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Linda Baker-Nobles, MS, OTR
Originally appeared in the Ski-Hi Institute News Exchange, Vol.1, No.3, Summer 1996
Professionals who work in early intervention are often called upon to work with infants with multiple disabilities. Sometimes these infants have diagnoses of cortical blindness or cortical visual impairment (CVI), a diagnosis which is becoming more prevalent with the improvement in medical intervention and diagnostic technology. In fact, this diagnosis is the leading cause of visual impairment in developed countries.
CVI is a condition that does not affect the eyes or optic nerves, but rather impacts the visual tracts or the visual cortex in the brain. This results in the visual cortex having difficulty processing and interpreting the information that the eyes see. CVI is most often caused by anoxia (lack of oxygen to the brain). The infant brain appears to be the most susceptible to this anoxia during or shortly after birth. Other causes of CVI include cardiac arrest during heart surgeries, trauma, epilepsy, infections, drugs, and poisons. Most often, these infants have other sensory and motor problems associated with central nervous system involvement and are receiving home-based early intervention services.
Infants with cortical visual impairment demonstrate different visual characteristics than infants with ocular, visual impairment. The eyes of an infant with CVI usually look normal, although they will often not be able to visually track an object. Their visual attention span can be very short, and they may appear to look at the object peripherally. Sometimes they are observed to briefly look, look away, and then return again for another brief look. If they reach for an object, they may not look at the object while trying to reach, but rather look at the object, look away, and then attempt to reach. Some of the infants keep their eyes half-closed or closed completely for periods of time. They may compulsively light gaze, a characteristic not associated with infants with just an ocular impairment. When they move around, they may get very close to objects, not for magnification, but rather to "block out" background visual information. Infants with CVI do not usually have problems with the perception of color and are often attracted to the primary colors, especially reds and yellows.
Many of the visual characteristics presented above are related to the difficulty with visually processing the information in the environment. Vision is the most important sense in humans. It is critical for survival, orientation and navigation, anticipation, adaption, non-verbal communication, and integration of information from all of the other senses. As a result, we live in a very visually enriched and stimulating environment. Often this environ-ment is too overwhelming for infants and children with CVI. They are unable to process and interpret all that they see. The overstimulating visual environment appears to cause them to visually "disengage" or shut down the environment. They do this by looking away, closing their eyes, or sometimes sleeping. At times this visual input, especially when it is also combined with noise or other sensory input can cause the infant to become so disorganized that it results in agitation and crying. This is referred to as infant behavioral state.
The ability of the infant to orient and attend to the environment is primary in learning. The term "behavior state" refers to the infant's ability to adapt to the sensory demands of the world and to be able to attend for the purpose of learning. Behavioral state is affected by a variety of both intrinsic and extrinsic factors. Examples of intrinsic factors are effects of medication, nutritional status, and seizure activity. Examples of extrinsic factors include: visual input, noise, and touch. Although there may be times when intrinsic factors cannot always be controlled, we as early interventionists need to be aware of the extrinsic factors and their effect on the behavioral state of the infant. When the infant is giving cues that indicate either a lack of alertness and responsiveness, avoidance or aversion, it is important to realize that the infant is not making an adaptive response to a stimulus and is not learning from the environment. In addition, the infant is communicating to us that whatever we are doing may be "too much" and we need to reduce the amount of sensory input such as talking, music, visual stimulation, and/or touch experiences that we are providing.
The majority of infants with the diagnosis of CVI have other central nervous system involvement and their ability to regulate their behavioral state and team from the environment can be affected. Since vision is such a critical factor in learning for humans, it is important to consider the visual environment when planning intervention programs. As stated earlier, normal visual environments can be too enriched and too complicated for infants and children with CVI. This may result in the child visually disengaging and not using vision for learning. Evaluating responses to visual input and how it affects the behavioral state of the infant can be helpful. Parents are usually the best sources of information about how sensory stimuli affect the behavior of their infant. Parents often report that their infant is totally visually unresponsive to the environment or only looks at certain times. Sometimes they report that certain visual input will agitate or upset the infant. They may provide information about certain colors or toys that influence visual attention. It is also helpful to see whether the infant responds to certain light and/or patterns.
