Stroke refers to neurological signs and symptoms that result from disease involving blood vessels [1]. It leads to mortality and morbidity in many countries [2]. Stroke is the third most common cause of death in western counties [1]. Unilateral neglect (ULN) which is a common behavioral syndrome following stroke, manifests by failure in reporting, responding, and orienting to stimuli presented on the contralateral side of the lesion that can not be attributed to sensory and motor dysfunction [3, 4, 5, 6, 7, 8, 9, 10]. It is commonly associated with anosognosia which is a lack of knowledge or unawareness of disease [3, 5, 11]. Anosognosia occurs in about 20% to 58% of patients [3]. The incidence of ULN following right hemisphere stroke is from 10% to 82%, whereas the incidence of ULN following left hemisphere stroke is from 15% to 65% [3, 6, 7, 8, 10]. ULN is more likely to occur in the right hemisphere stroke because the right hemisphere is dominant for arousal and directs spatial attention to both sides of the body, whereas the left hemisphere directs attention only to the right side of visual field [3, 12, 13]. As a result of this (see appendix I), the right hemisphere allows for compensating for loss of the left hemisphere's functions, but not in the opposite direction [3, 12, 13]. ULN is a common consequence of lesions in many areas. These include the inferior parietal lobe, frontal lobe, posterior parietal cortex, thalamus, basal ganglia and temporo-parietal junction [3, 13, 14]. The signs and symptoms associated with ULN are bumping into objects when walking, shaving only one side of face, eating food from only one side of the plate, slowness in responding or complete lack of awareness of one side of the body, and head and eye deviation towards the ipsilateral to lesion side [6, 9, 13, 14]. Sensory, motor, representational, personal, and spatial neglect are the most common types of ULN [3, 6, 7, 8, 14]. Sensory neglect is being unaware of sensory stimuli on the opposite side of the brain lesion, which can be classified according to the modality. These include visual, auditory, and tactile neglect [3, 6, 14]. Motor neglect is the lacking or failure of spontaneous movement response to stimulus to use contralesional limb even if the patient is aware of stimulus [3, 6, 7]. Representational neglect is defined as the patient's ignoring the contralesional half of mental representation or visualization of the task [3, 6]. Personal neglect is deficit in exploring the contralesional side of the body [3, 6, 7, 14]. Spatial neglect which is known as failure in recognizing the stimuli on the space opposite to lesion side is divided into peripersonal and extrapersonal neglect [6]. Peripersonal neglect is the lack of attention to the area within reach of the person, whereas extrapersonal neglect is lacking in attention to the area beyond the reaching space [3, 6, 7, 14]. Patients have side effects as consequences of ULN. These side effect include poor activities of daily living (ADL) function, increase length of hospital stay, and hurt himself/herself as a result of repeatedly bumping into objects on the contralesional space [3, 5, 7, 8, 9, 10, 11, 12, 13, 14]. This threatens the patient's safety on the contralesional side and being unaware of this deficit is also a side effect of ULN [3, 7, 8, 9, 11, 13, 14]. As a result of this ULN impacts rehabilitation programs compared with stroke patients without ULN [3]. Physical Therapy (PT) has an important role in treating the side of neglect by bringing the attention toward the side of neglect and ameliorating the function ADL [3, 5, 7, 8, 11, 12, 13, 14]. Because the patient may have neglect in one domain of space but not another, it is important for PT to assess the spatial distribution of the patient's behavior [6, 9, 13, 14]. The nature of neglect behavior must be understood by PT. For the purpose of this paper the important role of physical therapy in assessing and treating patients with visuomotor neglect will be discussed. The PT shows the effectiveness of several methods in determining the visuomotor neglect. The PT also shows the effectiveness of different rehabilitation methods in reducing visuomotor neglect.
