Development of an 'individualised sensory environment' for adults with learning disabilities and an evaluation of its effects on their interactive behaviours
This thesis is about the development and evaluation of an intervention incorporating structured sensory stimulation. It was designed for use with adults with learning disabilities who were not yet intentional communicators. The intervention was termed an 'Individualised Sensory Environment' (I.S.E.). The main objective was to reduce the levels of non-purposeful engagement and to increase the levels of purposeful interaction. Appropriate opportunities for adaptive responding were organised by the provision of sensory stimulation that was identified as personally motivating to the individual. The reinforcing sensory experience was contingent on the participant's responses. The focal sensory domains of the intervention were the tactile and vestibular systems for input, and the proprioceptive for participant response feedback. An alternating treatments design was used to evaluate the effects of the intervention (I.S.E.) on engagement levels of participants. An attention placebo condition was also used. The participants attended a social service's Day Centre and formed therapy groups whose membership ranged from two to four, based on their location within the service's structure. Groupings were then randomly assigned to two experimental groups, the order of interventions for one being the reverse of the other. Data was collected by systematic observation of participant's engagements in the natural environment: at baseline, after each phase of therapy and at two follow-up points. Analysis of variance was the main method of statistical interpretation. The results showed that high levels of non-purposeful behaviour were emitted at baseline when compared with the construct purposeful interaction. When the intervention (I.S.E.) was introduced, a significant decline in the level of non-purposeful behaviour was observed, which maintained its new lower level up to one month after the termination of therapy. The placebo condition also effected a similar change initially. However, a significant increase in purposeful interactions was only observed after a phase of the 'Individualised Sensory Environment'. Some limitations of the study are discussed and recommendations for future work are indicated.