Sensory overloads, meltdowns, and shutdowns in Autism: A combined quantitative and qualitative perspective

This project will address the following research questions:
1. What are the key differences between sensory overloads, meltdowns, and shutdowns in adults with ASD?
a. Can a clear definitional and phenomenological framework be developed to categorise these experiences?
b. Do individuals with ASD experience these phenomena differently to individuals with Sensory Processing Disorder?
2. How does multi-modal sensory input impact modality-specific executive function in ASD versus SPD?
This study will utilise semi-structured qualitative interviews as well as diary methodology to explore the lived experiences of overloads/meltdowns/shutdowns across adults with ASD or SPD, with these findings then informing the development of a quantitative experiment to compare multi-modal sensory processing between these groups. Interviews and diary reports will primarily explore the subjective psychological and physiological aspects of overwhelming sensory experiences, with a particular focus on identifying experiential differences between overloads, meltdowns, and shutdowns, as well as drawing comparisons between ASD and SPD experiences. This comparison will enable the study to consider whether there are autism-specific components to overwhelming sensory experiences in ASD versus SPD, or whether there are commonalities of experience across both groups.
This qualitative data will then be used to inform the development of a multi-modal sensory processing experiment, with feedback and input sought from both ASD and SPD participants throughout the design and piloting stages. Participants will be presented with multi-modal sensory information, as informed by the outcomes of the qualitative study, while asked to conduct a task involving executive function related to a specific sensory modality. The non-task modality input would effectively act as a 'distractor', to test the sensory filtering and 'gating' processes necessary for processing sensory input and selecting input for action. A condition without distractors would be used as a control. Both the experimental and control tasks would be performed by all participant groups, with the order of tasks randomised to prevent order effects.
During the experiment, data will be gathered from multiple sources:
1. Behavioural performance measures including task accuracy and speed
2. Physiological indices of stress including heart rate and skin conductance
3. Eye tracking and EEG measures to provide insight into cognitive processes, and the effects of multi-modal inputs as distractors
These quantitative measures will be accompanied by brief post-experiment interviews/discussions with participants to gather qualitative accounts of their experiences during the task, including subjective reports of stress and task performance, and their reflections on participating in this research.
Qualitative data will be analysed using thematic analysis, with the potential for a grounded theory approach to be used to develop a framework for understanding, defining, and distinguishing between overloads, meltdowns, and shutdowns. Key themes and concepts identified during the interview stage will inform the development of the experimental phase, particularly in terms of material and task design.
Quantitative data from the experimental phase will likely be analysed using ANOVAs to compare responses and performance across participant groups, with participant group acting as a between-groups independent variable while the experimental conditions (multi-modal vs unimodal sensory input) will act as a within-group independent variable. Qualitative data from post-experiment interviews will be used to contextualise the quantitative data, while also providing an informative groundwork for future ASD research by reflectively engaging with participants' experiences of research.