JCPSLP November 2017

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. 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). 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,

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JCPSLP Volume 19, Number 3 2017

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