To Fall Off the Edge of the World Sebastian Crutch

Professor Sebastian Crutch is a neuropsychologist at the Dementia Research Centre at UCL. Sebastian studied at Imperial College London and the University of Oxford. He is a Chartered Psychologist (CPsychol) and Professorial Research Associate/Alzheimer's Research UK Senior Research Fellow.

Sebastian explains to Níall and Yeoryia that he is interested in the representation of abstract conceptual knowledge, reading and number/quantity processing. He specialises in working with people with rare or early-onset dementias, such as posterior cortical atrophy (PCA), which is a progressive degenerative condition leading to the loss and dysfunction primarily of the cells located at the back of the brain. He makes the point that this research is useful to those affected by these particular forms of dementia, but also to those with more typical forms of Alzheimer’s, as ‘we know Alzheimer’s disease ultimately will attack the back of the brain’.

Sebastian stresses that we must recognise that Alzheimer’s is a physical disease, attacking the physical tissue of the brain itself. In PCA, this degeneration leads to a reduction in the individual’s ability to experience the world on an allocentric level – a sophisticated form of mental manipulation whereby the world is assessed and understood by examining and imagining the relationships between multiple objects – rather than on a purely egocentric level, whereby the world is understood only in examining the direct relationship between objects and the self. Sebastian, Níall and Yeoryia debate whether this allocentric ability – the ‘ability to abstract away from personal experience’ – is learned or innate. Sebastian outlines how the brain combines, connects and integrates different sensory stimuli to create a coherent, rounded experience of the world, and offers evidence to suggest that this is a combination of acquired skill and inherent human ability. The eyes may send the correct information to the brain, but it may be misinterpreted, leading to an illusory perception of reality. Balance and orientation may be affected — Sebastian recalls being told ‘I felt like I was about to fall off the edge of the world’, and asked ‘am I the right way up?’ The loss of ability to perceive a space may be accompanied (or potentially exacerbated) by loss of the ability to understand words related to that space. Alzheimer’s attacks the ‘constellation of connections’ in the brain, often eroding the learned, more complex cognitive processes first.

The difficulty in designing for individuals with dementia is precisely that the effects are so inherently individual, as there are a ‘huge number of distinct, and individually damage-able processes’. The functions of these processes vary over time, and furthermore, as Sebastian states, the translation of all human experience is fundamentally personal. However, he offers some insights into how architects might consider issues of visual contrast and spatial depth perception and possibilities for the inclusion of light and colour cues in their work. Níall compares the merits of more literal visual trails and the logical ‘spatial daisy-chains’ that an architect invariably seeks to compose.

Sebastian, Níall and Yeoryia discuss the possibility that the wandering and searching desires associated with dementia are a manifestation of the loss of clarity it creates. Often the raw sensory processes of the brain are intact, but it struggles to make the necessary connections between them. Sebastian asserts that many of the so-called ‘challenging’ behaviours associated with dementia are perfectly reasonable for a person struggling to project or remember but existing in an uncertain ‘continuous present tense’.

This dialogue was recorded in Yeoryia's office at UCL: the background noises are the trains rumbling in and out of Euston Station.