It is important for the PT to find adequate rehabilitation methods in order to overcome the side effect and consequences of ULN. PT rehabilitation for ULN patients includes conventional methods, video technology, and a VR method [1, 2, 3, 4, 8, 9, 10, 12, 13, 14, 17, 18, 19]. Conventional methods include patching of visual hemifield (one half of each eye), visual scanning training (VST), limb activation, and neck vibration therapy [1, 2, 3, 4, 9, 10, 12, 13, 14, 17, 18]. Constraint induced therapy and trunk rotation therapy are also types of conventional methods [2, 3, 12, 19]. In patching of visual hemifield of one half of each eye (see appendix IX), the ipsilesional hemifield of both lenses is blocked out by an opaque patch [3, 13]. It helps the visual input (see appendix X) to follow the left pathway and confluence primarily on the ipsilesional superior colliculus which generates the contralesional ward saccades [12]. This will increase the effectiveness of the ipsilesional colliculus in making eye movements into the contralesional visual field by reducing the visual input to the contralesional superior colliculus [3, 13]. This treatment will improve in functional ADL, visual exploration, and visuospatial tasks [3, 13]. This method will also help in controlling the intention and direction of gaze [12]. Eye glasses should be worn approximately 12 hours per day [12]. In VST, the patient is asked to name the digit presented and to press on a button as fast as possible after the patient determined the digit that appears in different sequences on a large screen (2.20x1.50m) [1, 2, 4]. There is also a machine for scanning which consists of light stimuli that appears in different positions on a board [14]. The patient is asked to track the target object that moves from one side to another and search for the lights that present in different positions on the board [14]. There are some strategies that the PT can use in conjunction with visual scanning training because the patient has no voluntary movement on the contralesional upper limb and patient usually uses the ipsilesional upper limb [14]. One of the strategies is encouraging the patient to actively scan from contralesional to ipsilesional hemispace [14]. The second one is using both visual and verbal cues in facilitating the attention to the contralesinal side (examples: attention being drawn to red shiny ribbon placed on the contralesional side and find your contralesional arm) [14]. In case the patient has sufficient sensation to appreciate stimulus, the PT gives tactile cues by tapping on the patient's contralesional arm [14]. The third strategy is done when the preceding tasks have been successfully achieved; the activities progress from simple to complex in terms of numbers, sizes, complexity, and amount of distracting information [14]. The last strategy is to give feedback to the patient about performance success in each task and also giving praise for each correct response [14]. VST helps to bring reorientation of visual scanning toward the neglected side by providing explicit instructions that help the patient to direct voluntary gaze control [14]. Limb activation therapy methods include moving the contralesional arm or leg in the contralesional hemispace without visual feedback [4, 17, 10, 14]. This method improves the perception in the neglected hemispace by activating the premotor circuits of the damaged hemisphere which facilitates the sensory cells connected together which then reduce neglect [4, 17, 9, 14]. In this therapy the inhibitory competition from the undamaged hemisphere may be counteracted by the activation of the damaged hemisphere [18]. There are some strategies that the PT can adopt in conjunction with limb activation therapy [14]. One of the strategies is asking the patient to concentrate on moving only the contralesional upper limb with no additional use of the ipsilesional upper limb [14]. The second one is involving the voluntary active movement of the contralesional upper and lower limb if possible otherwise the therapist assists the action [14]. The last one is teaching the patient to activate the contralesional limb by tapping the patient's hand or fingers on adjacent contralesional surface [14]. Neck vibration therapy is done by using trans-cutaneous electrical stimulation (TENS) [2]. The superficial electrode of TENS (see appendix IX) placed on the contralesional side of the posterior neck below the occipit just lateral to the spine [2]. This vibration shifts the perceived head and trunk position to the ipsilateral space which helps in displacing the perceived sagittal midline of the body to the contalesional side and improves space representations [3]. This therapy transissions the remission of neglect produced by visual detection within the contralesionl space, and produces straight ahead judgment [2]. Constraint induced therapy (see appendix XII) which is based on learning nonuse principle [3]. This therapy consists of using mechanical restraints like a sling or a mitt on the intact extremity in order to attempt to stimulate the nonuse limb [3]. The mechanical restraint must be worn about 90% of waking hours in order to help in eliciting the functional improvements, increasing the ipsilesional cortical limb representation, and increasing the visual attention to contralesional space [3]. The application of this therapy requires active wrist and hand extention for non use limb and it becomes a problem especially for neglected patient who exhibit dense