Visuoperceptual Impairments Research Articles

Relationship between somatosensory and visuo-perceptual impairments and motor functions in adults with hemiparetic cerebral palsy.

Children with cerebral palsy (CP) exhibit a variety of sensory impairments that can interfere with motor performance, but how these impairments persist into adulthood needs further investigation. The objective of this study was to describe the sensory impairments in adults having CP and how they relate to motor impairments. Nineteen adults having CP performed a set of robotic and clinical assessments. These assessments were targeting different sensory functions and motor functions (bilateral and unilateral tasks). Frequency of each type of impairments was determined by comparing individual results to normative data. Association between the sensory and motor impairments was assessed with Spearman correlation coefficient. Impairment in stereognosis was the most frequent, affecting 57.9% of participants. Although less frequently impaired (26.3%), tactile discrimination was associated with all the motor tasks (unilateral and bilateral, either robotic or clinical). Performance in robotic motor assessments was more frequently associated with sensory impairments than with clinical assessments. Finally, sensory impairments were not more closely associated with bilateral tasks than with unilateral tasks. Somatosensory and visuo-perceptual impairments are frequent among adults with CP, with 84.2% showing impairments in at least one sensory function. These sensory impairments show a moderate association with motor impairments.

Ocular disorders in Parkinson’s disease: A review

Parkinson’s disease (PD) is a common degenerative disorder characterized by decreased dopamine levels from damage to the substantia nigra causing classic motor deficits. Several ocular deficits have been recognized in association with PD such as oculomotor disturbances and diplopia, glaucoma and visual field loss, dry eye disease, color and contrast impairment, visual hallucinations, and visuospatial and visuoperceptual impairments. These disorders remain underreported, underrecognized, and poorly understood. Patients with PD are largely dependent on visual cues for compensating the motor deficits. Hence, early recognition and timely management of the above ocular disorders can lead to greater patient safety, independence, and a better quality of life.

Using illusions to understand hallucinations: differences in perceptual performances on illusory figures may underscore specific visuoperceptual impairments in Parkinson's disease.

Visual hallucinations are prevalent, potentially disabling symptoms of Parkinson's Disease. Multiple impairments in bottom-up sensory processing and top-down perceptual modulation are implicated in the pathophysiology of these phenomena. In healthy individuals, visual illusions are elicited by illusory figures through parametric manipulations of geometrical configurations, contrast, color, or spatial relationships between stimuli. These illusory percepts provide insight on the physiologic processes subserving conscious and unconscious perception. In this exploratory, cross-sectional, controlled study, perceptual performance on illusory figures was assessed on 11 PD patients with hallucinations, 10 non-hallucinating PD patients, and 10 age-matched healthy individuals. In order to characterize potential neural substrates of perceptual performances, patients' brain metabolic patterns on FDG PET were also analyzed. Illusions relying on attentional modulation and global perception were attenuated in PD patients without hallucinations. This pattern was no longer recognizable in hallucinating patients. Conversely, illusory effects normally counteracted by figure to background segregation and overlapping figures recognition were enhanced in PD patients with hallucinations. FDG PET findings further suggest that perceptual differences between PD patients might be linked to abnormal top-down perceptual modulation.

Cognitive assessment and rehabilitation tools for stroke and dementia: An online survey of Russian speaking clinicians

Our objective was to survey opinions on cognitive assessment and rehabilitation of Russian-speaking clinicians working with stroke and dementia patients. An online survey was circulated to professional communities soliciting feedback from clinicians about methods used for cognitive assessment and rehabilitation; expected cognitive impairments in dementia and stroke; variables affecting the cognitive abilities of patients; and topics presented during psycho-educational initiatives. Forty-eight physicians, 50 psychologists, and 12 speech-language pathologists completed the survey. 96% of participants reported estimating the cognitive abilities of patients while performing diagnostics and treatment in clinical settings. The most popular tools for cognitive assessment were Russian versions of the MoCA, MMSE, Luria Neuropsychological Battery, and Frontal Assessment Battery (FAB). 60% of participants reported the provision of cognitive rehabilitation, and 61% provided psychoeducation. All groups reported that the cognitive reserve and the idiopathic features of a brain lesion were the main factors influencing patients’ cognitive profile. In the case of stroke patients, clinicians observed aphasia, as well as impairments in attention, memory, and reasoning. For patients with dementia, memory deficits were coincident with executive/frontal, praxis, and visuo-perceptual impairments. Psychotherapy-related psychoeducation was delivered by most of the clinicians. The captured patterns of clinical practice followed, in part, Russian national guidelines for cognitive rehabilitation and, in part, international protocols, wherein we found some professional group differences in implementation of practice. The profile in approaches to stroke and dementia assessment and rehabilitation reveal a new benchmark for future studies and for the development of policies for neuropsychological assessment and treatment in Russian language.

