Causes and Symptoms of Visuospatial Neglect

Causes and Symptoms of Visuospatial Neglect

Introduction

Visuospatial neglect is a consequence of unilateral brain injury that is associated with stroke. The patients with severe and persistent visuospatial neglect are those whose right hemisphere has been damaged.  According to statistics, 80% of patients with severe visuospatial neglect are caused by damage in the right hemisphere. It is a disorder of attention (Svaerke et al., 2019). Thus, the patients who are experiencing the condition fail to orientate, respond to stimuli in the contralesional side, and they have challenges in reporting. The leading cause of the problem is a series of strokes that affect the middle cerebral artery, and it is heterogeneous. Such leads to the failure of the affected patient to manifest features of visuospatial neglect. The disorder can be treated; however, a universal approach to its therapy does not exist.  Most patients affected recover spontaneously; however, from the evidence, they continue to exhibit cognitive impairments that relate to attention.  For further understanding of the condition, one will discuss its causes, symptoms, and recent studies concerning visuospatial neglect.

Causes of visuospatial neglect

Various issues cause visuospatial neglect. One of the major reasons for the condition is stroke. The majority of the patients who have the condition resulted from the right-hemispheric stroke. As outlined by Vallar et al. (2014), stroke causes damage in the brain, leading one to become unable to perceive people, objects, and events. Stroke leads to a lesion in the border of parietal and temporal lobes, mainly in the human right hemisphere. The lesion leads to impairment in the brain, causing the patient to develop misperceive in the left half of the brain. Thus, leading to an underestimation of the right half of the brain. Hemorrhagic stroke or ischemic in the right region of the brain is attributed to the development of neglect.   Injury in the subcortical regions of the brain also causes visuospatial neglect. Based on studies, the use of perfusion-weighted imaging (PWI), cognitive disorders resulting from subcortical lesions that are induced by structural dysfunction leads to abnormally perfused cortical tissue (Svaerke et al., 2019).  Cortical injury leads to the separation of egocentric measures, which are located superior temporal cortex, leading to an egocentric deficit in objects. Brain trauma also leads to the development of the condition. Brain trauma can be caused by a failure in suicide attempts, among other life-threatening factors, which may lead to depressing issues. Such problems lead to the development of subdural hematoma, which mainly affects the right hemisphere. The subdural hematoma causes hemispatial neglect due to the resultant extensive lesion developed as a result of trauma.

Symptoms of visuospatial neglect

Patients who have been ailing from visuospatial neglect experience various symptoms. Primarily, it experiences a reduction in attention capacity.  Visuospatial negligence leads to the lateralization of attention materials to the right ventricle frontoparietal regions leading to its interaction with the dorsal frontoparietal (Ten et al., 2019). This causes a reduction of attention material in the right part of the brain necessary for dual-task paradigms. This increases rightward spatial bias. Visuospatial is also characterized by tonic rotation of either the eyes or the body in the right direction. A coexisting motor imbalance causes the problem. Despite that, some of the patients experiencing the problem may have the ability to detect stimulus in the left hemifield. However, if the stimulus is presented in both the rights and left directions at the same time, they will only be able to detect ones on the right side. Another indicator of visuospatial neglect is the manifestation of defects in planning in the rotating of either the head or eye towards the left side space (Tobler-Ammann et al., 2017). The patients are inclined to such that; they fail to locate or reach objects which are located on the left side. However, they may not demonstrate any visual biasness. Thus, neglect is called directional hypokinesis since it emphasizes the relationship existing between visuospatial and action among the patients. Visuospatial neglect also shows signs of attitudinal neglect affecting the vertical axis. For example, a person experiencing the condition cannot perform bisection upwards since their asymmetry is not related to the primary sensory deficit.  The condition makes one fail in orienting their attention towards the lower hemisphere.

Recent studies on Visuospatial neglect

One of the studies based on the condition in which one will discuss is “Visuospatial Neglect-A Theory-Informed Overview of Current and Emerging Strategies and Systematic Review on Therapeutic Use of Non-Invasive Brain Simulation.” According to the research, the condition constitutes a supramodal cognitive deficit, which is characterized by loss or reduction in spatial awareness (Zebhauser et al., 2019). The condition affects mainly patients who suffer from a stroke. From the analysis, Iwański et al., (2020) view that the condition occurs in 40% right-lesion brain in stroke patients affecting the frontal and subcortical brain areas.

