 88). Care partners completed the Geriatric Depression Scale and Zarit Burden Interview. PD participants completed mood questionnaires and a motor exam at baseline and 2 year follow-up. Relationships among care partner burden and depression over time with patient and care partner predictors (i.e., demographic, mood, and disease characteristics) were assessed using correlations and regression analyses. RESULTS: Care partner burden and depression significantly increased over an approximate 2 year period. Greater baseline disease severity predicted worsening of care partner burden (p = 0.028), while baseline patient depression predicted worsening of care partner depression (p = 0.002). CONCLUSIONS: Results highlight differential impacts of specific PD symptoms on worsening care partner burden compared to depression; increased PD disease severity predicts increased burden, while patient mood predicts worsening of depression over time. Targeting PD disease severity and mood symptoms may prevent the progression of care partner burden and depression.

Informant-Reported Cognitive Decline is Associated with Objective Cognitive Performance in Parkinson's Disease.

OBJECTIVE: The utility of informant-based measures of cognitive decline to accurately describe objective cognitive performance in Parkinson's disease (PD) without dementia is uncertain. Due to the clinical relevance of this information, the purpose of this study was to examine the relationship between informant-based reports of patient cognitive decline via the Informant Questionnaire of Cognitive Decline in the Elderly (IQCODE) and objective cognition in non-demented PD controlling for cognitive status (i.e., mild cognitive impairment; PD-MCI and normal cognition; PD-NC). METHOD: One-hundred and thirty-nine non-demented PD participants (PD-MCI n = 38; PD-NC n = 101) were administered measures of language, executive function, attention, learning, delayed recall, visuospatial function, mood, and motor function. Each participant identified an informant to complete the IQCODE and a mood questionnaire. RESULTS: Greater levels of informant-based responses of patient cognitive decline on the IQCODE were significantly associated with worse objective performance on measures of global cognition, attention, learning, delayed recall, and executive function in the overall sample, above and beyond covariates and cognitive status. However, the IQCODE was not significantly associated with language or visuospatial function. CONCLUSIONS: Results indicate that informant responses, as measured by the IQCODE, may provide adequate information on a wide range of cognitive abilities in non-demented PD, including those with MCI and normal cognition. Findings have important clinical implications for the utility of the IQCODE in the identification of PD patients in need of further evaluation, monitoring, and treatment.

REM Sleep Behavior Disorder in Parkinson's Disease: Effects on Cognitive, Psychiatric, and Functional outcomes.

OBJECTIVE: Rapid eye movement sleep behavior disorder (RBD) affects 33-46% of patients with Parkinson's disease (PD) and may be a risk factor for neuropsychological and functional deficits. However, the role of RBD on neuropsychological functioning in PD has yet to be fully determined. We, therefore, examined differences in neurocognitive performance, functional capacity, and psychiatric symptoms among nondemented PD patients with probable RBD (PD/pRBD+) and without (PD/pRBD-), and healthy comparison participants (HC). METHODS: Totally, 172 participants (58 PD/pRBD+; 65 PD/pRBD-; 49 HC) completed an RBD sleep questionnaire, psychiatric/clinical questionnaires, performance-based and self-reported functional capacity measures, and underwent a comprehensive neuropsychological battery assessing attention/working memory, language, visuospatial function, verbal and visual learning and memory, and executive function. RESULTS: Controlling for psychiatric symptom severity, the PD/pRBD+ group had poorer executive functioning and learning performance than the PD/pRBD- group and poorer neuropsychological functioning across all individual cognitive domains than the HCs. In contrast, PD/pRBD- patients had significantly lower scores than HCs only in the language domain. Moreover, PD/pRBD+ patients demonstrated significantly poorer medication management skills compared to HCs. Both PD groups reported greater depressive and anxiety severity compared to HCs; PD/pRBD+ group also endorsed greater severity of apathy compared to HCs. CONCLUSIONS: The presence of pRBD is associated with poorer neuropsychological functioning in PD such that PD patients with pRBD have poorer cognitive, functional, and emotional outcomes compared to HC participants and/or PD patients without pRBD. Our findings underscore the importance of RBD assessment for improved detection and treatment of neuropsychological deficits (e.g., targeted cognitive interventions).

