Structural MRI Correlates of Episodic Memory Processes in Parkinson's Disease Without Mild Cognitive Impairment.

BackgroundChanges in episodic memory are common early in Parkinson's disease (PD) and may be a risk factor for future cognitive decline. Although medial temporal lobe (MTL) memory and frontostriatal (FS) executive systems are thought to play different roles in distinct components of episodic memory impairment in PD, no study has investigated whether different aspects of memory functioning are differentially associated with MTL and FS volumes in nondemented patients without mild cognitive impairment (PD-woMCI).ObjectivesThe present study investigated MRI markers of different facets of memory functioning in 48 PD-woMCI patients and 42 controls.MethodsRegional volumes were measured in structures comprising the MTL and FS systems and then correlated with key indices of memory from the California Verbal Learning Test.ResultsIn PD-woMCI patients, memory was impaired only for verbal learning, which was not associated with executive, attention/working memory, or visuospatial functioning. Despite an absence of cortical atrophy, smaller right MTL volumes in patients were associated with poorer verbal learning, long delayed free recall, long delayed cued recall, and recognition memory hits and false positives. Smaller right pars triangularis (inferior frontal) volumes were also associated with poorer long delayed cued recall and recognition memory hits. These relationships were not found in controls.ConclusionsThe findings indicate that MTL volumes are sensitive to subtle changes in almost all facets of memory in PD-woMCI, whereas FS volumes are sensitive only to memory performances in cued-testing formats

The profile of prospective memory impairment in Parkinson's disease and implications for everyday functioning

Prospective memory (ProM) is an aspect of episodic memory that involves remembering to perform an intended action at some designated point in the future, and is critically involved in everyday functioning. Studies suggests that ProM is dependent on the functional integrity of the frontal lobe system and associated executive functions, with time-based ProM relying more heavily on executive processes than event-based ProM. Although individuals with Parkinson's disease (PD) demonstrate impairments in executive functions and strategic aspects of episodic memory, few studies have examined ProM in PD. The present study examined ProM and the relationship between ProM and everyday functioning in 33 PD patients and 26 demographically comparable adults. PD participants were disproportionately impaired in TB ProM (Cohen's d = 1.30) compared to EB ProM (d = 0.63), committed an increased number of omission errors on TB trials, and were worse (at a trend level) than healthy older adults in retrospective memory for the contents of the intentions. TB ProM performance correlated with standardized measures of executive function, working memory, and retrospective episodic memory in PD. Taken together, these results suggest that PD participants are impaired in the executive /strategic and retrospective memory aspects of ProM. There were no significant differences between groups in strategic time monitoring or basic temporal perception, suggesting that TB ProM impairment in PD may not be related to declines in these cognitive processes. Alternatively, these findings may be related to methodological limitations of the tasks used to measure these processes in the present study. Within the PD sample, ProM deficits correlated with two performance-based measures of everyday functioning (financial capacity, medication management) and a self-report measure of medication management. Moreover, ProM impairment uniquely predicted declines on a performance-based measure of financial capacity, but not medication management, over and above other predictors of everyday functioning. Although future studies with larger samples and longitudinal designs are warranted, these results suggest that ProM may provide unique information regarding everyday functioning skills. The present findings have implications for the assessment of ProM in clinical neuropsychological evaluations and for intervention strategies aimed at improving ProM dysfunction in individuals with P

Delineation of Apathy Subgroups in Parkinson's Disease: Differences in Clinical Presentation, Functional Ability, Health-related Quality of Life, and Caregiver Burden.

BackgroundApathy is a prevalent, multidimensional neuropsychiatric condition in Parkinson's disease (PD). Several authors have proposed apathy subtypes in PD, but no study has examined the classification of PD patients into distinct apathy subtypes, nor has any study examined the clinical utility of doing so.ObjectivesThe current study used a data-driven approach to explore the existence and associated clinical characteristics of apathy subtypes in PD.MethodThe Apathy Scale (AS) was administered to 157 non-demented individuals with PD. Participants were classified into apathy subgroups through cluster analysis. Differences among apathy subtypes on external clinical indicators were explored across apathy subgroups.ResultsIndividuals with PD were classified into three subgroups: a Non-Apathetic group with low levels of apathy symptoms, a Low Interest/Energy group, characterized by elevated symptoms of low interest/energy and minimal low initiation/emotional indifference symptoms, and a Low Initiation group, characterized by an absence of low interest/energy symptoms and elevated levels of low initiation/emotional indifference symptoms. Both Low Interest/Energy and Low Initiation groups exhibited worse depression, fatigue, anxiety, health-related quality of life, and caregiver burden than the Non-Apathetic subgroup. The Low Initiation group exhibited worse overall cognition, emotional well-being, state anxiety, communicative ability, and functional ability than the Low Interest/Energy group. Importantly, disease-related characteristics did not differ across apathy symptom subgroups.ConclusionsNon-demented PD patients can be separated into distinct apathy symptom subgroups, which are differentially associated with important clinical variables. Apathy subgroup membership may reflect disruption to different neural systems independent of disease progression

