Unilateral Spatial Neglect

USN e-learning module

Please visit our USN e-learning module: http://elearning.strokengine.org/module.php

What is USN?

Unilateral spatial neglect (USN) is most typically characterized by the inability to orient or respond to stimuli appearing on the contralateral side/hemispace of the brain lesion1. Terms including unilateral neglect, hemi-inattention, visual neglect and hemi-spatial neglect are used to describe USN. Over 30% of patients will have post-stroke USN2. USN is more frequent in those with a right hemisphere stroke, such that symptoms of USN commonly appear on the left hemispace. Research has shown that damage to the following brain areas leads to USN: right parieto-temporal junction3, the angular gyrus, the right inferior parietal lobe, the parahippocampal region4 and the right superior temporal cortex5. Depending on the brain area affected, there are three different types of USN and patients can have one or a combination of the three types with varying degrees of severity1:

Personal neglect: Neglect of one side of his/her body (e.g. patients shave/apply makeup to half of their face, usually the left half); acquired from damage to the parietal lobe (post-central and supramarginal gyri)6;

Near extrapersonal neglect: Neglect of the environment within reaching distance (e.g. patients ignore food on one side of the plate, usually the left half);

Far extrapersonal neglect: Neglect of the space beyond reaching distance (e.g. patients collide into their surroundings, usually the left, when trying to wheel a wheelchair).                                      

*Extrapersonal neglect arises from damage to the frontal lobe (ventral premotor and dorsolateral prefrontal cortex) and the temporal lobe (middle and anterior superior temporal gyrus, and the superior temporal sulcus)6

Why is it critical to assess for USN?

Patients with USN are at an increased risk for falls and related injuries, usually have longer rehabilitation stays as well as poorer functional recovery post-stroke1. Given that USN can result in falls and lack of independence in daily activities, and that it is treatable, all patients must be quickly screen or assessed for USN during the acute phase post-stroke. Patients identified with the presence of USN must receive effective interventions aimed at reducing impairment and maximizing function.

Who should be assessed?

Perceptual deficits, including USN, are more common in individuals with right hemisphere lesions (RHD). Thus, routine screening for USN in those with RHD is very important. Research has shown that the left hemisphere modulates arousal and attention for the right visual field, whereas the right hemisphere controls these processes in both right and left visual fields. This may be a partial explanation for why USN is not typical in persons with left hemisphere damage (LHD); the intact right hemisphere is capable of compensating for perceptual deficits that result from LHD7. It also substantiates why individuals with RHD experience more severe and longer lasting symptoms of USN compared to those with LHD. The Opponent–processor model argues that each hemisphere attends to the contralateral visual hemispace by inhibiting the other hemisphere. It goes on to propose that with a right hemisphere lesion the left hemisphere is not inhibited, and this results in exaggerated attentional shift to the right (i.e. left USN)3. USN continues to be commonly associated with a right stroke, but evidence from the literature suggests that all patients with stroke might benefit from USN screening.

Can USN be treated?

Yes, below is an overview of four different types of treatment categories that exist for USN8:

  1. Visual Scanning: The patient with USN is encouraged to explore the neglected visual field (usually the left side) by performing tasks on that side. The treatment often includes a visual target that the patient uses as an anchor while scanning.

2. Sensory Stimulation: The therapist uses various types of sensory stimulation to encourage the patient to pay attention to their neglected side. These include:

Visual/Verbal/Auditory Cues: The use of a visual cue (i.e. red tape or flashing lights), verbal cue (i.e. the voice of the therapist or a family member) or auditory cue (i.e. horn or bell) on the neglected side to improve awareness of that space.

Limb Activation: The patient actively moves their arm/hand on the neglected side to encourage scanning of that space (usually the left upper extremity towards the left). The patient receiving treatment can do these movements alone or with help from the therapist.

Caloric Stimulation: The therapist uses a syringe to put either cold or warm water into the patient’s ear (external ear canal) to encourage scanning of the neglected side. Cold water seems to encourage scanning toward the stimulated ear. Warm water encourages scanning of the field opposite to the stimulated ear.

Eye Patching/Hemiglasses: This treatment uses standard eyeglass frames with either monocular patches (entire eye) or half of both lenses blacked out on the same side (usually the right half). This forces the patient to look through the side of the lens and scan the neglected side (usually the left side).

Fresnel Prisms: This treatment involves placing prisms over regular eyeglass frames which cause a shift of the visual field. If there is neglect on the left side, these prisms will cause what is seen on the left to be shifted to the right to encourage visual scanning of the left visual field.

