Visual Neglect

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Disease Entity

Visual neglect (visual hemi-inattention) is a neuropsychological disorder of attention in which patients exhibit a lack of response to stimuli in one half of their visual field that cannot be explained by primary damage to the visual geniculostriate pathways.[1] It is part of the broader hemispatial neglect syndrome which frequently occurs following cerebral injury to the right parietal lobe[2] and almost always affects the hemispace contralateral to the cerebral lesion.[3] It is frequently seen in the context of cerebrovascular disease, affecting up to 5 million stroke patients each year.[4]

Neglect is generally defined as the inability to orient, report, or respond to sensory stimuli in a region of space contralateral to a cerebral lesion.[5] Though the phenomenon may occur alongside a primary sensory deficit, the underlying deficit is one of attention rather than sensation, and the failure to respond to unilateral stimuli must, by definition, not be better explained by the primary sensory deficit.[6] Neglect may manifest as personal, extra-personal, motor, or sensory inattention. Visual neglect is the most common[6] and most striking manifestation of neglect. Contralesional visual neglect is frequently seen in the context of hemiplegic stroke, and represents a major source of morbidity, frequently impeding rehabilitation and predicting poor functional outcomes.[7][8][9] Patients are often unaware of their deficit (anosognosia), further complicating rehabilitation.[10]

The diagnosis of visual neglect can be difficult, requiring careful clinical evaluation. Neglect is distinct from other disorders of visuospatial processing such as visual extinction (pseudohemianopia)[11] or simultanagnosia,[12] phenomena in which a stimulus fails to be perceived or recognized only in the context of competing stimuli. Unlike visual neglect, these phenomena only affect perception when competing stimuli are present; visual attention is intact in the absence of competitive stimuli. Severe visual neglect also requires careful clinical evaluation to distinguish from homonymous hemianopia,[13][14] as both can present with visual field defects on confrontation and standard visual field testing.[15] Conversely, mild visual neglect can present with normal visual fields on confrontation, requiring more detailed testing to identify the deficit.[1] Finally, visual neglect may coexist with visual extinction and homonymous hemianopia, complicating the diagnosis.[2]

Presentation

Visual neglect primarily presents with an apparent inability to perceive stimuli in one hemispace, contralesional to the cerebral injury. This hemispace may be egocentric (body-centered) or allocentric (object-centered). Patients with dense egocentric left visual neglect may exhibit right gaze preference, and fail to acknowledge persons or objects to their own left side.[15] This is the most commonly identified form of visual neglect.[3] By contrast, allocentric or object-centered neglect occurs relative to the midline of external stimuli, regardless of their position in space.[16] A patient experiencing dense allocentric visual neglect may only read one half of a newspaper or eat one half of a plate of food. This type of neglect may also manifest in object drawing, placing all numbers on the ipsilesional clock face during a clock-drawing or drawing only one half of an object.[17]

Neglect can furthermore involve personal stimuli (neglect of visual stimuli from within the bodily space) or extra-personal stimuli (neglect of visual stimuli from beyond the bodily space).[18] Personal hemineglect involves recognition of only one half of the body, with neglect of the other side. For example, the patient will groom, comb, and respond to visual stimuli on the ipsilesional side of the body only.[2] Hemiplegic patients with personal hemineglect may also exhibit anosognosia, failure to recognize their own deficits, due to unawareness of the affected side.[3] Extra-personal neglect is often more apparent than personal neglect, and can be the most obvious sign of visual neglect. The patient will ignore objects in the contralesional hemispace, behaving as though the space does not exist. They will often bump into objects and fail to recognize familiar people in the affected hemispace.[3]

It is important to distinguish the presentation of visual hemineglect from homonymous hemianopia. Homonymous hemianopia tends to sharply obey the vertical meridian, whereas visual neglect represents a gradient of inattention that may cross over into the ipsilateral hemispace.[17] Furthermore, patients with homonymous hemianopia are usually aware of the visual field defect and will often exhibit compensatory mechanisms such as head-turning and eye movement to compensate for the visual defect. By contrast, patients with visual neglect are unaware of the neglected visual field and do not attempt to compensate for it.[19][20] However, these distinctions may be blurred in cases where homonymous hemianopia and visual neglect are both present, requiring more detailed testing to identify the presence of both syndromes.[21]

