Digital Therapeutics (DTx) for Egocentric and Allocentric Neglect: History
View Latest Version
Please note this is an old version of this entry, which may differ significantly from the current revision.
Contributor:
Woo-Hyuk Jang
,
Sang-Min Seo

Neglect is a clinical feature observed in cases of brain injury, particularly those affecting the right hemisphere, in which individuals have difficulty recognizing the contralesional side of space. Various therapeutic approaches have been developed for neglect. Many studies have demonstrated the effect of digital therapeutics (DTx) on neglect. Digital therapeutics (DTx) is a newly emerging concept of therapeutic approach in the healthcare system. It is a subdivision of digital health, which is defined as a healthcare system driven by any form of digital technology. The components of digital therapeutics include smartphones, personal digital assistants, virtual reality (VR), and tablet computers that converge with software algorithms. DTx can help reduce healthcare costs and improve availability to patients. However, few studies have reported the effects of DTx on egocentric and allocentric neglect. The differentiation of types of neglect and separate interventions is crucial in the rehabilitation process.

  • egocentric neglect
  • allocentric neglect
  • digital therapeutics
  • apple cancellation test
  • Broken Heart Test

1. Introduction

Neglect is a clinical feature observed in cases of brain injury, particularly those affecting the right hemisphere, in which individuals have difficulty recognizing the contralesional side of space [1][2]. According to previous studies, patients with neglect tend to have poorer rehabilitation outcomes [3], longer hospital stays [4], and are less likely to be discharged to their homes [5] than patients without neglect. Consequently, neglect has been identified as a significant predictor of decreased levels of functional independence [6], increased utilization of healthcare resources [7], and increased burden on the patient’s family [8]. These findings highlight the detrimental effects of neglect on various aspects of patient outcomes.
Neglect has been divided into various subtypes according to classification criteria because of its heterogeneous characteristics [9][10]. For example, neglect is classified as sensory, motor, and representational (imaginal) neglect. In addition, in terms of the spatial domain, neglect is classified as personal neglect, peri-personal neglect, and extra-personal neglect. In terms of the frame of reference, neglect is categorized as egocentric neglect and allocentric neglect (Table 1) [9][10].
Table 1. Subtypes of neglect.
Criteria Aspect of Neglect Range of Space Frame of Reference
Subtype Sensory neglect Personal neglect Egocentric neglect
Motor neglect Peri-personal neglect Allocentric neglect
Representational neglect Extra-personal neglect
The frame of reference is defined as the process in which the brain accepts information and identifies the up–down, left–right, front–back directions, and the relative scale of each axis by specifying the central location [11]. The brain receives information differently depending on whether the central criterion is a viewer or an object. Therefore, the symptoms of neglect are also very different [12]. Egocentric neglect is characterized by responses missing on the contralateral side with respect to the viewer. In contrast, allocentric neglect is characterized by responses missing on the contralateral side with respect to the object [13]. Because of these different characteristics of the two types, allocentric neglect may have a more negative impact on participation in activities of daily living than egocentric neglect [14]. A differential diagnosis between allocentric neglect and egocentric neglect has become possible with the development of evaluation tools, such as the Apple Cancellation Test and the Broken Heart Test [15][16]. In general, these evaluations are performed by counting the number of correct (target of complete shape) and incorrect (one of the left and right targets is incomplete) responses after the patient has marked the target of a complete shape [15][16]. Egocentric neglect is determined by the asymmetry score (commission error) between the correct answers on the right and the left based on the center of the evaluation paper. On the other hand, allocentric neglect is discriminated by the asymmetry score (omission error) between the incorrect answer on the right and the wrong answer on the left based on the target in all incorrect answers [15][16]. The criteria for diagnosing egocentric (cut-off ≥ 3) and allocentric neglect (cut-off ≥ 2) are the same in the Apple Cancellation Test and the Broken Heart Test [15][16]. Egocentric and allocentric neglect, which have been reported on relatively recently, have been mentioned by many scholars as requiring differential diagnosis and intervention according to the type [17].

