Mental object rotation in Parkinson's disease

Visual Dysfunction in Parkinson's Disease

Non-motor symptoms in Parkinson's disease (PD) include ocular, visuoperceptive, and visuospatial impairments, which can occur as a result of the underlying neurodegenerative process. Ocular impairments can affect various aspects of vision and eye movement. Thus, patients can show dry eyes, blepharospasm, reduced blink rate, saccadic eye movement abnormalities, smooth pursuit deficits, and impaired voluntary and reflexive eye movements. Furthermore, visuoperceptive impairments affect the ability to perceive and recognize visual stimuli accurately, including impaired contrast sensitivity and reduced visual acuity, color discrimination, and object recognition. Visuospatial impairments are also remarkable, including difficulties perceiving and interpreting spatial relationships between objects and difficulties judging distances or navigating through the environment. Moreover, PD patients can present visuospatial attention problems, with difficulties attending to visual stimuli in a spatially organized manner. Moreover, PD patients also show perceptual disturbances affecting their ability to interpret and determine meaning from visual stimuli. And, for instance, visual hallucinations are common in PD patients. Nevertheless, the neurobiological bases of visual-related disorders in PD are complex and not fully understood. This review intends to provide a comprehensive description of visual disturbances in PD, from sensory to perceptual alterations, addressing their neuroanatomical, functional, and neurochemical correlates. Structural changes, particularly in posterior cortical regions, are described, as well as functional alterations, both in cortical and subcortical regions, which are shown in relation to specific neuropsychological results. Similarly, although the involvement of different neurotransmitter systems is controversial, data about neurochemical alterations related to visual impairments are presented, especially dopaminergic, cholinergic, and serotoninergic systems.

Which Test Is the Best to Assess Visuo-Cognitive Impairment in Patients with Parkinson's Disease with Mild Cognitive Impairment and Dementia? A Systematic Review and Meta-Analysis

BACKGROUND

Visuo-cognitive impairment is common in patients with Parkinson's disease with mild cognitive impairment (PD-MCI) and constitutes a prognostic factor for the conversion to Parkinson's disease dementia (PDD). However, systematic analyses on which neuropsychological tests are most suitable to assess visuo-cognition in PD-MCI and PDD and to differentiate these cognitive stages are lacking.

OBJECTIVE

To review neuropsychological tests used to assess visuo-cognition including visuo-perceptual and visuo-spatial processing, visuo-constructive copying and drawing on command abilities; and to identify the visuo-cognitive subdomain as well as tests most suitable to discriminate between PD-MCI and PDD.

METHODS

MEDLINE, PsycINFO, Web of Science Core Collection, and CENTRAL were systematically searched for relevant studies assessing visuo-cognitive outcomes in patients with PD-MCI and PDD. Risk of bias was assessed using a customized form based on well-established tools. Random-effect meta-analyses were conducted.

RESULTS

33 studies were included in the systematic review. Data of 19 studies were entered in meta-analyses. Considerable heterogeneity regarding applied tests, test versions, and scoring systems exists. Data indicate that visuo-constructive command tasks are the subdomain best suited to discriminate between PD-MCI and PDD. Furthermore, they indicate that the Rey-Osterrieth-Complex-Figure Test (ROCF), Corsi Block-Tapping Test, Judgment of Line Orientation (JLO), and Clock Drawing Test (CDT) are tests able to differentiate between the two stages.

CONCLUSION

We provide suggestions for suitable visuo-cognitive tests (Corsi Block-Tapping Test, or JLO, ROCF, CDT) to improve diagnostic accuracy. Methodological challenges (e.g., heterogeneity of definitions, tests) are discussed and suggestions for future research are provided.

REGISTRATION

https://www.crd.york.ac.uk/prospero/, ID: CRD42018088244.