Etiology

Right hemispheric lesions have classically been identified as the major cause of visual hemi-neglect,[2] in particular those affecting the temporo-parieto-occipital area.[22] Visual hemi-neglect occurs less frequently in left hemispheric injury, and the presentation tends to be less severe.[2] 

Visual neglect arises most frequently due to middle cerebral artery stroke[22] affecting the right inferior parietal lobe[23] and parieto-occipital junction.[5] Up to 80% of stroke patients with parietal lobe involvement exhibit some level of visual neglect. [24] Visual neglect has also been described in the context of posterior cerebral artery stroke[25][26] and frontal lobe infarction.[27] Less commonly, stroke involving sub-cortical structures such as the thalamus[28] and basal ganglia[29][30] may also cause visual neglect.

Visual neglect has also been reported as a sequela of traumatic brain injury,[31][32] posterior cortical atrophy,[33][34] and intracranial malignancy.[35] Finally, visual neglect has been reported as a manifestation of conversion disorder.[36]

Pathophysiology

Several theories have been proposed regarding the neurologic basis of visual neglect.[17] The most prominent view is that visual neglect is a problem of directed attention. Conscious visual perception requires two major components: intact afferent visual pathways (the eyes, optic nerves, chiasm, optic tracts, geniculostriate pathway, and visual cortex) and intact visual awareness. It is thought that visual neglect is a deficit of visual awareness, representing impaired directed attention towards visual stimuli despite intact afferent visual pathways.[1] Spatial processing and attention is primarily mediated by the right frontal and parietal lobes.[2] Lesions affecting these structures cause contralesional deficits in directed attention and spatial processing and give rise to visual neglect.

The precise neuroanatomy of visual neglect is complex and remains a matter of considerable controversy. It has been hypothesized that attention is specifically mediated by an intricate neural network involving the right parietal lobe, frontal lobe, and cingulate gyrus.[37][38] Disruption of this network may therefore cause contralesional deficits in attention directed towards the left hemispace. There has also been evidence to suggest that personal and extrapersonal attention are mediated by two distinct networks, one in the right parietal lobe mediating personal attention and another involving the right frontal lobe and superior temporal gyrus mediating extrapersonal attention, accounting for variations in the presentation of neglect.[18]

Recent fMRI studies have found that the left cerebral hemisphere in patients with hemispatial neglect may be overly active compared to the right,[39] suggesting a functional imbalance that biases attention towards the right hemispace.[4] This is further suggested by studies demonstrating that temporary disruption of contralesional cortical networks using transcranial magnetic stimulation (TMS) decreases severity of neglect.[40] TMS disruption of neural networks in the right posterior parietal cortex and superior temporal gyrus has also been shown to temporarily induce symptoms of left hemineglect in healthy patients.[41]

Diagnosis

History & Physical

The diagnosis of visual neglect is established based on both clinical presentation and diagnostic testing. History is often significant for right hemispheric stroke or other cortical injury. Physical exam may demonstrate an ipsilesional (usually rightward) deviation of the eyes and head at rest.[42] Behavioral features include lack of observation or exploration of a single hemispace, usually contralateral to the cortical lesion.[2]

Diagnostics

Alone, no single test for visual neglect is sufficiently sensitive for diagnosis. Test results must be combined with supportive findings from patient history and clinical observation. Combinations of tests may be performed to increase sensitivity,[43] and several test batteries have been proposed.[15] The most commonly employed clinical diagnostics may generally be divided into two types: pen and paper tests and behavioral tests.

