Disability and Rehabilitation

ISSN: 0963-8288 (Print) 1464-5165 (Online) Journal homepage: http://www.tandfonline.com/loi/idre20

Effects of lateralized light flash and color on unilateral neglect Yang-teng Fan, Ching-yi Wu, Wen-chung Tsai & Keh-chung Lin To cite this article: Yang-teng Fan, Ching-yi Wu, Wen-chung Tsai & Keh-chung Lin (2015) Effects of lateralized light flash and color on unilateral neglect, Disability and Rehabilitation, 37:26, 2400-2406, DOI: 10.3109/09638288.2015.1031284 To link to this article: http://dx.doi.org/10.3109/09638288.2015.1031284

Published online: 20 Apr 2015.

Submit your article to this journal

Article views: 79

View related articles

View Crossmark data

Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=idre20 Download by: [Chinese University of Hong Kong]

Date: 09 November 2015, At: 13:17

http://informahealthcare.com/dre ISSN 0963-8288 print/ISSN 1464-5165 online Disabil Rehabil, 2015; 37(26): 2400–2406 ! 2015 Informa UK Ltd. DOI: 10.3109/09638288.2015.1031284

RESEARCH PAPER

Effects of lateralized light flash and color on unilateral neglect Yang-teng Fan1, Ching-yi Wu2,3, Wen-chung Tsai4, and Keh-chung Lin1,5

Downloaded by [Chinese University of Hong Kong] at 13:17 09 November 2015

1

School of Occupational Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan, 2Department of Occupational Therapy and Graduate Institute of Behavioral Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan, 3Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan, 4Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, and College of Medicine, Chang Gung University, Taoyuan, Taiwan, and 5Division of Occupational Therapy, Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan Abstract

Keywords

Purpose: Bottom-up-based sensory stimulation has been useful in promoting recovery from post-stroke neglect. Light and color are salient stimuli for guiding our orienting behaviors and influence the degree of spatial bias. This study evaluated the effects of lateralized light flash and color on spatial bias in unilateral neglect (UN). Method: We enrolled 15 individuals with UN as a consequence of a right hemispheric stroke of less than 65 d. This was a 3  3 design study with three conditions of lens color (colorless, red, and blue) and three conditions of flash light locations (no flash, left, and right). Results: All participants showed a decrease in ipsilesional spatial bias under left-side light flash and a red lens. Right-side light flash and a blue lens induced more rightward bias than other conditions. Conclusions: This evidence confirms the use of sensory stimulation to complement post-stroke UN remediation. Lateralized light flash to the contralesional space and red-colored lenses have beneficial effects on amelioration of UN, whereas ipsilesional light flash and the color blue may exacerbate ipsilesional spatial bias in stroke survivors with UN.

Color, lateralized lights, stroke, unilateral neglect History Received 22 April 2014 Revised 5 March 2015 Accepted 16 March 2015 Published online 20 April 2015

ä Implications for Rehabilitation  

Contralesional light flash and the color red may ameliorate ipsilesional spatial bias in stroke survivors with unilateral neglect (UN). Ipsilesional flash of light and the color blue may worsen ipsilesional spatial bias in stroke survivors with UN.

Introduction Unilateral neglect (UN) is a major clinical feature as well as a prognostic indicator resulting from stroke [1]. This syndrome is clinically characterized by the inability to perceive, respond, or orient to stimuli presented to the space contralateral to a brain lesion, independent of primary sensory or motor deficits [2]. Although spontaneous recovery of UN occurs in some patients at an early stage [3–5], UN remains severe in many patients and is a well-recognized predictor of slower recovery patterns of sensorymotor deficits [6,7] and poor functional outcomes after stroke [5,8,9]. Several rehabilitation treatments have been proposed to alleviate the problems generated by post-stroke UN [10,11], and some novel strategies show the beneficial effects [12,13]. Such UN interventions are commonly categorized as involving

