Katja Werheid

Syntactic Comprehension in Parkinson's Disease: Investigating Early Automatic and Late Integrational Processes Using Event-Related Brain Potentials

Parkinsons disease (PD) has been associated with a general impairment of procedures and with an impairment of syntactic procedures in particular. The present study investigated comprehension processes in PD using event-related brain potentials (ERPs). PD patients and controls listened to sentences that were either correct or syntactically or semantically incorrect. The language-related ERP component correlated with semantic processes (N400) was present in both groups. In the syntactic domain, early automatic processes (early negativity) appeared normal in PD, whereas late integrational processes (P600) were modulated by this disease. The present findings suggest that the basal ganglia primarily do not support early automatic syntactic processes during comprehension but rather support processes of syntactic integration.

Facial attractiveness modulates early and late event-related brain potentials.

Facial attractiveness is of high importance for human interaction and communication, and everyday experience suggests that the mere aspect of a face elicits spontaneous appraisal of attractiveness. However, little is known about the time course of brain responses related to this process. In the present study, event-related brain potentials were recorded during attractiveness classification of facial portraits that were standardized with respect to facial expression. The faces were either preceded by another face of high or low attractiveness or by an affectively neutral object. Attractive as opposed to non-attractive target faces elicited an early posterior negativity (EPN; approximately 250 ms) and a late parietal positivity (LPC; 400-600 ms), which were not modulated by affectively congruent prime faces. Elevated LPC activity had previously been shown in response to attractive versus non-attractive faces, possibly reflecting task-related evaluative processes. An enhanced EPN had been reported for faces with emotional compared to neutral emotional expression, and related to facilitated selection of emotional information. Extending these findings, our study is the first to report an attractiveness-related ERP modulation prior to the LPC, suggesting that appraising facial attractiveness starts already at processing stages associated with stimulus selection.

The Appraisal of Facial Beauty Is Rapid but Not Mandatory

Facial attractiveness is an important source of social affective information. Here, we studied the time course and task dependence of evaluating attractive faces from a viewer’s perspective. Event-related brain potentials (ERPs) were recorded while participants classified color portraits of unfamiliar persons according to gender and facial attractiveness. During attractiveness classification, enhanced ERP amplitudes for attractive and nonattractive faces relative to faces of intermediate attractiveness were found for an early component around 150 msec and for the late positive complex (LPC). Whereas LPC enhancement conforms to previous studies employing various types of affective stimuli, the finding of an early effect extends earlier research on rapid emotion processing to the dimension of facial attractiveness. Dipole source localization of this early ERP effect revealed a scalp distribution suggesting activation of posterior extrastriate areas. Importantly, attractiveness-related modulations of brain responses were only marginal during the gender decision task, arguing against the automaticity of attractiveness appraisal.

Impaired self-initiated task preparation during task switching in Parkinson's disease.

Patients with Parkinsons disease (PD) typically show reduced performance in clinical tests involving cognitive control processes, presumably due to reduced availability of dopamine in striatofrontal neuronal circuits. Although task switching paradigms are considered as an ideal experimental measure of cognitive control, previous studies on task switching in PD have yielded ambiguous results, indicating that performance deficits depend on the specific task requirements. Among these, the aspect of self-initiated as opposed to externally triggered task preparation seems to play an important role, as evidenced by recent research. To address this topic, the present study investigated PD patients and age-matched controls (n=16) with a sequential switching task in which the upcoming task was predicted by two different types of cues. Firstly, every task was predicted by an external visual cue of varying utility (long versus short precuing interval). Additionally, the tasks were predictable on the basis of a fixed task sequence (AABB), which placed relatively higher demands on self-initiated task preparation. After considerable practice, the sequence was changed to random. Increased reaction times following sequence removal indicated prior use of the sequence in both groups. However, in contrast to healthy age-matched controls, PD patients did not learn to use the predictable task sequence to a greater extent when the utility of the visual task cue was low due to a short precuing interval. This finding is interpreted as evidence for a specific impairment in self-initiated as opposed to externally triggered task preparation.