Trajectories of memory, language, and visuoperceptual problems in people with stroke during the first year and controls in Colombia

Aim Neuropsychological normative data for Latin America have been recently published, and for Colombia, in particular, but longitudinal neuropsychological outcomes after stroke have not yet been examined in this global region. The purpose of the current study was to compare functioning of individuals with stroke in Colombia, South America during the first year post-stroke to healthy controls across neuropsychological assessments of memory, language, and visuoperceptual impairments. Method A sample of 50 individuals with stroke (mean age = 51.58) and 50 matched healthy controls (mean age = 51.54) from Colombia were included in this study. Because of a lack of access to health services, individuals with stroke did not receive any inpatient or outpatient cognitive or behavioral rehabilitation. Participants were assessed on 10 visuoperceptual, language, and memory tasks at 3, 6, and 12 months. Results Trajectories of neuropsychological performance were significantly worse among individuals with stroke than healthy controls across every index. Further, hierarchical linear models suggested that although both individuals with stroke and controls generally improved over time on these assessments, the improvements among individuals with stroke were often of no greater magnitude than the improvements seen in controls, suggesting extremely low levels of rehabilitation gains in Colombia. Only three of the 10 neuropsychological assessments did a significant time*group interaction occur, suggesting greater gains for the stroke group than controls. Conclusion These findings suggest profound disparities in post-stroke cognitive functioning in Colombia compared to other more developed global region and underscore the importance of comprehensive cognitive rehabilitation services for individuals with stroke in Colombia and other similar global regions. Implications for rehabilitation Because this study found only negligible cognitive improvements beyond practice effects over the first year after stroke in Colombia among individuals without access to acute rehabilitation, it is imperative that comprehensive cognitive rehabilitation services be implemented immediately during the acute rehabilitation period. Memory, language, and visuoperceptual training strategies can be implemented for people with stroke in underserved global regions as part of the standard of care for stroke rehabilitation. Cognitive rehabilitation strategies should be adapted into Spanish and pilot tested in Latin America to ensure cultural equivalence. Culturally competent cognitive rehabilitation strategies should be tailored based on varied educational and literacy levels.

Exploring the contribution of visual imagery to scene construction – Evidence from Posterior Cortical Atrophy

Posterior Cortical Atrophy (PCA) is a rare neurodegenerative syndrome characterised by profound visuoperceptual processing disturbances, attributable to focal parieto-occipital cortical atrophy. Despite relative sparing of the medial temporal lobes, converging evidence reveals significant autobiographical memory impairments in this syndrome, underscoring the crucial role of visual imagery for episodic memory processes. The contribution of visual imagery to complex constructive endeavours, however, remains unclear. Here, we investigated the capacity for atemporal scene construction in 5 well-characterised cases of PCA and contrasted their performance with 10 typical amnestic Alzheimer's Disease (AD) and 10 healthy older Control participants. Behavioural data were analysed using case-Control statistics comparing each PCA patient's scene construction scores to the mean scores of AD and Control groups. In keeping with their clinical phenotype, PCA patients demonstrated significant visuoperceptual and episodic memory impairments on standard neuropsychological tasks. Scene construction performance was grossly impaired in PCA, at a level comparable to that observed in the AD group, manifesting in impoverished and spatially fragmented scenes. Structural neuroimaging confirmed prominent grey matter intensity decrease predominantly in posterior cortical regions in PCA, in the absence of frank hippocampal atrophy. Using an a priori motivated region-of-interest approach across all participants, scene construction performance was found to correlate with grey matter intensity in the left angular gyrus, right precuneus, and right hippocampus. This study is the first to reveal compromised scene construction capacity in PCA, extending our understanding of the cognitive profile of this rare syndrome and pointing towards the fundamental contribution of visual imagery to atemporal forms of imagination.