Neck/Hand Vibration or Stimulation: Vibration or stimulation is applied to the side of the neck or hand affected by USN to encourage scanning of the neglected side.

Trunk Rotation: This strategy involves twisting the trunk toward the neglected side in order to improve visual scanning and awareness of that hemispace.

Visuo-motor Imagery: Visual imagery involves mental tasks where the patient is required to describe details of a familiar room, environment, or geographic area from their memory. Motor imagery consists of the patient imagining a body movement or posture and describing this sequence. This type of imagery treatment may stimulate areas of the brain that can activate those actual movements during daily activities in order to improve neglect symptoms.

Constraint-Induced Movement Therapy: This treatment involves restraining the unaffected arm with a sling in order to encourage use of the affected arm. While used primarily to encourage motor return in the affected arm, this intervention will also encourage visual scanning of the patient’s neglected side.

Optokinetic Stimulation: This involves observation of moving visual targets from left to right, in order to encourage visual scanning of the neglected side.

3. Video Feedback: This treatment involves filming the patient while he/she does specific activities. The therapist and patient then watch the video together. The therapist points out to the client how they are neglecting their body or the space on the side of their body. They then discuss strategies to encourage the patient to attend to their body and their neglected hemispace.

 4. Pharmacological Therapy: This involves the use of specific medications (dopamine-agonist drugs) to improve visual attention skills. A physician must prescribe these medications.

Which types of treatments are most effective for post-stroke USN?

The benefits of various interventions to treat post-stroke USN symptoms have been carefully studied9. Click this link for more information on effective treatments for post-stroke USN: https://www.strokengine.ca/index.php?page=topic&subpage=quick&id=32

 
 
Treatment type
Effective (Yes/No)
Prisms
Yes
Strong (1a)
Yes
Limited (2a)
Yes
Limited (2a)
Yes
Limited (2a)
Visual-motor imagery
Yes
Limited (2b)

Neck/Hand Vibration

Yes
Consensus (3)

Caloric Stimulation

Yes
Consensus (3)
Unsure
Conflict (4)

Verbal/Visual/Auditory Cues

No
Limited (2a)

Optokinetic Stimulation

No
Limited (2a)
 
The other treatments methods described in the section above such as constraint-induced movement therapy, video feedback and pharmacological therapy require further research before their effectiveness can be confirmed.
How are these USN treatments administered?
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To administer fresnel prism therapy, the patient must wear the prisms (deviates their visual field 10º to the right) on their glasses or on goggles. Next, the therapist must engage the patient in a visual scanning task where they repetitively point or reach for two different targets located at each side of their field of vision. According to the studies, the intensity of repetitions varied from 30 to 100 per treatment. The frequency of treatment also varied from 5 sessions of 10 minutes over 2 weeks, to two 20 minute treatments per day for 2 weeks or 30 minutes of scanning performed daily, 5 times per week for 2 weeks 10-13.
 
 
To administer eye patching treatment, the therapist must apply right half patches to both lenses of the patient’s glasses or on goggles for those who do not wear glasses. Patients should wear the glasses/goggles during their waking hours and while doing all tasks. Duration of the eye patching treatment varied from 1 week to 3 months with improved results according to the length of time worn 14-15.
 
 
Trunk rotation treatments require the use of a thoracolumbosacral orthosis (e.g. Bon Saint Come’s device) to which a metal bar is attached. The bar is designed to project forward horizontally just above the patients head. The therapist then sets up some visual targets on the patient’s neglected side and asks the patient to repetitively rotate their body towards the target and touch it with the metal bar. This encourages visual scanning of the neglected area. The movements can be performed in a seated or standing position. In the study of the effectiveness of this intervention, patients received 1 hour of trunk rotation per day, every week day for 1 month (total of 20 hours) 16.
 
 
In visual imagery, the therapist guides the patient to mentally visualize scenes that encourage scanning of all areas including the neglected side. For example, the patient imagines that they are a lighthouse and their eyes are the sweeping light at the top scanning the surrounding area. Or, the patient describes a specific room or geographical area. For the motor imagery tasks, the patient is asked to imagine specific postures which they later have to reproduce, as well as specific sequences of movements that would involve the right arm followed by the left arm. Treatment intensities and frequencies ranged from three 30-minute sessions per week for an average of 3 weeks to 40 trials of 50 minute sessions 17-18.
 