Dopamine does not appear to affect mental rotation in Parkinson's disease

Objective

Patients with Parkinson’s disease (PD) often have deficits with mental rotation (MR). The neuropathological factors underlying these deficits, however, remain to be elucidated. One hypothesis suggests that dopamine depletion in nigro-striatal systems adversely influences MR. Another hypothesis suggests that deterioration of cortical (fronto-temporo-parietal basal ganglia) networks that mediate this function are responsible for this deficit. The goal of this study was to test the dopamine hypothesis by determining if dopamine abstinence negatively influences MR performance.

Methods

Thirty three non-demented right-handed individuals with PD were assess for their ability to perform a pencil and paper MR test while “on” and “off” dopaminergic medications. Dopamine abstinence followed the typical overnight withdrawal procedures.

Results

No differences in mental rotation abilities were found between “on” and “off” dopaminergic medications.

Conclusions

These results suggest that other neuropathological factors, such as cortical-basal ganglia neurodegeneration, or dysfunction of other neurotransmitters systems, might account for these cognitive deficits and future research will have to test these alternative hypotheses.

Genetic impact on cognition and brain function in newly diagnosed Parkinson's disease: ICICLE-PD study

Parkinson's disease is associated with multiple cognitive impairments and increased risk of dementia, but the extent of these deficits varies widely among patients. The ICICLE-PD study was established to define the characteristics and prevalence of cognitive change soon after diagnosis, in a representative cohort of patients, using a multimodal approach. Specifically, we tested the 'Dual Syndrome' hypothesis for cognitive impairment in Parkinson's disease, which distinguishes an executive syndrome (affecting the frontostriatal regions due to dopaminergic deficits) from a posterior cortical syndrome (affecting visuospatial, mnemonic and semantic functions related to Lewy body pathology and secondary cholinergic loss). An incident Parkinson's disease cohort (n = 168, median 8 months from diagnosis to participation) and matched control group (n = 85) were recruited to a neuroimaging study at two sites in the UK. All participants underwent clinical, neuropsychological and functional magnetic resonance imaging assessments. The three neuroimaging tasks (Tower of London, Spatial Rotations and Memory Encoding Tasks) were designed to probe executive, visuospatial and memory encoding domains, respectively. Patients were also genotyped for three polymorphisms associated with cognitive change in Parkinson's disease and related disorders: (i) rs4680 for COMT Val158Met polymorphism; (ii) rs9468 for MAPT H1 versus H2 haplotype; and (iii) rs429358 for APOE-ε2, 3, 4. We identified performance deficits in all three cognitive domains, which were associated with regionally specific changes in cortical activation. Task-specific regional activations in Parkinson's disease were linked with genetic variation: the rs4680 polymorphism modulated the effect of levodopa therapy on planning-related activations in the frontoparietal network; the MAPT haplotype modulated parietal activations associated with spatial rotations; and APOE allelic variation influenced the magnitude of activation associated with memory encoding. This study demonstrates that neurocognitive deficits are common even in recently diagnosed patients with Parkinson's disease, and that the associated regional brain activations are influenced by genotype. These data further support the dual syndrome hypothesis of cognitive change in Parkinson's disease. Longitudinal data will confirm the extent to which these early neurocognitive changes, and their genetic factors, influence the long-term risk of dementia in Parkinson's disease. The combination of genetics and functional neuroimaging provides a potentially useful method for stratification and identification of candidate markers, in future clinical trials against cognitive decline in Parkinson's disease.

Abnormalities of mental rotation of hands associated with speed of information processing and executive function in chronic schizophrenic patients

AIM

Deficits in mental imagery ability have been reported in patients with schizophrenia. However, there is scarce evidence about the correlation between impairment in mental rotation and other cognitive deficits in the patients. The aim of this study was to assess mental rotation ability, along with other measures of cognitive function in patients with schizophrenia.

METHODS

The performance of 29 patients with schizophrenia was compared with 29 healthy controls. Mental rotation was measured with the Hand Rotation Task, and cognitive functions were measured with the Brief Assessment of Cognition in Schizophrenia (BACS).

RESULTS

On Hand Rotation Task, the patients were significantly slower and less accurate compared to controls. Moreover, mental rotation accuracy was significantly correlated with all the BACS domains except verbal memory. In multiple regression analysis, the two BACS subscales, Tower of London and Symbol Coding tasks, were significant predictors and accounted for 41% of the variance in accuracy in the patients.