Perceptuo-motor planning during functional reaching after stroke

In healthy young adults, reaching movements are planned such that the initial grasp position on the object is modulated based on the final task goal. This perceptuo-motor coupling has been described as the end-state comfort effect. This study aimed to determine the extent to which visuo-perceptual and motor deficits, but not neglect, due to stroke impact end-state comfort measured as the grasp-height effect. Thirty-four older adults (17 controls, 17 chronic stroke) performed a functional goal-directed two-sequence task with each arm, consisting of reaching and moving a cylindrical object (drain plunger) from an initial to four target platform heights, standardized to body height, in a block randomized sequence. Arm motor impairment (Fugl-Meyer Assessment) and visual–perceptual deficits (Motor-Free Visual Perception Test) were assessed in stroke subjects, and arm and trunk kinematics were assessed in all subjects. The primary outcome measure of the grasp-height effect was the relationship between the grasp heights used at the home position and the final target platform heights. Mixed model analysis was used for data analysis. The grasp-height effect was present in all participants, but decreased in stroke subjects with visuo-perceptual impairments compared to controls. In stroke subjects with sensorimotor impairments alone, indicated by altered kinematics, the grasp-height effect was comparable to controls. This first study examining the grasp-height effect in individuals with stroke provides new knowledge of the impact of visuo-perceptual deficits on movement planning and execution, which may assist clinicians in selecting more effective treatment strategies to improve perceptuo-motor skills and enhance motor recovery.

Eyetracking Metrics in Young Onset Alzheimer's Disease: A Window into Cognitive Visual Functions.

Young onset Alzheimer’s disease (YOAD) is defined as symptom onset before the age of 65 years and is particularly associated with phenotypic heterogeneity. Atypical presentations, such as the clinic-radiological visual syndrome posterior cortical atrophy (PCA), often lead to delays in accurate diagnosis. Eyetracking has been used to demonstrate basic oculomotor impairments in individuals with dementia. In the present study, we aim to explore the relationship between eyetracking metrics and standard tests of visual cognition in individuals with YOAD. Fifty-seven participants were included: 36 individuals with YOAD (n = 26 typical AD; n = 10 PCA) and 21 age-matched healthy controls. Participants completed three eyetracking experiments: fixation, pro-saccade, and smooth pursuit tasks. Summary metrics were used as outcome measures and their predictive value explored looking at correlations with visuoperceptual and visuospatial metrics. Significant correlations between eyetracking metrics and standard visual cognitive estimates are reported. A machine-learning approach using a classification method based on the smooth pursuit raw eyetracking data discriminates with approximately 95% accuracy patients and controls in cross-validation tests. Results suggest that the eyetracking paradigms of a relatively simple and specific nature provide measures not only reflecting basic oculomotor characteristics but also predicting higher order visuospatial and visuoperceptual impairments. Eyetracking measures can represent extremely useful markers during the diagnostic phase and may be exploited as potential outcome measures for clinical trials.

Visuoperceptual processing in children with neurofibromatosis type 1: True deficit or artefact?

Impairments in visuoperceptual processing have long been considered a hallmark deficit of individuals with Neurofibromatosis type 1 (NF1). However, it is unclear which specific visuoperceptual subprocesses are impaired and whether impairments on these tasks really result from visuoperceptual impairments or rather from confounding factors like Executive Functioning (EF) impairments, lower intelligence (IQ) and/or co-occurring symptoms of Autism Spectrum Disorder (ASD). To answer these questions, we administered four visuoperceptual tasks and two control tasks in 39 children with NF1, 52 typically developing children and 52 children with ASD (8-18 years), all matched for age and gender. Furthermore, EF, IQ, and symptoms of ASD were assessed. Children with NF1 displayed intact visual form discrimination and intact information integration along the dorsal visual pathway. Moreover, their reduced performance on a task requiring integration of information along the ventral visual stream and their more detail-oriented processing style appeared to result from confounding EF impairments and not from visuoperceptual impairments per se. The co-occurring ASD symptoms and lower IQ of the children with NF1 did not impact substantially upon their visuoperceptual performance. These findings point to the large impact of EF impairments on the performance of visuoperceptual task and suggest that individuals with NF1 show intact visual form discrimination, intact visual integration, and typical visual processing style when potential confounding factors are controlled for. This may have large repercussions for the interpretation of other findings on visuoperceptual processing in individuals with NF1. © 2017 Wiley Periodicals, Inc.