Address for correspondence: Keh-chung Lin, ScD, OTR/L, School of Occupational Therapy, College of Medicine, National Taiwan University and Division of Occupational Therapy, Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, 17, F4, Xu Zhou Road, Taipei, Taiwan. Tel: +886-2-33668180. Fax: +886-2-23511331. E-mail: [email protected]

top-down or bottom-up processing [11,14]. The top-down approach relies on the patient learning a new skill that brings a reorientation of visual scanning toward the neglected side [15–18]. The bottom-up approach attempts to rearrange external stimuli to take advantage of inherent salient properties of perceptual information [12,18,19]. Although both approaches have shown positive outcomes for UN, some interventions may not be easily translated to clinical applications [20] and do not take onset time of stroke into consideration [4,12,13]. For example, identifying an optimal period for the most favorable treatment response is important, especially in the early stage, because the brain is primed to neurological recovery in the first 3 months after stroke [4,21,22]. Bottom-up-based sensory stimulation uses a technique associated with a reflexive shift of attention [18,23]. This technique is hypothesized to change the inter-hemispheric imbalance by reducing the disinhibition of the orienting mechanism of the unneglected side [24]. For example, visual stimuli to the right brainstem components of the orienting system generate leftward saccades and reduce spatial bias toward the ipsilesional side of space for post-stroke UN [24,25]. More specifically, transient visual stimuli are potent activators of neurons in the deeper collicular layers [26] and capture attention to the location of the

Light and color stimulation in unilateral neglect

DOI: 10.3109/09638288.2015.1031284

2401

Downloaded by [Chinese University of Hong Kong] at 13:17 09 November 2015

Table 1. Demographic and clinical characteristics of right-handed study participants.

Patient

Age (y)

Sex

Days from stroke (d)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

59 62 64 63 73 74 61 60 66 53 69 62 70 71 58

Female Male Male Male Male Male Female Female Female Male Male Male Female Male Female

37 62 43 28 57 40 53 65 23 59 39 46 31 33 51

Type of stroke

Comorbidity

Lesion site

Severity of neglect

Ischemic Ischemic Ischemic Ischemic Hemorrhagic Hemorrhagic Ischemic Hemorrhagic Ischemic Hemorrhagic Ischemic Hemorrhagic Ischemic Hemorrhagic Ischemic

HTN HTN, DM CD, DM HTN, DM HTN CD HTN HTN, DM HTN CD, DM CD HTN CD HTN HTN, DM

PT, BG, Th FP, BG FPT, BG FP, Th PT, BG BG, Th IC, PT FP, Th PT, BG Th FTPO P, BG PT, Th PT P, BG, Th

Moderate Mild Mild Mild Moderate Mild Mild Mild Mild Mild Mild Mild Mild Moderate Moderate

Laterality index (%) 100 90 80 90 100 80 90 90 100 100 100 90 80 90 100

Visual fields

Visual acuity: uncorrected (corrected)

Rehabilitation procedures

Full Full Full Full Full Full Full Full Full Full Full Full Full Full Full

20/20 20/25 20/30 (20/20) 20/20 20/25 20/30 (20/20) 20/20 20/25 20/20 20/30 (20/20) 20/30 (20/20) 20/30 (20/20) 20/40 (20/20) 20/25 20/30 (20/20)

OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT,

PT PT PT PT PT PT PT PT PT PT PT PT PT PT PT

HTN, hypertension; DM, diabetes mellitus; CD, cardiac diseases; F, frontal; P, parietal; T, temporal; O, occipital; BG, basal ganglia; Th, thalamus; IC, internal capsule; OT, occupational therapy; PT, physical therapy.

stimuli [25]. Butter et al. used dynamic (e.g. flickering light) and static (e.g. continuous light) visual stimuli randomly in the contralesional space and found that both stimuli attenuated neglect; however, this effect was more effective under the condition of dynamic visual stimuli [27]. Other studies showed that lateralized visual stimuli or kinetic visual cues to the neglected space substantially improved neglect on several neuropsychological tests (such as the line and letter cancellation tests and the line bisection test) and in some daily activities [28–30]. These findings imply that lateralized visual stimuli can counterbalance the distortion of spatial attention, thus directing patients with post-stroke UN to perceive stimuli in the neglected side of space [31]. Color is a fundamental component of human perception and has specific effects on attention and orienting behaviors [32–35]. For example, red is a warm color, and blue is a cool color. Cool and warm colors bring about different physiological and behavioral reactions of human [36]. In general, warm colors can generate more arousal and attention than cool colors [37], and cool colors elicit greater relaxation than warm ones [38]. These responses have also been found in patients affected by neurological disorders [39]. Although research has demonstrated that colors can modulate spatial attention in stroke patients, such effects on UN have received little attention. Patients with UN may show intact searching patterns for the contralesional space in the color priming task [40]. Wilkinson et al. used a red bar and green distracters and showed no differences in error rates between right and left hemifields [41]. Lucas and Vuilleumier [42] found that visual searching on both sides of space was intact in UN patients under the condition of red-colored cueing. A recent study examined the effect of color lightness in UN patients and showed fewer omissions on the left side of the cancellation test in the condition of a warm background color than in the condition of cool background color [43]. These results suggest that warm colors may elicit more attention toward the neglected side of space than cool colors for patients with UN. These studies, however, mainly focused on the effects of color priming or cueing. In the present study, we assessed whether the perceived colors of the visual display would modulate spatial bias in stroke survivors with UN. The present study was designed to examine the effects of sensory stimulation on spatial bias by using lateralized light flash

