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VISUAL IMPAIRMENT: ITS EFFECT ON COGNITIVE DEVELOPMENT
AND BEHAVIOUR: A review of the literature
Liyange Aruni Gunaratne (UK)
"Visual impairment" refers to all degrees of reduction
in vision. "Blind" is defined as having no more vision
than light perception in both eyes and where corrective lenses
would make no difference. The prevalence of significant visual
impairment is around 1/2000 in the Western world.
Visual impairment present at birth could be due to genetic anomalies
or due to injury to the developing visual system. Dependent on
the cause, the possible presence of other impairments may be indicated,
as in rubella.
The degree of residual functional vision refers to acuity, the
ability to interpret visual information in a practical sense and
the conditions under which residual vision is optimal.
Visually impaired individuals are all very different. The degree
of impairment, personality, intelligence, background and the presence
of other disabilities all have varying effects. For instance,
cognitive ability will affect the ability to conceptualise the
environment in the absence or reduction of visual information.
Temperament and personal characteristics may facilitate or interfere
with adaptive tasks. As a visually impaired child grows older,
although acuity may remain constant, visual function seems to
improve as they gradually learn how to use the residual vision
more.
Visual impairment and communication
One of the most common misconceptions about blind children is
that they are equally or more adept in language skills than their
normally sighted peers (Fraiberg 1977). In reality severe and
early impairments are likely to affect the language development
of affected children. The differences are in part due to limited
access to the environment and to differences in verbal feedback
from people around them. They lack visual references and have
reduced integration of information from their parents. More recent
studies have found that the language of visually impaired children
is more self-oriented and that the word meanings are more limited
than for normally sighted children (Anderson et al 1984).
Vision enables us to perceive objects in their totality and in
context. Severely visually impaired children have to rely on sequential
observation. They can see or touch only part of an object and
from this limited information build up an image of components.
Awareness of relationships between objects occurs later, and initially
connections between sounds and objects are not often made. Based
on the different conceptualisation of the environment, blind children
may follow alternative paths of language development. The use
and nature of language differs in non-verbal patterns of communication,
loudness, posture, smiling and other facial expressions, and their
reliance on formulaic and standard expressions.
A study by McConachie and Moore (1993) found that, almost paradoxically,
parents of blind children were less likely to amplify or emphasise
the meanings of their communication to the child, or to describe
objects and events in detail. This delays and complicates the
process of making links between early language and the surrounding
world even further.
Auditory memory skills may play a different role in language
development which may lead to a skewed perception of the ability
to use language in comparison to sighted children. Verbal reasoning
skills appear to lag behind auditory memory skills that can cause
problems when having to change topics quickly or when incorporating
broader meanings of a word, particularly in social situations.
Syntax and grammar seem to develop in a similar manner to sighted
children, but the blind child and sighted listener may have difficulty
understanding each other's referents (Landau 1997).
Burlingham (1972) reported a higher incidence of echolalia, both
immediate and delayed, for blind children This could be expression
of better-developed auditory memory skills in blind children.
However, although visually impaired children may be more aware
of the presence of auditory clues in conversations, this does
not necessarily mean that they have correctly identified the implied
meaning.
For visually impaired children, the process of adapting to society
will differ from that of normally sighted children. Many social
clues take the form of body language and therefore require vision
in order to be understood, so may be only partially or not at
all accessible (Groenveld 1993). Congenitally blind children are
not aware of the reactions from others to their own body language
unless they are specifically taught. Partially sighted children
who have behavioural adaptations to make their sight more functional
may, unbeknown to them, communicate body language that implies
feelings that they are not actually experiencing.
Visually impaired children often face problems in social integration.
Although they may have a great desire to belong to a group, they
may have fears about how to go about it. This shift from family
norms to peer group norms can be very difficult and pressure to
be "normal" can further inhibit this integration, so
much so that partially sighted children may start to deny their
impairment altogether.