Kognitives Training bei Alzheimer-Demenz

ZusammenfassungGedächtnisrehabilitation bei Demenz ist ein Thema von zunehmender Dringlichkeit. Unter der wachsenden Zahl derer, die von Alzheimer-Demenz betroffen sind, steigt insbesondere der Anteil von Patienten im Frühstadium der Erkrankung. Gründe hierfür sind die verbesserte Frühdiagnostik, die wachsende Sensibilisierung der Bevölkerung gegenüber kognitiven Störungen sowie der Einsatz progressionsverzögernder Medikamente. Aufgrund mäßiger Erfolge früher Therapieprogramme der 1980er Jahre herrscht vielerorts berechtigte Skepsis gegenüber kognitiven Therapiemaßnahmen bei Alzheimer-Demenz. Neuere internationale Arbeiten auf diesem Gebiet geben jedoch Anlass zu verhaltenem Optimismus. Gedächtnistherapie bei leichter bis mittelgradiger Alzheimer-Demenz kann erfolgreich sein, wenn sie auf individuelle, alltagsrelevante Problembereiche zugeschnitten ist und sich auf vorhandene kognitive Ressourcen stützt. Der vorliegende Artikel bietet einen Überblick aktueller Befunde der klinischen und kognitiven Neurowissenschaften, die zu einem Wandel der Behandlungsstrategie bei Demenz geführt haben. Es werden Therapieprinzipien und -methoden vorgestellt, die sich in aktuellen Forschungsarbeiten als wirksam erwiesen haben. Basierend auf diesen Ergebnissen werden Empfehlungen für künftige Studien zur Evaluierung kognitiver Demenztherapie formuliert.SummaryMemory rehabilitation in dementia patients is gaining importance. Among the increasing number of people affected by Alzheimer’s dementia (AD), the number detected in early stages of the disease is growing disproportionately quickly. The reasons are obvious: improved clinical assessment in the initial disease stage, increased sensitization of the elderly towards cognitive deficits, and the prescription of drugs retarding cognitive decline. Given the limited success of early training programs in the 1980s, skepticism towards cognitive training in dementia is still common among clinicians. However, recent international studies in the field give reason for cautious optimism. Memory therapy in the early-to-moderate stages of AD can be successful, if it is tailored to patients’ individual daily problems and based on their residual cognitive capacities. The present paper gives an overview of recent findings in clinical and cognitive neuroscience which have led to a conceptual change in the memory rehabilitation of patients with dementia. Based on a review of general principles and rehabilitation techniques proven successful in recent research, recommendations are formulated for future studies evaluating cognitive therapy in dementia.

The influence of self-efficacy, pre-stroke depression and perceived social support on self-reported depressive symptoms during stroke rehabilitation

Post-stroke depression (PSD) is the most common mental disorder following stroke; however, little is known about its pathogenesis. We investigated the predictive value and mutual relationship of psychological factors such as self-efficacy and social support and known risk factors such as pre-stroke depression, activities of daily living (ADL), cognitive functioning, and age for the emergence of depressive symptoms in the acute phase after stroke. Ninety-six ischaemic stroke inpatients residing at a rehabilitation centre completed an interview about 6.5 weeks post-stroke. The interview included demographic data, psychiatric anamnesis, the Barthel Index, Mini-Mental State Examination, Social Support Questionnaire, Generalized Self-Efficacy Scale, Stroke Self-Efficacy Questionnaire, and the Geriatric Depression Scale. A multiple regression analysis was performed to ascertain the predictive value of the factors on depressive symptoms. High self-efficacy, no history of pre-stroke depression, and high levels of perceived social support were the strongest protective factors for depressive symptoms. The influence of cognitive functioning on depressive symptoms was fully mediated by general self-efficacy, and general self-efficacy was a stronger predictor than stroke-specific self-efficacy. Neither ADL nor age significantly predicted depressive symptoms. Our findings suggest that consideration of self-efficacy and perceived social support in the inpatient rehabilitation setting may help prevent PSD.