 
For limb activation, the therapist instructs the patient to actively move their upper extremity on the neglected side. The therapist can provide verbal or physical cues to guide the patient during this task. The goal is to use active voluntary movements of the upper extremity to promote scanning of the neglected hemispace. For example, the patient can repetitively lift a rod on the left side or displace cones from the right to the left side. Recommended frequency of limb activation therapy is 1 hour per day, for 10 days over a 2-week period 19-20.
 
 
Visual scanning treatment involves a wide range of activities that encourage the patient to attend to their neglected side. Therapists can engage patients in reading, copying, describing figures or scenes, computer tasks (finding digits on the screen) etc. All of the studies agreed upon an intensity and frequency of 1 hour of treatment per day on a daily basis (5 days per week). However, duration varied from 2, 4 or 8 weeks of treatments 21-25. Positive effects of the visual scanning treatments did not increase according to the duration of treatments.
When is the best time to receive treatments for USN?

USN interventions can be provided during the acute, sub-acute, and chronic stages post-stroke.

What type of client is USN treatment for?

USN treatments can be offered to individuals of all ages but should be tailored to the client’s specific level of functioning. Clients with either mild or no cognitive deficits can benefit from therapy (i.e. score ≥22 on the Mini-Mental State Examination is recommended) as they must be able to follow simple commands. Clients must have receptive language abilities in order to be able to understand instructions; however expressive language is not a requirement. Last, patients may have other post-stroke visual impairments such as hemianopsia and it is important o differentiate between the two when assessing treatment benefits.

Who offers these treatments?

Occupational therapists (OTs) typically assess for and provide treatment for USN in an acute care hospital, rehabilitation center, or private clinic 8.

Special considerations for OTs

There are minimal equipment costs (e.g. prism therapy, eye patching, limb activation) and training required for providing USN treatments. Therapists need to consider that clients with USN may be unable to attend to either one side of his/her body (personal neglect), the space within reaching distance (near extrapersonal neglect), the space beyond reaching distance (far extrapersonal neglect), or to a combination of these three spaces in their environment. Therefore the assessment and treatment of USN within these hemispaces must be considered. It is also important to explain to the patient and their family what USN is and to provide them with safety recommendations such as remembering to put on the wheelchair brake on the left side, and ensuring that the patient does not trip over obstacles on the left. Therapists can also engage the family members aiding with therapy by instructing them to allow the patient to search and find objects in their room which are located on the left side instead of placing all objects within the patient’s field of view.

 

Screening Tool Administration Procedures
 
Comb and Razor Test: Patients are required to groom themselves using common objects. For males, this consists of combing and mock shaving (shaving with a shield on) each for 30 seconds. Female patients are asked to comb and demonstrate the use of a facial compact for 30 seconds each. During the 30 second intervals, the evaluator categorizes each “stroke” or touch as having occurred on the left side of the head, the right side of the head, or as ambiguous 26.
To score the test, observational data is plugged into a formula (% left = left strokes/total strokes x 100), which yields a % value. This value indicates the degree to which the individual being tested has neglected the left side of their head. Left personal neglect is diagnosed when an individual’s mean% left score is less than 35%.  The test takes approximately 5 minutes and requires no specialized training to administer 26.
 
Albert’s Test: Patients are required to cross through the center of 41 randomly oriented lines, each about 2 cm long, arranged on a sheet of paper. The test sheet is presented to the patient at their midline. The examiner asks the patient to cross out all of the lines, and demonstrates what is required by crossing out the 5 central lines him/herself. The patient is encouraged to cross out all the lines until he/she is satisfied that they have all been crossed 26.
The presence or absence of USN is based on the number of lines left uncrossed on each side of the test sheet. If any lines are left uncrossed, and more than 70% of uncrossed lines are on the same side as the brain lesion or motor deficit, USN is suspected. This may be quantified in terms of the percentage of lines left uncrossed. The test takes approximately 5 minutes and requires no specialized training to administer 26.
 
Baking Tray Task:This test requires that the patient pick-up 16 “buns” and spread them as evenly as possible on a 75×100 cm board. Cubes can be used to represent the “buns”. The therapist must note how the “buns” are spread out and USN can be easily detected depending on their arrangement on the board (i.e. if they are placed on the right side of the board only, left USN is suspected). Patients do not usually exceed 3-5 minutes to complete the task and no specialized training is required to administer the test 7.
 
