|
Principle: Create an Optimal Physical Learning
Environment
Hyperarousal to sensory input among those with Autism
(Belmonte and Yurgelan-Todd, 2003 Hirstein et al,
2001; Tordjman et al, 1997) accompanied by an impairment
to choose between competing stimuli is widely observed.
EEG studies involving tasks requiring people with
Autism to selectively attend to relevant stimuli and
ignore irrelevant stimuli have shown either an abnormal
heightened P1 evoked potential to the relevant stimuli
or an abnormally generalized response to irrelevant
stimuli (Townsend and Courchesne, 1994). Additionally,
the N2 to novel stimuli is heightened in children
with Autism, even when these stimuli are irrelevant
to the task (Kemner et al, 1994). Similar results
have been seen using auditory stimuli (Kemner et al,
1995). This supports behavioral observations that
children with Autism can either be overly focused
on one aspect of a task or greatly distracted by stimuli
irrelevant or peripheral to the task. During tasks
requiring shifts of attention between hemifields,
those with Autism have been shown to exhibit both
hemispheres activating indiscriminately instead of
the usual hemispheric-specific patterns of activation
(Belmonte, 2000). Physiological measures suggest that
perceptual filtering in Autism occurs in an all-or-nothing
manner with little specificity in selecting the location
of the stimulus, for the behavioral-relevance of the
stimulus or even the sensory modality in which the
stimulus occurs (Belmonte, 2000). It has been suggested
that this tendency for hyperarousal to sensory input
must result from some pervasive underlying abnormality
in neural processing rather than one specific brain
locus (Belmonte et al, 2004; Johnson et al, 2002;
Akshoomoff et al, 2002). Some authors suggest this
neuronal dysfunction to be low signal-to-noise ratio
developing from abnormal neural connectivity (Bauman
and Kemper, 1994; Raymond et al, 1996; Casanova and
Buxhoeveden, 2002; Belmote et al, 2004).
The result of this type of processing is that all
stimuli are given equal priority by the autistic brain
causing an overwhelming flood of sensory information
to be handled. The typical brain is able to identify
and ignore irrelevant stimuli and focus valuable attention
on that which is task-relevant creating a much more
efficient processing system. The autistic brain, on
the other hand, takes it all in and then must actively
discard irrelevant information at a later processing
stage causing, in effect, a processing bottleneck
(Belmonte, 2004). Functional neuroimaging studies
show that the brains of those with Autism tend to
show increased activation in areas that rely on primary
sensory processing and decreased activity in areas
typically supporting higher-order processing (Ring
et al, 1999; Critchley et al, 2000; Schultz et al,
2000; Pierce et al, 2001; Baron-Cohen et al, 1999;
Castelii et al, 2002).
It has been proposed that this low-level
processing disruption underlies the higher-level abnormalities
exhibited in Autism (Belmonte, 2004) and that the
widely observed symptomology of Autism (including
issues of Theory of Mind and executive function) is
an emergent property of abnormal neural growth (Akshoomoff,
2002). There is molecular evidence that this abnormality
is present at birth (Nelson et al, 2001) even though
obvious behavioral symptoms often do not typically
arise until 18-24 months. A child born reliant on
this over-aroused, under-selective sensory processing
is open to a flood of stimuli that is thought to overload
the newly emerging higher-order cognitive processes
(Belmonte and Yurgelun-Todd, 2003). When faced with
this processing constraint, the developing and plastic
brain is forced to re-organize to accommodate that
constraint (Johnson et al, 2002). This is manifested
in the abnormal organization of the autistic brain
as described above and the cognitive style characteristic
of Autism that relies heavily on lower-order, local
feature processing at the expense of higher-order,
global information processing known as weak central
coherence (Happe, 1999; Frith and Happe, 1994).
Central coherence describes the ability
to process incoming information in context, pulling
information together for higher-level meaning, often
at the expense of memory for detail (Happe, 1999).
Weak central coherence then is the tendency of those
with Autism to rely on local feature processing (the
details) rather than taking in the global nature of
the situation. Kanner (1943) saw, as a universal feature
of Autism, the “inability to experience wholes
without full attention to the constituent parts.”
It is this cognitive style that makes people with
Autism superior at resisting visual illusions (Happe,
1999), have a higher occurrence of absolute pitch
(Heaton et al, 1998), excel at the Embedded Figures
Task (Shah and Frith, 1983; Jolliffe and Baron-Cohen,
1997) and possess the ability to copy “impossible”
figures (Mottron et al, 2000).
These neurophysiological and neuroanatomical
studies paint a picture of the world occupied by those
with Autism as chaotic, overwhelming and filled with
“noise”. Coupled with this is an internal
environment of hyperarousal (Hirstein, 2001; Cohen
and Johnson, 1977; Hutt and Hutt, 1979; Hutt et al,
1965; Kootz and Cohen, 1981; Kootz et al, 1982). This
is corroborated by autobiographical reports from some
people with Autism (Bluestone, 2002; Williams, 1994;
Gillingham, 1995; Jones et al, 2003). Considering
this fragmented, chaotic and overwhelming world implies
then that a child’s external environment is
a key and primary factor to be considered when designing
a treatment program for children with Autism. Physical
environments with higher amounts of sensory stimulation
(e.g bright visual displays, background noise, etc.)
will add to the “noise” in an already
overloaded sensory system, making any new learning
extremely challenging. While there is acknowledgment
that children with special needs do require specifically
designed environments (Carbone, 2001; Reiber and McLaaughlin,
2004; Schilling and Schwartz, 2004), the extent to
which rooms can be tailored to meet the needs of these
children is highly constrained by a typical classroom
setting, mainly due to the presence of other children
and the subsequent size of the room––even
something as ubiquitous as fluorescent lighting has
been shown to affect the behavior of children with
Autism (Colman et al, 1976). These environmental considerations
are often overlooked and their importance underestimated.
The SRP bypasses the constraint of
the classroom by employing a room (usually in the
child’s home) that is specifically designed
to lower sensory stimulation. Only neutral colors
are used and distracting patterns or highly contrasting
colors are avoided. There are no distracting visual
displays or noises and only incandescent or natural
lighting is employed. All toys and objects are kept
off the floor on wall-mounted shelves to provide a
distraction-free floor area for play. Most importantly,
play sessions in the playroom usually include one
adult and one child. This means that the child does
not have to try and filter out the noise and movement
of other children but deals only with a predictable
adult whom s/he trusts. The SRP holds that these simple
measures aid in soothing the autistic child’s
over-active nervous system by making the world digestible
and manageable. There is evidence for a sub-set of
children with Autism who do not exhibit an overactive
autonomic system but instead display unusually low
levels of arousal (Hirstien et al, 2001). These are
the children who tend to engage in “extreme”
activities (e.g. climbing very high, constantly moving,
etc.) in order to “kick-start” their arousal
levels. The SRP playroom provides a safe and contained
environment in which to do these activities, many
of which are not feasible in a typical classroom.
It can be seen that this treatment
principle of SRP is supported by the current neuroanatomical
and physiological data. Direct investigation of the
effects on children with Autism of the SRP playroom
in contrast with traditional classrooms has not yet
been undertaken. Children in home-based Son-Rise Programs®
often instigate going into the playroom, will play
in there even when they are alone and talk about how
much they enjoy their special room. There is much
anecdotal evidence supporting this claim but to date,
no study has looked at either qualitative measures
of children’s perceptions of their playrooms
or quantitative physiological measures of nervous
system activity of children with Autism in these environments.
|
Back to top
