Visuospatial Disorders Research Articles

DIFICULTADES DE APRENDIZAJE DEL CÁLCULO: CONTRIBUCIONES AL DIAGNÓSTICO PSICOPEDAGÓGICO

Existe suficiente evidencia científica sobre la Discalculia del Desarrollo (DD) que describe los procesos cognitivos específicos del cálculo y procesos neuropsicológicos relacionados como la memoria de trabajo y percepción visoespacial. Sin embargo es llamativa su baja identificación diagnóstica en la infancia. Este estudio tiene el objetivo de proporcionar evidencia clínica que contribuya a un diagnóstico riguroso. Se presentarán dos estudios de caso (7 y 8 años) que demuestran a través de pruebas normalizadas y de administración individual, déficits en la comprensión del número y la realización de cálculos elementales, en la percepción visoespacial, atención y memoria de trabajo. Se mostrarán los principales signos que permiten identificar el problema al inicio de la escolarización a efectos de realizar precozmente las orientaciones psicopedagógicas necesarias. La inteligencia es normal de acuerdo a pruebas estándar, la instrucción educativa es adecuada, y se descartan alteraciones sensoriales y emocionales. Estos hallazgos contribuyen en la descripción adecuada de la semiología esperada ante una DD para un adecuado diagnóstico. En los casos descritos, se encuentran perturbaciones visuoespaciales posiblemente relacionadas.

Lack of awareness for spatial and verbal constructive apraxia

It is still a matter of debate whether constructive apraxia (CA) should be considered a form of apraxia or, rather, the motor expression of a more pervasive impairment in visuo-spatial processing. Constructive disorders were linked to visuo-spatial disorders and to deficits in appreciating spatial relations among component sub-parts or problems in reproducing three-dimensionality. We screened a large population of brain-damaged patients for CA. Only patients with constructive disorders and no signs of neglect and/or aphasia were selected. Five apractic subjects were tested with both visuo-spatial and verbal tasks requiring constructive abilities. The former ones were tests such as design copying, while the latter were experimental tasks built to transpose into the linguistic domain the constructive process as phrasing by arranging paper scraps into a sentence. A first result showed a constructive impairment in both the visuo-spatial and the linguistic domain; this finding challenges the idea that CA is confined to the visuo-spatial domain. A second result showed a systematic association between CA and unawareness for constructive disorders. Third, lack of awareness was always associated with a lesion in the right dorsolateral prefrontal cortex, a region deemed as involved in managing a conflict between intentions and sensory feed-back. Anosognosia for constructive disorders and the potential role of the right prefrontal cortex in generating the impairment, are discussed in the light of current models of action control.The core of CA could be the inability to detect any inconsistency between intended and executed action rather than a deficit in reproducing spatial relationship.

Long-term cognitive deficits following posterior fossa tumor resection: A neuropsychological and functional neuroimaging follow-up study.

The posterior fossa syndrome (PFS) consists of transient cerebellar mutism, cognitive symptoms, and neurobehavioral abnormalities that typically develop in children following posterior fossa (PF) tumor resection. The pathophysiological substrate of the syndrome remains unclear. We investigated eight children of whom five presented with a variety of clinically relevant non-motor language symptoms associated with cognitive and behavioral disturbances after PF tumor resection. Four children developed transient cerebellar mutism followed by dysarthric speech. Non-motor language symptoms consisted of agrammatism, anomia, impaired verbal fluency, comprehension deficits, and a spontaneous speech. Neurocognitive deficits included executive dysfunctions, concentration deficits, and visuo-spatial disorders. In addition, all children presented with behavioral and affective disturbances. Functional neuroimaging studies during the phase of mutism by means of SPECT showed perfusional deficits in the anatomo-clinically suspected supratentorial areas subserving language dynamics, syntax, naming, executive functioning, affective regulation, and behavior. A significant improvement of frontal perfusional deficits paralleled the clinical remission of mutism. These results add to the view that the PFS might represent a cerebello-cerebral diaschisis phenomenon, reflecting the metabolic impact of the cerebellar lesion on supratentorial cognitive and affective functions.