Mild cognitive impairment, psychiatric symptoms, and executive functioning in patients with Parkinson's disease.

OBJECTIVE: Mild cognitive impairment (MCI) and psychiatric symptoms (anxiety, depression, and apathy) are common in Parkinson's disease (PD). While studies have supported the association between psychiatric symptoms and cognitive performance in PD, it is unclear if the magnitude of link between psychiatric symptoms and cognitive health is stronger by MCI status. The purpose of this study was to examine the association between cognitive performance and psychiatric symptoms in PD and whether MCI status moderates this association. METHODS/DESIGN: Participants (N = 187) completed a comprehensive neuropsychological assessment that included measures of attention, language, executive function (EF), visuospatial ability, episodic memory, and psychiatric symptoms. Participants were classified as PD-MCI (N = 73) or PD-normal cognition (NC; N = 114). Linear regression analyses were conducted to examine the association between psychiatric symptoms and cognitive performance and the moderating effect of PD-MCI status. RESULTS: There were no differences in mean psychiatric symptoms between PD-MCI and PD-NC. Psychiatric symptoms were predominantly associated with worse EF. The magnitude of the association between anxiety and worse EF was larger in participants with PD-MCI compared with PD-NC. A multivariable regression analysis examining the independent contributions of each symptom demonstrated the most robust association between EF and anxiety. CONCLUSIONS: Symptoms of anxiety, depression, and apathy are associated with worse executive functioning in individuals with PD. PD-MCI may be important in moderating the association between cognitive performance, specifically anxiety, and EF. Factors that promote cognitive resilience may serve as key therapeutic modalities in managing neuropsychiatric symptoms in PD.

The role of dispositional mindfulness in a stress-health pathway among Parkinson's disease patients and caregiving partners.

PURPOSE: Parkinson's disease (PD) patients and their caregivers experience significant distress that impacts physical, emotional and social functioning in the patient, and in turn, has a significant impact on the caregiver. Lower levels of stress have been associated with a better prognosis in PD. The quality of dispositional mindfulness-innate present moment, non-judgmental awareness-has consistently been associated with less perceived stress, greater well-being, and better physical health in both clinical and healthy populations. To date, associations of mindfulness with distress, depression, sleep problems, and other variables that define health-related quality of life have not been examined in the context of PD patient/caregiver dyads. METHODS: We investigated the impact of dispositional mindfulness in a stress-health model among eighteen dyads consisting of PD patients and their caregivers. RESULTS: Multilevel linear modeling (actor-partner interdependence models) revealed significant associations between dispositional mindfulness and stress appraisal, interpersonal support, depressive symptoms, sleep, and health-related quality of life (HRQOL) within both dyadic partners. As expected, results demonstrated significant associations of distress with interpersonal support, depressive symptoms, sleep and HRQOL for both PD patients and caregivers. CONCLUSIONS: Dispositional mindfulness was associated with reduced distress and its downstream clinical consequences. These results support an ameliorative role for dispositional mindfulness among PD patients and caregivers, as a protective factor against psychosocial burdens imposed on couples related to disease and caregiving. Findings suggest future studies should explore mindfulness training as a therapeutic option.

Detecting Mild Cognitive Deficits in Parkinson's Disease: Comparison of Neuropsychological Tests.

