Social decision-making in Parkinson's disease.

INTRODUCTION: Parkinson's Disease (PD) commonly affects cognition and communicative functions, including the ability to perceive socially meaningful cues from nonverbal behavior and spoken language (e.g., a speaker's tone of voice). However, we know little about how people with PD use social information to make decisions in daily interactions (e.g., decisions to trust another person) and whether this ability rests on intact cognitive functions and executive/decision-making abilities in nonsocial domains. METHOD: Non-demented adults with and without PD were presented utterances that conveyed differences in speaker confidence or politeness based on the way that speakers formulated their statement and their tone of voice. Participants had to use these speech-related cues to make trust-related decisions about interaction partners while playing the Trust Game. Explicit measures of social perception, nonsocial decision-making, and related cognitive abilities were collected. RESULTS: Individuals with PD displayed significant differences from control participants in social decision-making; for example, they showed greater trust in game partners whose voice sounded confident and who explicitly stated that they would cooperate with the participant. The PD patients displayed relative intact social perception (speaker confidence or politeness ratings) and were unimpaired on a nonsocial decision-making task (the Dice game). No obvious relationship emerged between measures of social perception, social decision-making, or cognitive functioning in the PD sample. CONCLUSIONS: Results provide evidence of alterations in decision-making restricted to social contexts in PD individuals with relatively preserved cognition with minimal changes in social perception. Researchers and practitioners interested in how PD affects social perception and cognition should include assessments that emulate social interactions, as non-interactive tasks may fail to detect the full impact of the disease on those affected.

Mental Time Travel and Time Reference Difficulties in Alzheimer's Disease: Are They Related? A Systematic Review.

Mental time travel and language enable us to go back and forth in time and to organize and express our personal experiences through time reference. People with Alzheimer's disease have both mental time travel and time reference impairments, which can greatly impact their daily communication. Currently, little is known about the potential relationship between time conceptualization (i.e., mental time travel) and time reference difficulties in this disease. A systematic review of the literature was performed to determine if this link had already been investigated. Only three articles integrated both time conceptualization and time reference measures. However, the link between the two was not systematically analyzed and interpreted. This review highlights the lack of research addressing the question of the influence of time conceptualization impairments in Alzheimer's disease on other cognitive domains, and especially language.

Patterns of brain activity during a set-shifting task linked to mild behavioral impairment in Parkinson's disease.

Mild behavioral impairment (MBI) is a neurobehavioral syndrome characterized by later life emergence of sustained neuropsychiatric symptoms, as an at-risk state for incident cognitive decline and dementia. Prior studies have reported that neuropsychiatric symptoms are associated with cognitive abilities in Parkinson's disease (PD) patients, and we have recently found a strong correlation between MBI and cognitive performance. However, the underlying neural activity patterns of cognitive performance linked to MBI in PD are unknown. Fifty-nine non-demented PD patients and 26 healthy controls were scanned using fMRI during performance of a modified version of the Wisconsin card sorting task. MBI was evaluated using the MBI-checklist, and PD patients were divided into two groups, PD-MBI and PD-noMBI. Compared to the PD-noMBI group and healthy controls, the PD-MBI group revealed less activation in the prefrontal and posterior parietal cortices, and reduced deactivation in the medial temporal region. These results suggest that in PD, MBI reflects deficits in the frontoparietal control network and the hippocampal memory system.

Action fluency identifies different sex, age, global cognition, executive function and brain activation profile in non-demented patients with Parkinson's disease.

Patients with Parkinson's disease (PD) have difficulties processing action words, which could be related to early cognitive decline. The action fluency test can be used to quickly and easily assess the processing of action words in PD. The goal of this study was to characterize how the action fluency test relates to personal characteristics, disease factors, cognition, and neural activity in PD. Forty-eight participants with PD (34 male, 14 female) and 35 control participants (16 male, 19 female) completed functional neuroimaging using a set-shifting task and a neuropsychological assessment including the action fluency test. PD participants with a score one standard deviation below the norm or lower on the action fluency test were identified. All PD participants with poor performance (PD-P, n = 15) were male. They were compared to male PD participants with scores within the normal range (PD-N, n = 19) and male healthy controls (HC, n = 16). PD-P were older, had lower global cognition scores, lower executive functions scores, and decreased activity in fronto-temporal regions compared with PD-N. There was no difference between the two PD groups in terms of the duration of the disease, dose of dopaminergic medication, and severity of motor symptoms. PD-N were younger than HC, but there was no other significant difference between these groups. The action fluency test identified a subgroup of PD patients with distinct sex, age, global cognition, executive functions, and brain activity characteristics. Implications for the evaluation of cognition are discussed.

