Originally presented at Anchor Center for Blind Children Pediatric Interest Group, 4/24/97
GOAL: To facilitate alert, secure behavioral state to engage child in learning through any one or any combination of sensory modalities.
WORKING DEFINITION: "Eyes are fine, brain isn't".
Cortical Vision Impairment (CVI) affects the visual cortex or visual tracts in the brain. Visual processing and interpretation as well as discrimination/acuity are affected. Eyes look normal and pupil responses are normal. However, CVI often is present in conjunction with other eye conditions that cause specific visual impairment in addition to the above. For example, premature babies may have restricted vision due to retinopathy of prematurity and CVI due to intraventricular hemmorhage.
PRIMARY STRATEGY: Make sure sensory message is clear to the child.
CVI is most often caused by anoxic episodes, often in the vulnerable period shortly during or after birth. Other common etiologies associated with CVI are seizure disorders, drug implications, cardiac arrest during surgery, and traumatic head injury.
In working with a child with CVI to try for more visual function to assist motor development goals begin with the orienting reflex (you reflexively arouse and alert to what is important to you).Capture child's attention on a reflexive level, then provide learning structure. Example: ATNR--provide flashlight wrapped in red crinkley paper at arm's length. Work from there for grasp and visual gaze/fixation.
At other times offer the child multi-sensory materials to explore on his/her own terms. Use items that can be seen or touched or heard or can be activated using any combination of them. Common everyday objects rather than plastic models need to be used. Be sure to incorporate weight, temperature, smell, and resonance or vibration qualities in the materials used.
Color vision may be intact, consistent, and motivating. Red and yellow are usually most easily seen and tend to be children's favorites. They can also be seen from further away than other colors. Color interpretation tends to remain constant, so colors can be used to assist organization by color coding materials in communication systems and specific places in the learning environment for mobility reference points.
Preferred sensory modalities are individual to each child and may vary for different tasks and in different environments. Often vision is secondary or a supplement to hearing or touch. Even though vision may end up giving the child the most information in the end, the child may have to hear or touch the item before he/she will try to look at it. Since other senses are slower than vision, becoming familiar with a new item or activity may need to take a longer than usual familiarization period.
Introducing a new task in isolation, away from a group, and without any other physical or stressful sensory input or distraction, may best allow the child to become familiar with the sound, feel, and look of the materials involved before becoming involved in the structure of using the material in a given way. If the child is familiar with the materials and the task beforehand, he/she may better be able to perform the task within a group setting because he/she will know what to look and listen for.
Often, a child can only process one sensory modality at a time. Modify instruction so that only one sensory modality at a time has to be engaged. Listening often seems to "capture" the child more than other sensory input; if child is listening, he/she can not be looking. Give the child an oral direction, then perform it so he/she can visually imitate it, rather than talk child through task. Be aware that some children tend to get "stuck" or "locked-in" to electronic sounds like tapes, electronic game boards, keyboard songs, fans, and motors; they cannot break away on their own and need you to turn source off or break its cycle before they can attend.
A classic observation of the child with CVI is that he will briefly gaze at an object then look away while accurately reaching for and grasping object. Sensory integration is a significant problem when vision is not available to perform its role as synthesizer of all sensory input. Thus visual-motor skill development is a real challenge. A critical first step in development and remediation may be for the child to watch his hands. This is usually a skill observed early in infancy (4-6 mos.) To promote it in later periods try having child watch what his/her hands are holding and make sure that stimulus offers a clear and motivating visual component. Examples to try are bright vibrator-toy, fastening helium metallic balloon to wrist, putting neon-colored gloves on child's hands.
When visual-motor skills are emphasized, use materials that are already familiar and motivating to the child so that sensory input is already understood. This may be a time when intermittent sound accompaniment will help keep the child engaged with the activity. Simple music keyboards that play single notes, not an entire piece, before needing re-activation are good examples. The child is in control of the sound component so auditory is not competing with visual and motor senses.