along with warm and cool colors in participants with post-stroke UN. We predicted two possible outcomes: If the lateralized visual inputs capture attention to the neglected side of space, then these participants would exhibit an increased leftward-orienting tendency over their contralesional field during the condition of contralesional light flash. Alternatively, if spatial biases were also modulated by colors, then red, compared with blue, would enhance visumotor and visual performance in or toward the neglected space and be demonstrated on the neuropsychological assessments and oculomotor measures for post-stroke UN.

Methods The local ethics committee approved the study. Each participant signed an informed consent. Participants The study sample consisted of 15 right-handed participants (6 women and 9 men) with UN after a right hemispheric stroke (Table 1). Three additional participants were excluded from the final sample due to technical failures such as calibration problems and excessive blinking. The average age of the participants was 64.3 years (standard deviation, 6.1). The inclusion criteria for enrollment were pathologic performance on the Schenkenberg’s line bisection test (mean bias index 40.1) [43] and the symbol cancellation test (omission numbers of the left hemispace minus the right hemispace 45) [44]. They showed mild (n ¼ 11) to moderate (n ¼ 4) neglect in the symbol cancellation test [23,45]. All participants had normal or corrected-to-normal visual acuity. Other inclusion criteria were a negative neurologic and psychiatric history, a willingness to participate, and the ability to perform the right-handedness and intact visual fields on confrontation tests. Procedures This was 3  3 within-participant study design, and all of the possible conditions were counterbalanced and randomized across participants. Nine conditions were included:  no light flash with plain lens, red lens, or blue lens;  left-side light flash with plain lens, red lens, or blue lens; and  right-side light flash with plain lens, red lens, or blue lens. Before the main experiment, each participant underwent assessments of behavioral measures, including handedness,

2402

Y.-t. Fan et al.

Disabil Rehabil, 2015; 37(26): 2400–2406

Downloaded by [Chinese University of Hong Kong] at 13:17 09 November 2015

Figure 1. Eyelights. (A) Complete set; (B) light-emitting diodes of the eyelights glasses.

visual fields, and bilateral near-visual acuity. Handedness was determined using the Edinburgh Handedness Inventory [46], a measurement scale used to assess hand dominance in 10 different everyday activities. Visual fields were assessed by traditional confrontation testing with two examiners [47]. The examiner moved his finger out of the participant’s visual field and then brought it back in. The participants signaled when the examiner’s finger came back into view. Uncorrected and corrected nearvisual acuity measurements were obtained using a hand-held letter chart at a standard distance of 14 inches. Participants were asked to read the letters on the chart without moving their heads, starting with the largest letter [48]. At the beginning of each exposure condition, all participants performed the figure copying task while wearing goggles with different colored lenses and locations of light flash for about 6 min. After each copying task was completed, participants performed the Schenkenberg’s line bisection test, the symbol cancellation test, and the computerized landmark tasks under the nine conditions of exposure as noted above. To avoid possible carryover effects, a 5-min mandatory break was used between any two consecutive conditions.

wide) were displayed horizontally and centrally in the center of the screen. The lines were marked with a vertical mark placed 4 mm to the left of center, 4 mm to the right of center, or at the center of a given line. Participants were instructed to respond ‘‘yes’’ if the line appeared to be correctly bisected and ‘‘no’’ if otherwise. Each condition consisted of 20 trials. The horizontal lines were correctly (in 50% of trials) or incorrectly (in the remaining 50% of trials) marked. Owing to technical problems, we did not collect the behavioral data on this task when we conducted the study. Participants’ eye movements were recorded simultaneously by the oculomotor analysis system (see description below).