Cognitive function and 99mTc-ECD brain SPECT are significantly correlated in patients with primary Sjögren syndrome: a case–control study

Objectives:To assess subclinical central nervous system (CNS) involvement in primary Sjögren syndrome (pSS), by comparing standard brain MRI, in-depth neuropsychological testing and 99mTc-ECD brain single-photon emission computed tomography (SPECT) of...

Visual phenotype in Williams-Beuren syndrome challenges magnocellular theories explaining human neurodevelopmental visual cortical disorders

Williams-Beuren syndrome (WBS), a neurodevelopmental genetic disorder whose manifestations include visuospatial impairment, provides a unique model to link genetically determined loss of neural cell populations at different levels of the nervous system with neural circuits and visual behavior. Given that several of the genes deleted in WBS are also involved in eye development and the differentiation of retinal layers, we examined the retinal phenotype in WBS patients and its functional relation to global motion perception. We discovered a low-level visual phenotype characterized by decreased retinal thickness, abnormal optic disk concavity, and impaired visual responses in WBS patients compared with age-matched controls by using electrophysiology, confocal and coherence in vivo imaging with cellular resolution, and psychophysics. These mechanisms of impairment are related to the magnocellular pathway, which is involved in the detection of temporal changes in the visual scene. Low-level magnocellular performance did not predict high-level deficits in the integration of motion and 3D information at higher levels, thereby demonstrating independent mechanisms of dysfunction in WBS that will require remediation strategies different from those used in other visuospatial disorders. These findings challenge neurodevelopmental theories that explain cortical deficits based on low-level magnocellular impairment, such as regarding dyslexia.

Disorders of cognitive and affective development in cerebellar malformations

Acquired cerebellar lesions in adults and children can lead to the development of a complex behavioural pattern termed 'Cerebellar Cognitive Affective Syndrome' (Schmahmann and Sherman, Brain, 1998; 121: 561-79), which is characterized by reduced cognitive efficiency associated with specific neuropsychological deficits (executive and visuospatial disorders), expressive language disorders (mild agrammatism and anomia) and affective disorders with blunting of affect. It is not known whether a symptomatological picture such as this can also be found in congenital cerebellar malformations. We studied the behavioural developmental profile of 27 patients including children and adults with congenital malformations confined to the cerebellum, the largest studied sample to date. Extensive clinical and neuropsychological investigations highlight the presence of a wide range of disorders supporting the important role played by the cerebellum in the acquisition of higher-order cognitive and affective skills. The type and extent of cerebral reorganization processes in the presence of malformative lesions are difficult to predict and may possibly account for the variability of clinical phenotypes. It is, therefore, more difficult to identify a syndromic picture defined as exactly as is the case with acquired lesions. However, the pattern of deficits that we document is in remarkable agreement with the general profile of the Cerebellar Cognitive Affective Syndrome. Malformations affecting the cerebellar vermis induce affective and social disorders and evolve towards more unfavourable pictures often associated with an autistic symptomatology. Malformations of cerebellar hemispheres are more frequently associated with selective neuropsychological deficits involving mainly executive functions and visuospatial and linguistic abilities. Motor deficits are generally less severe, and tend to improve slowly and progressively, in some cases reaching almost complete functionality. Finally, the overall favourable evolution with an onset of skills in advanced age in a consistent subset of subjects suggests that individual follow-ups should be performed in order to monitor the quality and stability of impairments and acquired abilities over time.

Prism adaptation in the rehabilitation of patients with visuo-spatial cognitive disorders

The traditional focus of neurorehabilitaion has been on the patients' attention on their deficit, such that they should become aware of their problems and gain intentional control of compensatory strategies (descending approach). We review prism adaptation as one of the approaches that emphasize ascending rather than descending strategies to the rehabilitation of visuo-spatial disorders. The clinical outcome of prism adaptation highlights the need for a theoretical reconsideration of some previous stances to neurological rehabilitation. Recent years have given rise to a growing body of experimental studies showing that the descending strategy is not always optimal, especially when higher-level cognition is affected by the patients' condition. Ascending approaches have, for example, used visuo-manual adaptation for the rehabilitation of visuo-spatial deficits. A simple task of pointing to visual targets while wearing prismatic goggles can produce remarkable improvements of various aspects of unilateral neglect. The neural mechanisms underpinning visuo-manual plasticity can be viewed as a powerful rehabilitation tool that produces straightforward effects not only on visual and motor parameters, but on visuo-spatial, attentional and higher cognitive neurological functions. The use of prism adaptation therapy in neglect and other visuo-spatial disorders has just started to reveal its potential, both at a practical and theoretical level.