Similarly, patients with stroke and lesion on the left side of the brain can also be affected by the condition. However, their prevalence rate is lower as compared to those who have a lesion on the brain’s right side (Nijboer, Kollen & Kwakkel, 2013).  The study views that; the condition is a multifaceted syndrome. Therefore, patients experiencing the problem require individualized diagnostic and therapeutic approaches (Zebhauser et al., 2019).  The research highlights that models such as the interhemispheric rivalry model can help in the understanding of the condition. The study supported the idea by suggesting that balancing of spatial attention is based on transcallosal inhibition of both brain hemispheres. Nonetheless, Ten et al., (2019) reiterated that the brain lesion, which is the leading cause of imbalance, can be corrected through its re-installation, deactivation, or activation. The correction can be facilitated through the use of noninvasive brain stimulation. The choice was based on its effectiveness in improving the patients’ long-term outcomes who were investigated in the research.

The second recent study in which one will discuss is “Impairments of Visuospatial Attention in Children with Unilateral Spastic Cerebral Palsy. Neural Plasticity”. According to the study by Ickx, et al., (2018), the causes of brain lesions in children either at prenatal, perinatal, or postnatal results from cerebral palsy. The health problem is associated with motor impairment, thus leading to deficits in sensory-motor, sensory, and also cognitive function. The research outlines that due to the relationship existing between the brain of the child and the defects resulting from motor impairment, children with cerebral palsy are likely to experience visuospatial attention. The egocentric and allocentric visuospatial representation is progressive in children with age (Ickx et al., 2018). However, the prevalence s high with children who suffer from cerebral palsies condition. The challenge is attributed to differences existing in the brain reorganization attributed to visuospatial abilities affecting both the mature and developing brain of the child. The variation leads to contralateral neglect; thus, such subjects the children to deficits in executive activities and global attention control (Iwański et al., 2020).

Based on the analysis of the research, the results depicted that children with cerebral palsy have abnormal brain lesions.  However, the magnitude of the condition is different among the children. The authors highlight that the condition was severe with cerebral palsy children with cortical or subcortical lesions as compared to those with periventricular lesions. The differences in deficits are also caused by lateralization aspects of the location of the lesion in the brain. For example, Oh-Park et al., (2014) view that cerebral palsy children with lesions in the right hemisphere, their learning, and control deficits were severe as compared to those with lesions on the left hemisphere. Prismatic rehabilitation can be used as an intervention measure for children with cerebral palsy and visuospatial neglect since it improves their motor abilities.

Conclusion

Spatially lateralized impairments characterize visuospatial neglect patients. Therefore, they are faced with difficulties in responding and perceiving items that are found on the opposite side of damaged brain parts. Since the major challenge is the consequence of lateralization, researchers view that there is a need to understand also the non-spatially lateralized mechanisms. The information will help in understanding one’s symptoms and causes, thus leading to the development of the best therapy and further understanding of the intact human brain. The implications of understanding and acknowledging both lateralized and non-lateralized consequences of visuospatial neglect helps in the development of individualized pharmacological and behavioral interventions. Thus, helping the patient cope with the deficit. The major cause of the medical condition is stroke, and therefore, most of the patients experiencing will have difficulties in brain mechanisms such as direction attention and motor issues.

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Iwański, S., Leśniak, M., Polanowska, K., Bembenek, J., Czepiel, W., & Seniów, J. (2020). Neuronavigated 1 Hz rTMS of the left angular gyrus combined with visuospatial therapy in post-stroke neglect. Neurorehabilitation.Bottom of Form

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Ten, B. A. F., Biesbroek, J. M., Oort, Q., Visser-Meily, J. M. A., & Nijboer, T. C. W. (2019). Peripersonal and extrapersonal visuospatial neglect in different frames of reference: A brain lesion-symptom mapping study. Behavioural Brain Research, 356, 504-515.

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Zebhauser, P. T., Vernet, M., Unterburger, E., & Brem, A. K. (2019). Visuospatial neglect – a Theory-Informed Overview of Current and Emerging Strategies and a Systematic Review on the Therapeutic Use of Non-invasive Brain Stimulation. Neuropsychology Review, 29, 4, 397-420. https://doi.org/10.1007/s11065-019-09417-4