Changements de Perception

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Perception is the brain’s ability to gather information and make sense of it. Perceptual changes may cause people with a brain injury not to realize what they feel, see or hear, even though their senses of touch, sight and hearing are fine. Perceptual changes may impair the ability to judge distance, size, position and speed of movement.


After acquiring a brain injury, the person may experience some of the following:

• Unilateral neglect (neglect of one side of the body)

• Visual field cut (each eye sees only half or a portion of its visual field)

• Apraxia (inability to use an object or do familiar tasks)

• Difficulty with spatial relations


Perceptual changes following brain injury can be temporary or permanent.  The following information is intended to help identify perceptual changes and how to adapt to them.




Problem: Visual field cut



  • Suddenly notices objects that seem to appear or disappear
  • Bumps into objects on the affected side
  • Turns the head toward the unaffected side
  • Cannot see food on the side of the plate on the affected side
  • Loses track of the last location on a page where the person was reading or writing
  • When reading, cuts words in half and they cannot be understood


What to do:

  • Remind the person to look around the environment, especially on the affected side.
  • Mark “on” and “off” switches of frequently  used items, such as televisions and kitchen appliances, with bright pieces of tape so the person can easily know when equipment is on or off.
  • Position bright objects or favourite things to the affected side and ask the person to turn his or her head until they spot the objects.
  • Draw a straight, brightly coloured line down one side of a book or notebook as a cue indicating the edge of the page.  Do this on the right side of the page if the right side is affected, and on the left side if the left side is affected.

Problem: Apraxia



  • Uses objects incorrectly; for example, might use a toothbrush to comb hair or a fork to eat soup Fails to follow spoken directions due to an inability to understand or do what is asked; for example, may not give the “thumbs-up” sign when asked
  • Puts clothes on backwards, upside down or inside out


What to do:

  • Stop the person from continuing a task the wrong way.
  • Show the person what to do by demonstrating the position or movement.
  • Place your hand over the person’s hand and move it through the correct motions to perform a task.
  • Redirect the person to put on clothing in correct order, one step at a time. Develop a daily routine for hygiene and dressing.

Problem: Spatial relations



  • Mistakes the location of a chair when sitting down
  • Has difficulty finding items in a cluttered room
  • Has trouble using a fork or spoon to pick up food from a plate
  • Misjudges distance; for example, misses the cup when pouring coffee
  • Misjudges space between steps when going up or down stairs
  • Reaches too far or not far enough to get objects
  • Stands too close or too far away from others in social situations
  • Requests eye appointments often, because of perception that vision is affected


What to do:

  • Limit clutter; keep the home and drawers organized and neat.
  • Keep items used often in the same location. Provide cues with words and pictures.
  • Place brightly-coloured tape across the edge of each step on stairways.
  • Remind that handrails should be used when available.
  • Encourage using both hands to feel for objects.
  • Provide gentle reminders and ask the person to move when standing too close or too far away.
  • Wait for six months after the brain injury — or the time recommended by your physician — to schedule an eye appointment.  It is unlikely that the problem with perception is the result of a new problem with the eyes.