Diseases and Disorders

Hemispatial Neglect Syndrome: An Overview

Victoria Man, Sophie Block


Abstract

Hemispatial neglect syndrome is  a long-lasting damage to the right (and sometimes, but rarely, the left) hemisphere of the brain after a stroke. Hemispatial neglect usually manifests as a neurological condition. There are behavioral tests performed to quickly and easily diagnose individuals with the syndrome. If diagnosed with the syndrome, patients will be given a wide range of treatments. This article will provide a brief overview of hemispatial neglect syndrome’s effects, symptoms, diagnosis, and treatments.
 

Introduction

Hemispatial neglect was first documented in 1876 by John Hughlings Jackson. Hemispatial neglect is a neuropsychological syndrome that typically follows unilateral brain damage, usually in the right hemisphere. Individuals suffering from hemispatial neglect will no longer be able to acknowledge the space on their contralesional side (refer to figure 1). These individuals would only focus on items in the space on their ipsilesional side [1][2]. Large objects, people, and even the individual’s own body parts could be foreign to them due to hemispatial neglect. Additionally, extrapersonal and personal space are sometimes ignored by those with hemispatial neglect, which is because the stimuli are reduced on the contralesional side [1].

 

Figure 1. An individual with left hemispatial neglect may not pay attention to the pasta on the left side of the plate [8].

Although hemispatial neglect can be caused by many pathological instances like neurodegenerative disease, neoplasia, and trauma, the most common cause for hemispatial neglect is a hemispheric stroke. Large strokes located in the middle cerebral artery can cause hemispatial neglect [1][3]. Strokes in the middle cerebral artery territory span from the critical parietal region to the frontal region. These strokes result in persistent hemispatial neglect conditions that will gravely impact an individual’s daily life. Apart from injury in the parietal and frontal regions, cortical impairment relating to the right inferior parietal lobe or the temporoparietal junction can also cause hemispatial neglect. It is also apparent now, after research, that hemispatial neglect syndrome may manifest from focal lesions of the inferior frontal lobe— lesions located in the frontal lobe will more likely become transient neglect (a specific short-term hemispatial neglect) {1}{4}. Furthermore, some individuals that suffer a posterior cerebral artery territory stroke can also become victims of the syndrome; however, there has not been much research  on this type of hemispatial neglect causation [1].

 

Effects and Symptoms

Patients can see and acknowledge items on the same side of their brain damage, but are unaware or do not acknowledge items on their contralesional side. While the severity varies, this can result in patients being unaware of people and other large objects. Despite no real physical limits, patients fail to use their limbs and body parts on their contralesional side. Despite the prevalence of the symptoms, many hemispatial neglect patients fail to recognize these issues and sometimes even deny the diagnosis or suggestion that there is anything wrong. This syndrome is also heterogeneous, meaning that not all individuals who suffer from hemispatial neglect will have all the effects of the syndrome [1]. The effects and symptoms of hemispatial neglect, including more biochemical ones, continue to be researched, as there is little data at present time.

Conservative estimates report that of those with strokes, around 17% with right-brain anions and 5% of left-brain lesions will show neglect symptoms three months after developing hemispatial neglect [5].

 

Diagnosis

It is often difficult to determine if a patient has hemispatial neglect. However, once the syndrome is suspected in a patient, it is relatively easy and quick to diagnose an individual with the use of special assessments. Doctoral guidelines recommend individuals suspected of hemispatial neglect be assessed with the Behavioural Inattention Test (BIT). The BIT is considered very effective and includes 6 pen-paper and 9 behavioural evaluations on the patient. The most widely explored and performed assessments are that of pen-paper assessments [5]. 

Pen-paper assessments include star cancellation, letter cancellation, line crossing, line bisection, free drawing and shape copying. In the cancellation and line tests, individuals are given a set of images and icons which they will need to mark or cross out. With cancellation tasks, it is often seen that a patient with hemispatial neglect will start the search on symbols on the ipsilesional side and ignore symbols towards the contralesional side (see figure 2).

 

Figure 2. Sample of a star cancellation test performed by a patient with hemispatial neglect on the left side [5].

For the line bisection task, patients will be asked to identify the middle point of horizontal lines to evaluate if they can incorporate the space on the contralesional side. Most usually, patients with spatial neglect will have the midpoint marked more towards the ipsilesional side on the horizontal line. In shape and drawing evaluations, individuals are asked to draw simple images of geometric shapes or everyday items such as clocks and flowers. Patients suffering from hemispatial neglect will very likely ignore and not draw the contralesional side of the objects and shapes [5].

 

Treatments 

Current treatments include teaching patients compensatory strategies, including visual scanning therapy (refer to figure 3).  Visual scanning therapy trains patients to look towards their “neglected” side. Patients are instructed to read, write, or search for an object on this side. While this therapy is time-consuming, often requiring around 40 hours of therapy, and only targets the visual aspects of hemispatial neglect, it has been proven to benefit patients [5]. Prism adaptation is another behavioural therapy, where patients wear glasses that contain prisms, which bend light. This causes objects within sight to look shifted to the right. In the training, patients develop the skills to shift their hand-eye coordination leftwards towards the neglected half of space. This therapy improves postural imbalance and reading, but the benefits only last for around 24 hours after a training session.  Still, if repeated daily over several weeks, the improvements can last for several weeks; this, though, is time-consuming, expensive, and labour-intensive [6]. Other activities within behavioural therapies include cancellation tasks, where targets are crossed out on a paper in front of the patient; line bisection, where the patient has to find the horizontal line at the midpoint on a sheet of paper; and copying tasks, where the patient has to copy drawings created by the examiner [2].