The Nonverbal Processing of Actions Is an Area of Relative Strength in the Semantic Variant of Primary Progressive Aphasia.

Purpose Better performance for actions compared to objects has been reported in the semantic variant of primary progressive aphasia (svPPA). This study investigated the influence of the assessment task (naming, semantic picture matching) over the dissociation between objects and actions. Method Ten individuals with svPPA and 17 matched controls completed object and action naming tests, and object and action semantic picture matching tests. Performance was compared between the svPPA and control groups, within the svPPA group, and for each participant with svPPA versus the control group individually. Results Compared to controls, participants with svPPA were impaired on object and action naming, and object and action semantic picture matching. As a group, participants with svPPA had an advantage for actions over objects and for semantic picture matching tests over naming tests. Eight participants had a better performance for actions compared to objects in naming, with three showing a significant difference. Nine participants had a better performance for actions compared to objects in semantic picture matching, with six showing a significant difference. For objects, semantic picture matching was better than naming in nine participants, with five showing a significant difference. For actions, semantic picture matching was better than naming in all 10 participants, with nine showing a significant difference. Conclusion The nonverbal processing of actions, as assessed with a semantic picture matching test, is an area of relative strength in svPPA. Clinical implications for assessment planning and interpretation and theoretical implications for current models of semantic cognition are discussed.

Network basis of the dysexecutive and posterior cortical cognitive profiles in Parkinson's disease.

BACKGROUND: The dual syndrome hypothesis of cognitive impairment in PD suggests that two cognitive profiles exist with distinct pathological mechanisms and a differential risk for further cognitive decline. How these profiles relate to network dysfunction has never been explicitly characterized. OBJECTIVE: First, to assess intranetwork functional connectivity while considering global connectivity, and second, to relate network connectivity with measures of the dysexecutive and posterior cortical profiles. METHODS: Eighty-two subjects with idiopathic PD and 37 age-matched controls underwent resting-state functional MRI and comprehensive neuropsychological assessment. Intranetwork and global connectivity was compared between groups. Measures of the dysexecutive and posterior cortical profiles were related to network connectivity while considering demographic and disease-related covariates. RESULTS: PD subjects show decreased connectivity within several cortical networks. However, only the sensorimotor network displayed a loss of connectivity independent of the observed decreased global connectivity. The dysexecutive factor was independently related to increased motor severity, less education, and decreased connectivity in the sensorimotor network. The posterior cortical factor was related to increased age, less education, decreased connectivity in the central executive network, as well as increased connectivity in the temporal network. CONCLUSIONS: Our results provide evidence supporting a network-specific process of degeneration in the sensorimotor network which contributes to the dysexecutive cognitive profile. In contrast, connectivity of the temporal and central executive network is related to the posterior cortical profile, representing a distinct network signature of this syndrome. © 2019 International Parkinson and Movement Disorder Society.

Inflectional Morphology in Fluent Aphasia: A Case Study in a Highly Inflected Language.

Inflectional morphology difficulties are typically reported in non-fluent aphasia with agrammatism, but a growing number of studies show that they can also be present in fluent aphasia. In agrammatism, morphological difficulties are conceived as the consequence of impaired phonological encoding and would affect regular verbs more than irregular verbs. However, studies show that inflectional morphology difficulties concern both regular and irregular verbs, and that their origin could be more conceptual/semantic in nature. Additionally, studies report more pronounced impairments for the processing of the past tense compared to other tenses. The goal of this study was to characterize the impairment of inflectional morphology in fluent aphasia. RY, a 69-year-old man with chronic fluent aphasia completed a short neuropsychological and language battery and three experimental tasks of inflectional morphology. The tasks assessed the capacity to select the correct inflected form of a verb based on time information, to access the time information included in an inflectional morpheme, and to produce verbs with tense inflection. His performance was compared to a group of five adults without language impairments. Results showed that RY had difficulties selecting the correct inflected form of a verb, accessing time information transmitted by inflectional morphemes, and producing inflected verbs. His difficulties affected both regular and irregular verbs, and verbs in the present, past, and future tenses. The performance also shows the influence of processing limitations over the production and comprehension of inflectional morphology. More studies of inflectional morphology in fluent aphasia are needed to understand the origin of difficulties.

Contribution of language studies to the understanding of cognitive impairment and its progression over time in Parkinson's disease.