The child with CVI may initially choose to reach for objects seen close to his/her face by using his/her head instead of his/her hands. Encourage this as it is actually another form of reaching that carries with it the same spatial and cognitive understanding that using hands does. Expect that eventually the child will replace head-reach with hand-reach on his/her own. Head-reaching is a satisfying compensatory skill for the child with tactile defensiveness around his hands.
The ability to inhibit or prioritize visual input is often absent for children with CVI. They tend to look at stimuli very close to their faces in order to block out competing visual background distraction. Depth perception and figure-ground discrimination are not observed in most cases. Thus background wallpaper is equivalent to shape block held in hand. Providing a high-contrast background (usually black, non-glare fabric or matte paper is good) is imperative to send a clear visual message to the child with CVI.
Resist taking child's hands to physically model how a task should be done by imposing structure. Consider ways that child can perform what you want done by trying to make the same sounds you do performing task or by providing physical boundaries and borders that will assist in successful task completion. Work-play trays with rimmed edges and high-contrast background may help a lot. Encourage child to initiate placing his/her hands in yours to do task "together" (child's palms on top of adult's hands); this way child initiates molding and can prepare for touch.
For children who need physical cueing and facilitation to complete a task, work out a consistent system to prepare child for your upcoming physical assistance. Many children with visual impairment prefer to place their hand on top of the back of the adult's hand because the movements and kinesthetic experiences better. approximate what they will need to do to duplicate the task on their own.
Attraction to lights and staring at lights is frequently observed in children with CVI so seat child with his back to light sources and not underneath fluorescent lights. Indirect lighting is best and usually brighter is preferred. Some children with CVI are overly sensitive to light and glare; they may prefer less-bright lighting as well as wanting to play in shaded areas outdoors. Encourage these children to wear sunglasses and brimmed caps while travelling in cars and playing outdoors.
Many children with CVI tend to have remarkably intact "faces" vision when other less difficult stimuli go undetected. Often spontaneous eye contact may occur even if it is fleeting. It is more difficult to achieve when you ask the child to look at you. It is especially important for the child who is highly motivated by faces to have the instructor work in front of him/her, close to face.
Familiarity with the sensory attributes of an object or activity helps the child feel secure enough to attend to what can be done with the object. Repetition and practice effect improve visual response time significantly. Also, using the same materials for continual building of new skills can be helpful by eliminating time to gain familiarity with new items. An efficient approach may be to introduce new materials for generalization of already accomplished skills For example, use bright pink plastic eggs filled with sand on a tray to promote beginning eye-hand co-ordination or grasp. Then try putting one green egg in the tray for "different" concept. Try adding more colors for matching or sorting. Hide them for developing scanning skills.
Travel vision may be good in comparison to near work but will be inconsistent unless familiar routines for safety and orientation are impressed upon the child. Safety monitoring should always occur, especially when drop-offs, figure-ground and depth-perception issues occur, such as shadows on steps. Environmental adaptations such as painting a fluorescent orange strip across the drop-off or top step are helpful in warning the child of what is coming.
Incidents in which the child sees and picks up "a raisin from the floor" are frequently reported. However the child will be unable to visually locate the raisin if asked to look for it. This phenomenon of "incidental" vision seems to indicate that there are times or perhaps slits of intact vision but the child has no control over where and when such incidents will occur. It is difficult for most children with CVI to scan to visually locate a stationary object in a busy background unless it is very familiar and motivating. It can be made easier if a movement component is added such as moving arm across field systematically to point and "look up, look down, look all around". After modeling for child, he can learn to do this as a regular part of his scanning technique.
Spacing is important to consider especially in designing augmentative communication systems. Start by trying 4" backgrounds of high-contrast with 2" figures. Keep pictures simple with only important inner detail included. It is important to keep positional sequencing consistent so the system can be effective when vision is "off" and spatial or kinesthetic memory is required to supplement vision.
Mid-line difficulties are often encountered in working with children with CVI, thus positioning of objects or items on a communication board may need to be placed on the side s rather than at mid-line in front. Some children do better with vertical placement of items than with horizontal placement because it eliminates need to cross mid-line. Explore what may work best; each child is different.
Timing: Everything always takes lots longer when visual tracts are not intact. Allow quiet response time of up to one minute initially before intervening.