BACKGROUND: Numerous neuropsychological tests and test versions are used in Parkinson's disease research, but their relative capacity to detect mild cognitive deficits and their comparability across studies are unknown. The objective of this study was to identify neuropsychological tests that consistently detect cognitive decline in PD across studies. METHODS: Data from 30 normed neuropsychological tests across 20 international studies in up to 2908 nondemented PD patients were analyzed. A subset of 17 tests was administered to up to 1247 healthy controls. A 2-step meta-analytic approach using standardized scores compared performance in PD with normative data. RESULTS: Pooled estimates of the differences between PD and site-specific healthy controls identified significant cognitive deficits in PD patients on 14 test scores across 5 commonly assessed cognitive domains (attention or working memory, executive, language, memory, and visuospatial abilities), but healthy control performance was statistically above average on 7 of these tests. Analyses based on published norms only, as opposed to direct assessment of healthy controls, showed high between-study variability that could not be accounted for and led to inconclusive results. CONCLUSIONS: Normed neuropsychological tests across multiple cognitive domains consistently detect cognitive deficits in PD when compared with site-specific healthy control performance, but relative PD performance was significantly affected by the inclusion and type of healthy controls versus the use of published norms only. Additional research is needed to identify a cognitive battery that can be administered in multisite international studies and that is sensitive to cognitive decline, responsive to therapeutic interventions, and superior to individual cognitive tests. © 2018 International Parkinson and Movement Disorder Society.

Does the Geriatric Depression Scale measure depression in Parkinson's disease?

The Geriatric Depression Scale (GDS) is recommended for screening depression in individuals with Parkinson's disease (PD). Empirical evidence, however, is limited regarding its validity and factor structure in PD. Thus, the current study sought to evaluate the convergent and divergent validity of the GDS, as well as the structure and validity of the derived factors. METHOD: Nondemented individuals with PD (n = 158) completed the GDS-30, and items were subjected to a principle component analysis. Geriatric Depression Scale total and factor scores were correlated with depression items from the Movement Disorder Society Unified Parkinson's disease Rating Scale (MDS-UPDRSd) and Hamilton Rating Scale for Depression (HAMDd), as well as with the Apathy Scale (AS), State-Trait Anxiety Inventory (STAI), Modified Fatigue Impact Scale (MFIS), Parkinson's disease Sleep Scale, and a Subjective Cognitive Function composite score. RESULTS: The GDS total score was strongly correlated with divergent neuropsychiatric measures (AS, r = 0.57; STAI, r = 0.66; MFIS, r = 0.60), while only moderately correlated with convergent measures (MDS-UPDRSd, r = 0.36; HAMDd, r = 0.32; Ps < 0.05). Linear regression analyses revealed standardized measures of anxiety, apathy, and fatigue independently predicted the GDS total score, while depression items (MDS-UPDRSd and HAMDd) failed to reach significance. Three independent factors were identified: Anxiety, Apathy, and Fatigue. These factors were significantly predicted by their respective convergent measures. CONCLUSIONS: Taken together, our findings suggest that the GDS and its subscales appear to primarily measure anxiety, apathy, and fatigue in PD, or alternatively, these symptom dimensions may be predominant in PD-depression. Future research with clinically diagnosed samples is needed to confirm these initial findings.

Neuropsychiatric Predictors of Cognitive Decline in Parkinson Disease: A Longitudinal Study.

OBJECTIVES: To examine the relationship between anxiety, depression, apathy, and cognitive decline in Parkinson disease (PD). DESIGN: Longitudinal study design to assess whether specific neuropsychiatric, demographic, and clinical features predict future cognitive decline. SETTING: Veterans Affairs San Diego Medical Center and the University of California, San Diego. PARTICIPANTS: PD patients (N = 68) and healthy controls (N = 30). MEASUREMENTS: Participants were administered self-report measures of depression (Geriatric Depression Scale), anxiety (State Trait Anxiety Scale), and apathy (Apathy Scale), and a comprehensive neuropsychological battery assessing attention, language, visuospatial function, verbal and visual learning and memory, and executive function. Participants were tested at baseline and after an approximate 2-year period. RESULTS: Anxiety and depression at baseline were the strongest predictors of longitudinal decline on measures of verbal and visual learning, over and above other clinical and demographic characteristics. However, baseline neuropsychiatric symptoms did not significantly correlate with decline in other cognitive domains. No significant correlations were detected between neuropsychiatric symptoms and cognition in the healthy control group. CONCLUSIONS: These results suggest that anxiety and depression in PD may be risk factors for subsequent declines in learning. Emerging evidence suggests nonmotor symptoms are critical determinants of PD prognosis, and the results of this study highlight the importance of assessment of depression and anxiety early in PD.

