Abilities recovered
After CHI, some
areas of functioning improve more rapidly than others.
Verbal skills recovery more rapidly than visuomotor and
visuospatial abilities. Short term memory seems to be
resistant to trauma and is usually not affected much by CHI. Long
term memory, on the other hand, appears to remain impaired
for a considerable amount of time after CHI. One study found
that 50% of a group who had received severe closed head injuriess continued
to have memory deficits six to seven years after injury.
According to Geschwind, the memory problems exhibited by CHI
patients are the result of underlying attentional and
information processing deficits (executive function).
Because of the smooth interior of the skull near the primary
language centers specific aphasia syndromes are relatively
infrequent (Ylvisaker and Szekeres, in Chapey, 1994).
Remediation therefore focuses on attentional and
informational deficits and other aspects of executive
function including disorientation and confused language.
Processes Involved in
Recovery
According to
Bach-y-Rita (1989), neural plasticity or the ability of the
brain to relearn may account for recovery after head injury.
Neural plasticity includes the processes of neural
sprouting, neuronal unmasking, and denervation. All are
aspects of the brain's ability to reorganize after an
injury.
In monkeys and
lower mammals with damage to the motor cortex progressive
recovery within days or even hours of injury is attributable
to changes in allegiance of cell columns near the lesion.
These cells take on the function of the damaged cells. By
injecting a gamma-amino butyric acid (GABA) antagonist drug
into the cortex the motor territory can be enlarged (Fitz
Gerald, 1996). Fast synaptic transmission is mediated by
amino acids such as GABA (Bear et al. 2001).
Neuropharmacologic
agents have ben used to help individuals return to work
after injury. Stimulant and cognitive enhancing medications
are used with individuals to attend to tasks, enhance
concentration and heighten arousal levels. Medications are
used to improve memory and speech/language skills. Amongst
drugs used to increase attention are: Dexidrin
(dexamphetamine), Ritalin ( metylphenidate), Symmetrel
(amantadine),Parlodel (bromocriptine) and Sinemet
(carbidopa-levodopa) and Cognex (tacrine). According to
Ericksen etal, 2001 acetycholine levels can be increased in
order to enhance memory by using tacrine and rivastigmine
(Exelon) to block enzymes that degrade acetylcholine. This
enables aceylcholine to be used as a neurotransmitter signal
molecule. Physostigmine can produce similar effects.
Amantadine and
Sinemet are used to enhance muscle movements by decreasing
the rigidity and tremors seen in Parkinsons disease. These
medications have also been used with TBI, although there is
not enough research evidence to confirm their efficacy.
(Ericksen et.al, 2001).
Neural Sprouting
There
has been speculation recently as to whether the brain can
produce new neurons. It would seem that it can. The
hippocampus in the limbic system seems to be producing new
cells all the time. This in important to the making of new
memories. However, existing cells are able to sprout
additional axonal branches which allow them to make new
connections after an injury. (Think of sprouting as if it
were an after effect of neural "pruning.")
Generally, neural
sprouting is beneficial after an injury. If too much
sprouting occurs, though, it can negatively affect brain
functioning (Bach-y-Rita, 1989). According to Bhatnagar and
Andy, 1995, P.114 "The proximal ends of axons in the CNS
exhibit some growth (sprouting). However this growth is not
significant because the regenerated axons cannot cross the
astrocytic scars."
Neuronal Unmasking
Neurons which are normally quiescent
may begin working again after others have been destroyed.
This means that brain processes which are normally inhibited
by higher level controls will be able to function. This may
help in recovery. Negative effects of unmasking are reflexes
and responses like the startle reflex which are usually only
seen in young children. The Babinski reflex and the patella
reflex may also be abnormal after head injury
(Bach-y-Rita, 1989).
Denervation
After
head injury, there may be an increase in neural sensitivity
in the damaged area. To off-set this decrease, neurons that
are still healthy may become hypersensitive or increase in
number (Bach-y-Rita, 1989).
Therapy with CHI patients will focus
on improving attention, perceptual abilities, thought
organization, and the performance of higher level cognitive
processing tasks like problem solving. These deficit areas
should be addressed in the order listed here for obvious
reasons. (A patient who cannot attend will certainly be
unable to organize his/ thoughts or solve hypothetical
problems.) The techniques
listed below could be therapeutic for any patient who has
cognitive problems. They might be effective with some left
CVA patients, but are especially likely to be useful with
those who have right hemisphere damage (see below).
(Adamovitch and
Henderson, in La Pointe, 1990)
Improving
Attention
Provide an environment in which distractions are minimized. Be aware of the types of attention deficits that you may encounter with right hemisphere involved patients. They include divided, sustained, focused and alternating. As you begin
therapy, bear in mind that it may be necessary to limit the
length and intensity of sessions. Therapy sessions can be
longer and tasks can be made more difficult as the patient's
tolerance increases. It is often
helpful to integrate familiar and personally significant
items into therapy tasks, especially during initial
sessions. Sensory
stimulation in all modalities can be used to stimulate
attention.
Oral-peripheral
stimulation
Many
of the same techniques used with swallowing patients can be
applied to therapy with CHI patients if necessary. For
example, if a patient is ignoring one side of his mouth, a
lollipop could be used to encourage him to move his tongue
into that area.