Oculomotor abnormalities in posterior cortical atrophy: are they different from those in Alzheimer's disease after all?

This scientific commentary refers to ‘Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy’, by Shakespeare et al. (doi:10.1093/brain/awv103). Posterior cortical atrophy (PCA) is a progressive degenerative condition characterized by a gradual loss of visual skills and other posterior cortical functions due to atrophy of parietal, occipital and occipito-temporal brain regions (Lehmann et al. , 2011). It is associated with a relative preservation of memory, language skills and judgement until late in the clinical course. Core features of PCA include partial or complete Balint’s syndrome (simultanagnosia, optic ataxia and ocular apraxia) and Gerstmann’s syndrome (acalculia, agraphia, finger agnosia), along with various combinations of visuo-spatial and visuo-perceptual impairments (Crutch et al. , 2012), apparent despite an otherwise normal ophthalmological examination. In this issue of Brain , Shakespeare et al. (2015) compare and contrast eye movement abnormalities revealed by basic oculomotor tests in patients with PCA, typical Alzheimer’s disease and healthy controls, in order to determine the extent to which abnormalities in basic (lower-order) oculomotor function contribute to visuo-perceptual disturbances in PCA (Shakespeare et al. , 2015). Patients with PCA typically present when they are between 50 and 65 years of age (Crutch et al. , 2012). One of the most important manifestations of PCA is simultanagnosia, an inability to synthesize the overall meaning of a visual scene despite being able to identify its individual elements; this should be suspected when a patient presents with an inability to read pseudo-isochromatic plates, despite intact colour vision (Beh et al. , 2015). The relative rarity of PCA makes it difficult to recruit large cohorts, but recently the number of studies of this disorder, often referred to as the cardinal visual dementia and the most common atypical Alzheimer’s disease phenotype, has been increasing. The study of …

Lewy Body Dementia as an Underlying Etiology for Posterior Cortical Atrophy Initially Presented with Visual Agnosia and Alexia: A Case Report

Posterior cortical atrophy (PCA) is a neurodegenerative disorder with cerebral atrophy in the parietal, occipital, or occipitotemporal cortices, and is characterized by visuospatial and visuoperceptual impairments. The majority of the disorder is compatible pathologically with Alzheimer’s disease (AD). However, many patients show no memory loss until late stages of the disease. We encountered a case where a combination of several imaging modalities, in conjunction with symptoms and neuropsychological exams, led not only to a diagnosis of PCA but also identified its underlying etiology. A 62-year-old Japanese man presented to ophthalmology with visual impairment and without abnormalities in his visual acuity or visual fields. Alexia was identified, particularly pertinent to reading Kanji, at the neurology clinic. His initial Mini-Mental State Examination (MMSE) revealed a score of 27/30 points with delayed recall (-2) and constructional apraxia (-1). The score dropped to 25 points six months later. Brain MRI demonstrated occipital atrophy. Brain single photon emission computed tomography (SPECT) showed hypoperfusion in the medial and lateral occipital lobes. The myocardial meta-iodobenzylguanidine (MIBG) scintigraphy showed no evidence of myocardial postganglionic sympathetic dysfunction. Posterior cortical atrophy (PCA) was diagnosed in conjunction with the symptoms, including alexia and visual impairment. He developed symmetric parkinsonism one year later. Lewy body dementia (DLB) was thus considered as the underlying etiology for the PCA. Additionally, alexia pertinent to reading Kanji has not been reported before. We herein report this rare case.