Les pathologies neuro-visuelles chez l’enfant cérébrolésé: À propos de quatre cas

Cerebral visual impairment is one of the main causes of childhood visual impairment in developed countries. These disorders are often linked with pre- or perinatal hypoxic brain injuries. The patterns of brain injuries depend on the severity and duration of hypoxia and the child's age. In premature children, periventricular leukomalacia affects the optic radiations and the subcortical visual brain. In full-term newborn babies, chronic hypoxia leads to the damage of the visual cortex and acute hypoxia damages the basal ganglia. They recover from cortical blindness in variable ways. Visual dysfunction is characterized by fixation troubles, subnormal acuity (crowding), difficulty with perceiving visual fields, movements, depth, cognitive defects (agnosia of images, objects or faces, visuospatial disorders), ocular motility disorders (tonic gaze deviation, strabismus, nystagmus). Accompanying these cerebral injuries, there are accommodation defects and optic disk abnormalities that vary according to the gestational age at the time of hypoxia.

Interaction between Cortical Control of Vestibular Function and Spatial Representation in Man

An asymmetry of the vestibulo-ocular reflex is observed after unilateral posterior cortical lesions in human. The co-occurrence of vestibular deficits and visuo-spatial disorders suggests a functional link between the representation and update of space and the integration of vestibular information in the occipito-parieto-temporal cortex of the right hemisphere.

Proceso visuoperceptivo en la enfermedad de Parkinson: de la retina a la corteza frontal

The growing interest in the cognitive impairment shown by patients with Parkinson's disease has led to a wealth of research in this line over recent years. In this paper we review the visuospatial alterations in these patients, which are usually linked to other disorders such as those affecting planning, sequencing, attention or mnemonic processes. We report the most relevant findings, which suggest that the existence of these visuospatial disorders shown by patients with Parkinson's disease are not always secondary to other frontal-type cognitive impairments, as has been claimed in recent years. Instead, they may be due to disorders in other anterior points of the perceptive process (as a result of dopaminergic deficits in basal-thalamic-cortical circuits). Thus, visuoperceptual disorders are classified according to their location in the brain: from the retina to the lateral geniculate nucleus, the visual cortex and the extrastriate cortex and, finally, the frontal and prefrontal cortex. We propose this classification of the disorders according to their location to aid in achieving an objective selection of the sample and of the neuropsychological tests used in studies. In this regard, we consider that there should be a higher degree of agreement among researchers when it comes to designing research projects that deal with visuospatial disorders in patients with Parkinson's disease.

The cognitive impairments due to the occipito-parietal brain injury after gunshot: a successful neurorehabiliation case study

Objective : The presented case study describes the beneficial results of the neuropsychological rehabilitation of a gunshot victim, even with late initialization of the therapy--over 1 year after head trauma. Design : A case study of DE, a victim with bilateral damage of the parietal-occipital regions of the brain due to a gunshot. Methods : Neuropsychological rehabilitation, first preceded by an initial neuropsychological examination (standard psychological tests: WAIS-R, RAVLT, Rey's CFT, BVRT and clinical experiments tailored to DE's condition), was initiated 1 year after trauma. The rehabilitation programme consisted of computer-based tasks, paper-and-pencil exercises, and occupational therapy. The patient's progress was assessed as improvement in performance in standardized tests and computer-based tasks. Results : DE was diagnosed with complex cognitive deficits syndrome, including visual associative agnosia, apraxia, visuospatial and constructive disorders and linguistic defects. After 1 year of rehabilitation the patient's functioning significantly improved as measured by psychological tests and computer-based tasks ( p < 0.05) as well as the evaluation of the patient's quality of life. Conclusions : The case study demonstrates beneficial effects of neurorehabilitation even initialized at the so-called 'late stage' after a brain injury.