Pen and Paper Tests

Testing for visual neglect in the clinical setting is usually performed with bedside pen and paper tests due to their facility and relative sensitivity. Three major types of bedside pen and paper tests are typically used in the diagnosis of visual neglect: cancellation tests, the line-bisection test, object drawing, and reading.[2]

Cancellation Tests

Cancellation tests are the most sensitive indicators of visual neglect.[44] Additionally, cancellation testing can be used to quantify the severity of visual neglect and track its clinical progression.[45] These tests generally involve asking the patient to identify and cross out certain target items distributed across a sheet of paper. The patient is scored on how many targets are identified and marked. Patients with hemineglect will preferentially cross out objects on the ipsilesional side of the page and ignore objects on the contralesional side of the page.

Several types of cancellation test have been described. The most common are:

  • Line-Crossing Test:[46] Forty short lines are distributed in different orientations seemingly at random across the page, with an even number of lines in each half of the page. The patient is asked to cross out all of the lines and performance is scored based on how many of the peripheral lines are crossed out.
  • Letter Cancellation Test:[47] A large array of letters is distributed across the page at random, with each half of the page containing an equal number of a specific target letter. The patient is asked to cross out all instances of the target letter and scored on how many letters are crossed out.
  • Star Cancellation Test:[48] A large array of letters, short words, and stars are spread out at random across the page, with an equal number of stars on each half of the page. The patient is asked to cross out all of the stars and scored on the number of stars crossed out.
  • Bells Test:[49] Seven vertical columns, each containing five bells and forty distractors, are distributed evenly across the page, with three columns in each half of the page and one column down the center. The patient is asked to cross out all of the bells and scored on the number of bells crossed out in the non-central columns.


Among the cancellation tests, the Letter Cancellation and Bells tests have been shown to have the highest sensitivity for visual neglect.[43] The Star Cancellation test has also been shown to be a highly sensitive measure of neglect.[48]

Line Bisection

The line bisection test[50] is one of the oldest and most easily employed tests for visual neglect. Several long (15-20cm), parallel horizontal lines are drawn down the page shifted horizontally relative to one another such that an equal number of their centers lie either to the left, right, or along the center of the page. The patient is asked to bisect each line at its midpoint with a single mark without moving the page. A patient with visual neglect will bisect the lines unequally, with the midpoints shifted away from the center and towards the ipsilesional side. Total neglect of two or more lines has also been shown to reliably detect visual neglect.[50] The test may also be performed with a single line. Performance may be scored by measuring deviation as a percentage of the half-length of the line.[44]

This tool is particularly valuable for distinguishing visual neglect from homonymous hemianopia.[21] Unlike patients with visual neglect, patients with homonymous hemianopia will tend to deviate towards the contralesional side on line bisection.[51][52] That is, a patient with left homonymous hemianopia will place the midpoints left of center, whereas a patient with left visual neglect will place the midpoints right of center. In patients with both homonymous hemianopia and visual neglect, large ipsilesional deviations are observed, more than would be expected in pure visual neglect.[53]

Importantly, healthy individuals may also exhibit error on the line bisection test, most frequently erring in the direction of the hand used to perform the test. This phenomenon of “pseduoneglect”[54] must be clinically distinguished from pathologic error when testing for visual neglect.

Object Drawing

Despite their frequent clinical utilization, object drawing tests are the least sensitive and specific tests for visual neglect.[43][55] Patients with visual neglect who are asked to draw an object will often omit details from the contralesional half of the image. This is most commonly seen in a clock-drawing, where the patient with visual neglect places all of the numbers on one side of the clock face.

Behavioral Tests

Behavioral testing involves scoring the patient's performance of specific, real-life tasks such as picture scanning, telephone dialing, text reading, time telling, navigation, sorting, and text copying.[56] Behavioral testing generally has much higher sensitivity for visual neglect than pen and paper tests.[43] Reading tests in particular are simple to employ in the clinic and have high sensitivity for visual neglect.[43] Patients are asked to read several horizontal lines of text down the page and scored based on the number of words omitted and differences between right and left omissions.

Combined batteries of pen and paper and behavioral tests have also been developed to increase diagnostic accuracy, including the Behavioral Inattention Test (BIT) and the Catherine Bergego Scale (CBS).[3][15] These tests are highly sensitive and specific for visual neglect[43] and are predictive of daily functional performance.[57] However, the time-intensive nature of these tests limits their use in routine clinical evaluation.

