Increasing research evidence and development of meaningful, intelligible language and use by people with PMLD

Abstract

There has been major research and development of a wide range of AAC (Augmentative and Alternative Communication) devices to meet the needs of  people with communication difficulties.  However, significantly, children  and adults designated PMLD (Profound and Multiple Learning Disabilities) have been largely excluded from this expansion ( Beadle-Brown et al 2016) leaving many deprived of meaningful ways in which to achieve their potential and their rightful place in society.  The often-repeated claim that ‘the voice of the child with PMLD’ should be heard remains an intention yet seldom a reality.. (Whitehurst, 2006).  Why has this happened and how can this situation be remedied?

Firstly. the extreme physical and visual impairments associated with people designated PMLD  (Simmons and Watson, 2014) negate efforts to speak, hold, touch, point, pick up cards, symbols or objects or use switches, keyboards, screens and eye gaze technology. Impairments obscure observable responses to assessments too, making efforts to identify abilities extremely challenging. ( IASSID, 2016).  Where responses are not evident, the assumption of  profound linguistic and developmental levels is readily maintained.

Secondly, the expectation, indeed the belief, that individuals designated PMLD are invariably profoundly developmentally delayed, pre-linguistic and pre-intentional  prevails (Simmons and Watson, 2014) despite the lack of specific assessment evidence.  This means that the use of  AAC language-based systems is considered unrealistic; reliance on basic cause and effect technology  and infant derived approaches predominate.

In contrast, a recent study challenged these interpretations of the competencies of people designated PMLD by demonstrating language acquisition, present regardless of impediments to assessment. Collaborative research by De Montfort and Loughborough universities recorded and amplified sub vocal (SV) utterances by 20 young participants designated PMLD (Woods et al, 2023) as an innovative AAC approach. Although their impairments prevented verbal speech,  participants’ recorded and amplified SV utterances provided clear, audible and intelligible evidence of (chronologically appropriate) language acquisition and use.  The voice of the child designated PMLD was heard, demonstrating that negative assessments  may be a function of their physical and visual impairments and not their language or intellectual capacity.  This work has continued, extending evidence of SV language by people labelled PMLD.

These outcomes clearly identified the need to develop AAC systems that could explore potential language in people designated PMLD. The technology to do so is already there. Potential application of  AI, real time digital signal processing (DSP) in combination with deep learning (RNN) and language models suggest possible solutions, with some existing examples already operating. Many everyday appliances now rely on speech recognition techniques, while devices to improve or convert disordered speech to text or artificial voicing are established.  There are often difficulties to overcome in using digital pre-processing methods. where consistent sound samples are needed.  Nevertheless, the right to be heard for people who can clearly demonstrate typical language acquisition is indisputable, yet individuals designated PMLD are conspicuously absent from AAC research and development. Currently, they are being excluded and left behind, unheard voices that should and could be listened to because it is their tomorrow too.