Ines Ann Heber

Horizontal and vertical pseudoneglect in peri- and extrapersonal space

The present study investigates the influence of depth on pseudoneglect in healthy young participants (n=18) within three-dimensional virtual space, by presenting a variation of the greyscales task and a landmark task, which were specifically matched for stimulus-response compatibility, as well as perceptual factors within and across the tasks. Tasks were presented in different depth locations (peripersonal, extrapersonal) and different orientations (horizontal, vertical) within three-dimensional virtual space, using virtual reality technique. A horizontal leftward bias (pseudoneglect) for both tasks was found, which was stronger in peripersonal than in extrapersonal space. For the vertical condition, an upward bias was observed in the greyscales task, but not in the landmark task. These results support the hypotheses of right hemispheric dominance for visual spatial attention and our study is the first to examine horizontal and vertical orienting biases with the greyscales task in peri- and extrapersonal space. Furthermore, the differences in attentional asymmetries with respect to depth suggest dissociable neural mechanisms for visual attentional processing in near and far space and the lack of significant correlations implies independence of horizontal and vertical stimulus processing.

Deep brain stimulation of the subthalamic nucleus improves intrinsic alertness in Parkinson's disease.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a treatment option for patients with Parkinsons disease (PD) in the advanced stage. Besides motor improvement, DBS of the STN may also modulate cognitive and attentional functions of the basal ganglia. In our study, 13 patients with PD and bilateral DBS of the STN were assessed with DBS switched on and off by the use of a wide range of neuropsychological tasks. This included reasoning, cognitive flexibility, phonemic and semantic word fluency, verbal and nonverbal short‐term memory, learning, delayed verbal memory recall, and stimulus‐response incompatibility. Special emphasis was put on basic attentional functions, in particular intrinsic and phasic alertness as well as visual search. DBS significantly improved intrinsic alertness, whereas phasic alertness and other neuropsychological domains were not affected. Additionally, the effects on intrinsic alertness were independent of motor improvements by DBS. The findings suggest that DBS modulates the fronto‐parietal network of alertness.

Subtypes of mild cognitive impairment in patients with Parkinson's disease: evidence from the LANDSCAPE study

Objective Inconsistent results exist regarding the cognitive profile in patients with Parkinsons disease with mild cognitive impairment (PD-MCI). We aimed at providing data on this topic from a large cohort of patients with PD-MCI. Methods Sociodemographic, clinical and neuropsychological baseline data from patients with PD-MCI recruited in the multicentre, prospective, observational DEMPARK/LANDSCAPE study were analysed. Results 269 patients with PD-MCI (age 67.8±7.4, Unified Parkinsons Disease Rating Scale (UPDRS-III) scores 23.2±11.6) were included. PD-MCI subtypes were 39.4% non-amnestic single domain, 30.5% amnestic multiple domain, 23.4% non-amnestic multiple domain and 6.7% amnestic single domain. Executive functions were most frequently impaired. The most sensitive tests to detect cognitive dysfunctions were the Modified Card Sorting Test, digit span backwards and word list learning direct recall. Multiple stepwise regression analyses showed that global cognition, gender and age, but not education or disease-related parameters predicted PD-MCI subtypes. Conclusions This study with the so far largest number of prospectively recruited patients with PD-MCI indicates that non-amnestic PD-MCI is more frequent than amnestic PD-MCI; executive dysfunctions are the most typical cognitive symptom in PD-MCI; and age, gender and global cognition predict the PD-MCI subtype. Longitudinal data are needed to test the hypothesis that patients with PD-MCI with specific cognitive profiles have different risks to develop dementia.

Low arousal modulates visuospatial attention in three-dimensional virtual space

Clinical, experimental, and functional imaging studies suggest overlapping neuronal networks and functional interactions of alertness and visuospatial attention within the right hemisphere of the brain. To examine the interaction of arousal and visuospatial attention in peripersonal and extrapersonal virtual space, we tested 20 healthy male adults during 24 hr of sleep deprivation at four points during the night (9 p.m., 1 a.m., 5 a.m., and 9 a.m.). The main finding concerning covert orienting in a virtual environment is a highly significant slowing of reorientation toward the left visual hemifield in extrapersonal space due to decreased arousal. The results provide additional evidence for the proposed anatomical and functional overlap of the two attentional systems and indicate a modulation of visuospatial attention by the level of arousal in extrapersonal space.

Verbal memory declines more in female patients with Parkinson's disease: the importance of gender-corrected normative data.