Physical therapy is not the only treatment.  Recent pharmacological experimental treatments have been developed to try and target the underlying causes of hemispatial neglect. The administration of rotigotine, a drug traditionally used to treat Parkinson’s disease has proven to improve performance on cancellation tasks, an activity where you find targets hidden within distractor stimuli [3][7]. Another treatment uses carbidopa-levodopa, another drug that is used for Parkinson’s patients.  Levodopa is converted to dopamine in the brain, and carbidopa prevents levodopa from being broken down before reaching the brain. The use of carbidopa-levodopa resulted in improved behavioral inattention test scores in three out of four patients. However, these studies have not been replicated, and more clinical trials need to occur before the findings become concrete [5].

 

Figure 3. When copying objects, those with right hemispatial neglect will exclude components on the left and draw the middle of a line more to the right [4].

Non-invasive brain stimulation has also been shown to improve neglect, although only for a few minutes. Non-invasive brain surgery can create neuroplastic change. For hemispatial neglect patients, suppressing stimulation of the undamaged left parietal cortex can reduce the hyperactivity of the undamaged left side of the brain [6]. 

Oxford University, along with the University of Lyon, has investigated the possibilities of combining two therapies to increase efficiency. The behavioural therapy of prism adaptation is combined with brain stimulation. In this approach, the left sensorimotor cortex, a brain region that helps retain newly learned motor skills, was excited. As predicted, the improvement lasted longer than normal sessions, and the treatment became cumulative [6].

 

Conclusion

Individuals suffering from hemispatial neglect will most likely be restricted from performing daily activities. For example, one with hemispatial neglect might not use the keyboard of their laptop to type on the contralesional side and only use the ipsilesional side to type; they may not even recognize themselves that they are behaving abnormally. A patient might ignore one side of the clock on their contralesional side when telling the time and not be able to understand that there is another side to the clock. There are many instances where hemispatial neglect patients will limit participation in regular daily routines. For hemispatial neglect patients, life is challenging, and the recovery time and inefficiency of treatment are frustrating, never mind the cost of therapy, medication and treatments, some of which are not guaranteed to work. To improve the lives of those suffering from hemispatial neglect, more research and studies must be conducted to find improved therapies, diagnostic strategies, and medication. 

 

Glossary


References


  1. Verdon, Vincent, et.al. (03/2010). Neuroanatomy of hemispatial neglect and its functional components: a study using voxel-based lesion-symptom mapping. Brain. Volume 133, Issue 3. Pages 880–894. Retrieved: 01/07/2021.

  2. Husain, Masud. (2008). Hemineglect. Scholarpedia. http://www.scholarpedia.org/article/Hemineglect. Retrieved: 29/06/2021.

  3. Dalmaijer, E. S., et al. (08/11/2015) CancellationTools: All-in-one software for administration and analysis of cancellation tasks. Behavior research methods. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4636511/#:~:text=In%20a%20cancellation%20task%2C%20a,the%20neglect%20syndrome%20after%20stroke. Retrieved: 04/07/2021.

  4. Parton, A, et.al. (2004). Hemispatial neglect. Journal of Neurology, Neurosurgery & Psychiatry. https://jnnp.bmj.com/content/75/1/13. Retrieved: 30/06/2021.

  5. Gallagher, Maria, et.al. (2013). Hemispatial neglect: clinical features, assessment and treatment. British Journal of Neuroscience Nursing. https://www.researchgate.net/publication/272450104_Hemispatial_neglect_clinical_features_assessment_and_treatment. Retrieved: 03/07/2021.

  6. O'Shea, Jacinta. (29/09/2017). A new approach to improving hemispatial neglect after stroke. The University of Oxford. https://www.ox.ac.uk/news/science-blog/new-approach-improving-hemispatial-neglect-after-stroke. Retrieved: 30/06/2021.

  7. U.S. National Library of Medicine. (n.d.). Rotigotine Transdermal Patch: MedlinePlus Drug Information. MedlinePlus. https://medlineplus.gov/druginfo/meds/a607059.html. Retrieved: 01/07/2021.

  8. Sutton, Megan. Left Neglect After Stroke - Definition and Treatment Exercises. https://tactustherapy.com/what-is-left-neglect/. Retrieved: 03/07/2021.

  9. Li, Korina, and Paresh Malhotra. (2015). Spatial neglect. Practical neurology. https://doi.org/10.1136/practneurol-2015-001115. Retrieved: 30/06/2021.

Victoria Man

Victoria Man


This author has not yet uploaded a bio.

Sophie Block

Sophie Block


This author has not yet uploaded a bio.