Facial emotion recognition in paranoid schizophrenia and autism spectrum disorder

Schizophrenia (SZ) and autism spectrum disorder (ASD) share deficits in emotion processing. In order to identify convergent and divergent mechanisms, we investigated facial emotion recognition in SZ, high-functioning ASD (HFASD), and typically developed controls (TD). Different degrees of task difficulty and emotion complexity (face, eyes; basic emotions, complex emotions) were used. Two Benton tests were implemented in order to elicit potentially confounding visuo-perceptual functioning and facial processing. Nineteen participants with paranoid SZ, 22 with HFASD and 20 TD were included, aged between 14 and 33years. Individuals with SZ were comparable to TD in all obtained emotion recognition measures, but showed reduced basic visuo-perceptual abilities. The HFASD group was impaired in the recognition of basic and complex emotions compared to both, SZ and TD. When facial identity recognition was adjusted for, group differences remained for the recognition of complex emotions only. Our results suggest that there is a SZ subgroup with predominantly paranoid symptoms that does not show problems in face processing and emotion recognition, but visuo-perceptual impairments. They also confirm the notion of a general facial and emotion recognition deficit in HFASD. No shared emotion recognition deficit was found for paranoid SZ and HFASD, emphasizing the differential cognitive underpinnings of both disorders.

Inconsistent emotion recognition deficits across stimulus modalities in Huntington׳s disease

BackgroundRecognition of negative emotions is impaired in Huntington׳s Disease (HD). It is unclear whether these emotion-specific problems are driven by dissociable cognitive deficits, emotion complexity, test cue difficulty, or visuoperceptual impairments. This study set out to further characterise emotion recognition in HD by comparing patterns of deficits across stimulus modalities; notably including for the first time in HD, the more ecologically and clinically relevant modality of film clips portraying dynamic facial expressions. MethodsFifteen early HD and 17 control participants were tested on emotion recognition from static facial photographs, non-verbal vocal expressions and one second dynamic film clips, all depicting different emotions. ResultsStatistically significant evidence of impairment of anger, disgust and fear recognition was seen in HD participants compared with healthy controls across multiple stimulus modalities. The extent of the impairment, as measured by the difference in the number of errors made between HD participants and controls, differed according to the combination of emotion and modality (p=0.013, interaction test). The largest between-group difference was seen in the recognition of anger from film clips. ConclusionsConsistent with previous reports, anger, disgust and fear were the most poorly recognised emotions by the HD group. This impairment did not appear to be due to task demands or expression complexity as the pattern of between-group differences did not correspond to the pattern of errors made by either group; implicating emotion-specific cognitive processing pathology. There was however evidence that the extent of emotion recognition deficits significantly differed between stimulus modalities. The implications in terms of designing future tests of emotion recognition and care giving are discussed.

Fear recognition impairment in early-stage Alzheimer’s disease: When focusing on the eyes region improves performance

A decline in the ability to identify fearful expression has been frequently reported in patients with Alzheimer’s disease (AD). In patients with severe destruction of the bilateral amygdala, similar difficulties have been reduced by using an explicit visual exploration strategy focusing on gaze. The current study assessed the possibility of applying a similar strategy in AD patients to improve fear recognition. It also assessed the possibility of improving fear recognition when a visual exploration strategy induced AD patients to process the eyes region. Seventeen patients with mild AD and 34 healthy subjects (17 young adults and 17 older adults) performed a classical task of emotional identification of faces expressing happiness, anger, and fear in two conditions: The face appeared progressively from the eyes region to the periphery (eyes region condition) or it appeared as a whole (global condition). Specific impairment in identifying a fearful expression was shown in AD patients compared with older adult controls during the global condition. Fear expression recognition was significantly improved in AD patients during the eyes region condition, in which they performed similarly to older adult controls. Our results suggest that using a different strategy of face exploration, starting first with processing of the eyes region, may compensate for a fear recognition deficit in AD patients. Findings suggest that a part of this deficit could be related to visuo-perceptual impairments. Additionally, these findings suggest that the decline of fearful face recognition reported in both normal aging and in AD may result from impairment of non-amygdalar processing in both groups and impairment of amygdalar-dependent processing in AD.

A case of dressing apraxia? A case study

Dressing apraxia is defined as the condition in which automatic, spontaneous capacity for dressing is lost ( Brain, 1941 ). This case report details the rehabilitation of a 58-year-old man who required protracted ITU care for endocarditis complicated by bilateral hemispheric embolic infarcts. At presentation to the rehabilitation unit he exhibited significant visuo-perceptual changes and difficulties with dressing, domestic and community-based tasks. He developed insight into his spatial impairments and, following a period of intervention, compensated for these difficulties. However the dressing difficulties remained despite intervention. This is an unusual presentation and one that might typically be considered dressing apraxia. This case report aims to highlight the importance of considering apraxia related to dressing within a differential diagnosis of visuo-perceptual impairments. Our report suggests that there may be justification in the classification of dressing apraxia as an impairment outside the broader terms of ideomotor and ideational apraxia. It also highlights the difficulty in treating apraxia related to dressing particularly when the affected person has minimal insight into their difficulties.

