In the last decade, children who are cortically visually
impaired (CVI) have received increased attention and concern from the
medical, educational, and rehabilitative communities. The Association for
Education and Rehabilitation of the Blind and Visually Impaired has
increased the number of sessions on CVI at its bi-annual conferences, The
Journal of Visual Impairment & Blindness and RE:view have published many
articles on varying facts of this often confusing condition. Several recent
teleseminars were devoted to children with CVI. All of these efforts have
increased our understanding of CVI and given many of us confidence to work
with children who are cortically visually impaired. Because we should not
become overly confident about our knowledge, I offer the following words of
caution.
CVI Is a Complex Condition
We
need to be cautious not to oversimplify a complex condition. Despite its
label, the term cortical visual impairment refers not to an eye condition
but to a brain condition. About 80% of the brain, working as functional
systems, is required to efficiently process and understand a visual message.
We the workers, therefore, need knowledge of how the brain functions if we
are to understand the implications of brain dysfunction (Dutton et al.,
1996; Morse, 1990; Morse, 1992; Padula, 1996; Sacks, 1985).
Vision is also a psychological
process; as a result, disruptions in visual function cannot be considered in
isolation from other functions. Visual attention does not automatically mean
cognitive understanding. We the workers should understand the implications
of motor, cognitive, and communication problems when we plan habilitative
visual services (Dutton et al., 1996; Morse, 1990; Morse, 1992; Nielsen,
1991; Padula, 1996; Padula & Shapiro, 1993; Sacks, 1985; van der Kolk,
1994).
A final factor to consider is that
vision is an emotional process. All people with complete or partial sight
have patterns of visual use and nonuse. People tend to use the visual system
more when they feel confident about what they are expected to do, when they
are listening to something that interests them, or when they want to relate
to others. They tend not to use their vision when their senses are
overwhelmed, when they are planning or thinking how to do something that is
difficult (i.e., giving some bad news or when performing a difficult motor
act); or when they are bored, tired, stressed, or feel submissive. We the
workers should always consider what the child finds motivating and find ways
to give the child a sense of self-efficacy in the activity (Morse, 1991).
All Children With CVI Do Not Exhibit Similar Behaviors
We should be cautious not to
assume that all children with CVI exhibit the same behaviors. The
diagnosis means different things for different children; the effects depend
on factors such as how extensive and severe were the insults to the brain,
the developmental period during which the insult occurred, the child's
previous experience, the presence or absence of additional disabilities,
medications being taken, and the child's motivation. Some individuals with
CVI have no observable visual responses; others have occasional responses to
stimuli, whereas still others have a significant amount of usable vision.
Some children have field restrictions and others do not. Even some of those
who have significant peripheral field losses may be able to detect movement,
perhaps through the secondary visual system. Over time and with or without
intervention, many children show significant improvement in their general
use of vision. That improvement may be the result of being more able
neurologically to handle complex stimuli (Burke, 1991). Thus, we might see
that as children understand their daily experiences more and as they
anticipate routines, their functional visual behaviors also improve.
Even when visual behaviors improve
to the point of appearing normal, many of the children may have significant
difficulty with specific types of visual stimuli. For example, some
individuals may be able to see a human face, know it is a face, but be
unable to identify to whom the face belongs solely on the basis of the
experience of those of us who can discriminate cars from trucks but cannot
identify the make or year of he car on the basis of our visual
discrimination abilities. Faces are often confusing to individuals with CVI.
The face changes with every expression and with every physical movement of
different parts of the body. The face also presents a kaleidoscope of
sensory information—visual, auditory, and olfactory. Moreover, a specific
face may change depending on the hair style, on whether the individual
alternates between wearing glasses or contact lenses, or is using makeup or
not. Identifying faces requires complex visual analysis. Other individuals
with cortical visual impairment may be able to identify people and concrete
objects as well as photographs of them bet be unable to understand visual
symbolic information in forms such as line drawings or print.
Some children with CVI may have
difficulties with depth perception that go far beyond a situation such as a
mono-ocularity. Others may have significant difficulty in moving through
even a very familiar environment. Dutton et al. (1996) described several
children who can identify objects when they are moving very slowly but not
when they are stationary or moving quickly. Padula & Shapiro (1993)
discussed later-in-life trauma and see many who have associated strabismus,
oculomotor dysfunction, convergence and accommodative abnormalities,
diplopia, and balance and movement difficulties. Those patients described a
world of distortions that did not match their previous visual memories.
Those reports raise interesting questions about the individuals who
attribute their CVI to congenital causes or early postnatal insult. The
point here is that a major insult may have been localized to one or more
specific areas but other parts of the cerebral cortex may or may not come
into play and support the functions lost to the insult.