Differential diagnosis

  • Homonymous hemianopia
  • Visual extinction (simultanagnosia)
  • Balint Syndrome
  • Representational neglect

Management

No consensus has been established regarding the best rehabilitation strategies,[58] and there has been limited evidence to support the long-term efficacy of any particular therapy.[58]

Adaptive Rehabilitation

Conventional strategies for rehabilitation of visual neglect have largely focused on adaptive techniques to help the patient learn to function using a single hemispace.[1] For example, important objects are always presented to the non-neglected side, and contacts are taught to approach and address the patient from this side.

Specific Interventions

Top-Down Techniques

“Top-down” techniques involve the use of behavioral training to induce cognitive changes that counteract neglect. Most commonly, they involve training the patient to scan towards the neglected side (“visual scanning” or “visual exploration”).[59] These therapies have traditionally formed the mainstay of treatment for visual neglect[58] and there has been some high-quality evidence to support their efficacy.[60] However, these techniques require considerable training time to yield lasting results, and often improvement is limited in scope.[58] Moreover, because they rely on voluntary effort, these strategies fall short in cases where the patient does not recognize their deficit (anosognosia).[61]

Bottom-Up Techniques

Because visual neglect is often complicated by anosognosia, rehabilitation strategies that do not rely on voluntary reorientation of attention are frequently required. The recovery of spatial attention deficits in visual neglect has been shown to correlate with the re-activation of defective neural pathways and the re-orientation of normal activity within the cerebral hemispheres.[4] Thus certain interventions have been proposed to re-balance cognitive spatial representation. These “bottom-up” therapies attempt to induce a contralesional orientation bias to counteract the pathologic ipsilesional orientation bias of visual neglect without relying on patient volition.[58][59]

The most commonly studied bottom-up techniques include prism adaptation, optokinetic stimulation, vestibular stimulation, and neck-muscle vibration. However, evidence to support the long-term efficacy of all of these interventions remains limited.[59]

  • Prism Adaptation: Prism adaptation has received a great deal of attention and is one of the most well-supported and most widely-employed bottom-up therapies for visual neglect.[62]  Rehabilitation by prism adaptation involves the use of wedge-prisms to cause an ipsilesional shift in visual fields, producing a relative disconnect between visual and motor function. Patients asked to point towards a visualized target will therefore initially err in the direction of the prismatic visual shift (ipsilesional). As the patient learns to correct for the visual deviation, it is thought that a contralesional orientation bias is entrained.[63] Once the prisms are removed, this contralesional bias ideally remains, offsetting the ipsilesional orientation bias of the visual neglect. There is evidence to suggest that repetitive iterations of this prism adaptation process may produce significant and lasting effects on the severity of visual neglect.[64][65] However, others note limited improvement with short-term prism therapy in clinical practice,[1] and the long-term efficacy of this technique has been questioned.[59][62] Prism therapy may be offered by low-vision specialists in the rehabilitation of visual neglect.
  • Optokinetic Stimulation (OKS): Optokinetic Stimulation (OKS) is an investigational therapy that involves exposing the patient to several visual stimuli continuously moving towards the affected neglected hemispace (usually left). Patients are asked to follow the stimuli using smooth pursuit movements and repeatedly return their eyes to the ipsilesional side without moving their head. This effectively produces a nystagmus with the fast phase towards the side of the lesion.[66] When the screen encompasses the patient’s peripheral vision, the experience produces the subjective impression of head movement towards the ipsilesional side.[58] It is thought that doing so induces a re-orienting contralesional spatial bias.[67] Several studies have demonstrated that OKS therapy leads to significant and lasting improvement in neglect behavior and performance on cancellation and line-bisection testing.[58][68]
  • Vestibular Stimulation: Vestibular stimulation is an investigational therapy that involves using the vestibulo-ocular reflex to elicit vestibular nystagmus in which the fast phase beats towards the side of the lesion. As in OKS, this causes the illusion of ipsilesional head motion which is thought to induce a re-orienting contralesional spatial bias. The vestibulo-ocular reflex can be elicited using caloric stimulation (warm water in the ipsilesional ear or cold water in the contralesional ear) or galvanic stimulation (electrical stimulation of the vestibular nerve by electrodes applied to the mastoids). Both methods have been demonstrated to ameliorate neglect symptoms in several studies.[58] However, little work has been done to evaluate the lasting effects of such therapy, and its long-term utility has not yet been definitively established.
  • Neck-Muscle Vibration (NMV): Neck-muscle vibration (NMV) is an investigational therapy that relies on proprioceptive signals to induce re-orienting contralesional spatial bias. Asymmetrical vibration of the contralesional neck muscles is interpreted by the brain as a lengthening of the contralesional neck muscles, creating the illusion of head turning towards the ipsilesional side.[58] NMV therapy has been shown to induce lasting improvement in neglect behavior and performance on cancellation testing.[69] However, its use remains investigational.     