2. Therapy for Patients with Different Subtypes Neglect

Turgut et al. [18] examined the effects of digital therapy (eye-tracking training based on a computer program) in 32 stroke patients with neglect. They classified the patients into two groups (experimental group, 16 patients, and control group, 16 subjects). The control group received only basic rehabilitation training, and the experimental group received rehabilitation training and eye tracking (digital therapeutics, DTx) at the same time. The eye tracking training consisted of two programs: (1) when a blue square on the computer screen moved in the direction of the neglect, and (2) when the square changed to red, training to press the switch was performed (20 min/one session, total of eight sessions over two weeks). The differential evaluation of egocentric and allocentric neglect was performed using the Apple Cancellation Test. This eye-tracking task was performed simultaneously with transcranial direct current stimulation (tDCS, 1.5 and 2.0 mA) of the right posterior parietal lobe (P4). The assessments were conducted as two pre (T1, T2)/two post (T3, T4) comparisons, and there were no significant changes in the Apple Cancellation Test and the three horizontal line bisection test in both groups at T1 and T2. However, the neuropsychological test (body orientation) and the clock drawing test conducted at the last assessment of the experimental group (T4, 6 days after the end of training) showed effective significant changes in both egocentric and allocentric neglect [18]. This research had several limitations. This research was not designed to observe the long-term effects and only the effects of DTx because digital therapy was applied with tDCS. In addition, there were two pre-training assessments for both groups, but there was no statistical analysis, and both groups underwent separate rehabilitation during the intervention period.
Hagiwara et al. [19] reported the effects of the training to provide visual cues using virtual reality (VR) for treating allocentric neglect in four stroke patients. The visual cues were provided using a head-mount display (HMD) type VR, Oculus Rift (Oculus VR., Inc. 19800 MacArthur Blvd Irvine, CA 92612 United States). The training consisted of a four-digit reading task followed by four actions: (1) displaying the clue stimulation, (2) obscuring the surrounding environment, (3) moving the clue stimulation, and (4) removing the obscuration. This action drew the patient’s attention to the neglected side, and then a four-digit number was read again. This training was repeated 10 times. Evaluation was performed using the apple cancellation test and line bisection with three horizontal lines, twice before and after the intervention. Patients showed fewer errors in the Apple Cancellation and Line Bisection Tests after training than those before training [19]. On the other hand, this research was conducted only once. Therefore, the author could only demonstrate the immediate effects of the treatment. Thus, the long-term effects of the treatment were not reported. The small number of subjects was another limitation. Furthermore, although researchers used the Apple Cancellation Test, which can be used for differential diagnosis, researchers cannot understand egocentric neglect by analyzing only the results for commission.
Huygelier et al. [20] investigated the effect of therapy using a VR game on stroke patients with neglect. They classified the subjects into two groups (experimental group, seven stroke patients with neglect; control group, 15 normal subjects). Both groups underwent training via VR using an Oculus Rift head-mounted display (HMD) VR device (Oculus VR., Inc.). The VR training included a variety of contents for treating neglect, including stimulation and cueing on the neglected side. Six sessions (45 min/1 session/day) were performed over seven days. The assessments were the heart cancellation test in the psychometric properties of the Dutch Oxford Cognitive Screen (OCS-NL) and the letter cancellation test and figure copy task in the Behavioral Inattention Test (BIT) were administered before and after the intervention. The authors reported that presenting various stimuli and cues in the neglected area using VR was effective in accurate target recognition in egocentric neglect patients [20]. On the other hand, their study was limited by the short period (seven days) and the use of distinguishable evaluation tools (to determine whether neglect is present). In addition, although this research used the heart cancellation test of OCS-NL, which can distinguish between types of neglect, researchers could only indirectly check the effect on egocentric neglect by counting only omissions (the number of commissions was used to determine allocentric neglect).