Visual Impairment and Mental Health
The behaviour of visually impaired children is shaped by the
limitations of their visual input. This alters their perceptions
of the environment, their own understandings of cause and effect
and the relationships between people and/or objects. Their behaviour
may well be their normal reaction to different information that
they receive, rather than a deviation. Several studies have reported
a high incidence of psychiatric disorder in blind children (Jan
et al. 1977). However the criteria used in diagnoses are based
on the sighted population. It is therefore difficult to tell if
one is dealing with the outward symptoms of a psychiatric disorder
or of the visual impairment itself. It is therefore very important
that assessments regarding behavioural deviance are made by clinicians
who are familiar with people who are visually impaired.
For the congenitally blind child, the concept of self may be
delayed because of difficulties in communication due to the lack
of eye contact with the mother and responsive smiling. Representational
play also develops much later than normal, and the individual
may wrongly be labelled "autistic". Furthermore some
young blind children show pronoun reversal as is found is autism.
Autistic-type features in the behaviour of totally blind children
are quite common. These stereotypic movements include flicking
hands or fingers, rocking, spinning, body swaying, twirling and
tapping for example (Jan et al 1977) as are seen in autistic children.
Before labelling the child as autistic, the degree to which the
behaviour can be minimised or modified must be investigated. It
may be an expression of under-stimulation, so providing a stimulating
activity may reduce the behaviour. On the other hand the movements
may be due to over-stimulation. This is commonly found in children
with cortical visual impairment who resort to repetitive behaviour
when the environment becomes too visually complex for them to
cope with (Groenveld 1990). When the environment has been made
more visually acceptable for them, if the deviant behaviour is
reduced, it is more likely that the cause was the visual impairment
rather than a psychiatric disorder. Nevertheless, any deviant
behaviour must not be initially assumed to be as a result of the
visual impairment alone. Other factors must always be considered
such as additional intellectual disabilities, emotional problems
and language disorders. These may be compounded by the visual
impairment but not be caused by it.
As visually impaired children do not have access to visual modelling
and shaping of expected behaviour patterns, a number of their
behaviours may be mistakenly diagnosed as pathological. Depression
can be wrongly suspected or diagnosed because of misunderstanding
of body language. Blind children often have low muscle tone and
because they do not need to maintain eye contact for information,
sit with their head down. Furthermore a child may misinterpret
the meaning for the language and use overly dramatic statements
that carry their own personal meaning.
The "I-You" distinction in congenitally blind children
is delayed, as is representational play, which is part of the
basis for the development of symbolic language. Kitson and Thacker
(2000) suggest that as a result, congenitally blind adults may
have depersonalised relationships; they may seem unmotivated and
"schizoid". Professionals are likely to underestimate
mood, intelligence and personality in any client with reduced
expressive behaviour.
References:
Anderson, E.D., Dunlea, A., Kekelis, L.S. (1984) "Blind
children's language: resolving some differences." Journal
of Child Language, 11, pp 45-64
Burlingham, D. (1972) Psychoanalytic Studies of the Sighted and
the Blind. New York: National Universities Press
Fraiberg, S. (1997) Insights from the blind. New York: Basic
Books
Groenveld, M. (1993) Effects of visual disability on behaviour
and the family. In Fielder, A.R., Best A.B., Bax, M.C. (eds) The
Management of visual impairment in childhood. London: Cambridge
University Press
Groenveld, M. (1990) "The dilemma of assessing the visually
impaired child" Developmental Medicine and Child Neurology,
32, pp 1105-1109
Jan, J.E., Freeman, R.D., Scott, E.P. (1977) Visual Impairment
in Children and Adolescents. New York: Grune & Stratton
Kitson, N. & Thacker, A. (2000) Adult Psychiatry. In Hindley,
P. & Kitson, N.(eds) Mental Heath and Deafness. London: Whurr
Publishers Ltd.
Landau, B. (1997) "Language and Experience in Blind Children:
Retrospective and Prospective". In: Lewis, V., Collis, G.M
(Eds) Blindness and Psychological Development in Young Children.
Leceister: BPS Books, pp 9-28
McConachie, H. & Moore, V. (1994) Early expressive language
of severely visually impaired children, Developmental Medicine
and Child Neurology 36(3): 230-40.
This article first appeared on the site in 2002.
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