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JCPSLP Volume 19, Number 3 2017 145
Cognitive and sensorimotor skills
The relationship between symbolic language skills and
cognition is not simple or clear cut (Romski & Sevcik, 2005;
Rowland & Schweigert, 2003). In their review of the
literature on the connection between language development
and cognition, Kangas and Lloyd (1988) outline six models
that seek to describe this relationship and suggest that no
one model is sufficient to fully explain how language
development and cognition are linked. They conclude that
the research suggests a correlation rather than a causal
relationship.
Reichle (1991) details some specific classes of cognitive
milestones that are often thought to be prerequisite skills
to beginning AAC intervention, including means–end or
intentionality, imitation, and object permanence. There is
little or no evidence to support this, but rather, there is an
understanding that many of these cognitive skills develop
alongside language. When children are not provided the
means to learn and develop language, this potentially
precludes them from also developing some early cognitive
skills. Demonstration of early cognitive processes is severely
limited for individuals with sensorimotor and communication
impairments (Porter, 2012; Romski & Sevcik, 2005).
The literature supports implementing AAC intervention
with individuals who display cognitive impairments.
AAC intervention with children and adults with cognitive
disabilities results in positive outcomes for language
comprehension and expression. Aided language modelling
– where a communication partner highlights symbols as
they are spoken during natural contexts – is one such
intervention technique. Research completed on the effects
of aided language modelling with preschoolers, school-
aged children, and adults with cognitive impairments
indicates that this strategy increases symbol production,
comprehension and social skills (Beck, Stoner & Dennis,
2009; Dada & Alant, 2009; Harris & Reichle, 2004).
For individuals with complex cognitive needs, the use
of PAS may scaffold their understanding of the function
of communication, support them to become active
participants and increase their cognitive engagement. PAS,
alongside a robust AAC system, may provide the basis for
learning conceptual and linguistic knowledge while reducing
the demand on other skills that are both physically and
cognitively demanding, for example, switching, that are
both physically and cognitively demanding (Burkhart, 2016).
Physical skills
Treviranus and Roberts (2003) acknowledge that the
research on motor control of AAC systems is scarce for a
number of reasons, including the heterogeneity of the
population. They suggest that much of the decision-making
around designing an AAC system for individuals with
CPCSN is based on clinical experience and thorough
assessment of needs, and that the ideal access method
should be reflexive and controlled, so that the user can
concentrate on the message, rather than the physical skills
needed to create the message. For example, physical
access using a yes/no response with PAS may be as small
as an eye blink, or head turn to one side, whereas eye gaze
access to a high technology device requires sustained head
control to maintain position as well as controlled eye
movements with a period of sustained dwell or blink to
select. For any access method to become instinctive, there
must be a large amount of time and practice invested in
perfecting the motor patterns and skills needed (Treviranus
& Roberts, 2003). As discussed above, the time spent on
S is a visual scanner who accesses a low-tech 20 cell
per page PODD by eye gazing at yes/no symbols.
She does this while in her power wheelchair or in her
standing frame or while lying in supine while stretching.
Her communication partner holds the PODD book in
front of her and points to the first column on the left
of the first page. If the symbol she wants to select
is in that column, S looks at a “yes” symbol located
on the left side of her book. If the symbol she wants
to select is not in that column, she looks at the “no”
symbol (placed to the right of the book), thus moving
her partner to the next column. When the partner
reaches the column that contains the symbol she
wishes to select, and S has indicated affirmatively, the
partner then points to the top symbol in the column
and waits for S to respond. The partner then knows
whether to move on to the next symbol, or to respond
contingently to her selection. With PODD, symbols
may have links or operational commands to allow S to
control movement between levels (Porter, 2012), or tell
her partner where to go next.
S also independently uses a high-tech GridPad
3 with Mygaze (an eye gaze system) technology to
access PODD. There are times when she requests
to use her paper book, such as when she wants
to discuss personal or emotional topics, and other
times when she prefers to use her high-tech system,
particularly during break times when her teacher is
busy with other tasks or students.
Barriers to AAC intervention for
children with CPCSN
The Candidacy Model for AAC provision and intervention
influenced practice during the 1970s and 1980s (see Kangas
& Lloyd, 1988; Reichle & Karlan, 1985; and Romski & Sevcik,
1988 for refutations of this practice). During this time,
candidates for AAC intervention were required to display
certain levels of cognitive, social or physical skill, or be a
certain age. This model has been superseded by the
Participation Model (Beukelman & Mirenda, 2005), which
views access to communication as a basic human right for
anyone with any combination of communication ability and
need. Within the Participation Model, AAC provision is made
through a process of assessment, intervention and review
that is founded on principles that support fundamental
participation and communicative requirements based on same
age peers without disabilities (Beukelman & Mirenda, 2013).
American Speech-Language-Hearing Association (2016),
makes it clear that current best practice does not require
individuals to have any prerequisite skills before successfully
beginning to learn and use an AAC system. Despite the
shift away from the candidacy model, individuals with
CPCSN are still sometimes excluded from robust AAC
intervention because they are deemed “too something”, or
are not displaying the cognitive, physical and/or social skills
that indicate they are ready to learn language (Romski &
Sevcik, 2005).
The lack of skilled communication partners, to provide
aided language modelling and demonstrate the operational,
linguistic, social and strategic skills necessary to become
a competent AAC user, may be a further barrier to
communication development for individuals with CPCSN
(see Sennott, Light & McNaughton, 2016, for a review of
AAC modelling intervention research).