Neuropsychological tests and apparatus

Oculomotor analysis

The Schenkenberg’s line bisection test

This study used a Tobii 1750 binocular eye tracker with a 17-inch display at a distance of 70 cm between the monitors and the participant’s eyes (1280  1024 pixels resolution; Tobii Technology Inc., Fall Church, VA). The eye tracker had a tracking rate or frame rate of 50 Hz with cameras and illuminators hidden behind filters. The eye tracker was a bright-pupil eye tracker that used a high-resolution camera and a large field of view to capture images of the participant’s eyes. The tracker illuminated each participant’s corneas with two near-infrared diodes to generate reflection patterns on the corneas. A video camera gathered these reflection patterns and the stance of the participant. Digital image processing was used to extract the pupils from the video signal, and a 9-point calibrating system was used to map pupil locations to gaze locations on the screen. During the calibration period, participants were required to hold their heads still and look at calibration and fixation points on the monitor in front of them. Once calibration was successfully established, stimuli were presented. The laterality of the longest fixation duration and fixation numbers (laterality index: [R  L/R + L]) were extracted [50] with Tobii Studio software and adapted to SPSS databases for further analyses. Positive values denoted rightward deviations.

Schenkenberg et al. designed and standardized a version of this task with 20 lines of six different lengths drawn on an A4 page [49]. The participants mark the center of each line with a pencil. The present study calculated the deviation of the participant’s bisection of each of the lines from the true center measured in millimeters (the mean bias index) for this test. This transformation index resulted in a positive score that denoted rightward deviations, whereas a negative value indicated leftward deviations. The symbol cancellation test The test consisted of several shapes or symbols on a sheet of paper, and the participant was instructed to circle all of the targets of one particular shape [44]. The lateralized omission errors (R  L/R + L) were scored to assess the severity of UN. A more negative value on the laterality index represented greater left-side omissions. Computerized landmark task Participants were required to judge whether premarked lines were correctly bisected. For this test, the lines (12-cm long and 1.5-mm

The eyelights The eyelights (Eyelights Ltd., Bristoal, UK; Figure 1) spectacles are designed to incorporate light-emitting diodes (LED) that can be selectively activated in front of the left or the right eye (Figure 1B). The LED was on and flashed at 0.1 Hz for 2 s and was off for 8 s. The current study used plain, red, and blue lenses for color conditions.

Downloaded by [Chinese University of Hong Kong] at 13:17 09 November 2015

DOI: 10.3109/09638288.2015.1031284

Light and color stimulation in unilateral neglect

2403

Figure 2. Performance on traditional neglect assessments under different locations of light flash and colors. (A) Mean bias index of the Schenkenberg’s line bisection test. (B) Laterality omissions of the symbol cancellation test. Error bars indicate standard errors.

Data analysis Statistical analyses of behavioral and oculomotor performances were conducted using a two-way repeated-measures analysis of variance (ANOVA) with light flash location (left, right, none) and color type (plain, red, blue) as the within-subject factors. The dependent variables were the mean bias index of the Schenkenberg’s line bisection test, the laterality index of omission errors of the symbol cancellation test, and the two oculomotor variables (the laterality index of fixation with duration and numbers). Degrees of freedom were corrected using the Greenhouse-Geisser method. In addition to the set statistical threshold of 0.05, we reported the effect size partial eta-squared (2) to represent the magnitude of condition effect. If a significant main effect and interactions were observed, pairwise comparisons were performed with partial 2 [51].

Results Neuropsychological tests Our ANOVA model showed that the main effects for light flash location (F2,28 ¼ 85.29, 2 ¼ 0.86, p50.001) and color type (F2,28 ¼ 64.19, 2 ¼ 0.82, p50.001) were significant in the mean bias index of the Schenkenberg’s line bisection test. An interaction of light location and color type was also noted (F4,56 ¼ 4.16, 2 ¼ 0.23, p ¼ 0.005). The red lens elicited more contralesional deviation in the Schenkenberg’s line bisection test than the blue and plain lens within left-side light flash (2 ¼ 0.86), followed by no light flash (2 ¼ 0.80) and right-side light flash (2 ¼ 0.43, Figure 2A). Our ANOVA model also showed main effects for location of the light flash (F2,28 ¼ 43.06, 2 ¼ 0.76, p50.001) and color type (F2,28 ¼ 18.12, 2 ¼ 0.56, p50.001) in laterality omissions of the symbol cancellation test. Few omission errors were observed in the left hemispace under the left-side light flash condition, irrespective of different colors. However, the blue lens elicited more omissions in the left hemispace than the red and plain lenses, irrespective of different locations of light flash. Unlike Schenkenberg’s line bisection test, no significant interaction was

