Does the Montreal Cognitive Assessment (MoCA) identify cognitive impairment profiles in Parkinson's disease? An exploratory study.

An important proportion of patients with Parkinson's Disease (PD) present signs of cognitive impairment, although this is heterogeneous. In an attempt to classify this, the dual syndrome hypothesis distinguishes between two profiles: one defined by attentional and executive problems with damage in anterior cerebral regions, and another with mnesic and visuospatial alterations, with damage in posterior cerebral regions. The Montreal Cognitive Assessment (MoCA) is one of the recommended screening tools, and one of the most used, to assess cognitive impairment in PD. However, its ability to specifically identify these two profiles of cognitive impairment has not been studied. The aim of this study was, therefore, to analyze the capacity of the MoCA to detect cognitive impairment, and also to identify anterior and posterior profiles defined by the dual syndrome hypothesis. For this purpose, 59 patients with idiopathic PD were studied with the MoCA and a neuropsychological battery of tests covering all cognitive domains. Results of logistic regression analysis with ROC (Receiver Operating Characteristic) curves showed that MoCA detected cognitive impairment and identified patients with a profile of anterior/attentional and executive deficit, with acceptable sensibility and specificity. However, it did not identify patients with a posterior/mnesic-visuospatial impairment. We discuss the reasons for the lack of sensitivity of MoCA in this profile, and other possible implications of these results with regards the usefulness of this tool to assess cognitive impairment in PD.

Social Cognition and Cognitive Decline in Patients with Parkinson's Disease.

Social cognition (SC) comprises an array of cognitive and affective abilities such as social perception, theory of mind, empathy, and social behavior. Previous studies have suggested the existence of deficits in several SC abilities in Parkinson disease (PD), although not unanimously. OBJECTIVE: The aim of this study is to assess the SC construct and to explore its relationship with cognitive state in PD patients. METHOD: We compare 19 PD patients with cognitive decline, 27 cognitively preserved PD patients, and 29 healthy control (HC) individuals in social perception (static and dynamic emotional facial recognition), theory of mind, empathy, and social behavior tasks. We also assess processing speed, executive functions, memory, language, and visuospatial ability. RESULTS: PD patients with cognitive decline perform worse than the other groups in both facial expression recognition tasks and theory of mind. Cognitively preserved PD patients only score worse than HCs in the static facial expression recognition task. We find several significant correlations between each of the SC deficits and diverse cognitive processes. CONCLUSIONS: The results indicate that some components of SC are impaired in PD patients. These problems seem to be related to a global cognitive decline rather than to specific deficits. Considering the importance of these abilities for social interaction, we suggest that SC be included in the assessment protocols in PD.

Differences in cognitive performance in nondemented Parkinson's disease: A latent profile analysis of cognitive subtypes.

INTRODUCTION: Cognitive impairments are common in Parkinson's disease (PD) patients without dementia. These deficits are quite heterogeneous, which makes it difficult to recognize and treat them. For this reason, many authors have attempted to classify patients into more homogeneous groups with diverse results. The present study was designed to analyze the cognitive heterogeneity in PD patients using a novel data-driven approach, latent profile analysis (LPA), to classify patients according to cognitive characteristics. This methodology, which has been used in previous studies focused on motor and psychiatric symptomatology, seems to be better than traditional cluster analysis for the establishment and comparison between different subgroups because it does not require prior decision making about some theoretical or methodological aspects. METHOD: LPA was applied to 71 PD patients evaluated with a broad neuropsychological battery including different memory and executive function tests. The clusters obtained from the analysis were described by making comparisons with a control group of 51 healthy subjects matched in age, sex, and educational level. RESULTS: The LPA resulted in a four-cluster solution, which could be described as: (a) executive dysfunction (32.4%), (b) memory and executive dysfunction (28.2%), (c) memory dysfunction (23.9%), and (d) noncognitive dysfunction (15.5%). These four PD cluster differ in age and Mini-Mental State Examination (MMSE) score. However, there were no differences between clusters in disease duration, clinical impression of severity index, depression, and cognitive reserve. CONCLUSIONS: LPA is a very interesting method for the establishment of more homogeneous groups of PD patients based on their neuropsychological characteristics. Moreover, the distinction between different cognitive profiles will allow us to design interventions better adapted to each patient.