Using Reaction Time to Assess Patients With Unilateral Neglect and Extinction

Brain damage often results in visual defects and/or higher order visuo-spatial disorders including the syndromes of unilateral neglect and extinction. These syndromes and their associated behavioral sequelae are described along with several standard assessments and methods for behaviorally quantifying such deficits. In particular, the advantages of the reaction time measures commonly used by cognitive neuroscientists are surveyed. In order to illustrate how reaction time measures can be used to examine the subtleties of visuo-spatial deficits, several reaction time studies that have been conducted in patients with neglect and/or extinction are discussed. These studies stand as an example of how reaction time measures can contribute to both clinical and experimental neuropsychology.

Atypical and typical presentations of Alzheimer's disease: a clinical, neuropsychological, neuroimaging and pathological study of 13 cases.

There has been increasing awareness that some slowly progressive focal cortical syndromes can be the presenting features of Alzheimer's disease, but pathological evidence has been sparse. This clinico-pathological series presents our experience with pathologically proven atypical as well as typical Alzheimer's disease presentations. We report and compare four patterns of presentation: a typical pattern with initial amnesic syndrome (n = 4 cases), progressive visual dysfunction (n = 1), progressive biparietal syndrome (n = 2) and progressive aphasia (n = 6). The aphasic presentations include both fluent and non-fluent aphasic syndromes. The neuropsychological profiles and neuroimaging clearly reflect the presenting clinical features, and show a close relationship to the distribution of pathology in these cases. Of note was the sparing of medial temporal structures (hippocampus and/or entorhinal cortex) in several aphasic cases and the severe occipito-parietal involvement in those with prominent visuospatial disorders at presentation. Our data demonstrate the wide spectrum of Alzheimer's disease presentations. The recognition of atypical presentations of Alzheimer's disease is important when attempting to make an early accurate pre-morbid diagnosis of neurodegenerative disease.

Combined deficits of saccades and visuo-spatial orientation after cortical lesions.

Functionally, saccadic eye movements are closely linked to visuo-spatial orientation. Anatomically, the network of cortical areas controlling saccades also seems to be involved in spatial attention and orientation. Consequently, lesions should cause deficits in both categories. We investigated this in 34 patients with focal unilateral lesions of the posterior parietal cortex (PPC), the frontal eye fields (FEF), the supplementary motor area (SMA), or the dorsolateral prefrontal cortex (PFC). Saccadic eye movements were recorded using infrared reflection oculography. Visual hemineglect or other visuo-spatial disorders were investigated by a series of standardized paper-pencil tests. Further, the internal spatial coordinates (subjective visual vertical and subjective straight ahead) were assessed psychophysically. Depending on the site of the lesion, different patterns of deficits were identified: lesions of the PPC impaired reflexive exploration of visual space in terms of delayed and hypometric visually triggered saccades into the contralesional hemifield, related to the severity of visual hemineglect. Further, PPC lesions specifically affected basic functions of the perceptual analysis of space, such as the internal spatial coordinates and spatial constancy across saccades. The latter was tested by applying visual double-step stimuli, where saccade-related extraretinal information had to be taken into account for achieving spatial accuracy. Frontal lesions left these functions intact. FEF lesions, however, impaired systematic intentional exploration of space, thus causing an exploratory-motor type of visual hemineglect. Prefrontal (PFC) lesions impaired the working memory for saccade-related spatial information, and SMA lesions affected temporal properties such as the timing of saccadic sequences, but did not cause specific visuo-spatial deficits. In conclusion, patients with frontal or parietal cortical lesions often exhibit combined saccadic and visuo-spatial disorders, most of which are topically specific.

A double dissociation between knowledge of object identity and object orientation

Two patients are reported who demonstrate the independence of knowledge of object identity and object orientation. One patient, with a visuo-spatial disorder, was unable to identify the upright canonical orientation for line drawings of objects, although she could correctly name the objects. A second patient, with visual object agnosia, was unable to name many objects, but could provide the upright canonical orientation—even for objects that he could not name. This double dissociation suggests that information about the canonical upright orientation of objects may be derived both from stored knowledge of objects, and ‘directly’ from visual information about object structure. Copyright©1997 Elsevier Science Ltd.