found for light location  color type (F4,56 ¼ 0.23, 2 ¼ 0.016, p ¼ 0.92) in laterality omissions of the symbol cancellation test (Figure 2B). Oculomotor measures The laterality index of fixation numbers and the longest duration were analyzed by two-way repeated-measures ANOVA with the light flash location and color type as within-subject factors. The findings showed significant main effects in laterality of the longest fixation duration for light location (F2,28 ¼ 130.63, 2 ¼ 0.90, p50.001) and color type (F2,28 ¼ 81.34, 2 ¼ 0.85, p50.001). The longest fixation duration to the left hemispace was noted under the left-side light flash condition, irrespective of different colors. However, the blue lens elicited the shortest fixation duration to the left hemispace, irrespective of different locations of light flash (Figure 3A). There was no significant interaction for light location  color type (F4,56 ¼ 1.84, 2 ¼ 0.012, p ¼ 0.13). The ANOVA model also showed the main effects for light location (F2,28 ¼ 10.21, 2 ¼ 0.42, p ¼ 0.001) and color type (F2,28 ¼ 21.05, 2 ¼ 0.61, p50.001) in laterality of fixation numbers. In addition, the light location by color interaction effect was significant in the laterality index of fixation numbers (F4,56 ¼ 2.88, 2 ¼ 0.17, p ¼ 0.031). The red lens elicited more fixation numbers to the left hemispace than the blue and plain lens within the left-side light flash (2 ¼ 0.62), followed by no light flash (2 ¼ 0.32) and right-side light flash (2 ¼ 0.29, Figure 3B).

Discussion In summarizing the findings of this study, we note that the contralesional light flash and the red-colored lens ameliorate UN on the conventional neglect assessments and oculomotor performance in stroke survivors with mild to moderate UN. However, the ipsilesional light inputs and a blue lens may worsen ipsilesional spatial bias and deteriorate oculomotor responses to the neglected space. These results confirm the beneficial effects of lateralized visual inputs to the neglected space and provide the

Downloaded by [Chinese University of Hong Kong] at 13:17 09 November 2015

2404

Y.-t. Fan et al.

Disabil Rehabil, 2015; 37(26): 2400–2406

Figure 3. Oculomotor performance on the computerized landmark task under different locations of light flash and colors. (A) Laterality index of the longest fixation duration. (B) Laterality index of the fixation numbers. Error bars indicate standard errors.

evidence that colors have modulatory effects on spatial biases for individuals with post-stroke UN. Our findings suggest that the combination of lateralized light flash and color stimulation may have a beneficial effect on treating UN in the post-acute phase after stroke. The effects of lateralized light flash reported here are consistent with previous studies that showed dynamic visual inputs to the contralesional space could ameliorate UN [27–29]. We found that the flashing lights on the neglected side elicited the greatest leftward spatial tendency on the conventional neglect assessments than conditions of no light flash and ipsilesional light flash. Lateralized light flash to the ipsilesional side induced the most rightward bias on the Schenkenberg’s line bisection test and the symbol cancellation test than other conditions. Individuals with UN have the potential to rapidly adapt in response to transient signals so that their inattention to the contralesional space can be reduced, resulting in a balanced spatial lateralization [52,53]. Butter et al. argued that increased visual inputs from the contralesional eye should attenuate neglect by facilitating the production of eye movements in the contralesional space and vice versa [28]. Here, oculomotor responses to the neglected side were also noted under the condition of contralesional light flash. However, the right-side light flash produced the shortest fixation duration in the contralesional space than the conditions of no light flash and contralesional light flash. These findings support the notion that lateralized visual stimuli modify the control of spatial attention in individuals with UN and provide important practical implications for neglect rehabilitation. Notably, the current results showed different effects on spatial bias between warm and cool colors in participants with poststroke UN. Exposure to the red lens resulted in significant improvements in conventional neglect assessments; however, the opposite patterns were shown under the condition of the blue lens. Red colors are more arousing than blue on visual cortex neural activities and autonomic nervous system functions [37,54]. There is evidence that the parvocellular pathway of the visual system can process fine detail and that the receptive fields of its cells are

