LOSS OF VISUAL FIELD DUE TO BRAIN INJURY HEMIANOPSIA AND NEGLECT
contributed by Dr. Errol Rummel, FAAO, FCOVD, FNORA
Patients who have had a stroke or traumatic brain injury, may lose one half of their side vision to the right or left. This type of side vision loss is called "Hemianopsia" (hemi field loss). Patients who just have a hemianopsia are aware of the side vision loss and often can be easily taught to scan their eyes in the direction of the hemianopsia, in order to compensate for the field loss. This allows them to not miss things on the side of the hemianopsia.
"Neglect" is the inattention to, or lack of awareness of visual space to the right or left and is most often associated with a hemianopsia. The lesion in the brain causing neglect usually occurs in the right frontal-parietal lobe, resulting in a left side neglect. Some patients just have a hemianopsia with no neglect, but others may experience a lot of "neglect" and may be unaware that they can not see to the affected side.
SIGNS AND SYMPTOMS OF NEGLECT
TREATMENT FOR HEMIANOPSIA WITH VARIOUS DEGREES OF NEGLECT
- Can not or does not readily/spontaneously scan into the area of the hemianopsia.
- No awareness that a hemi field loss exists
- Says doesn't see out of the eye (on the side of the neglect)
- Bumps into things on side of the hemianopsia but doesn't learn to compensate for the problem
- Misses parts of words on the side of the neglect when reading
- Misses parts of eye chart line on the side of the neglect
- Tendency to orient head or body turned away from the neglect, and the patient may ambulate/drift in direction away from the neglect.
TREATMENT WITH A "PERIPHERAL VISION AWARENESS DEVICE"
- Encourage eye and head movements to the neglected side, including scan board exercises.
- Teach the patient to use closed eye movements toward the neglected side, (if
the patient has difficulty with open eye movements in that direction).
- Have the patient ambulate (walk) around the room in a direction toward the neglected side to reinforce the lack of a visual map of space on the neglected side
- Have the patient use a flashlight aimed alternately toward each foot while walking, to enhance vision with motor reinforcement on the neglected side
- Encourage the playing of games like crossword puzzles and real playing card (not computer) games, because these non-computer games involve tactile/sensory input.
- Instruct the patient's family to learn to sit on the side of the neglect, in order to encourage the patient to attend to space on the side of the neglect.
- Increase the patients sensory awareness in the area of the neglect: Have them squeeze a ball using either hand, but on the side of neglect. Have the patient trace a line that extends into the side of the neglect. Have the patient put their finger at the far side of the line in the area of the neglect, and then the therapist rubs the finger to stimulate sensory awareness on the neglected side.
- Have the patient look toward the area of neglect with their eyes closed. Then when the patient thinks they are looking toward the neglected side, have the patient open the eyes, so that both the patient and the therapist can see how far toward the neglect the patients eyes are actually postured.
- Tell the patient to forcibly/rapidly move their eyes as far toward the neglect while sensing the feeling of their eyes at the extreme gaze. Then see how far toward the neglect they actually moved their eyes. Encourage the patient to become aware of the "feel" of their eyes when gazing as far toward the neglect as possible.
- Have the patient wear a "beeper-timer" wristwatch to beep at intervals to remind them to scan toward the neglected field at regular intervals.
- Once the patient has awareness of their hemi field loss, teach the patient to ocularly scan about 20 degrees toward the field loss, and then to use head turning with ocular scanning when viewing past 20 degrees laterally.
- Use tactile reinforcement to help the patient find the margin of the page on the neglected side by having the patient feel a Velcro or sandpaper strip at the margin.
- Use therapies to stimulate movement into the area of neglect like balloon catching/tossing, and also searching for predictive (and later non-predictive) stimuli in the neglected field.
- Turning a page at a 45 degree angle will help reading ability for some patients with neglect who do not respond to other treatments.
- Do not train with "screen" activity use (TV, computer, Gameboy, etc). Screen activities do not have a wide field of view and are not spatially stimulating activities
- Once a patient has overcome their neglect of space on the side of the hemianopsia, and has learned spontaneous compensatory scanning in the direction of the hemianopsia, a Peripheral Vision Awareness Device can be prescribed to enhance awareness of objects in the lost field. This will help the patient deal with hemianopsia related ambulatory and safety issues, and will enhance the patient's performance of many activities of daily living.