CONCLUSION

These results support previous findings showing dysfunction of the posterior parietal cortex in schizophrenia, which is involved in general mental rotation, as well as other cognitive processes.

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.

Explorations of object and location memory using fMRI

Content-specific sub-systems of visual working memory (VWM) have been explored in many neuroimaging studies with inconsistent findings and procedures across experiments. The present study employed functional magnetic resonance imaging (fMRI) and a change detection task using a high number of trials and matched stimulus displays across object and location change (what vs. where) conditions. Furthermore, individual task periods were studied independently across conditions to identify differences corresponding to each task period. Importantly, this combination of task controls has not previously been described in the fMRI literature. Composite results revealed differential frontoparietal activation during each task period. A separation of object and location conditions yielded a distributed system of dorsal and ventral streams during the encoding of information corresponding to bilateral inferior parietal lobule (IPL) and lingual gyrus activation, respectively. Differential activity was also shown during the maintenance of information in middle frontal structures bilaterally for objects and the right IPL and left insula for locations. Together, these results reflect a domain-specific dissociation spanning several cortices and task periods. Furthermore, differential activations suggest a general caudal-rostral separation corresponding to object and location memory, respectively.

Predictors of HVOT performance in Parkinson's disease

Evidence suggests that the Hooper Visual Organization Test (HVOT) has naming and executive components that vary in size depending on neurological diagnosis. The current study used a sample of individuals with Parkinson's disease (PD) to demonstrate for the first time that an executive measure can be the best predictor of HVOT performance. Forty-eight nondemented and nondepressed individuals with idiopathic PD completed the HVOT and other measures of visuoperception, executive function, and visual confrontation naming. Despite average performance on all neuropsychological measures, an executive measure, time to complete Trail-Making Test Part B minus time to complete Part A, was clearly the best predictor of HVOT performance in a standard regression. The pattern of neurocognitive predictors is unlike that reported in healthy individuals and other patient samples. This finding suggests that the presence of a neuropathological process can alter neurocognitive correlates even when performance is intact, and supports the contention that executive function is paramount in the cognitive profile associated with PD.

WITHDRAWN: fMRI correlates of visual working memory: What vs. where

This article has been withdrawn at the request of the authors. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy. This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Functional Neuroanatomy of Mental Rotation

Brain regions involved in mental rotation were determined by assessing increases in fMRI activation associated with increases in stimulus rotation during a mirror-normal parity-judgment task with letters and digits. A letter–digit category judgment task was used as a control for orientation-dependent neural processing unrelated to mental rotation per se. Compared to the category judgments, the parity judgments elicited increases in activation in both the dorsal and the ventral visual streams, as well as higher-order premotor areas, inferior frontal gyrus, and anterior insula. Only a subset of these areas, namely, the posterior part of the dorsal intraparietal sulcus, higher-order premotor regions, and the anterior insula showed increased activation as a function of stimulus orientation. Parity judgments elicited greater activation in the right than in the left ventral intraparietal sulcus, but there were no hemispheric differences in orientation-dependent activation, suggesting that neither hemisphere is dominant for mental rotation per se. Hemispheric asymmetries associated with parity-judgment tasks may reflect visuospatial processing other than mental rotation itself, which is subserved by a bilateral fronto-parietal network, rather than regions restricted to the posterior parietal.

Conceptual hypometria? An evaluation of conceptual mapping of space in Parkinson's disease