color-opponent [55]. Research on UN also has demonstrated that some intact functions (e.g. color perception) may influence orienting performance to the affected space and that such processing exhibits significant activation in the intact visual system [42,56]. Moreover, we also observed that individuals with post-stroke UN exhibited increased fixation numbers and duration to the neglected side of space during the condition of red lenses but that blue lenses reduced these effects. Research on the autonomic system showed that warm colors activated sympathetic activity (increased skin conductance and heart rate) and eye muscle contraction, whereas cool colors elicited parasympathetic activity (reduced heart rate and galvanic skin response) and decreased eye movements [57,58]. Altogether, these findings imply that variously colored contexts would modulate the central and autonomic nervous systems and then influence spatial attention in individuals with post-stroke UN [40,59]. Here, we addressed how spatial bias was modulated by different colors for post-stroke UN. More behavioral and imaging research is needed to clarify possible mechanisms of UN within exposure to color stimuli. This study has some limitations that warrant consideration. First, is the lack of control groups, such as post-stroke patients without UN and individuals with pseudo-neglect, assessments for differences in neglect severity (e.g. mild versus moderate versus severe neglect), and subgroups of UN (e.g. left-sided versus rightsided neglect and object-centered versus space-centered neglect). Second, the study only examined the effectiveness after a shortterm exposure to light/color and did not explore treatment effects after some delay (e.g. hours to days) or longer-term treatment effects. Third, the lack of measures of the functional effects of the treatment and duration of the functional effects might limit the generalization of our results. Further study may include control groups for comparison, discriminate between patients with different levels of UN severity, address functional evaluations, and focus on the maintenance of therapy results over time. Furthermore, there is a need to study the possible differential effects of light/color stimulations for different lesions and stroke characteristics.

DOI: 10.3109/09638288.2015.1031284

Conclusions This study confirms previous findings about bottom-up-based sensory stimulation for post-stroke UN and demonstrates that light and color stimulation modulate spatial biases in post-acute stroke patients affected by UN. These findings suggest that lateralized light flash to the contralesional space and red-colored lenses have beneficial effects for UN and that light flash to the ipsilesional space and blue-colored lenses induce more spatial biases to the ipsilesional side. Future applications with a larger sample size and addressing issues related to the long-term effects might be helpful to confirm a benefit for patients suffering from UN.

Downloaded by [Chinese University of Hong Kong] at 13:17 09 November 2015

Declaration of interest No commercial party having a direct financial interest in the results of the research supported this article neither has nor will confer a benefit on the authors or on any organization with which the authors are associated. The study was partly funded by the Ministry of Science and Technology (MOST-94-2314-B-182-027; MOST-102-2811-B-002-081) in Taiwan. The authors declare no conflicts of interests.

References 1. Bernspa˚ng B, Viitanen M, Eriksson S. Impairments of perceptual and motor functions: their influence on self-care ability 4 to 6 years after a stroke. Occup Therap J Res 1989;9:27–37. 2. Heilman KM, Watson RT, Valenstein E. Neglect and related disorders. In: Heilman KM, Valenstein E, eds. Clinical neuropsychology. New York (NY): Oxford University Press; 1993:279–336. 3. Farne A, Buxbaum LJ, Ferraro M, et al. Patterns of spontaneous recovery of neglect and associated disorders in acute right braindamaged patients. J Neurol Neurosurg Psychiatr 2004;75:1401–10. 4. Nijboer TCW, Kollen BJ, Kwakkel G. Time course of visuospatial neglect early after stroke: a longitudinal cohort study. Cortex 2013; 49:2021–7. 5. Nijboer TC, van de Port I, Schepers V, et al. Predicting functional outcome after stroke: the influence of neglect on basic activities in daily living. Front Human Neurosci 2013;7:182. 6. 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;80:379–84. 7. Nijboer TC, Kollen BJ, Kwakkel G. The impact of recovery of visuo-spatial neglect on motor recovery of the upper paretic limb after stroke. PLoS One 2014;9:e100584. 8. Di Monaco M, Schintu S, Dotta M, et al. Severity of unilateral spatial neglect is an independent predictor of functional outcome after acute inpatient rehabilitation in individuals with right hemispheric stroke. Arch Phys Med Rehabil 2011;92:1250–6. 9. Cherney LR, Halper AS, Kwasnica CM, et al. Recovery of functional status after right hemisphere stroke: relationship with unilateral neglect. Arch Phys Med Rehabil 2001;82:322–8. 10. Luaute J, Halligan P, Rode G, et al. Visuo-spatial neglect: a systematic review of current interventions and their effectiveness. Neurosci Biobehav Rev 2006;30:961–82. 11. Barrett AM, Buxbaum LJ, Coslett HB, et al. Cognitive rehabilitation interventions for neglect and related disorders: moving from bench to bedside in stroke patients. J Cogn Neurosci 2006;18:1223–36. 12. Fasotti L, van Kessel M. Novel insights in the rehabilitation of neglect. Front Human Neurosci 2013;7:780. 13. Yang NY, Zhou D, Chung RC, et al. Rehabilitation interventions for unilateral neglect after stroke: a systematic review from 1997 through 2012. Front Human Neurosci 2013;7:187. 14. Ishiai S. Treatments and rehabilitation of unilateral spatial neglect. Neurol Therapeut 2009;26:577–84. 15. Bergego C, Azouvi P, Deloche G, et al. Rehabilitation of unilateral neglect: a controlled multiple-baseline-across-subjects trial using computerised training procedures. Neuropsychol Rehabil 1997;7: 279–93.