Visualizing the emergence of posterior cortical atrophy

Posterior cortical atrophy (PCA) is a neurodegenerative condition characterized by a progressive loss of visual processing skills and other posterior functions. Diagnosis is often delayed in PCA as symptoms can be difficult for the patient to articulate and for the clinician to detect. Diagnosis is particularly challenging in the earliest stages of the disease since visual symptoms are often mistaken as being related to ocular rather than cortical dysfunction. This report describes a 61-year-old man who volunteered as a healthy control participant in a longitudinal research study and was followed up for 5 years. During that time he showed a gradual decline in posterior cortical functions including visuoperceptual, visuospatial, and literacy impairments in the context of intact verbal episodic memory. Structural image analysis revealed atrophy which was initially most marked in inferior temporal and posterior parietal cortices before spreading to occipital cortices and subsequently to more anterior regions. Based on the clinical, neuropsychological and neuroimaging features, a diagnosis of PCA was made. The present case represents a unique opportunity to study and visualize the evolution of PCA from the very earliest symptomatic stages.

Closing-in without severe drawing disorders: The “fatal” consequences of pathological attraction

The closing-in phenomenon (CIP) is often observed in patients with severe drawing disorders, but its cognitive bases are not well understood. We describe an experimental investigation aimed to clarify the nature of closing-in and its relationships with drawing disorders in a patient with corticobasal degeneration. In copying simple or complex stimuli (Experiment 1), the patient showed adherent and near types of closing-in, not affected by stimulus complexity, and produced distorted and often unrecognisable drawings. On the contrary, in drawing to dictation (without any available model), patients' performances significantly improved with respect to copying (Experiment 2). These data were consistent with the hypothesis that in some patients closing-in may develop from frontal-related release of approach behaviour even in the absence of relevant visuoperceptual impairments. By asking the patient to reproduce given spatial locations within circular frames (Experiment 3), we could further demonstrate the sparing of visuospatial processing and the frontal genesis of closing-in. These findings allowed us to speculate on the heterogeneous nature of closing-in.

Visual perception in Parkinson disease dementia and dementia with Lewy bodies

To quantify visual discrimination, space-motion, and object-form perception in patients with Parkinson disease dementia (PDD), dementia with Lewy bodies (DLB), and Alzheimer disease (AD). The authors used a cross-sectional study to compare three demented groups matched for overall dementia severity (PDD: n = 24; DLB: n = 20; AD: n = 23) and two age-, sex-, and education-matched control groups (PD: n = 24, normal controls [NC]: n = 25). Visual perception was globally more impaired in PDD than in nondemented controls (NC, PD), but was not different from DLB. Compared to AD, PDD patients tended to perform worse in all perceptual scores. Visual perception of patients with PDD/DLB and visual hallucinations was significantly worse than in patients without hallucinations. Parkinson disease dementia (PDD) is associated with profound visuoperceptual impairments similar to dementia with Lewy bodies (DLB) but different from Alzheimer disease. These findings are consistent with previous neuroimaging studies reporting hypoactivity in cortical areas involved in visual processing in PDD and DLB.

Neuropsychological Interventions: Clinical Research and Practice

Neuropsychological Interventions: Clinical Research and Practice

Reliability and Normative Data for the Benton Visual Form Discrimination Test

Visuoperceptual disorders are a common consequence of brain disease. The Visual Form Discrimination Test is a task designed to assess the ability to make fine visual discriminations. Although its validity to assess the visuoperceptual impairments in patients with different neurological conditions has been well established, the normative data base for the test has remained small. The clinical use of the test has been limited by the scanty normative data available. Thus, with the aim of assisting the clinicians in interpreting more accurately the performances of their patients we investigated the test-retest reliability of the Benton’s VFDT and also provide normative data obtained on a sample of 397 healthy individuals.