The parietal and occipital lobes of the brain integrate the input from different senses. For example, the senses involved in recognising an apple may include touch (firm, spongy and smooth), sight (red or green, round, spotty, large etc.), sound (crunching and chewing), smell (fresh or rotting) and taste (a granny smith versus a red delicious, sweet or tangy).
The effects of brain injury may involve a range of sensory and perceptual problems which are often described according to the sensory perceptual system involved.
These systems include:
• Auditory (perception of sounds)
• Visual (perception of colour, shape, size, depth and distance)
• Tactile (the perception of touch relating to pain, pressure and temperature)
• Olfactory (perception of smells)
• Gustatory (perception of taste).
A closer look at visuo-spatial skills
While deficits may occur within each sensory system, the area of visuo-spatial is often more dramatic. Visuo-spatial deficits may include difficulties in the following areas:
• Drawing or copying objects
• Recognising objects (agnosia)
• Telling left from right
• Doing mathematics (discalculia)
• Analysing and remembering visual information
• Manipulating or constructing objects
• Awareness of the body in space e.g. climbing stairs
• Perception of the environment e.g. following directions.
People may experience selective difficulties or several deficits depending upon the nature of their injury. One well known syndrome involves neglect: The person fails to notice certain aspects on one side of the world in front of them, most typically the left hand side. For example, a person with neglect may fail to notice food on the left side of a plate or fail to copy aspects on the left side of a picture.
Management of visuo-spatial deficits
The presence of neglect may be undiagnosed despite significant safety issues. People with neglect are often unaware of their problems and tend to use other explanations for the mistakes caused by the neglect. A key component of rehabilitation is therefore to educate the person and increase their awareness of the impact of the perceptual deficit in everyday living. Further components to a program for managing visuo-spatial problems may include retraining skills, changing the environment, changing expectations, or compensatory strategies.
One approach involves retraining until the person regains, in varying degrees, the functional skill. Retraining typically involves repetitive and intensive exercises for a specific skill or task e.g. practise at drawing an object while receiving feedback. This approach tends to be more effective with specific skills.
Changing the environment or expectations
A second approach involves modifying the environment to provide more support or reduce the demands of a particular skill. One example may involve building a ramp or fitting a handrail for a person who finds it difficult to climb a flight of stairs to their house. Sometimes, the change in the environment can be as simple as shifting furniture to ensure greater space when walking around the house. The person may also learn to adjust their expectations and educate other people about their difficulties.
People often learn or may be taught a range of strategies to compensate for visuo-spatial problems. These strategies may be something like a person learning to turn their head or body to scan their environment, or moving objects into their ideal position. A range of specialised technology or equipment may also be available to fit into a person’s home or assist with community access. Some external prompts may include colour stickers for object recognition, bright lights on the floor, musical or sound prompts, hand rails, and other safety devices. An example of a compensatory approach for object recognition involves the person learning to rely more upon other senses such as touch, hearing and smell. They may choose to shut their eyes to avoid inconsistent information from the visual system. The rehabilitation strategies described may be developed by a neuropsychologist, occupational therapist or physiotherapist. The eventual goal of a rehabilitation program is often greater independence and use of selfmanagement strategies. Family members, friends and support workers can provide valuable support and reinforcement of rehabilitation techniques also.
This story was first seen in the Synapse bridge magazine www.synapse.org.au