Implementing Neuroscience Principles to Support Habilitation and ...

TABLE 8-8
Questions That Enable the Professional to
Consider Factors That Affect Cognition
Are basic sensory experiences intact
Can the individual interpret incoming sensory information
in a reliable manner'
Can the individual organize and integrate complex
configurations of stimuli
Can the individual create a plan to act on the interpretations
and configurations identified'
Can the individual use memory to support cognitive
activity
Can the individual use resources to make effective
decisions
Are there indications of somatic motor disruptions
that would interfere with the manifestations of cognition
Are drugs affecting the individual's ability to
demonstrate cognitive abilities
Do times of day affect cognitive performance
Are there any indications of disruptions in biological
rhythms that would diminish cognitive abilities
From Dunn, W. (109 1 ). Assessing human performance related to brain
functicm. In C. Royeen (Ed.), Nruro.scirnce,fo[~ncIc~~ic~~i.s of hurrrotr 11er-
,fOrmrrrrc~e. Rockville, MD: AOTA. Used with permission.
8. Three key features of the cognitive systems in people are
the arousal and attentional mechanisms. the language and
communication systems and the systems that support praxis.
Arousal and Attentional Mechanisms
DeMoja, Reitano and Caracciolo (1985) describe the
relationship between arousal and performance as a complex
matrix affected by three variables: the structure of the individual's
personality, the difficulty of the task, and the structure
of the situation in which the task is to be performed.
Vinogradova (1970) described several events which must
occur in order for the CNS to register a stimulus. First, the
appropriate receptors must recognize that a change has
occurred in the environment. Second, the CNS must determine
whether such a stimulus has occurred before. Third, the
CNS must decide whether or not to act on the stimulus.
Finally, the CNS must carry out the decision. Further, it
appears that under normal conditions the CNS tends to investigate
stimuli that are not familiar and inhibit conscious
awareness of familiar stimuli (McGuinness & Pribram,
1980). Table 8-9a provides a worksheet that enables
providers to consider the aspects of attention that may be
affecting performance.
As an example, think about yourself as a student in a theoretical
astronomy class. Although you might have an inherent
ability to initiate and hold attention to the typical features of
the classroom learning environment (e.g., the teacher's voice,
the writing on the overhead, the pencil and paper for notetaking),
the subject matter content may force you to expend an
extreme amount of effort. The heightened effort might reduce
your capacity. making it less possible to tolerate distractions in
the class. Table 8-9b contains a completed form about this
example to show you how this might look as a task is analyzed
from an attentional perspective.
DeGangi and Porges (1991) describe the neural mechanisms
that support arousal and attention. The sensory systems
must be able to register that a stimulus is occurring to
begin the processes. Specifically, the arousallalerting aspects
of each sensory system (see Tables 8-1, 8-2, and 8-3) send
collateral fibers to the reticular formation, a center for
arousal in the brain stem. The reticular formation then sends
excitatory information to higher centers in the brain. including
the limbic system (i.e., the hippocampus and the amygdala
if you are interested in the structures' names), the thalamus
and the cortex. The reticular mechanisms provide excitation
for the centers they connect with. making it easier for
those centers to activate in response to additional input. It is
a "pay attention" message for the other centers as more
focused information comes their way.
The Factors described above are all part of the functioning
arousal and attentional system. Each of these processes
can be disrupted when the CNS is not functioning properly;
when arousal and attention are disrupted, n person's performance
is also placed in jeopardy.
Dunn (1997) describes the interaction between the neurological
mechanisms that enable a person to notice and
respond to sensory stimuli and the behavioral responses possible
as a model for understanding a person's repertoire of
behaviors from a neurological point of view. Table 8- 10 provides
a summary of their proposal about this interaction.
A person's neurological thresholds refer to the amount of
stimuli necessary to reach a point of noticing or reacting to the
stimuli. Those who have high thresholds take a longer time to
react; some neurological and social science authors refer to
this condition as habituation. When habituation is operating,
the CNS is responding to the stimulus as if it is familiar.
requiring little attention. Low thresholds, on the other hand,
trigger more readily, and therefore cause the person to react
more frequently to stimuli in the environment. This heightened
reactivity is sometimes referred to as sensitization.
When addressing persons who have performance needs,
providers must observe behavior. The model in Table 8-10