Comparing the effects of positive and negative feedback in information-integration category learning.

Categorical learning is dependent on feedback. Here, we compare how positive and negative feedback affect information-integration (II) category learning. Ashby and O'Brien (2007) demonstrated that both positive and negative feedback are required to solve II category problems when feedback was not guaranteed on each trial, and reported no differences between positive-only and negative-only feedback in terms of their effectiveness. We followed up on these findings and conducted 3 experiments in which participants completed 2,400 II categorization trials across three days under 1 of 3 conditions: positive feedback only (PFB), negative feedback only (NFB), or both types of feedback (CP; control partial). An adaptive algorithm controlled the amount of feedback given to each group so that feedback was nearly equated. Using different feedback control procedures, Experiments 1 and 2 demonstrated that participants in the NFB and CP group were able to engage II learning strategies, whereas the PFB group was not. Additionally, the NFB group was able to achieve significantly higher accuracy than the PFB group by Day 3. Experiment 3 revealed that these differences remained even when we equated the information received on feedback trials. Thus, negative feedback appears significantly more effective for learning II category structures. This suggests that the human implicit learning system may be capable of learning in the absence of positive feedback.

The effect of interference on temporal order memory in individuals with Parkinson's disease.

Memory for the temporal order of items or events in a sequence has been shown to be impaired in older adults and individuals with Parkinson's disease (PD). The present study examined the effects of high and low interference on temporal order memory in individuals diagnosed with PD (n=20) and demographically similar healthy older adults (n=20) utilizing a computerized task used in previously published studies. During the sample phase of each trial, a series of eight circles were randomly presented one at a time in eight different spatial locations. Participants were instructed to remember the sequence in which the circles appeared in the locations. During the choice phase, participants were presented with two circles in two different locations and were asked to indicate which circle appeared earliest in the sample phase sequence. The two circles were separated by one of four possible temporal separation lags (0, 2, 4, and 6), defined as the number of circles occurring in the sample phase sequence between the two choice phase circles. Shorter temporal lags (e.g., 0 and 2 lags) were hypothesized to result in higher interference compared to longer temporal lags (e.g., 4 and 6 lags). The results demonstrated that on trials involving high interference, no differences were found between the two groups. However, healthy older adults significantly outperformed individuals with PD (p<0.05) on trials involving low interference. Although differences were found between the PD and healthy older adult groups, both groups significantly improved on low interference trials compared to high interference trials (p<0.001). The findings indicate that temporal order memory improves in healthy older adults and individuals with PD when interference is reduced. However, individuals with PD demonstrated poorer temporal order memory even with less interference. Therefore, temporal order memory is differentially affected by interference in healthy older adults and individuals with PD. Given that both groups did improve with lessened interference, behavioral interventions that minimize temporal interference potentially could improve memory function in older adults and to a lesser extent in individuals with PD.

Criterion learning in rule-based categorization: simulation of neural mechanism and new data.

