Page 207 - Handbook of Electronic Assistive Technology

Chapter 7 • Alternative and Augmentative Communication 195

of visual stimuli such as signs, symbols and letters. Information about a person’s acuity
(the clarity of their vision), particularly at near distance, should therefore inform clinical
decision-making, particularly when considering the design and content of a selection set.
Since the use of an AAC system requires the use of core functional vision skills such as fixa-
tion, directing gaze, disengaging and transferring gaze and visual scanning or searching of
an array, assessment of a user’s functional gaze control abilities will also form an impor-
tant part of the AAC assessment and selection process.
Where the user’s vision is impaired to the level that they would not be expected to use
it as a primary channel for learning and communication, the use of auditory scanning
techniques may be considered. This is where vocabulary items are spoken aloud in order,
by either a communication partner or automatically by a high-tech AAC device, and the
chosen item is selected using a purposeful movement either via a physical indicator, a
vocalisation or the activation of a switch (Clarke et al., 2016).
Assessment of a person’s hearing is also an important part of the assessment for AAC.
Where hearing is impaired, the user may require an AAC system that supports receptive as
well as expressive language, either using manual signs or specialist software that can pro-
vide transcription of a communication partner’s utterances. Additionally, where hearing
aids or cochlear implant systems are in place, clinicians will need to consider how these
will impact on a user’s individual, tailored needs from an AAC system.
As alluded to previously, the assessment of an individual’s functional physical abili-
ties will form a key part of an AAC assessment. This will include taking into consideration
a person’s level of mobility, which will guide the selection of hardware for a system. For
example, a user who is independently mobile will likely require an AAC device which is
easily portable. A user who spends the majority of their time in a wheelchair, support-
ive seating system or bed, on the other hand, will require an aid that can be mounted
to maximise its use. A user’s posture should also be taken into account, since a person
whose posture changes frequently will require an aid that can similarly be repositioned
with minimal difficulty. Physical abilities directly related to accessing the device will also
be an important consideration to identify a reliable point of control for an access method.
Clinicians should also be mindful of how carrying out the physical movements needed to
control a device may change over time, particularly where an individual fatigues quickly.
The assessment of intellectual function, including appraisal of receptive language
abilities, will further guide the selection of an AAC system for individuals. However, the
challenges associated with robust and meaningful description of abilities in these areas
for people with physical and/or sensory difficulties are significant. Standard, or commonly
used, tests of intellectual/language ability often assume physical toy/object manipulation
skills, and adequate vision to see small line drawings; this may frequently exclude use for
many people needing AAC.
As a consequence, understanding of intellectual and language abilities to guide, for
example, vocabulary selection, language structure options and symbol system choice will
need to comprise several approaches. In addition to structured and formal assessment
measures, possibly adapted or modified to allow completion by persons with physical