Executive Functions - Part 1


Uploaded by famsciEIU on 18.05.2011

Transcript:
Hi, my name is Jill Fahy and you are here today to attend a short
mini conference on executive functions, to talk about what is
that term, what are those executive functions, what does
that have to do with case loads that we see as
speech pathologists.
My background prior to teaching in the university setting is
primarily in medical and healthcare facilities mostly
with adults with some form prior brain injury whether that is
trauma or stroke, tumor, disease process and so on.
So, that background is encompassed from acute care,
inpatient, outpatient day rehab programs for individuals
with brain injury and also home health.
The things that I was most interested in in those years
that I was in health care had to do with the thinking, reasoning,
self-control, cognitive deficits that a lot of patients seem to
demonstrate when they had an injury to the frontal lobe of
the brain as well as right hemisphere deficits.
And in the brain injury literature, the study of
executive functions has been around for quite some time and
you will commonly see a patient who has what is called frontal
lobe syndrome or executive disfunction following injury to
the prefrontal cortex of the brain which is really just here.
So when I started to have the opportunity to work with younger
children with developmental disorders or delays in their
communication, I found a lot of them would often present with
the same kinds of deficits as these patients in the brain
injury population so I started to do a lot of reading and
research into the existing literature to find what kinds of
parallels there might be in a population of kids with
developmental disorders and delays in their communication
and cognitive skills and that group of
adults with acquired brain injuries.
Interestingly enough, there are tremendous similarities and
specifically in the last five years or so, there has been
quite an explosion in research in just this area.
For example, many people are looking at what does executive
functions have to do with say Asperger's or autism or
non-verbal learning disabilities or even
specific language impairment.
And do those children present with a specific profile?
If so, how can we evaluate that, how can we incorporate that into
our treatment and what are the effective ways to do that.
In addition, there have been a lot of research recently that is
looking at the normal development of these skills that
we will talk about today.
These executive functions.
That's also become really fascinating area as more and
more research begins to compile a pretty specific and clear
picture of how the frontal lobe in the human develops over a
course of about 20 to 25 years.
It is actually the longest developmental span of
any skill that we have.
Interestingly, it is tied very specifically to the
development of language.
Language acts as kind of the mediator as the force that
grounds those executive skills as they develop.
Of course, the development of the frontal lobe of the brain is
dependent on lots of things, not just language but that is the
piece that I found to be the most interesting.
I think in our profession as speech pathologists with our
knowledge of the normal and disordered or delayed
development of language, I think we are very well positioned and
well suited to seeing how those language skills play out in this
area of executive functions and how the development of those
skills either does or does not support how we demonstrate
social competence, social pragmatic communication skills,
problem solving, reasoning abilities, how we regulate our
own behavior, how we compensate for our own unique profiles of
strengths and weaknesses that we all have.
How we use language to take in information in any given moment,
in any given circumstance.
And use those linguistic skills to help our executive functions
draw appropriate conclusions and make good decisions and then
carry them out and so that is really kind of a global over
view of executive functions and how they fit into our view and
there is a growing as I said, there is a tremendous amount of
new research all of the time coming out on what is normal,
what is expected, what is a profile if there is one for a
child with SLI or with a learning disability, verbal
learning disability, or non-verbal learning disability.
What do their executive functions look like?
And what do their language profiles look like?
So that being said, that is sort of has generated the interest in
giving some time to just the topic of what are executive
functions and that is the focus of today's discussion.
What I would like to do is give an overview today, define the
components of executive functions, so that we can
understand cognitive processes are required to support those
executive function components.
Survey the development of executive functions as a product
of language development and then briefly discuss profiles of the
executive function deficit in various disorders.
This is a really broad topic, so we will touch a little bit on
the development but that is something that perhaps we could
generate another one of these conferences to talk more
specifically about that.
So, what are executive functions.
In a nutshell, some short definitions that
I think are really useful.
Marlowe talks about functions being the enabling, how we
enable the generation of appropriate behaviors in novel
circumstances and we do so in a developmental progression.
That is the ability of a two year old to generate and control
and initiate appropriate behaviors is quite different
from the ability of a 12 year-old to do that which is
quite different from the ability of an
18 year-old or 30 year-old.
Executive functions, they are how form stable plans, how we
develop intentions that are capable
of controlling conscious behaviors.
It's really the executive function in a nutshell.
It is how we determine how our behavior should be, how we
generate a plan for those behaviors, how language helps us
think through that process, how language helps us control our
impulses so that we initiate and carry out goals at the
appropriate time.
And with the necessary amounts of success.
Those capacities are the definition of Lezak.
Those capacities that enable a person engage in independent
behavior this is with purpose, purposive, and that it is with
self-serving behavior.
And by that, I don't mean self-serving in any way but
rather how we are able to use language to mediate our
decisions, our actions in a way that is helpful to us.
Think of the child who has minimal behavior control or does
not use language as effectively as a self-taught tool to help
guide their thinking and decision-making through the
course of their day.
Those kids are the ones who maybe described as being out of
control or behaviorally disruptive or aggressive or who
are often described as having inappropriate
social behaviors and interactions.
So I guess the point here is that we don't just magically
require these skills, this cluster of abilities is truly a
part of how the prefrontal cortex of the brain develops
neural networks with every other part of the brain in order to
engage in that kind of good behavior decision-making control
and I promise this is not a long lecture on anatomy, so just a
few slides to kind of give you a brief refresher.
But the prefrontal cortex is really where we are talking
about for the seat of these functions.
The prefrontal cortex is only the front most
third of the frontal lobe.
So in the frontal lobe, we've got the motor strip which
regulates and initiates motor control, the premotor area,
which helps to plan and sequence motor movement.
And just anterior to that, the most prefrontal area of all is
the part of the brain that plans and
sequences and executes behaviors.
So it is all about planning and executing
and controlling and guiding behavior.
Parts of the frontal lobe do that for all muscle movements
and the other part of that does that for our behavioral
movements in a larger context.