Light and color stimulation in unilateral neglect

2405

16. Gordon WA, Hibbard MR, Egelko S, et al. Perceptual remediation in patients with right brain damage: a comprehensive program. Arch Phys Med Rehabil 1985;66:353–9. 17. Weinberg J, Diller L, Gordon WA, et al. Training sensory awareness and spatial organization in people with right brain damage. Arch Phys Med Rehabil 1979;60:491–6. 18. Lin KC. Right-hemispheric activation approaches to neglect rehabilitation poststroke. Am J Occup Therap 1996;50:504–15. 19. Wu CY, Wang TN, Chen YT, et al. Effects of constraint-induced therapy combined with eye patching on functional outcomes and movement kinematics in poststroke neglect. Am J Occup Therap 2013;67:236–45. 20. Bowen A, Lincoln NB. Cognitive rehabilitation for spatial neglect following stroke. Cochrane Database Syst Rev 2007;2:CD003586. 21. Kwakkel G, Kollen B, Lindeman E. Understanding the pattern of functional recovery after stroke: facts and theories. Restorat Neurol Neurosci 2004;22:281–99. 22. Murphy TH, Corbett D. Plasticity during stroke recovery: from synapse to behavior. Nat Rev Neurosci 2009;10:861–72. 23. Kinsbourne M. Mechanisms of unilateral neglect. In: Jeannerod M, ed. Neurological and neurophysiological aspects of spatial neglect. Amsterdam, Netherlands: Elsevier; 1987:69–86. 24. Butter CM. Varieties of attention and disorders of attention: a neuropsychological analysis. In: Jeannerod M, ed. Neurological and neurophysiological aspects of spatial neglect. Amsterdam, Netherlands: Elsevier; 1987:1–37. 25. Posner MI, Rafal RD. Cognitive theories of attention and the rehabilitation of attentional deficits. In: Meire MJ, Benton A, Diller L, eds. Neuropsychological rehabilitation. New York (NY): Guilford; 1987:182–201. 26. Schiller PH, Koerner F. Discharge characteristics of single units in superior colliculus of the alert rhesus monkey. J Neurophysiol 1971; 34:920–36. 27. Butter CM, Kirsch NL, Reeves G. The effect of lateralized dynamic stimuli on unilateral spatial neglect following right hemisphere lesions. Restorat Neurol Neurosci 1990;2:39–46. 28. Butter CM, Kirsch N. Combined and separate effects of eye patching and visual stimulation on unilateral neglect following stroke. Arch Phys Med Rehabil 1992;73:1133–9. 29. Butter CM, Kirsch N. Effect of lateralized kinetic visual cues on visual search in patients with unilateral spatial neglect. J Clin Exp Neuropsychol 1995;17:856–67. 30. Pizzamiglio L, Frasca R, Guariglia C, et al. Effect of optokinetic stimulation in patients with visual neglect. Cortex 1990;26: 535–40. 31. Pizzamiglio L, Fasotti L, Jehkonen M, et al. The use of optokinetic stimulation in rehabilitation of the hemineglect disorder. Cortex 2004;40:441–50. 32. Maehara G, Okubo M, Michimata C. Effects of background color on detecting spot stimuli in the upper and lower visual fields. Brain Cogn 2004;55:558–63. 33. Mehta R, Zhu RJ. Blue or red? Exploring the effect of color on cognitive task performances. Science 2009;323:1226–9. 34. Morrone MC, Denti V, Spinelli, D. Color and luminance contrasts attract independent attention. Curr Biol 2002;12:1134–7. 35. Snowden RJ. Visual attention to color: parvocellular guidance of attentional resources? Psychol Sci 2002;13:180–4. 36. Hau Y, Zhang L, Miao D. The relationship between color vision and arousal level. Internet J Ophthalmol Vis Sci 2009;6:4. 37. Birren F. Color & human response: aspects of light and color bearing on the reactions of living things and the welfare of human beings. New York (NY): Van Nostrand Reinhold; 1978. 38. Jacobs KW, Suess JF. Effects of four psychological primary colors on anxiety state. Percept Motor Skills 1975;41:207–10. 39. Liberman J. Light: medicine of the future. Santa Fe (NM): Bear; 1991. 40. Kristjansson A, Vuilleumier P, Malhotra P, et al. Priming of color and position during visual search in unilateral spatial neglect. J Cogn Neurosci 2005;17:859–73. 41. Wilkinson D, Ko P, Milberg W, McGlinchey R. Impaired search for orientation but not color in hemi-spatial neglect. Cortex 2008;44: 68–78. 42. Lucas N, Vuilleumier P. Effects of emotional and non-emotional cues on visual search in neglect patients: evidence for distinct sources of attentional guidance. Neuropsychologia 2008;46: 1401–14.