In perceptual categorization, rule selection consists of selecting one or several stimulus-dimensions to be used to categorize the stimuli (e.g., categorize lines according to their length). Once a rule has been selected, criterion learning consists of defining how stimuli will be grouped using the selected dimension(s) (e.g., if the selected rule is line length, define 'long' and 'short'). Very little is known about the neuroscience of criterion learning, and most existing computational models do not provide a biological mechanism for this process. In this article, we introduce a new model of rule learning called Heterosynaptic Inhibitory Criterion Learning (HICL). HICL includes a biologically-based explanation of criterion learning, and we use new category-learning data to test key aspects of the model. In HICL, rule selective cells in prefrontal cortex modulate stimulus-response associations using pre-synaptic inhibition. Criterion learning is implemented by a new type of heterosynaptic error-driven Hebbian learning at inhibitory synapses that uses feedback to drive cell activation above/below thresholds representing ionic gating mechanisms. The model is used to account for new human categorization data from two experiments showing that: (1) changing rule criterion on a given dimension is easier if irrelevant dimensions are also changing (Experiment 1), and (2) showing that changing the relevant rule dimension and learning a new criterion is more difficult, but also facilitated by a change in the irrelevant dimension (Experiment 2). We conclude with a discussion of some of HICL's implications for future research on rule learning.

Validation of the Modified Fatigue Impact Scale in mild to moderate traumatic brain injury.

OBJECTIVE: To evaluate the validity of the Modified Fatigue Impact Scale (MFIS) in veterans with a history of mild to moderate traumatic brain injury (TBI). PARTICIPANTS: Veterans (N = 106) with mild (92%) or moderate (8%) TBI. SETTING: Veterans Administration Health System. PROCEDURE: Factor structure, internal consistency, convergent validity, sensitivity, and specificity of the MFIS were examined. RESULTS: Principal component analysis identified 2 viable MFIS factors: a Cognitive subscale and a Physical/Activities subscale. Item analysis revealed high internal consistency of the MFIS Total scale and subscale items. Strong convergent validity of the MFIS scales was established with 2 Beck Depression Inventory II fatigue items. Receiver operating characteristic curve analysis revealed good to excellent accuracy of the MFIS in classifying fatigued versus nonfatigued individuals. CONCLUSION: The MFIS is a valid multidimensional measure that can be used to evaluate the impact of fatigue on cognitive and physical functioning in individuals with mild to moderate TBI. The psychometric properties of the MFIS make it useful for evaluating fatigue and provide the potential for improving research on fatigue in this population.

The Relationship Between Postconcussive Symptoms and Quality of Life in Veterans With Mild to Moderate Traumatic Brain Injury.

OBJECTIVE: To assess the relationship between postconcussive symptoms and quality of life (QOL) in Veterans with mild to moderate traumatic brain injury (TBI). METHODS: Sixty-one Operation Enduring Freedom/Operation Iraqi Freedom/Persian Gulf War Veterans with a history of mild or moderate TBI, more than 6 months postinjury, and 21 demographically matched Veteran controls were administered self-report measures of QOL (World Health Organization Quality of Life-BREF) and postconcussive symptom severity (Neurobehavioral Symptom Inventory). RESULTS: Perceived QOL was significantly worse in Veterans with mild-moderate TBI than in controls. In the TBI group, QOL was predominantly associated with affective symptoms, and moderate to strong correlations with fatigue and depression were evident across all QOL areas. Multivariate analyses revealed depression and fatigue to be the best predictors of Psychological, Social, and Environmental QOL, whereas sleep difficulty best predicted Physical QOL in mild-moderate TBI. CONCLUSION: Veterans with post-acute mild-moderate TBI evidence worse QOL than demographically matched Veteran controls. Affective symptoms, and specifically those of fatigue, depression, and sleep difficulty, appear to be the most relevant postconcussive symptoms predicting QOL in this population. These findings underscore the importance of examining specific symptoms as they relate to post-acute TBI QOL and provide guidance for treatment and intervention studies.

Volumetric correlates of cognitive functioning in nondemented patients with Parkinson's disease.