Prognosis

The prognosis of untreated visual neglect is generally good.[70] It has been suggested that around 25% of patients attain complete recovery from visual neglect within three months of cerebral injury.[71] However, the severity of visual neglect has been shown to be a reliable predictor of functional outcomes after stroke,[8][9][10] and persistent neglect represents a major source of stroke-related morbidity.[72]

References

  1. 1.0 1.1 1.2 1.3 1.4 Pelak VS. Visual Neglect (Hemi-inattention). In: Liu GT, Volpe NJ, Galetta SL, eds. Liu, Volpe, and Galetta’s Neuro-Ophthalmology. 3rd ed. Elsevier Inc.; 2019:350-352.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Li K, Malhotra PA. Spatial neglect. Pract Neurol. 2015;15(5):333-339. 
  3. 3.0 3.1 3.2 3.3 3.4 Ting DSJ, Pollock A, Dutton GN, et al. Visual Neglect Following Stroke: Current Concepts and Future Focus. Surv Ophthalmol. 2011;56(2):114-134.
  4. 4.0 4.1 4.2 Corbetta M, Kincade MJ, Lewis C, Snyder AZ, Sapir A. Neural basis and recovery of spatial attention deficits in spatial neglect. Nat Neurosci. 2005;8(11):1603-1610. 
  5. 5.0 5.1 Heilman KM, Watson R, Valenstein E. Neglect and related disorders. In: Heilman KM, Valenstein E, eds. Clinical Neuropsychology. 3rd ed. Oxford: Oxford University Press; 1993:279-336.
  6. 6.0 6.1 Heilman KM, Valenstein E, Watson RT. Neglect and related disorders. Seminars in Neurology. 1984;4(2):209-219.
  7. Denes G, Semenza C, Stoppa E, Lis A. Unilateral Spatial Neglect and Recovery From Hemiplegia. Brain. 1982;105(3):543-552.
  8. 8.0 8.1 Jehkonen M, Ahonen JP, Dastidar P, et al. Visual neglect as a predictor of functional outcome one year after stroke. Acta Neurologica Scandinavica. 2000;101(3):195-201.
  9. 9.0 9.1 Di Monaco M, Schintu S, Dotta M, Barba S, Tappero R, Gindri P. Severity of unilateral spatial neglect is an independent predictor of functional outcome after acute inpatient rehabilitation in individuals with right hemispheric stroke. Archives of Physical Medicine and Rehabilitation. 2011;92(8):1250-1256.
  10. 10.0 10.1 Gialanella B, Mattioli F. Anosognosia and Extrapersonal Neglect as Predictors of Functional Recovery following Right Hemisphere Stroke. Neuropsychological Rehabilitation. 1992;2(3):169-178.
  11. Riddoch MJ, Rappaport SJ, Humphreys GW. Extinction: a window into attentional competition. Progress in Brain Research. 2009;176:149-159.
  12. Mazza V. Simultanagnosia and object individuation. Cognitive Neuropsychology. 2017;34(7-8):430-439.
  13. Walker R, Findlay JM, Young AW, Welch J. Disentangling neglect and hemianopia. Neuropsychologia. 1991;29(10):1019-1027.
  14. Kooistra C, Heilman K. Hemispatial visual inattention masquerading as hemianopia. Neurology. 1989;39:1125-1127.
  15. 15.0 15.1 15.2 15.3 Parton A, Malhotra P, Husain M. Hemi-spatial neglect. Journal of Neurology, Neurosurgery & Psychiatry. 2004;75:13-21.
  16. Hillis AE, Rapp B, Benzing L, Caramazza A. Dissociable coordinate frames of unilateral spatial neglect: “Viewer-centered” neglect. Brain and Cognition. 1998;37(3):491-526.
  17. 17.0 17.1 17.2 Kerkhoff G. Spatial hemineglect in humans. Progress in neurobiology. 2001;63:1-27. 