Delineation of Apathy Subgroups in Parkinson's Disease: Differences in Clinical Presentation, Functional Ability, Health-related Quality of Life, and Caregiver Burden.

BackgroundApathy is a prevalent, multidimensional neuropsychiatric condition in Parkinson's disease (PD). Several authors have proposed apathy subtypes in PD, but no study has examined the classification of PD patients into distinct apathy subtypes, nor has any study examined the clinical utility of doing so.ObjectivesThe current study used a data-driven approach to explore the existence and associated clinical characteristics of apathy subtypes in PD.MethodThe Apathy Scale (AS) was administered to 157 non-demented individuals with PD. Participants were classified into apathy subgroups through cluster analysis. Differences among apathy subtypes on external clinical indicators were explored across apathy subgroups.ResultsIndividuals with PD were classified into three subgroups: a Non-Apathetic group with low levels of apathy symptoms, a Low Interest/Energy group, characterized by elevated symptoms of low interest/energy and minimal low initiation/emotional indifference symptoms, and a Low Initiation group, characterized by an absence of low interest/energy symptoms and elevated levels of low initiation/emotional indifference symptoms. Both Low Interest/Energy and Low Initiation groups exhibited worse depression, fatigue, anxiety, health-related quality of life, and caregiver burden than the Non-Apathetic subgroup. The Low Initiation group exhibited worse overall cognition, emotional well-being, state anxiety, communicative ability, and functional ability than the Low Interest/Energy group. Importantly, disease-related characteristics did not differ across apathy symptom subgroups.ConclusionsNon-demented PD patients can be separated into distinct apathy symptom subgroups, which are differentially associated with important clinical variables. Apathy subgroup membership may reflect disruption to different neural systems independent of disease progression

Differences in Temporal Order Memory Among Young, Middle-Aged, and Older Adults May Depend on the Level of Interference

Age-related changes in temporal order memory have been well documented in older adults; however, little is known about this ability during middle age. We tested healthy young, middle-aged, and older adults on a previously published visuospatial temporal order memory test involving high and low interference conditions. When interference was low, young and middle-aged adults did not differ, but both groups significantly outperformed older adults. However, when interference was high, significant differences were found among all three age groups. The data provide evidence that temporal order memory may begin to decline in middle age, particularly when temporal interference is high

Factor Analysis of the Apathy Scale in Parkinson's Disease.

BackgroundThe Apathy Scale (AS), a popular measure of apathy in Parkinson's disease (PD), has been somewhat limited for failing to characterize dimensions of apathy, such as those involving cognitive, behavioral, and emotional apathy symptoms. This study sought to determine whether factors consistent with these apathy dimensions in PD could be identified on the AS, examine the associations between these factors and disease-related characteristics, and compare PD patients and healthy control (HCs) on identified factors.MethodsConfirmatory (CFA) and exploratory factor analysis (EFA) were conducted on AS scores of 157 nondemented PD patients to identify AS factors. These factors were then correlated with important disease-related characteristics, and PD and HC participants were compared across these factors.ResultsPreviously proposed AS models failed to achieve an adequate fit in CFA. A subsequent EFA revealed two factors on the AS reflecting joint cognitive-behavioral aspects of apathy (Motivation-Interest-Energy) and emotional apathy symptoms (Indifference). Both factors were associated with anxiety, depression, health-related quality of life, and independent activities of daily living, with Indifference associated more with the latter. In addition, only the Indifference factor was associated with cognitive functioning. PD patients reported higher levels of symptoms than HCs on both factors, with the group difference slightly larger on the Motivation-Interest-Energy factor.ConclusionThe AS can be decomposed into two factors reflecting Motivation-Interest-Energy and Indifference symptoms. These factors are differentially associated with clinical variables, including cognition and independent activities of daily living, indicating the importance of evaluating apathy from a multidimensional perspective

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.MethodNondemented 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.ResultsThe 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.ConclusionsTaken 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