hemiparesis [3]. In trunk rotation therapy (see appendix XIII), the patient is asked to scan for visual targets while the patient is standing in a supportive device which allows the trunk to rotate [3]. This standing device was developed by Wiart et al through retraining control over voluntary trunk movement coupled with execution of exploratory visual tasks [3, 12]. The perceiving position of the head on trunk to the ipsilesional space or midline will shift to the contralesional space as a result of changing in the body centered representation of space which is the same effect a using the neck vibration therapy [3]. Karnath et al found 15° contralesional trunk rotation decreased contralesional omissions by 20-30% [2, 3, 12]. This method improves the visual detection, the exploration toward the contralesional space, and the cancellation and line bisection tests [2]. Although there are a lot of varieties in the treatment for the patients with vasomotor neglect, the patient needs to detect his/her condition especially those who suffer from anosognosia through interpretation of evidence in order to be aware of the patient's disorder [11]. Video technology (VT) is one of the therapeutic tools, which is used to provide feedback to increase self awareness of the patient's deficit [11]. TV improves the patient's ability in identifying his/her own strengths and weakness [11]. VT helps in achieving clearer information and more accurate perception of the patient's own performance and gives the ability to observe patient's neglected behavior on the contralesional side of the task [11]. VT helps the patient to use new strategies in ADL function such as baking cakes [11]. It provides concreteness of feedback. It is also a method that includes video feedback [11]. In this method, the patient is asked to perform the BTT while the PT videotapes the patient at the same time [11]. The PT gives the patient an opportunity to see his/her performance on the ipsilateral side of the TV monitor directly after testing in order to draw the patient's attention to his/her own neglect behavior [11]. After that, the patient is asked to explain and remark on his/her own performance and the result of the BTT [11]. Also, the PT remarks on the patient's performance and the results [11]. Then the patient is asked to fabricate his/her own strategies in order to perform better on the task [11]. The PT discusses with the patient about possible compensatory strategies and gives instructions about how to use tactile discrimination with the epsilateral hand to find out the location of the contralateral edge of the tray and then systematically locate the blocks from left to right, upside down [11]. This method helps the patient to be more aware of his/her own abilities and disabilities [11]. There is little experimental data documenting their effectiveness in improving ULN symptoms although there are several VR based methods for rehabilitation of ULN that have been proposed recently, [13]. VR is the second method which is used in treating patient with ULN. VR is a computer system which gives the participants a look at themselves as part of a virtual environment in order to reinforce the sense of immersion and presence [8, 13]. VR activates the brain on the affected side which leads to neuroplastic changes [8]. VR helps the patient to receive the feedback immediately about his/her performance by allowing him/her to look at him/herself while interacting with a virtual environment which permits them to focus the attention to a full visual field and make mistakes in order to promote self awareness [8]. VR permits the PT to manipulate the presentation of stimulus easily by allowing the PT to gradually increase the attentional demands on the user [8]. VR also has the capability of introducing the alterations which are impossible or difficult to achieve in the real world [8]. VR helps in improving the impact of each rehabilitation session [13]. The VR rehabilitation method includes a personal computer (PC) screen for visual display combined with a DataGlove for hand-motion tracking (see appendix XIV) [13]. In this method, the patient is asked to observe the grasping of virtual object located within virtual environment by virtual hand while the patient reaches and grasps a real object [13]. During this therapy the patient's real hand and real object are not visible to the patient, and the virtual object is located in the contralesional space while the real object is in the center of the patient or to the ipsilesional space [13]. This method helps in extending the space representation to include the virtual space [13].
Visuomotor neglect is a common phenomenon that leads to poor functional outcomes in patients following stroke. It can be characterized as failure to report and respond to a meaningful stimuli presented in the contralesional side of the brain lesion which can not be attributed to sensory or motor dysfunction. There are several methods that the physical therapist (PT) can use to the presence of visuomotor neglect in patients with stroke. These methods include conventional, ecological, and virtual reality (VR) strategies. Each method has unique advantages and disadvantages in a clinical setting. It is important for the PT to find the best suited treatment of visuomotor neglect in order to ameliorate the everyday functional activities of the patient. These treatments include conventional methods, video technology (VT), and VR methods.
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