  18. 18.0 18.1 Committeri G, Pitzalis S, Galati G, et al. Neural bases of personal and extrapersonal neglect in humans. Brain. 2007;130(2):431-441.
  19. Meienberg O, Zangemeister WH, Rosenberg M, Hoyt WF, Stark L. Saccadic eye movement strategies in patients with homonymous hemianopia. Annals of Neurology. 1981;9(6):537-544.
  20. Ishiai S, Furukawa T, Tsukagoshi H. Eye-fixation patterns in homonymous hemianopia and unilateral spatial neglect. Neuropsychologia. 1987;25(4):675-679.
  21. 21.0 21.1 Bartolomeo P. Visual Neglect. Current Opinion in Neurology. 2007;20:381-386.
  22. 22.0 22.1 Vallar G. Spatial hemineglect in humans. Trends in Cognitive Sciences. 1998;2(3):87-97.
  23. Driver J, Mattingley JB. Parietal neglect and visual awareness. Nature Neuroscience. 1998;1(1):17-22.
  24. Stone SP, Halligan PW, Greenwood RJ. The Incidence of Neglect Phenomena and Related Disorders in Patients with an Acute Right or Left Hemisphere Stroke. Age and Ageing. 1993;22:46-52.
  25. Park KC, Lee BH, Kim EJ, et al. Deafferentation-Disconnection neglect induced by posterior cerebral artery infarction. Neurology. 2006;66(1):56-61.
  26. Bird CM, Malhotra P, Parton A, Coulthard E, Rushworth MFS, Husain M. Visual neglect after right posterior cerebral artery infarction. Journal of Neurology, Neurosurgery and Psychiatry. 2006;77(9):1008-1012.
  27. Husain M, Kennard C. Visual neglect associated with frontal lobe infarction. Journal of Neurology. 1996;243(9):652-657.
  28. Watson RT, Valenstein E, Heilman KM. Thalamic Neglect: Possible Role of the Medial Thalamus and Nucleus Reticularis in Behavior. Archives of Neurology. 1981;38(8):501-506.
  29. Healton EB, Navarro C, Bressman S, Brust JC. Subcortical neglect. Neurology. 1982;32(7):776-778.
  30. Vallar G, Perani D. The Anatomy of Unilateral Neglect After Right-Hemisphere Stroke Lesions. Neuropsychologica. 1986;24(5):609-622.
  31. Butter CM, Evans J, Kirsch N, Kewman D. Altitudinal Neglect Following Traumatic Brain Injury: A Case Report. Cortex. 1989;25(1):135-146.
  32. Goodrich GL, Kirby J, Cockerham G, Ingalla SP, Lew HL. Visual function in patients of a polytrauma rehabilitation center: A descriptive study. Journal of Rehabilitation Research and Development. 2007;44(7):929-936.
  33. Silveri MC, Ciccarelli N, Cappa A. Unilateral Spatial Neglect in Degenerative Brain Pathology. Neuropsychology. 2011;25(5):554-566.
  34. Andrade K, Samri D, Sarazin M, et al. Visual neglect in posterior cortical atrophy. BMC Neurology. 2010;10(1):68-74.
  35. Willanger R, Danielsen UT, Ankerhus J. Visual neglect in right‐sided apoplectic lesions. Acta Neurologica Scandinavica. 1981;64(5):327-336.
  36. Saj A, Arzy S, Vuilleumier P. Functional Brain Imaging in a Woman With Spatial Neglect Due to Conversion Disorder To. JAMA. 2009;302(23):2552-2554.
  37. Mesulam M. A Cortical Network for Directed Attention and Utlllateral Neglect. Annals of Neurology. 1981;10:309-325.
  38. Mesulam MM. Spatial attention and neglect: parietal, frontal and cingulate contributions to the mental representation and attentional targeting of salient extrapersonal events. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences. 1999;354(1387):1325-1346.