Recognition memory for emotional faces in amnestic mild cognitive impairment: An event-related potential study

ABSTRACT This study examined the temporal course of emotional face recognition in amnestic mild cognitive impairment (aMCI). Patients and healthy controls (HC) performed a face recognition task, giving old/new responses to previously studied and novel faces displaying a negative or neutral expression. In aMCI patients, recognition accuracy was preserved for negative faces. Event-related potentials (ERPs) revealed disease-related changes in early perceptual components but not in ERP indices of explicit recognition. Specifically, aMCI patients showed impaired recognition effects for negative faces on the amplitudes of N170 and P2, suggesting deficient memory-related processing of negative faces at the stage of structural encoding and during an early recognition stage at which faces are individuated, respectively. Moreover, while a right-lateralized emotion effect specifically observed for correctly recognized faces on the amplitude of N170 was absent in aMCI, a similar emotion effect for successfully recognized faces on P2 was preserved in the patients, albeit with a different distribution. This suggests that in aMCI facilitated processing of successfully recognized emotional faces starts later in the processing sequence. Nonetheless, an early frontal old/new effect confined to negative faces and a parietal old/new effect unaffected by facial emotion were observed in both groups. This indicates that familiarity and conceptual priming processes may specifically contribute to recognition of negative faces in older adults and that aMCI patients can recruit the same retrieval mechanisms as controls, despite disease-related changes on early perceptual ERP components.

Familiar smiling faces in Alzheimer's disease: Understanding the positivity-related recognition bias

Recent research has revealed a recognition bias favoring positive faces and other stimuli in older compared to younger adults. However, it is yet unclear whether this bias reflects an age-related preference for positive emotional stimuli, or an affirmatory bias used to compensate for episodic memory deficits. To follow up this point, the present study examined recognition of emotional faces and current mood state in patients with mild Alzheimer disease (AD) and healthy controls. Expecting lower overall memory performance, more negative and less positive mood in AD patients, the critical question was whether the positivity-related recognition bias would be increased compared to cognitively unimpaired controls. Eighteen AD patients and 18 healthy controls studied happy, neutral, and angry faces, which in a subsequent recognition task were intermixed with 50% distracter faces. As expected, the patient group showed reduced memory performance, along with a less positive and more negative mood. The recognition bias for positive faces persisted. This pattern supports the view that the positivity-induced recognition bias represents a compensatory, gist-based memory process that is applied when item-based recognition fails.

Age Differences in Valence Judgments of Emotional Faces: The Influence of Personality Traits and Current Mood

Previous research on emotion processing revealed a positivity bias that progressively evolves across the adult age range. This study obtained gradual valence judgments of emotional faces across the adult age span, to see whether this positivity bias persists when positive and negative stimuli are matched for arousal; and whether bias relates to personality traits or to current mood. With increasing age subjects judged negative and neutral faces less negatively. Further, younger participants scoring high in “agreeableness” and “conscientiousness” scales showed a positivity bias when judging positive faces, suggesting an association of the positivity effect with trait variables.

Latent Change Score Modeling as a Method for Analyzing the Antidepressant Effect of a Psychosocial Intervention in Alzheimer's Disease

Background: Developing and evaluating interventions for patients with age-associated disorders is a rising field in psychotherapy research. Its methodological challenges include the high between-subject variability and the wealth of influencing factors associated with longer lifetime. Latent change score modeling (LCSM), a technique based on structural equation modeling, may be well suited to analyzing longitudinal data sets obtained in clinical trials. Here, we used LCSM to evaluate the antidepressant effect of a combined cognitive behavioral/cognitive rehabilitation (CB/CR) intervention in Alzheimers disease (AD). Methods: LCSM was applied to predict the change in depressive symptoms from baseline as an outcome of the CORDIAL study, a randomized controlled trial involving 201 patients with mild AD. The participants underwent either the CORDIAL CB/CR program or standard treatment. Using LCSM, the model best predicting changes in Geriatric Depression Scale scores was determined based on this data set. Results: The best fit was achieved by a model predicting a decline in depressive symptoms between before and after testing. Assignment to the intervention group as well as female gender revealed significant effects in model fit indices, which remained stable at 6- and 12-month follow-up examinations. The pre-post effect was pronounced for patients with clinically relevant depressive symptoms at baseline. Conclusions: LCSM confirmed the antidepressant effect of the CORDIAL therapy program, which was limited to women. The effect was pronounced in patients with clinically relevant depressive symptoms at baseline. Methodologically, LCSM appears well suited to analyzing longitudinal data from clinical trials in aged populations, by accounting for the high between-subject variability and providing information on the differential indication of the probed intervention.