Visuoconstructive deficit following infarction in the right Basal Ganglia: A case report and some experimental data

Visuospatial disorders are typically described as a consequence of right hemisphere, cortical lesions. We report the case of a female with visuoconstructive deficits with an infarct in the right basal ganglia, with no evidence of visual field defect, hemi-inattention, or sensory or motor loss. Using a process approach to obtain additional quantitative data, we showed that her visuoconstructive disorder could not be attributed to a defect in visual perception, per se. All other aspects of her neuropsychologic skills were normal. These findings provide additional support for the role of subcortical structures in spatially-related motor function and for the utility of applying experimental techniques to clarify the nature of deficits.

Recovery and rehabilitation of visual cortical dysfunction

Damage to the human cerebral cortex can result in a number of distinct visual perceptual impairments, including visual field defects, impaired eye movements, visual agnosia, visuospatial disorders, impaired binocular fusional convergence, achromatopsia, visual hallucinations and defective visuoperceptual discrimination. Such impairments are common following stroke, traumatic brain injury, and other forms of cortical dysfunction, and may have significant implications for the ability to participate in rehabilitation of nonvisual functions and performance of normal daily activities. We review these cortically-based visual impairments, with emphasis on the course of recovery and methods of rehabilitation. In addition, longitudinal data are presented on the recovery of impaired visuoperceptual discrimination in 25 patients with cortical damage caused by stroke. Although the majority of these patients experienced good recovery without specific intervention, approximately one-third were left with significant chronic impairments of visuoperceptual discrimination. Despite promising recent developments in the treatment of cortically-based visual defects, there remains considerable need for information on the natural course of recovery of such impairments, as well as development of empirically validated rehabilitation procedures.

Rehabilitation of acquired visuospatial disorders

British Journal of Clinical PsychologyVolume 34, Issue 2 p. 316-318 Rehabilitation of acquired visuospatial disorders Andrew Worthington, Corresponding Author Andrew Worthington University College London; Rayners Hedge Rehabilitation Centre, AylesburyRayners Hedge, Croft Road, Aylesbury, Bucks HP21 721 7D, UK.Search for more papers by this author Andrew Worthington, Corresponding Author Andrew Worthington University College London; Rayners Hedge Rehabilitation Centre, AylesburyRayners Hedge, Croft Road, Aylesbury, Bucks HP21 721 7D, UK.Search for more papers by this author First published: May 1995 https://doi.org/10.1111/j.2044-8260.1995.tb01466.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume34, Issue2May 1995Pages 316-318 RelatedInformation

Visuoconstructive deficit following infarction in the right Basal Ganglia: A case report and some experimental data

Visuospatial disorders are typically described as a consequence of right hemisphere, cortical lesions. We report the case of a female with visuoconstructive deficits with an infarct in the right basal ganglia, with no evidence of visual field defect, hemi-inattention, or sensory or motor loss. Using a process approach to obtain additional quantitative data, we showed that her visuoconstructive disorder could not be attributed to a defect in visual perception, per se. All other aspects of her neuropsychologic skills were normal. These findings provide additional support for the role of subcortical structures in spatially-related motor function and for the utility of applying experimental techniques to clarify the nature of deficits.

Specific Neurocognitive Deficits in Cornelia de Lange Syndrome

Cornelia de Lange Syndrome (DLS) is a dysmorphogenic disorder typically associated with severe mental retardation. This report describes a rare case with normal-range verbal intelligence and specific cognitive deficits suggestive of a developmental visuospatial disorder. This was apparent in selective deficits in the ability to integrate visual percepts, copy spatial configurations, and manipulate representations of objects in space. Visual memory and psychomotor skills were also impaired. These deficits occurred within the context of normal language abilities and language-related academic achievement. The observed pattern of neuropsychologic impairment, in addition to aspects of socioemotional development, was similar to that seen in children with developmental right-hemisphere dysfunction. These findings suggest that the factors underlying DLS can be associated with fairly specific aberrations of cortical functioning.