Schenke et al. [21] reported on the effects of digital therapy (auditory cueing and computer-based eye-tracking training) in stroke patients with egocentric neglect. This research consisted of Study 1 and Study 2. In Study 1, they classified the patients with neglect into two groups (experimental group, 11 patients; control group, 14 patients). The experimental group underwent auditory cueing with basic rehabilitation. The control received only basic rehabilitation. This research involved training detect to the movement of sound from the right to left headphones while wearing headphones (30 min/session, five times/week for three weeks). In Study 2, another eight patients with neglect (one group) were subjected to computer-based training (digital therapeutics), which provided patients with auditory cueing and eye-tracking training simultaneously. In this research, the patients had to press a button in the following situations: (1) when the target moved from right to left on the computer screen and (2) when they heard the word “here” through the headphones (30 min/session, five times/week for three weeks). In Study 1, the line bisection test (3 lines) was administered (twice) before and (twice) after training, and the Apple Cancellation Test was administered (twice) before and (once) after training. In Study 2, the visual scanning test was administered twice before and after training. After three weeks of treatment, both studies reported that the severity of egocentric neglect decreased on the line bisection, the Apple Cancellation Test, and the visual scanning test. In addition, Study 2 confirmed that digital therapeutics allowed for the simultaneous provision of auditory cues and eye-tracking training and that convenient treatment was possible [21]. On the other hand, they did not report the long-term effects of this DTx and control group in Study 2. In addition, there was no mention of allocentric neglect despite the use of the discriminative apple cancellation test.
In 2021, Vestito et al. [22] examined the effects of computer-assisted cognitive training (CCT) on egocentric neglect in one patient with posterior cortical atrophy. The four-week training consisted of CCT only for the first two weeks (T1) using the Remote Monitoring Validation Engineering System (ReMoVES: University of Genova). In this research, three of the most appropriate games for the treatment of neglect in ReMoVES, including ShelfCans, OwlNest, and ChinaLanterns, which did not provide detailed information about the games, were applied (20 min/session, five times/week for two weeks). During the next two weeks (T2), CCT and tDCS (P4, 1.5 mA on the right posterior parietal lobe (P4) were delivered simultaneously (20 min/session, five times/week, for two weeks). Evaluations were carried out using Albert’s Test, line bisection test (22 lines), and Apple Cancellation Test installed in ReMoVES. Three tests were performed: one before training (T0, once) and one each at the end of T1 and T2 training. Researchers only report significant results for all tests performed after T2. Therefore, they reported that the simultaneous application of both modalities (CCT and tDCS) was more effective than only CCT alone [22]. This research used the Apple Cancellation Test for a differential diagnosis. On the other hand, there was no direct relationship between the changes in egocentric and allocentric neglect. Another limitation of this research was that the improvements in egocentric neglect could be identified indirectly by the difference in omission on the Apple Cancellation Test.
Turgut et al. [23] compared the effect of two DTx in sixty patients with neglect. In Study 1, 30 stroke patients (right hemisphere injury) were divided into an experimental group (20 patients with neglect) and a control group (10 patients without neglect). In Study 2, another 30 stroke patients (right hemisphere injury) were divided into an experimental group (17 patients with neglect) and a control group (13 patients without neglect). In both studies, computerized “three blocks of Posner’s covert shift of attention task (Posner task)” were used for DTx. The Posner task was performed by pressing a square on the 24-inch monitor, where the stimulus image was presented between the two blank squares on the monitor. The cue elicits a rapid response by predicting where the stimulus picture will appear. The task was performed in two sessions consisting of three blocks of 100 trials each, with two days between the sessions. Response time to a stimulus was measured. In Study 1, endogenous cueing (centrally presented arrows as cues) was provided. In Study 2, exogenous cueing (peripherally presented crosses were used as cues) was provided and compared. In both studies, response time was measured twice, three days apart. The tools used for evaluation are the Apple Cancellation Test and the line bisection test. They reported that response time and omissions decreased with endogenous cueing but not with exogenous cueing. Therefore, endogenous cueing was more effective for egocentric neglect [23]. This research had a short study period of 4 days to explore the feasibility of training with the Posner task. This suggests that a longer-term training study is needed. On the other hand, this research presented the average unilateral neglect type between groups using the Apple Cancellation Test, but the results only compared omission error and response time to identify egocentric neglect. Therefore, their study was limited by the lack of a detailed comparison of the rehabilitation effects according to neglect type. Finally, there is no detailed description of the evaluation tool used for line bisection, making it difficult to understand the exact tool.

