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GAZETTE
SEPTEMBER 1992
Evaluat ion of Cogni t ive Di sorders
Fol lowing Head Injury
by Dr. Martina O ' Conno r*
The incidence of brain injury
following events such as motor
vehicle accidents and falls has risen
drastically over the past ten years.
Various emotional and social
sequelae deficits may, result from
head injury.
The specific area of brain injury
being addressed in this article is
cognitive disorders, a frequent
consequence of brain injury.
What Are Cognitive Disorders?
The term
cognitive
refers to the state
of
knowing
or
understanding.
Brain
injury often alters a person's ability
to know or understand the world
about him or her. Such individuals
often experience difficulty with
information processing or with
responding appropriately to events in
the environment. They may be unable
to organise and use their environment
in an effective way. Impairments in
cognition or thinking may prevent an
individual from returning to work or
independent living.
Cognitive impairments can logically
be described as discrete areas of
disability (i.e., a memory deficit
versus a visual processing
impairment). It is important,
however, to realise that different
cognitive impairments often occur
together and that they interrelate.
For example, a person may present
what appears to be a significant
memory deficit when the underlying
difficulty is actually a problem with
attention and concentration. With
this in mind, each of the different
types of cognitive impairments will
be described and the reader should
remember that they are not
necessarily distinct and separate
disorders.
Dr. Martina
O'Connor
There are six broad areas of
cognition that are commonly
impaired following brain injury.
These include disorders of
1. attention and concentration,
2. visual processing,
3.
memory,
4.
reasoning and judgement,
5.
executive functions,
and
6.
communication.
In addition, there is usually slowed
mental processing such that an
individual takes longer to think and
respond than prior to the brain
injury. Some people experience
difficulty in all these areas, while
others present with more focused
disorders.
Attention/Concentration Deficits
An inability to sustain attention
while carrying out a task is often a
consequence of brain injury. Patients
frequently complain of "losing track
of what I'm saying" or "not being
able to concentrate and follow the
plot of a television programme."
Attention problems may be present
at an even more basic level where a
person is unable to adequately attend
and respond to simple stimuli, such
as sounds or objects. This is more
often seen in the early stages of
recovery. A higher level attention
problem is the inability to
shift
attention from one task to another.
Attention/concentration represents a
basic level of thinking and
disruption of this process may
preclude an individual from
adequately functioning in society.
Visual Processing
Problems with visually interpreting
the world are also frequently present
following brain injury. Although
individuals may have difficulty with
visual acuity (or how well they see),
in this population the primary
problem is generally the
interpretation
of visual information.
At the most basic level, brain injury
may cause difficulty with the
recognition of objects and faces.
Other problems can be seen in a
patient's analysis of visual stimuli.
He or she may be unable to pick out
visual detail or discriminate features
of objects. Hand-eye coordination
may also be disrupted such that a
person would have trouble building a
model or doing construction. Finally,
space and judgement may be
impaired. This difficulty may be
manifested when a person misjudges
the distance between a plate of food
and the serving tray such that the
food spills on the table. The visual
problems, if not remedied, make
many activities impossible or unsafe,
such as reading, driving and
cooking.
Memory Deficits
Memory deficits are the most
common complaint of individuals
who have suffered brain injury. Early
on, individuals may be unable to
remember events from one moment
to the next. This gradually improves
over time, yet most individuals with
severe brain injuries suffer some sort
of memory impairment.
Memory impairment requires that an
individual structure his or her life in
certain ways so that the impairment
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