Parkinson's disease is a frequent neurodegenerative disease that is mostly known for its motor symptoms. However, cognitive impairment is now recognised as an important part of the disease. Studies of cognitive impairment in Parkinson's disease reveal considerable heterogeneity in terms of which cognitive domains are impaired, and of how cognitive impairment progresses over time. In parallel, a growing body of research reports language difficulties in Parkinson's disease, more specifically in the domains of sentence processing and lexical-semantic processing. In this review, the performance of patients with Parkinson's disease in these domains of language will be reviewed with a focus on the links that they have with the rest of cognition and on how they could contribute to the earlier and more precise characterization and prediction of cognitive impairment in Parkinson's disease. More specifically, the potential for modulation of complexity and sensitivity of language tasks to mild deficits and difficulties that are predictive of further decline will be emphasized. Other motivations for studying language difficulties in this disease will also be discussed.

Regularity and beyond: Impaired production and comprehension of inflectional morphology in semantic dementia.

Studies on inflectional morphology in semantic dementia (SD) have focused on the contrast between the regular and the irregular English past-tense. These studies aimed to contrast the claims of single- and dual-mechanism theories. However, both theories can account for impaired production of irregular verbs observed in SD. According to the dual-mechanism theory, this impairment is related to word-retrieval difficulties, while according to single-mechanism theory it is the consequence of semantic impairment. However, authors suggest that it is time to envision a broader role for semantic memory in the production of semantically encoded aspects of inflectional morphology. This study reports the performance of 10 French-speaking patients with SD in three tasks of inflectional morphology. Their performances were compared to those of a group of 20 age-, gender- and education-matched adults without cognitive impairment. Results show that SD patients had difficulties producing tense and person inflection in verbs and pseudo-verbs, whether regular or pseudo-regular. In a second task in which participants were directly exposed to regularity manipulations, SD patients tended to choose a more typical or predictable alternative over a correctly inflected verb. Results of the third task show that their difficulties in producing semantically encoded aspects of inflection, such as tense, are related to difficulties to understand the semantic content conveyed by inflectional morphemes. Overall, these results support the claim that semantic impairment can cause morphological deficits that do not only affect irregular verbs, but that also have impacts on the production and comprehension of semantic information conveyed by inflectional morphemes.

[Consensual recommendations for the description of three variants of primary progressive aphasia: limits and controversies regarding language impairments]. / Recommandations consensuelles pour la description de trois variantes de l'aphasie primaire progressive : limites et controverses quant aux troubles du langage.

Consensual recommendations for the diagnostic criteria of three variants of primary progressive aphasia (PPA) were published in 2011. Since their publication, these recommendations were the object of criticism, which has recently led to the proposition of their revision. This article gives a description of the criteria that preceded the consensual criteria currently in use, and presents the different limits and controversies regarding the description of each PPA variant's language profile. These controversies will be examined in terms of the description of each variant's central manifestations, their differential diagnosis, the links between each clinical entity and its underlying pathology, and the evolution of the language profile. Lastly, this article offers perspectives regarding language evaluation in PPA that have several implications for clinical practice and research.

The role of basal ganglia in language production: evidence from Parkinson's disease.

According to the dominant view in the literature, basal ganglia do not play a direct role in language but are involved in cognitive control required by linguistic and non-linguistic processing. In Parkinson's disease, basal ganglia impairment leads to motor symptoms and language deficits; those affecting the production of verbs have been frequently explored. According to a controversial theory, basal ganglia play a specific role in the conjugation of regular verbs as compared to irregular verbs. We report the results of 15 patients with Parkinson's disease in experimental conjugation tasks. They performed below healthy controls but their performance did not differ for regular and irregular verbs. These results confirm that basal ganglia are involved in language processing but do not play a specific role in verb production.

Toward an executive origin for acquired phonological dyslexia: a case of specific deficit of context-sensitive grapheme-to- phoneme conversion rules.

Phonological dyslexia is a written language disorder characterized by poor reading of nonwords when compared with relatively preserved ability in reading real words. In this study, we report the case of FG, a 74-year-old man with phonological dyslexia. The nature and origin of his reading impairment were assessed using tasks involving activation and explicit manipulation of phonological representations as well as reading of words and nonwords in which the nature and complexity of grapheme-to-phoneme conversion rules (GPC rules) were manipulated. FG also underwent an extensive neuropsychological assessment battery in which he showed impaired performance in tests exploring verbal working memory and executive functions. FG showed no phonological impairment, and his performance was also largely unimpaired for reading words, with no effect of concreteness, grammatical class, morphological complexity, length or nature and complexity of the GPC rules. However, he showed substantial difficulties when asked to read nonwords with contextual GPC rules. The contribution of FG's executive deficits to his performance in reading is discussed.