Balloons Test: This bedside test was developed to screen for USN and contains 2 subtests. Subtest A requires the client to cross out the 22 target balloons of the 202 circles that appear on a page within the fixed time limit of 3 minutes. In subtest B, the number and position of balloons is exactly reverse from subtest A, where the client is asked to cross out 10 target circles from the 90 balloons that appear on a page within the fixed time limit of 3 minutes. No specialized training is required to administer the test 27.
 
Bells Test: In the Bells Test, the patient is asked to circle with a pencil all 35 bells embedded within 280 distracters (houses, horses, etc.) on an 11 x 8.5 – inch page. The objects are actually equally distributed in 7 columns containing 5 targets and 40 distracters each. Of the 7 columns, 3 are on the left side of the sheet, 1 is in the middle, and 3 are on the right. To administer the test, the examiner must sit facing the patient and place the page at the patient’s midline. The examiner gives the following instructions: “Your task will consist of circling with the pencil all the bells that you will find on the sheet that I will place in front of you without losing time. You will start when I say “go” and stop when you feel you have circled all the bells. I will also ask you to avoid moving or bending your trunk if possible.” If the patient stops before all the bells are circled, the examiner gives only one warning by saying “are you sure all the bells are now circled? Verify again.” 26
To score the Bell’s test, the total number of circled bells is recorded as well as the time taken to complete. The maximum score is 35. An omission of 6 or more bells on the right or left half of the page indicates USN. Judging by the spatial distribution of the omitted targets, the evaluator can then determine the severity of the visual neglect and the hemispace affected (i.e. left or right) 26.
 
Clock Drawing Test (CDT): There are a few variations to the CDT:
 
Free drawn clock: the individual is given a blank sheet of paper and asked first to draw the face of a clock, place the numbers on the clock, and then draw the hands to indicate a given time. To successfully complete this task, the patient must first draw the contour of the clock, then place the numbers 1 through 12 inside, and finally indicate the correct time by drawing in the hands of the clock. A markedly abnormal clock is an important indication that the individual may have a cognitive deficit, warranting further investigation.                                                                                         
 
Pre-drawn clock: alternatively, some clinicians prefer to provide the individual with a pre-drawn circle and the patient is only required to place the numbers and the hands on the face of the clock. Copying a clock: the individual is given a fully drawn clock with a certain time pre-marked and is asked to replicate the drawing as closely as possible. The successful completion of the copy command requires less use of language and memory functions but requires greater reliance on visuospatial and perceptual processes.
Clock reading test: a modified version of the copy command CDT simply asks the patient to read aloud the indicated time on a clock drawn by the examiner 26.
The time setting “10 after 11” is an ideal setting as it forces the patient to attend to both sides of the clock and requires the recoding of the command “10” to the number “2” on the clock.
The scores are used to evaluate any errors or distortions such as neglecting to include numbers, putting numbers in the wrong place, or having incorrect spacing. Scoring systems may be simple or complex, quantitative or qualitative in nature. The CDT should take approximately 1-2 minutes to complete and requires no specialized training to administer 26.
 
Double Letter Cancellation Test (DLCT): The patient is asked to put a mark through all the letters C and E on presented 105 times a sheet of paper containing 6 lines with 52 letters per line. To begin the DLCT, the therapist places the test sheet at the patient’s midline, secures it with tape, and points to the trial line, asking the patient to mark the Cs and Es. If the patient is unable to perform the trial, further instruction is given. If the trial is correctly performed, the therapist will then proceed to give instructions as follows: “Look at the letters on this page. Put one line through each C and E. Ready, begin here”. The therapist points to the first letter in the first row. The time taken to complete the test is recorded 26.
The score is calculated by subtracting the number of omissions (Cs and Es that were not crossed out) from the possible perfect score of 105. Higher scores indicate better performance. The timing and total number of errors should be noted. The test requires less than 5 minutes to complete and requires no specialized training to administer 26.
 
Draw-A-Man Test: This test was initially designed to measure intelligence levels in children, however, has good reliability in detecting USN. To administer the test, the therapist asks the patient to complete three individual drawings (draw a man, a woman, and themselves) on separate pieces of paper. No further instructions are given. There is no right or wrong type of drawing, although the patient must make a drawing of a whole person each time – i.e. head to feet, not just the face. The test has no time limit, however, it is rare that someone takes longer than 10 or 15 minutes to complete all three drawings 26. Specific scoring instructions for USN can be found in an article by Chen-Sea MJ. Validating the Draw-A-Man Test as a personal neglect test. Am J Occup Therap. 2000;54:391–397.
 