  39. Suchan J, Rorden C, Karnath HO. Neglect severity after left and right brain damage. Neuropsychologia. 2012;50(6):1136-1141. doi:10.1016/j.neuropsychologia.2011.12.018
  40. Shindo K, Sugiyama K, Huabao L, Nishijima K, Kondo T, Izumi SI. Long-term effect of low-frequency repetitive transcranial magnetic stimulation over the unaffected posterior parietal cortex in patients with unilateral spatial neglect. Journal of Rehabilitation Medicine. 2006;38(1):65-67.
  41. Shindo K, Sugiyama K, Huabao L, Nishijima K, Kondo T, Izumi SI. Long-term effect of low-frequency repetitive transcranial magnetic stimulation over the unaffected posterior parietal cortex in patients with unilateral spatial neglect. Journal of Rehabilitation Medicine. 2006;38(1):65-67.
  42. Fruhmann-Berger M, Karnath HO. Spontaneous eye and head position in patients with spatial neglect. Journal of Neurology. 2005;252(10):1194-1200.
  43. 43.0 43.1 43.2 43.3 43.4 43.5 Azouvi P, Samuel C, Louis-Dreyfus A, et al. Sensitivity of clinical and behavioural tests of spatial neglect after right hemisphere stroke. French Collaborative Study Group on Assessment of Unilateral Neglect (GEREN/GRECO). Journal of Neurology, Neurosurgery and Psychiatry. 2002;73:160-166.
  44. 44.0 44.1 Ferber S, Karnath H. How to Assess Spatial Neglect - Line Bisection or Cancellation Tasks? Journal of Clinical and Experimental Neuropsychology. 2001;23(5):599-607.
  45. Rorden C, Karnath HO. A simple measure of neglect severity. Neuropsychologia. 2010;48(9):2758-2763.
  46. Martin A. A simple test of visual neglect. Neurology. 1973;23(6):658-664.
  47. Sandra W, M. Marsel M. Visual hemispatial inattention: Stimulus parameters and exploratory strategies. Journal of Neurology Neurosurgery and Psychiatry. 1988;51(12):1481-1488.
  48. 48.0 48.1 Halligan PW, Marshall JC, Wade DT. Visuospatial Neglect: Underlying Factors and Test Sensitivity. The Lancet. 1989;334(8668):908-911.
  49. Gauthier L, Dehaut F, Joanette Y. The Bells Test: A quantitative and qualitative test for visual neglect. International Journal of Clinical Neuropsychology. 1989;11(2):49-54.
  50. 50.0 50.1 Schenkenberg T, Bradford DC, Ajax ET. Line Bisection and Unilateral Visual Neglect in Patients with Neurologic Impairment. Neurology. 1980;30(5):509-517
  51. Barton JJ, Black SE. Line bisection in hemianopia. Journal of Neurology, Neurosurgery & Psychiatry. 1998;64(5):660-662.
  52. Mitra AR, Abegg M, Viswanathan J, Barton JJS. Line bisection in simulated homonymous hemianopia. Neuropsychologia. 2010;48(6):1742-1749.
  53. Doricchi F, Angelelli P. Misrepresentation of horizontal space in left unilateral neglect: Role of hemianopia. Neurology. 1999;52(9):1845-1852.
  54. Jewell G, McCourt ME. Pseudoneglect: A review and meta-analysis of performance factors in line bisection tasks. Neuropsychologia. 2000;38(1):93-110.
  55. Halligan PW, Marshall JC, Wade DT. Visuospatial Neglect: Underlying Factors and Test Sensitivity. The Lancet. 1989;334(8668):908-911.
  56. Plummer P, Morris ME, Dunai J. Assessment of unilateral neglect. Physical Therapy. 2003;83(8):732-740.
