14 Clinical Psychology Forum 328 – April 2020 Defining and measuring adaptive behaviour in deaf adults Kathryn Roscoe, Hannah Merdian, Mark Gresswell & Kevin Baker Assessing adaptive behaviour for deaf people is particularly complicated due to confounding cultural, linguistic, and methodological issues. A thematic analysis of expert comments yielded a potential new working defnition of adaptive behaviour and initial guidelines for assessing adaptive behaviour accordingly. A ROUND 10 million people in the UK have some form of hearing loss: around 800,000 of this group are severely or profoundly deaf (Action on Hearing Loss, 2011). Some deaf people perceive them- selves as a cultural and linguistic minority group, using British Sign Language (BSL) as a preferred form of communication and although specifc fgures are inconsistently reported, this group could comprise between 15,000 (Offce for National Statistics, 2011) and 156,000 (British Deaf Association, 2013) people. Currently, there are no established standardised assessments of adaptive behav- iour for a d/Deaf population, highlighting a signifcant gap in the feld. Adaptive behaviour describes a ‘collec- tion of conceptual, social, and practical skills that people have learned to be able to function in their daily lives’ (Schalock et al., 2010, p.15). Adaptive behaviour is assessed in order to identify educational and rehabilitative inter- ventions for individuals (Tassé et al., 2012) and signifcant defcits in adaptive behaviour are a criterion for the diagnosis of Intel- lectual Disability (Department of Health, 2001). However, ‘adaptive behaviour lacks a unifying theoretical foundation’ (National Research Council et al., 2002, p.150) and measures have been criticised for their focus on low-level skills, for example, self-care (National Research Council et al., 2002). These limitations create a particular chal- lenge when assessing individuals with addi- tional needs, such as deafness. The different terminology used in the context of deafness is important in conveying meaning: deaf, Deaf, hearing impaired, and hard-of-hearing all describe the medical condi- tion of not being able to hear, but denote different underlying assumptions (Roberts & Hindley, 1999). Lower-case ‘deaf’ refers to a medical conceptualisation of deafness, refer- ring to hearing impairment, often used in the context of people who have acquired deafness later in life or are deaf but do not consider themselves part of the Deaf community, using spoken language and hearing technologies as preferred forms of communication (Ladd, 2003). Upper-case ‘Deaf’ refers to those who consider themselves part of a cultural community and linguistic minority who are usually deafened pre-lingually and use sign language as their frst or preferred language (Meadow-Orlans & Erting, 2000). Given the above, current measures of adaptive behaviour may fail to accurately discriminate between outcomes related to cognitive impairment and those linked to deafness or concomitant factors, such as spoken and signed language exposure (Szatmari et al., 1995). In addition, there are considerable differences in adaptations made to testing of a d/Deaf client which typically rely on translating test instruc- tions or test materials (British Psycholog-