Line Bisection Test: This is a quickly administered test that requires the patient to mark a line through the center of a series of 17 horizontal lines on an 11x 8.5-inch page. The test is scored by measuring the deviation of the bisection (in centimetres or millimetres) from the true center of the line. A deviation of more than 6 mm from the midpoint indicates USN 26.
Most testers utilize a formula that divides the deviation by half the length of the line and then multiplies this quotient by 100 to yield a percentage. Omission of two or more lines on one half of the page indicates USN. This test takes less than 5 minutes to complete and requires no specialized training to administer 26.
 
Single Letter Cancellation Test: The test consists of one 8.5″x11″ sheet of paper containing 6 lines with 52 letters per line. The stimulus letter “H” is presented 104 times. The page is placed at the patient’s midline. The therapist instructs the patient to put a line through each “H” that is found on the page. The time taken to complete the test is recorded 26.

The score is calculated by subtracting the number of omissions (H’s that were not crossed out) from the possible perfect score of 104 (0 to 53 on the left and 0 to 51 on the right). Higher scores indicate better performance. Presence of USN can be inferred by calculating the frequency of errors to the left or to the right from the center of the page. Omissions of 4 or more on one side have been found to be pathological 26.

Star Cancellation Test (SCT): In the Star Cancellation Test, the patient must cross out 56 small stars which are interspersed with 52 large stars, 13 letters, and 10 short words on a sheet of paper. Two small stars in the centre are used for demonstration. The therapist must place the page at the patient’s midline 26.

The maximum score that can be achieved on the test is 54 points (56 small stars in total minus the 2 used for demonstration). A cut-off of < 44 indicates the presence of USN. A Laterality Index or Star Ratio can be calculated from the ratio of stars cancelled on the left of the page to the total number of stars cancelled. Scores between 0 and 0.46 indicate USN in the left hemispace. Scores between 0.54 and 1 indicate USN in the right hemispace. The test takes under 5 minutes to administer and requires no specialized training for the tester 26.

National Institute of Health Stroke Scale (NIHSS): The NIHSS is a 15-item impairment scale, intended to evaluate neurologic outcome and degree of recovery for patients with stroke. The scale assesses various outcomes with the one item involving the assessment of USN for the personal space and near extrapersonal space. There are no specific instructions for assessing USN, however, the test states that sufficient information to detect neglect may be obtained from testing the prior items and is rated from 0 – 226.

Short Version – Rivermead Behavioral Inattention Test (RBIT): The short version of the RBIT involves three conventional subtests (line crossing, Star Cancellation Test, and figure copying) and five behavioural subtests (scanning a picture, reading a menu, eating a meal, reading an article, and sorting coins). Administration procedures and scoring methods can be found in the RBIT manual 7.

Semi-Structured Scale for the Functional Evaluation of Hemi-inattention in Extrapersonal Space: Patients are asked to perform different tasks with real objects. To assess personal neglect, patients must demonstrate the use of three common objects: comb, razor/powder compact, and eyeglasses. The objects are placed at the patient’s midline one at a time and he/she is asked to demonstrate how each are used. To assess extrapersonal neglect, patients must serve tea, deal cards, describe a picture, and describe an environment 26.

1. Serving tea: The patient is brought to a table with a tray containing 4 cups and saucers, a teapot, a sugar bowl, teaspoons, and paper napkins. Examiners are seated both on the right, in front, and to the left of the patient who is asked to serve tea for him/herself and for those who are with him/her, to distribute napkins and teaspoons, and also to serve the sugar. The examiner, who is seated in front of the patient asks: “Would you like to serve the tea?”. If the patient serves the tea but not the napkins and/or teaspoons, the examiner asks: “Would you like to give us the teaspoons (napkins)?”.

2. Card dealing.
The examiners and the patient are seated the same way as they were for the tea-serving situation. The patient is asked if he/she knows how to play “Scopa”. If necessary, he/she is reminded of the basic rules (3 cards for each player and 4 in the middle of the table). The examiner seated in front of the patient asks: “Would you like to deal the cards for a game of Scopa?”.

3. Picture description.
A picture is placed in front of the patient and he/she is asked: “Will you describe everything you see in this picture?”. Three pictures are used. Two are cards 3 and 6 of Set 1 of the Progressive Picture Compositions by Byrne (1967); one is Tissot’s painting ‘The dance on the ship’. The examiner indicates the persons and objects pointed out by the patient with progressive numbers on a photocopy of the stimulus figure in the order in which they are reported, without soliciting in any way.

4. Description of an environment.
The patient is placed in a

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