Selective attention and facial expression recognition in patients with Parkinson's disease.

Parkinson's disease (PD) has been associated with facial expression recognition difficulties. However, this impairment could be secondary to the one produced in other cognitive processes involved in recognition, such as selective attention. This study investigates the influence of two selective attention components (inhibition and visual search) on facial expression recognition in PD. We compared facial expression and non-emotional stimuli recognition abilities of 51 patients and 51 healthy controls, by means of an adapted Stroop task, and by "The Face in the Crowd" paradigm, which assess Inhibition and Visual Search abilities, respectively. Patients scored worse than controls in both tasks with facial expressions, but not with the other nonemotional stimuli, indicating specific emotional recognition impairment, not dependent on selective attention abilities. This should be taken into account in patients' neuropsychological assessment given the relevance of emotional facial expression for social communication in everyday settings.

Working memory and facial expression recognition in patients with Parkinson's disease.

Facial expression recognition impairment has been reported in Parkinson's disease. While some authors have referred to specific emotional disabilities, others view them as secondary to executive deficits frequently described in the disease, such as working memory. The present study aims to analyze the relationship between working memory and facial expression recognition abilities in Parkinson's disease. We observed 50 patients with Parkinson's disease and 49 healthy controls by means of an n-back procedure with four types of stimuli: emotional facial expressions, gender, spatial locations, and non-sense syllables. Other executive and visuospatial neuropsychological tests were also administered. Results showed that Parkinson's disease patients with high levels of disability performed worse than healthy individuals on the emotional facial expression and spatial location tasks. Moreover, spatial location task performance was correlated with executive neuropsychological scores, but emotional facial expression was not. Thus, working memory seems to be altered in Parkinson's disease, particularly in tasks that involve the appreciation of spatial relationships in stimuli. Additionally, non-executive, facial emotional recognition difficulty seems to be present and related to disease progression.

Discrimination and categorization of emotional facial expressions and faces in Parkinson's disease.

Our objective was to compare the ability to discriminate and categorize emotional facial expressions (EFEs) and facial identity characteristics (age and/or gender) in a group of 53 individuals with Parkinson's disease (PD) and another group of 53 healthy subjects. On the one hand, by means of discrimination and identification tasks, we compared two stages in the visual recognition process that could be selectively affected in individuals with PD. On the other hand, facial expression versus gender and age comparison permits us to contrast whether the emotional or non-emotional content influences the configural perception of faces. In Experiment I, we did not find differences between groups, either with facial expression or age, in discrimination tasks. Conversely, in Experiment II, we found differences between the groups, but only in the EFE identification task. Taken together, our results indicate that configural perception of faces does not seem to be globally impaired in PD. However, this ability is selectively altered when the categorization of emotional faces is required. A deeper assessment of the PD group indicated that decline in facial expression categorization is more evident in a subgroup of patients with higher global impairment (motor and cognitive). Taken together, these results suggest that the problems found in facial expression recognition may be associated with the progressive neuronal loss in frontostriatal and mesolimbic circuits, which characterizes PD.

A holistic analysis of relationships between executive function and memory in Parkinson's disease.

Apart from motor symptoms, Parkinson's disease is characterized by executive and memory problems that have been observed from early stages of the disease. This study explores the possible relationships between these cognitive impairments in a group of 23 individuals with Parkinson's disease (PD) in comparison to a group of 18 healthy individuals. Compared with young individuals, normal aging is characterized by an increased association between executive function and episodic memory, especially with verbal material. We hypothesize that this association between verbal episodic memory and executive function may be weaker in PD as a consequence of the decline in these two cognitive abilities. To test this hypothesis, three categories of standardized tests were administered to both groups: (a) tests for executive function, (b) tests for visuospatial episodic memory, and (c) tests for verbal episodic memory. Performance outputs were analyzed using factor analysis, canonical regression, and structural equation modeling to obtain a holistic perspective of the linkage of these processes and to compare the differences between groups. In general, PD patients performed worse than controls in both executive function and episodic memory (with verbal and visuospatial material). Moreover, we found that relationships between executive function and visuospatial memory scores were high and quite similar in both groups. However, the relationship between verbal episodic memory and executive function was weaker in PD than in healthy individuals. These results suggest that a different brain mechanism could explain executive and verbal memory impairments in PD.