On casual observation, vision use
in some children may appear normal. During the school years, however, some
of these children may be described as being preoccupied, distractible, and
inattentive when, in reality, some of their behaviors result from CVI. The
observable school behaviors may be a result of fatigue from trying to
interpret difficult visual stimuli. The visual components of a task
frequently become more difficult when combined with the demands of listening,
maintaining position in space, and simultaneously performing complex motor
actions (Dutton et al., 1996).
A Single Approach Does Not Work for All Children
We should be cautious not to think
that a single approach works for all children. As Sacks (1985) pointed out,
a diagnosis of seizures is an insufficient label for prescribing a treatment
regimen, and so too is a diagnosis of CVI.
Some children increase their
visual awareness by such means as the use of lighted toys in a darkened
room, the light box, distinctive geometric patterns, the use of bright
colors, and sound toys (Baker-Nobles & Rutherford, 1995; Jan &
Groenveld, 1993). Other children, however, tend to use their vision more
efficiently and more frequently when they understand and feel comfortable
with the tactile-kinesthetic-motor demands of the task. Farenkopf, McGregor,
Nes, and Koenig (1997) stated, “[T]ypical visual enrichment strategies do
not work with children who have CVI because the visual sense is overwhelmed
by the visual information” (p. 484). For example, a common lament among
educators and therapists is that many children who are diagnosed with CVI
tend to turn their head away as they reach for an object. One hypothesis is
that the children are using their peripheral vision when they turn their
heads away. That may be true for some. I have followed a significant number
of children with CVI for over a decade (many on video tape) and believe that
many of the children avert their gaze until they understand what their hands
are doing. For these children, intervention might be referred to as vision
through the back door, through the hands. That approach considers the
complexities of the task's motor demands and the saliency of the tactual
experiences so the brain becomes aware of what the hands are doing. It is
the hand first; then the vision. When the hands explore real objects, they
feed the abstract visual and cognitive systems (Affolter, 1991; Dutton et
al., 1996; Hyvarinen, 1994; Morse, 1992; Nielsen, 1995; Padula & Shapiro,
1993; Sacks, 1985).
Many of these same children are
extraordinarily attentive to environmental sounds. We need to be cautious
that we do not assume that an interest in sounds automatically means an
understanding of those sounds. Many, but not all, children with cortical
visual impairment display varying degrees of difficulty with language.
Indeed, processing auditory information may actually interfere not only with
the use of vision but also with motor exploration. Much energy may go into
trying to interpret the meaning of the sounds or the sounds themselves may
provide a recreational diversion. According to studies by Farenkopf et al.
(1997) and Lane (1996), verbal prompts are not as effective as physical
prompts. These children come to understand their visual world better when
the language used around them does not interfere with attending to what the
hands are doing. Interestingly, language is promoted more effectively when
the words used conform to what the hands are experiencing (Affolter, 1991;
Hodgdon, 1997; Koenig & Farenkopf, 1997; Lane, 1996; Morse, 1992).
Treatment Is a Dynamic Process
We should be cautious not to view
treatment as a linear and isolated training process. We need to recognize
that simplification of the visual environment is not enough. Infants with no
disabilities come to recognize those objects and people that have the most
meaning to them (parents, bottle, favorite toy) through physical interaction
in their everyday activities. For many children with CVI, reaching out and
actively participating is a frightening experience. To them, the world may
seem chaotic and unfriendly. Our interventions should examine the
environments in which these children function, the activities in which they
engage, the sensory—motor demands of tasks, time pressures, and
interfering variables. We need to relate those factors to the individual
child's ability to modulate his or her states of arousal, ability to
determine which aspects of the task are the important ones to attend to, and
memory. For many of the children, we need to reduce the number of words we
use while they are involved in highly demanding tasks. We should be more
consistent in what we call objects and people. We also need to learn when
not to talk. (Hynd & Willis, 1988; Morse, 1990; van der Kolk, 1994).
We need to be cautious about
allowing our own egos and desire for student progress to interfere with our
objective professional evaluation of the child's progress. Many of these
students also have severe multiple disabilities that may prevent them from
making obvious quantitative changes. Rather, many make qualitative changes.
One of the most objective ways to measure change is to video tape a child 3
or 4 times during a school year. Determine ahead of time which behaviors are
to be taped during which activities and develop an accompanying data sheet.
Subsequently, have staff independently watch the tape and fill in their own
data sheet from their professional perspective. The findings then constitute
one measure of change. Subsequently, the composite data and the video tape
may become part of the child's permanent record.
Those of us who work on behalf of
children who have visual handicaps need to applaud our efforts to secure
quality information to use on behalf of children with CVI. However, we
should be forever diligent that we do not fool ourselves into thinking that
there is a step-by-step single or simple method of enticing these children
into their visual world and of assisting them in comprehending what they see.
3.
Children
with cortical vision impairment: Implications for education
Associate
Dean
School
of Special Education and Disability Studies
Flinders
University