When interacting with objects in their environment, patients with Parkinson's disease (PD) often make hypometric movements (e.g., micrographia). The purpose of this study was to learn if patients with PD, in the absence of overt actions or environmental stimuli, have egocentric (body-centered) conceptual (representational) hypometria. Actions can take place in either proximal or distal peri-personal space. Normally, the right hemisphere has a distal and the right a proximal attentional bias. We also want to learn if a patient with onset of disease in the right hemisphere would have a greater conceptual action hypometria than individuals with left hemispheric onset. Seventeen subjects with PD and 15 age-matched controls were given a questionnaire evaluating subjective perception of personal action space. The questionnaire asked individuals to rate, using a 0-5 scale, the distances between their body and hand when performing the various actions that take place in peri-personal space. When compared to control participants, participants with PD, and especially those with predominant left sided symptoms (right greater than left hemispheric dysfunction) had hypometric mental perceptions for actions that normally occur in far peri-personal space. Individuals with PD appear to demonstrate a conceptual hypometria, suggesting that there is a perturbation of their interactive representational maps and these maps appear to be more disordered by right than left hemisphere dysfunction. However, it is also possible that when making action distance computations, participants used covert actions and it was the hypometric covert actions that induced the computational hypometria.

Learning and retention of movement sequences in Parkinson's disease

The purpose of this study was to examine motor learning and retention given extensive practice in two fundamentally different movement sequences. One sequence was a memory-driven task (performing a series of whole body positions from memory) and the other a context-driven task (buttoning). Practice took place over 3 weeks, with performance measured weekly; retention was measured weekly for 3 weeks after practice. There were 7 people with Parkinson's disease (PD) and 7 age-matched neurologically healthy people who participated in this study. Both groups improved performance on both tasks with practice, with the majority of the change for the PD group occurring between 1 and 2 weeks of practice. Although those with PD did not necessarily perform as well as age-matched controls, they learned both sequences in a manner similar to age-matched controls, and exhibited retention across the 3-week retention interval. If people with PD are given sufficient practice they can learn and retain both memory-based and context-driven movement sequences as well as age-matched controls. The results provide support for maintaining physical activity and for intervention through movement therapy.

Assessment of visual-spatial deficits in patients with Parkinson's disease and closed head injuries using virtual environments

Cognitive spatial deficits have been reliably reported in patients with Closed Head Injury (CHI), though in patients with Parkinson's disease (PD) the phenomenon is disputed. CHI and non-demented PD patients were tested using a Judgement of Line Orientation Test, and two spatial tests using virtual environments (VEs). Performance on the Line Orientation and one VE test was worse in the CHI group than controls, but PD patients showed no apparent spatial deficits. However, performance on the second VE test (virtual tray of objects task) did reveal a deficit, both CHI and PD groups being significantly impaired. The data illustrate that particular spatial deficits can be differentiated using appropriate VE-based tasks, and that non-demented PD patients show a paradigm-specific visual-spatial impairment.

Dementia in Parkinson's disease: cause and treatment

PURPOSE OF REVIEW

Dementia in Parkinson's disease is increasingly being recognized. A number of studies have recently appeared on the epidemiology, clinical features, pathological correlations and treatment of dementia in Parkinson's disease. The purpose of this article is to provide an overview of recent findings on dementia associated with Parkinson's disease, from February 2003 to the present.

RECENT FINDINGS

The cumulative prevalence of dementia in Parkinson's disease can be as high as 78%; dementia is especially prevalent in older patients. The profile of dementia seems to be different from that of Alzheimer's disease and similar to that of dementia with Lewy bodies. Clinicopathological correlation studies have suggested that dementia correlates best with Lewy bodies in certain limbic and cortical areas, but not all patients with sufficient Lewy bodies for a pathological diagnosis of dementia with Lewy bodies are demented. Cholinergic deficits in the cerebral cortex can be shown with in-vivo imaging studies, and seem to be more severe than in Alzheimer's disease. Several small studies with three different cholinesterase inhibitors suggest that these drugs can be effective in the treatment of PD dementia.

SUMMARY

Dementia is highly prevalent in Parkinson's disease. The prototype of dementia in Parkinson's disease is a dysexecutive syndrome with impaired attention, executive functions and secondarily impaired memory. Neurochemically the most significant deficit seems to be cholinergic; dementia seems to correlate best with cortical and limbic Lewy bodies. Preliminary evidence suggests that cholinesterase inhibitors may be effective in Parkinson's disease dementia, and the results of large-scale, randomized and controlled studies are awaited to confirm these findings.