A challenge in Parkinson's disease (PD) is to identify biomarkers of early cognitive change because functioning in some domains may be more prognostic of dementia. Few studies have investigated whether structural magnetic resonance imaging (MRI) correlates in a regionally specific manner with functioning in different cognitive domains. The aim of this study was to identify neuroanatomical correlates of executive functioning, memory, and visual cognition in PD without dementia. 3T MRI was conducted in 51 PD patients and 39 control participants. Brain volumes were measured in structures comprising the frontostriatal cognitive-control system, the medial temporal memory system, the ventral object-based system, and the dorsal spatial-based system. Measures of executive functioning (Stroop Test; Letter Fluency), memory (California Verbal Learning Test), visuospatial cognition (Judgment of Line Orientation), and visuoconstruction (Pentagon Copy) were correlated with volumes comprising each system. Poorer executive functioning largely correlated with decreased frontostriatal volumes. Poorer memory correlated with decreased volumes in all medial temporal regions, but also with frontostriatal volumes. Poorer visuospatial cognition correlated with decreased volumes in the object-based system, whereas poorer visuoconstruction correlated with decreased frontal and object-based system volumes. These relationships were nonsignificant in the control group. This is the first study to demonstrate that subtle changes in multiple cognitive domains in PD without dementia correlate with regional volumes in specific systems implicated in the development of cognitive impairment. The findings suggest that structural MRI holds promise as a marker of early changes in different brain systems, some of which may predict future cognitive deterioration.

"Forgetting to remember" in Huntington's disease: a study of laboratory, semi-naturalistic, and self-perceptions of prospective memory.

Prospective memory (PM) is dependent on executive processes known to be impaired in Huntington's disease (HD); however, no study to the authors' knowledge has investigated PM in this group. We examined performance-based, semi-naturalistic, and self-reported PM in 20 individuals diagnosed with mild-moderate HD and 20 demographically similar controls. Relative to controls, HD participants demonstrated significantly lower scores in time-based PM, event-based PM (at a trend level), and the semi-naturalistic PM trial, all of which were marked by omission errors. HD participants demonstrated comparable recognition memory for the PM intentions relative to controls. HD and control participants also showed comparable scores in self-reported PM complaints. The results suggest that HD is associated with deficits in the strategic aspects of PM. HD-associated PM deficits also are evident in real-world situations, which may relate to an apparent meta-memory deficit for PM functioning as indicated by HD participants' overestimation of their PM performance on self-report.

The relationship between objective and subjective executive function in Parkinson's disease.

INTRODUCTION: Difficulties in executive functioning (EF) are common in PD; however, the relationship between subjective and objective EF is unclear. Understanding this relationship could help guide clinical EF assessment. This study examined the relationship between subjective self-reported EF (SEF) and objective EF (OEF) and predictors of SEF-OEF discrepancies in PD. METHOD: One-hundred and sixteen non-demented PD participants completed measures of OEF (i.e. problem-solving, cognitive flexibility, inhibition, and working memory) and SEF (Frontal Systems Behavior Scale-Self Executive Dysfunction Subscale). Pearson bivariate correlations and linear regressions were performed to examine the relationship between SEF and OEF and the non-motor symptoms (e.g. mood, fatigue), demographic, and PD characteristic (e.g. MCI status) predictors of discrepancies between OEF and SEF (|OEF minus SEF scores|). Correlates of under-, over-, and accurate-reporting were also explored. RESULTS: Greater SEF complaints and worse OEF were significantly associated (ß =.200, p = .009) and 64% of participants accurately identified their level of OEF abilities. Fewer years of education and greater symptoms of depression, anxiety, and fatigue significantly correlated with greater discrepancies between OEF and SEF. Fatigue was the best predictor of EF discrepancy in the overall sample (ß = .281, p = .022). Exploratory analyses revealed apathy and fatigue associated with greater under-reporting, while anxiety associated with greater over-reporting. CONCLUSIONS: SEF and OEF are significantly related in PD. Approximately 64% of non-demented persons with PD accurately reported their EF skill level, while 28% under-reported and 8% over-reported. SEF-OEF discrepancies were predicted by fatigue in the overall sample. Preliminary evidence suggests reduced apathy and fatigue symptoms relate to more under-reporting, while anxiety relates to greater over-reporting. Given the prevalence of these non-motor symptoms in PD, it is important to carefully consider them when assessing EF in PD.

