No abstract

Background Background: The 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. Methods Methods: Confirmatory (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 diseaserelated characteristics, and PD and HC participants were compared across these factors. ResultsResults: Previously 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, healthrelated 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. Conclusion Conclusion: The 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.Apathy is among the most common psychiatric symptoms in Parkinson's disease (PD). Prevalence estimates of apathy in PD range from 17% to 62%. Although there is a substantial overlap between apathy and depression (e.g., common symptoms of lack of energy, fatigue, and loss of interest), a growing body of literature suggests that symptoms of apathy and depression are dissociable in PD, with 5% to 33% of individuals reporting apathy in isolation from any other psychiatric symptom. 1-8 This is likely attributed to nonoverlapping symptoms, such as diminished initiation and interests in the absence of affective evaluation in apathy as opposed to depression. 9 Apathy is associated with diminished quality of life, 10 a reduction in activities of daily living, 2,11 and may be a predictor of future executive dysfunction and global cognitive decline. 4,5,12 1 Veterans Administration San Diego Healthcare System,

Background Changes 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). Objectives The present study investigated MRI markers of different facets of memory functioning in 48 PD-woMCI patients and 42 controls. Methods Regional 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. Results In 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. Conclusions The 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.