This entry is adapted from the peer-reviewed paper 10.3390/brainsci13081170

References

  1. Heilman, K.M.; Valenstein, E. Mechanisms Underlying Hemispatial Neglect. Ann. Neurol. 1979, 5, 166–170.
  2. Vallar, G.; Perani, D. The Anatomy of Unilateral Neglect After Right-hemisphere Stroke Lesions: A Clinical/CT-scan Correlation Study in Man. Neuropsychologia 1986, 24, 609–622.
  3. Chen, P.; Chen, C.C.; Hreha, K.; Goedert, K.M.; Barrett, A.M. Kessler Foundation Neglect Assessment Process Uniquely Measures Spatial Neglect During Activities of Daily Living. Arch. Phys. Med. Rehabil. 2015, 96, 869–876.
  4. Katz, N.; Hartman-Maeir, A.; Ring, H.; Soroker, N. Functional Disability and Rehabilitation Outcome in Right Hemisphere Damaged Patients With and Without Unilateral Spatial Neglect. Arch. Phys. Med. Rehabil. 1999, 80, 379–384.
  5. Paolucci, S.; Antonucci, G.; Grasso, M.G.; Pizzamiglio, L. The Role of Unilateral Spatial Neglect in Rehabilitation of Right Brain-Damaged Ischemic Stroke Patients: A Matched Comparison. Arch. Phys. Med. Rehabil. 2001, 82, 743–749.
  6. Jehkonen, M.; Laihosalo, M.; Kettunen, J.E. Impact of Neglect on Functional Outcome after Stroke: A Review of Methodological Issues and Recent Research Findings. Restor. Neurol. Neurosci. 2006, 24, 209–215.
  7. Rundek, T.; Mast, H.; Hartmann, A.; Boden-Albala, L.; Lennihan, L.; Lin, I.F.; Pail, M.C.; Sacco, R.L. Predictors of Resource Use after Acute Hospitalization: The Northern Manhattan Stroke Study. Neurology 2000, 55, 1180–1187.
  8. Chen, P.; Fyffe, D.C.; Hreha, K. Informal Caregivers’ Burden and Stress in Caring for Stroke Survivors with Spatial Neglect: An Exploratory Mixed-method Study. Top Stroke Rehabil. 2017, 24, 24–33.
  9. Upshaw, J.N.; Leitner, D.W.; Rutherford, B.J.; Miller, H.D.; Libben, M.R. Allocentric versus Egocentric Neglect in Stroke Patients: A Pilot Study Investigating the Assessment of Neglect Subtypes and Their Impacts on Functional Outcome Using Eye Tracking. J. Int. Neuropsychol. Soc. 2019, 25, 479–489.
  10. Zebhauser, P.T.; Vernet, M.; Unterburger, E.; Brem, A.K. Visuospatial Neglect—A Theory-informed Overview of Current and Emerging Strategies and A Systematic Review on The Therapeutic Use of Non-Invasive Brain Stimulation. Neuropsychol. Rev. 2019, 29, 397–420.
  11. Mozer, M.C. Frames of Reference in Unilateral Neglect and Visual Perception: A Computational Perspective. Psychol. Rev. 2002, 109, 156–185.
  12. Behrmann, M.; Plaut, D.C. The Interaction of Spatial Reference Frames and Hierarchical Object Representations: Evidence from Figure Copying in Hemispatial Neglect. Cogn. Affect Behav. Neurosci. 2001, 1, 307–329.
  13. Gainotti, G.; Ciaraffa, F. Is “Object-Centred Neglect” A Homogeneous Entity? Brain Cogn. 2013, 81, 18–23.