  57. Hartman-maeir A, Katz N. Validity of the Behavioral Inattention Test (BIT): Relationships With Functional Tasks. The American Jouranal of Occupational Therapy. 1995;49(6):507-516.
  58. 58.0 58.1 58.2 58.3 58.4 58.5 58.6 58.7 58.8 Kerkhoff G, Schenk T. Rehabilitation of neglect: An update. Neuropsychologia. 2012;50(6):1072-1079.
  59. 59.0 59.1 59.2 59.3 Azouvi P, Jacquin-Courtois S, Luauté J. Rehabilitation of unilateral neglect: Evidence-based medicine. Annals of Physical and Rehabilitation Medicine. 2017;60(3):191-197.
  60. Gillen G, Nilsen DM, Attridge J, et al. Effectiveness of interventions to improve occupational performance of people with motor impairments after stroke: An evidence-based review. American Journal of Occupational Therapy. 2015;69(1):1-9.
  61. Kortte KB, Hillis AE. Recent trends in rehabilitation interventions for visual neglect and anosognosia for hemiplegia following right hemisphere stroke. Future Neurology. 2011;6(1):33-43.
  62. 62.0 62.1 Yang NYH, Zhou D, Chung RCK, Li-Tsang CWP, Fong KNK. Rehabilitation interventions for unilateral neglect after stroke: A systematic review from 1997 through 2012. Frontiers in Human Neuroscience. 2013;7(187):1-11.
  63. Serino A, Angeli V, Frassinetti F, Làdavas E. Mechanisms underlying neglect recovery after prism adaptation. Neuropsychologia. 2006;44(7):1068-1078.
  64. Shiraishi H, Yamakawa Y, Itou A, Muraki T, Asada T: Long-term effects of prism adaptation on chronic neglect after stroke. NeuroRehabilitation. 2008;23(2):137–151.
  65. Vangkilde S, Habekost T: Finding Wally: Prism adaptation improves visual search in chronic neglect. Neuropsychologia. 2010;48(7):1994–2004.
  66. Kerkhoff G, Keller I, Ritter V, Marquardt C. Repetitive optokinetic stimulation induces lasting recovery from visual neglect. Restorative Neurology and Neuroscience. 2006;24(4-6):357-369.
  67. Karnath HO. Optokinetic stimulation influences the disturbed perception of body orientation in spatial neglect. Journal of Neurology Neurosurgery and Psychiatry. 1996;60(2):217-220.
  68. Lisa LP, Jughters A, Kerckhofs E. The effectiveness of different treatment modalities for the rehabilitation of unilateral neglect in stroke patients: a systematic review. Neurorehabilitation 2013;33:611–20.
  69. Schindler  G. IK, Karnath H-O, Keller I, Goldenberg G. Neck muscle vibration induces lasting recovery in spatial neglect. Journal of Neurology, Neurosurgery and Psychiatry. 2010;73(C):412-419.
  70. Stone SP, Patel P, Greenwood RJ, Halligan PW. Measuring visual neglect in acute stroke and predicting its recovery: The visual neglect recovery index. Journal of Neurology Neurosurgery and Psychiatry. 1992;55(6):431-436.
  71. Wade DT, Wood VA, Hewer RL. Recovery of cognitive function soon after stroke: a study of visual neglect, attention span and verbal recall. Journal of Neurology, Neurosurgery, and Psychiatry. 1988;51:10-13.
  72. Appelros P, Karlsson GM, Seiger Å, Nydevik I. Neglect and anosognosia after first-ever stroke: Incidence and relationship to disability. Journal of Rehabilitation Medicine. 2002;34(5):215-220.