Downloaded by [Chinese University of Hong Kong] at 13:17 09 November 2015

2406

Y.-t. Fan et al.

43. Sato S, Tsubahara A, Aoyagi Y, et al. Influence of colour lightness differences in patients with left unilateral spatial neglect. Austral J Rehabil Counsel 2010;16:1–13. 44. Mesulam MM. Attention, confusional states, and neglect. In: Mesulam MM, ed. Principles of behavioral neurology. Philadelphia (PA): F. A. Davis; 1985:125–68. 45. Kinsbourne M. Orientational bias model of unilateral neglect: evidence from attentional gradients within hemi-space. In: Robertson IH, Marshall JC, eds. Unilateral neglect: clinical and experimental studies. New Jersey: Lawrence Erlbaum; 1993:63–86. 46. Oldfield RC. The assessment and analysis of handedness: the Edinburgh Inventory. Neuropsychologia 1971;9:97–113. 47. Scheiman M. Understanding and managing vision deficits: a guide for occupational therapists. Thorofare (NJ): Slack; 2011. 48. Bruce JM, Bruce AS, Arnett PA. Mild visual acuity disturbances are associated with performance on tests of complex visual attention in MS. J Int Neuropsychol Soc 2007;13:544–8. 49. Schenkenberg T, Bradford DC, Ajax ET. Line bisection and unilateral visual neglect in patients with neurologic impairment. Neurology 1980;30:509–17. 50. Ishiai S, Furukawa T, Tsukagoshi H. Visuospatial processes of line bisection and the mechanisms underlying unilateral spatial neglect. Brain 1989;112:1485–502.

Disabil Rehabil, 2015; 37(26): 2400–2406

51. Cohen J. Statistical power analysis for the behavioral sciences. New Jersey: Lawrence Erlbaum Associates; 1998. 52. Liubinas J. Learning to learn: theory and treatment. Sydney, Australia: Rite Pty; 2003. 53. Robertson IH, Mattingley JB, Rorden C, Driver J. Phasic alerting of neglect patients overcomes their spatial deficit in visual awareness. Nature 1998;395:169–72. 54. Finke K, Matthias E, Keller I, et al. How does phasic alerting improve performance in patients with unilateral neglect? A systematic analysis of attentional processing capacity and spatial weighting mechanisms. Neuropsychologia 2012;50:1178–89. 55. Gottlieb R, Wallace L. Syntonic phototherapy. J Behav Optomet 2001;12:31–8. 56. Schiller PH, Logothetis NK. The color-opponent and broad-band channels of the primate visual system. Trends Neurosci 1990;13: 392–8. 57. Driver J, Vuilleumier P, Eimer M, Rees G. Functional magnetic resonance imaging and evoked potential correlates of conscious and unconscious vision in parietal extinction patients. Neuroimage 2001; 14:S68–75. 58. McManemin FA. Autonomic nervous system and light frequencies. J Optomet Phototherap March 2005:33–6. 59. Spitler HM. The syntonic principle. Ohio: The College of Syntonic Optometry; 1990.

Effects of lateralized light flash and color on unilateral neglect.

Bottom-up-based sensory stimulation has been useful in promoting recovery from post-stroke neglect. Light and color are salient stimuli for guiding ou...
1009KB Sizes 3 Downloads 10 Views