  14. Chen, P.; Hreha, K.; Kong, Y.; Barrett, A.M. Impact of Spatial Neglect on Stroke Rehabilitation: Evidence from The Setting of An Inpatient Rehabilitation Facility. Arch. Phys. Med. Rehabil. 2015, 96, 1458–1466.
  15. Bickerton, W.L.; Samson, D.; Williamson, J.; Humphreys, G.W. Separating Forms of Neglect Using the Apples Test: Validation and Functional Prediction in Chronic and Acute Stroke. Neuropsychology 2011, 25, 567–580.
  16. Demeyere, N.; Riddoch, M.J.; Slavkova, E.D.; Bickerton, W.L.; Humphreys, G.W. The Oxford Cognitive Screen (OCS): Validation of A Stroke-specific Short Cognitive Screening Tool. Psychol. Assess. 2015, 27, 883–894.
  17. Turgut, N.; Möller, L.; Dengler, K.; Steinberg, K.; Sprenger, A.; Eling, P.; Kastrup, A.; Hildebrandt, H. Adaptive cueing treatment of neglect in stroke patients leads to improvements in activities of daily living: A randomized controlled, crossover trial. Neurorehabil. Neural. Repair. 2018, 32, 988–998.
  18. Turgut, N.; Miranda, M.; Kastrup, A.; Eling, P.; Hildebrandt, H. tDCS Combined with Optokinetic Drift Reduces Egocentric Neglect in Severely Impaired Post-acute Patients. Neuropsychol. Rehabil. 2018, 28, 515–526.
  19. Hagiwara, A.; Yasuda, K.; Saich, K.; Muroi, D.; Kawaguchi, S.; Ohira, M.; Matsuda, T.; Lwata, H. Development of A Visual Cueing System Using Immersive Virtual Reality for Object-centered Neglect in Stroke Patients. In Proceedings of the 2018 IEEE International Conference on Systems, Man, and Cybernetics (SMC), Miyazaki, Japan, 7–10 October 2018; pp. 1022–1025.
  20. Huygelier, H.; Schraepen, B.; Lafosse, C.; Vaes, N.; Schillebeeckx, F.; Michiels, K. An Immersive Virtual Reality Game to Train Spatial Attention Orientation after Stroke: A Feasibility Study. Appl. Neuropsychol. Adult 2020, 29, 915–935.
  21. Schenke, N.; Franke, R.; Puschmann, S.; Turgut, N.; Kastrup, A.; Thiel, C.M.; Hildebrandt, H. Can Auditory Cues Improve Visuo-spatial Neglect? Results of Two Pilot Studies. Neuropsychol. Rehabil. 2021, 31, 710–730.
  22. Vestito, L.; Trombini, M.; Mori, L.; Dellepiane, S.; Trompetto, C.; Morando, M.; Bandini, F. Improved Visuospatial Neglect after tDCS and Computer-assisted Cognitive Training in Posterior Cortical Atrophy: A Single-case Study. Neurocase 2021, 27, 57–63.
  23. Turgut, N.; Jansen, A.L.; Nielsen, J.; Heber, I.; Eling, P.; Hildebrandt, H. Repeated Application of The Covert Shift of Attention Task Improves Endogenous but Not Exogenous Attention in Patients with Unilateral Visuospatial Inattention. Brain Cogn. 2021, 151, 105732.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.
This entry is offline, you can click here to edit this entry!
Video Production Service
Feedback