BACKGROUND Data on gender-specific profiles of cognitive functions in patients with Parkinsons disease (PD) are rare and inconsistent, and possible disease-confounding factors have been insufficiently considered. METHOD The LANDSCAPE study on cognition in PD enrolled 656 PD patients (267 without cognitive impairment, 66% male; 292 with mild cognitive impairment, 69% male; 97 with PD dementia, 69% male). Raw values and age-, education-, and gender-corrected Z scores of a neuropsychological test battery (CERAD-Plus) were compared between genders. Motor symptoms, disease duration, l-dopa equivalent daily dose, depression - and additionally age and education for the raw value analysis - were taken as covariates. RESULTS Raw-score analysis replicated results of previous studies in that female PD patients were superior in verbal memory (word list learning, p = 0.02; recall, p = 0.03), while men outperformed women in visuoconstruction (p = 0.002) and figural memory (p = 0.005). In contrast, gender-corrected Z scores showed that men were superior in verbal memory (word list learning, p = 0.02; recall, p = 0.02; recognition, p = 0.04), while no difference was found for visuospatial tests. This picture could be observed both in the overall analysis of PD patients as well as in a differentiated group analysis. CONCLUSIONS Normative data corrected for gender and other sociodemographic variables are relevant, since they may elucidate a markedly different cognitive profile compared to raw scores. Our study also suggests that verbal memory decline is stronger in women than in men with PD. Future studies are needed to replicate these findings, examine the progression of gender-specific cognitive decline in PD and define different underlying mechanisms of this dysfunction.

Attentional Asymmetries in Virtual Space

The present study investigated the influence of virtual depth on attentional asymmetries in healthy young participants (n = 20), by administering a variation of a luminance judgment task as well as a line bisection task in different depth locations (peripersonal, extrapersonal) within three-dimensional virtual space. Pseudoneglect was present in both tasks and depth locations with clear emphasis on peripersonal space. The results show highly significant attentional asymmetries in virtual space that are comparable to real space and suggest that Virtual Reality (VR) is an appropriate tool for assessing visuo-spatial attention in virtual space.

Posterior Cortical Atrophy: A Case Report of a 6-Year Natural Progression.

BACKGROUND We describe a 6-year natural history of a patient with posterior cortical atrophy (PCA), demonstrating the difficulties of diagnosis in the early stages of the disease. First clinical signs were predominantly visual with normal neuroimaging and neurodegeneration markers. The mild clinical signs were followed by a progressive decline of various cognitive functions, including perception, attention, memory, and executive function. Repeated neuroimaging and cerebrospinal fluid (CSF) measurements finally revealed a PCA with underlying atypical Alzheimer disease (AD) pathology. PCA is a neurodegenerative syndrome characterized by progressive deterioration of visuospatial, visuoperceptual, praxic, and literacy abilities due to degeneration of posterior cortical regions.1 Pathologic studies show that this often underrecognized syndrome is associated with a range of different disease pathologies. Most commonly it is attributed to AD, but it may also be caused by Lewy body dementia, corticobasal degeneration, and prion diseases, such as Creutzfeld-Jakob disease or familial fatal insomnia.2 PCA often presents a considerable challenge in differential diagnostics because of its initial disease characteristics being quite distinct from other dementias. Here we present a case of PCA which was followed up for almost 6 years with extensive clinical, neuropsychological, neuroimaging, and CSF biomarker testing.

Performance and Comfort When Using Motion-Controlled Tools in Complex Tasks

The use of interaction tools in modern work often challenges the human motor system, especially when these tools create awkward postures and discomfort (e.g., mouse arm syndrome). The question whether the trackball is a serious alternative to the mouse was evaluated in this experimental study in terms of motor performance, usability and comfort. In an applied pointing-selection task we varied gain and task difficulty. Results showed a considerably stronger impact of gain and task difficulty on the trackball than on the mouse, especially for the high gain trackball performance slowed down. Second, usability ratings were significantly better for the mouse than for the trackball (independent of the experimental condition). Finally, while the discomfort after mouse usage rose notably, trackball usage led to an even bigger increase in perceived discomfort.

Cognitive decline in Parkinson’s disease: the impact of the motor phenotype on cognition

Objectives Parkinson’s disease (PD) is the second most common neurodegenerative disorder and is further associated with progressive cognitive decline. In respect to motor phenotype, there is some evidence that akinetic-rigid PD is associated with a faster rate of cognitive decline in general and a greater risk of developing dementia. The objective of this study was to examine cognitive profiles among patients with PD by motor phenotypes and its relation to cognitive function. Methods Demographic, clinical and neuropsychological cross-sectional baseline data of the DEMPARK/LANDSCAPE study, a multicentre longitudinal cohort study of 538 patients with PD were analysed, stratified by motor phenotype and cognitive syndrome. Analyses were performed for all patients and for each diagnostic group separately, controlling for age, gender, education and disease duration. Results Compared with the tremor-dominant phenotype, akinetic-rigid patients performed worse in executive functions such as working memory (Wechsler Memory Scale-Revised backward; p=0.012), formal-lexical word fluency (p=0.043), card sorting (p=0.006), attention (Trail Making Test version A; p=0.024) and visuospatial abilities (Leistungsprüfungssystem test 9; p=0.006). Akinetic-rigid neuropsychological test scores for the executive and attentive domain correlated negatively with non-tremor motor scores. Covariate-adjusted binary logistic regression analyses showed significant odds for PD-mild cognitive impairment for not-determined as compared with tremor-dominant (OR=3.198) and akinetic-rigid PD (OR=2.059). The odds for PD-dementia were significant for akinetic-rigid as compared with tremor-dominant phenotype (OR=8.314). Conclusion The three motor phenotypes of PD differ in cognitive performance, showing that cognitive deficits seem to be less severe in tremor-dominant PD. While these data are cross-sectional, longitudinal data are needed to shed more light on these differential findings.