FACT SHEET Also Known as: Cortical Visual Impairment,Delayed Visual Maturation, Cortical Blindness
Neurological Visual Impairment (NVI) is now the preferred name for a type ofvision impairment that has been and is still referred to as Cortical Visual Impairmentor Cortical Blindness. NVI is now divided into three categories: Cortical VisualImpairment, Delayed Visual Maturation, and Cortical Blindness. These threedivisions are made according to what area of the brain has been effected.
A variety of studies indicate that the percentage of children with vision impairmentswho have NVI is between 3.6 and 21%, making it the major cause of visionimpairment in children who are deaf-blind. NVI occurs when the part of the brainthat is responsible for seeing is damaged. In other words, the eye itself is normalbut the brain does not process the information properly. NVI has a variety of
causes including, but not limited to, lack of oxygen before, during, and after birth,viral or bacterial illness such as meningitis and cytomegalovirus, or traumatic braininjury. These children can but do not always have additional disabilities. Othertypes of vision impairments such as optic atrophy (defect of the optic nerveresulting in the inability of the nerve to conduct images to the brain) and opticnerve hypoplasia (a vision impairment caused by a congenital defect of the opticdisk) are more common in children with NVI.
NVI effects vision in a variety of ways and causes vision loss that can be from mildto severe, temporary or permanent. There is no way to predict what a youngchild’s vision will be like as they mature but many children with NVI experienceimprovement with their vision. Fluctuating vision is common. This is mostpronounced in children with seizure disorders or in those on certain medicationssuch as Dilantin, Tegretol, or Phenobarbital. A child may be able to see an objectone day and be unable to the next. These children may also have better peripheralthan central vision and thus look at objects out of the side of their eye. They mayhave visual field losses that are not symmetrical (one eye may be worse than theother). This uneven loss does not necessarily correspond to hand function. If theleft eye is better than the right, the left hand is not necessarily stronger than theright.
Children with NVI experience problems with specific types of visual tasks. Theyhave difficulty with figure-ground (seeing an object instead of the background), andwith complex visual displays such as cluttered pictures (a picture of five differentanimals instead of two). Spatial confusion is common; for example, being unable
to locate their chair even though they can see it. They may also be visuallyinattentive, not wanting to look at objects, and may prefer their sense of touch. Itis common to see a child turn his/her head away as they explore an object withtheir hands. Seeing with NVI can be compared with trying to listen to one voice ina noisy room or to speaking a foreign language.
Vision stimulation is proven to help most children with vision impairments improvethey way they use their vision; this is especially true of children with NVI. Forvision stimulation to be effective it needs to happen in everyday real life situations,not only in therapy sessions. Identifying colors in an activity, visually tracking theirclassmate as they move across the room, and identifying the shape of every dayobjects are examples. Suggested Instructional Strategies for Children with NVI
1. Materials, such as pictures, should be simple in form, high contrast (the colors of
a picture or object should be different, such as a yellow toy against a black
background instead of an orange one), and presented one at a time.
2. Bright lighting can help a child see and attend to visual materials more
consistently. Adjust the light, both natural and artificial, to determine what isbest. Controlled incandescent lighting may be better than fluorescent lighting.
3. Give the child time to respond to the materials that are being presented.
4. Color vision is usually intact, and color can be used effectively. Yellow and read
are possibly easier to see and can be used to outline numbers, letters, or pictures,to color code, or to attract attention to something you want the child to lookat.
5. It is also important to keep the color of materials constant to avoid confusion.
This also applies to visual cues in general which should also be consistent overtime and location. If the child uses a red bowl at home and this is how heknows it is time to eat then the same should be done at school. Watch to see ifthe child has a preference for size or color.
6. Use a multisensory approach such as pairing an object that you want them to
7. Touch should be considered a major sense for learning. Children with NVI
appear to learn effectively through this sense.
8. Repetition and routines can help the child understand their visual environment.
If changes are needed make them slowly to allow time to adjust.
9. Fluctuations in visual performance can be limited by reducing fatigue. Try
working in short spurts, or divide a long task into shorter periods.
10. Reduce outside noise and other environmental stimulation that may distract the
11. Objects can be more easily seen when they are moving. This is especially true
when they are in the peripheral fields.
12. Positioning is also important. The more energy being expended on holding
yourself up, the less can be used for seeing.
13. Language helps a child to understand a visual situation by adding meaning to it.
Be consistent in the language you use. References
Groenveld, M., Jan, J.E., & Leader, P. (1990). Observations on the Habilitation of Children with
Cortical Visual Impairment. Journal of Visual Impairment and Blindness, 84, 11-15.
Levack, N. (1991). Low Vision: A Resource Guide with Adaptations for Students with Visual
Impairments. Austin: Texas School for the Blind.
Morse, M.T. (1990) Cortical Visual Impairment in Young Children with Multiple Disabilities,
Journal of Visual Impairment and Blindness, 84, 200-203.
Takeshita, B. (1996, March). Neurological Visual Impairment. Paper presented at the annual
conference of the Transcribers and Educators of the Visually Handicapped. The Project for New The Center for Development & Disability Mexico Children & Youth Who Are Deafblind Fact sheets from the Project for NM Children & Youth Who Are Deafblind are to be used by both families and professionalsserving individuals with dual sensory impairments. The information applies to students 0 – 21 years of age. The purpose of thefact sheet is to give general information on a specific topic. More specific information for an individual student can be providedthrough individualized technical assistance. The fact sheet is a starting point for further information. Information for this FactSheet kindly supplied by California Deaf-Blind Services and the Nevada Dual Sensory Impairment Project.
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Vibration Isolation Support System for SCHENBERG Detector J.L. Melo, W.F. Velloso Jr. and O. D. Aguiar Instituto Nacional de Pesquisas Espaciais - INPE . Avenida dos Astronautas, 1758 São José dos Campos, SP 12227-010, Brazil e-mail : firstname.lastname@example.org Abstract : We designed a mechanical isolation system for a spherical resonant gravitational wave detector we are building in Brazil. We have