Modifying the visual environment to regulate the infant's behavioral state and to promote visual orientation and attention to the world is an important part of assisting that child -to initiate movement for the purpose of play and learning. When the infant begins to experience some control over the environment, this helps to also regulate behavioral state since something is not always happening to the child, but rather the child is controlling what occurs. Typical intervention strategies for infants and children with visual impairment concentrate on enriching the visual environment so that the infant is more aware of visual items. Although this is good for infants and children with an ocular or eye impairment, it is often detrimental for an infant or child with a cortical visual impairment. Because infants with this diagnosis tend to visually disengage with an enriched environment, it is more helpful to simplify the visual environment. Examples of visual simplification include: use a solid color blanket or sheet when playing with infant or child and introduce one simple visually contrasting object or toy at a time; using a background shield when introducing a contrasting object or toy to reduce the effects of figure-ground; removing extra visual stimuli from the infant's room and crib and using one or two high contrast items to assist the infant to focus attention; provision of a tactile cue to the hand when the infant appears to be visually attentive; using a primary-colored bottle during feeding to reinforce visual discrimination of a common object; and using common objects that have meaning in the infant and child's life. Simple primary colored cause and effect toys that have a light and sound can be reinforcing in promoting reaching.
It is important to note that if an infant or child is diagnosed with cortical visual impairment and a motor impairment, you may not be able to work on visual engagement if you are working towards motor responses such as head or trunk control. When the infant is fighting gravity, it is very difficult to control visual muscles and attend to a visual stimulus; it is likely that the infant will visually disengage and not respond. When you are working on visual goals, it is helpful to eliminate the effects of gravity and have the infant well positioned.
Being aware of the infant's behavioral state in response to sensory stimuli in the environment and adapting the visual environ-ment for infants with CVI can be two important factors in promoting attention and response in these infants. Working with parents to collaborate on strategies to simplify visual home environments and learning to read behavioral cues in infants with multiple disabilities can promote partnerships that assist the infant to begin self-directed movement for play.
Linda Baker Nobles is an assistant professor of occupational therapy at Rockhurst College in Kansas City, Missouri, where she teaches both occupational therapy and physical therapy students. She has over 20 years experience working with infants and children with visual impairments and a variety of other disabilities.
Video: Cortical Visual Impairment #11407, 54 minutes. Lecture by Dr. Good, Pediatric Ophthalmologist in California. Available for $65 from Child Health and Development Education Media, 5632 Van Nuys Boulevard, Suite 286, Van Nuys, CA 91401, (818) 994-0933 (Voice), (818) 994-0153 (Fax)
Booklets: (1) Monograph on CVI for $12 from North Rocks Press, Royal New South Wales Institute for Deaf and Blind Children, 361-365 North Rocks Road, North Rocks, NSW 2151 Australia; (2) CVI in Children: A Handbook for Parents and Professionals for $15 from Royal Blind Society of N.S.W., 4 Mitchell Street, Enfield, NSW 2136 Australia.
Baker-Nobles, L., & Rutherford, A. (1995). Understanding cortical visual impairment in children, American Journal of Occupational Therapy, 49(9), 899-903.
Good, W. V., Jan, J. E., DeSa, L.. Barkovich, A. J., Groenveld. M., & Hoyt, C. S. (1994). Cortical visual impairment in children, Survey of Opthalmology. 38(4), 351-361.
Groenveld, M., Jan, J. E., & Leader, P. (1990, January). Observations on the habilitation of children with cortical visual impairment, Journal of Visual Impairment and Blindness, 11-15.
Guess, D., Rues, J., Roberts, S., Siegel-Causey, E., Ault, M., Guy, B., & Thompson, B. (1993). Analysis of behavior state conditions and associated environmental variables among students with profound handicaps, American Journal of Mental Retardation. 97(6), 634-653.
Jan, J. E., & Groenveld, M. (1993, April). Visual behaviors and adaptations associated with cortical and ocular impairment. Journal of Visual Impairment and Blindness, 101-105.