Cognitive set-shifting in anorexia nervosa.

OBJECTIVE: Adult anorexia nervosa (AN) is associated with inefficient cognitive flexibility and set-shifting. Whether such inefficiencies also characterize adolescent AN is an important area of research. METHOD: Adolescents with AN and matched controls were administered a computerized task that required initial learning of an explicit rule using corrective feedback and learning of a new rule after a set number of trials. Adult patients with AN and controls were also examined. RESULTS: Adolescents with AN did not differ from matched controls with respect to set-shifting cost (decrease in performance after rule change), whereas adults with AN had significantly greater set-shifting cost compared with controls. DISCUSSION: This study suggests that set-shifting inefficiencies may not be a vulnerability factor for AN development in adolescents with AN, but might become an important aspect of the disorder at later age, and could point towards developmental neurobiologic brain changes that could affect AN at different ages.

Association of Stress-Health Factors among Parkinson's Disease Patient/Caregiving-Partner Dyads.

OBJECTIVE: Few studies have explored the shared effects of Parkinson's disease (PD) within patient/caregiver dyads. To fill this gap, we compared stress-health outcomes of patients with those of caregiving-partners, examined individual stress-health associations, and explored stress-health associations within dyads. METHOD: A total of 18 PD patient/caregiving-partner dyads (N = 36) reported on disease-specific distress, anxiety, quality of life (QOL), and provided saliva samples for cortisol assessment. This cross-sectional, secondary analysis of a prospective pilot study used Actor-Partner Interdependence Models to test aims. RESULTS: Patients reported greater anxiety, poorer QOL, and demonstrated flatter cortisol slopes and higher mean bedtime cortisol compared to caregiving-partners. Both patients and caregiving-partners with greater anxiety had elevated bedtime cortisol and poorer QOL. Greater disease-specific distress in an individual was associated with higher diurnal mean cortisol in their partner. CONCLUSIONS: Findings highlight the potential for psychosocial interventions at the dyadic level to reduce shared burden and promote coping among PD patient/caregiving-partner dyads.

REM Sleep Behavior Disorder in Parkinson's Disease: Change in Cognitive, Psychiatric, and Functional Outcomes from Baseline to 16-47-Month Follow-Up.

OBJECTIVE: Rapid Eye Movement Sleep Behavior Disorder (RBD) is common in Parkinson's Disease (PD) and is associated with cognitive impairment; however, the majority of the evidence on the impact of RBD on multidomain cognitive batteries in PD is cross-sectional. This study evaluated the longitudinal impact of probable RBD (pRBD) on cognitive, psychiatric, and functional outcomes in people with PD. METHOD: Case-control study. A total of 65 people with PD completed the study protocol at baseline and 16-to-47-month follow-up. Participants were classified as pRBD+ (n = 25) or pRBD- (n = 40) based on an established cutoff of 6 on the RBD Sleep Questionnaire (RBDSQ). Participants also completed a) comprehensive cognitive testing, b) self-report measures of depression, anxiety, and apathy, and c) performance-based and other-report forms of instrumental activities of daily living. RESULTS: Baseline mean age was 67.8 (SD = 8.1; range = 45-86) and baseline mean years of education was 16.4 (SD = 2.1; range = 12-20). The two groups did not differ on measured demographic characteristics. Baseline mean T-scores for cognitive tests were in the average range (46-55). Hierarchical linear models tested group differences in cognitive and functional decline from baseline to follow-up, controlling for appropriate demographic and psychiatric variables. Compared to the pRBD- group, pRBD+ participants showed greater decline in attention/working memory (r = -0.31; p = 0.01) and UPSA financial skills (r = -0.31; p = 0.01). No other group differences approached significance. CONCLUSIONS: RBD may differentially affect attention/working memory and financial abilities in PD. Results underscore the importance of regular RBD screening in older adults with PD in order to triage symptomatic patients to appropriate cognitive and medical interventions.