Auditory
stimulation
Bells
or other simple auditory stimuli could be used at first. As
the patient's ability to attend improves, present more
complicated stimuli like music or speech.
Tactile
stimulation
Contrasts like hot and cold or soft
and rough could be used to stimulate attention.
Visual
stimulation
Different colors might be used. Also,
light might be contrasted with dark.
Taste
Again,
contrasts such as sweet vs. sour may cause the patient to
attend.
Olfactory
stimulation
Start
with strong, noxious smells like ammonia, which really
command attention, and then present more pleasant scents,
such as perfume.
Improving
perception
According to
Henderson and LaPointe (1990), the clinician should identify
the sensory modality in which perception is most impaired
and begin therapy by presenting stimuli in that modality.
The least affected modality should be used for cueing. Other
sources disagree with this technique and suggest initially
presenting stimuli in the most intact modality.
To
improve visual tracking, the patient could be asked to
follow a light with his eyes. To address auditory tracking,
ask him to point in the direction of a sound source with his
eyes closed.
Shape
recognition
Patients could be asked to trace or
copy shapes.
Word recognition
Read a
passage to the patient. Ask him to raise his hand every time
he hears you say a particular target word.
Discrimination/Matching
First,
the clinician should ask the patient to match two identical
objects. Next, s/he might match pictures with objects and
pictures with other pictures. Letters, words, sentences and
geometric forms can be incorporated into therapy tasks as
the patient's abilities improve.
Thought
Organization/Information Processing
Patients can be asked to sort items
by size, shape, color, etc. Also, they might be asked to
name the item that does not belong in a particular
group.
Closure
To
improve visual closure, the patient might practice
completing pictures with missing parts. Tasks like
completing sentences or words with phonemes missing can be
used to work on auditory closure.
Sequencing
For
example, the patient might be asked to order objects from
small to large or light to dark. Also, he might practice
unscrambling words or sentences. As the patient improves,
introduce more practical activities like sequencing the
steps in daily activities or following complex
directions.
Executive
Function/Problem Solving
According to Ylvisaker, Szekeres and Feeney, 2001 .page 276, "a functional operational definition of the executive system is
1. Awareness of strengths and weaknesses and associated understanding of the difficulty level of tasks.
2. Based on this awareness, an ability to set reasonable goals, plan and organize behavior designed to achieve the goals, initiate behavior towards achieving goals, inhibit behavior incompatible with achieving those goals, monitor and evaluate performance in relation to the goals, flexibly revise plans and strategically solve problems in the event of difficulty or failure.
3. Ability to assume a non-egocentric perspective. (and)
4. Ability to think abstractly and transfer skills from training to application contexts."
The following remedial guidelines are suggested:
Convergent
thinking
Convergent problems require one
specific answer. For example, the clinician might ask the
patient to identify the attribute that a group of objects
have in common (Chapey, 2001).
Divergent
thinking
Divergent problems have numerous
potential solutions and therefore stimulate flexible,
creative thinking. For example, the patient might be asked
to list all the ways that an everyday object, like a brick,
might be used. Other divergent thinking tasks include
explaining all the meanings of words with multiple
definitions (e.g., knot, to, board), and explaining proverbs
and idioms (Chapey, 2001).
Deductive
reasoning
Ask
the patient to complete syllogisms. For example, the patient
could be given the premises "all children go to school" and
"Bob and Jane are children," then have to decide whether or
not Bob and Jane go to school. As the patient improves, ask
him/her to practice deducing the consequences and causes of
everyday problems (Chapey, 2001).
Inductive
reasoning
To
improve the patient's inductive reasoning abilities, ask
him/her to finish stories, answer why questions or listen to
short stories and then guess what kinds of emotions the
characters in the story might be experiencing (Chapey,
2001).
Multi-process
reasoning
Ask
the patient to devise solutions for everyday kinds of
problems. For example, the clinician might present a
hypothetical argument between two people then require the
patient to explain the pros and cons of both points of view
and suggest a compromise that might be used to settle the
debate (Chapey, 2001).
Working memory
Although working memory (it is
measured by digit span) is not a very common memory
impairment in CHI, it is sometimes impaired. Ylvisaker and
Szekeres (1994) suggest increasing functional capacity
through the use of grouping by meaningful units (semantic
grouping), or grouping syntactically or by melodic
chunking.
Orientation
training
When
patients are beyond the confused and agitated stage of
recovery, orientation training should begin. It is comprised
of environmental prompts and systematic stimulation,
training, and behavior management (Brookshire, 1997).
Environmental prompts are strategies that help compensate
for cognitive deficits. They can include memory note books,
calendars of daily events/appointments, maps, alarm clocks
or clock radios, simple maps to help then find their way
around, etc. (Ylvisaker and Szekeres, 1994). Orientation to
place, person, and time must be considered. I have always
liked to use photographs of the patient's neighborhood
(orientation to place), and of family members and friends
(orientation to person). Orientation to all of the above
should be accomplished through involving as many people as
possible in the effort. It should include hospital staff,
friends and family. Occasionally I get patients who are in
extreme denial and with very poor prognosis. I think that in
some situations orientation to reality may not be in their
best interests.