The most striking pathological manifestation of spatial cognition is visuospatial neglect. Despite decades of extensive neuropsychological exploration, this fascinating syndrome has still not revealed all its mysteries. Patients with visuospatial neglect omit contralesional stimuli. For example, they leave the left half of their plate uneaten, they overlook the leftmost words of text lines while reading, or they only use the right-hand side of a page when drawing.
Three underlying deficits have been identified, affecting attention, intention and spatial representation. We put forward a 4th disturbance that concerns the selection of color and its distribution in space, which had not been studied before in the literature.
The clinical case we report is the result of a unique encounter with a patient painter who agreed to analyze the paintings he produced after a right vascular accident. We are talking about 40 paintings created over a long period of 3 years, freely and without instructions. They are original works of art, the result of a personal and prolonged process.
To capture the complexity of paintings colour and the vast amount of information with the three components of colour (Saturation, Hue, Value), we analysed the spatial distribution of colour entropy in these paintings alongside recovery. This original approach, borrowed from statistical physics and information theory. This method, which is well described in the manuscript and supplementary data, could be used by other authors wishing to explore this issue.
The results revealed left-right asymmetries in boundary line length of monochromatic patches and, most remarkably, in colour components. While the unpainted canvas surface disappeared as soon as 26 weeks post-stroke, left-right colour patch asymmetries displayed a slow recovery over one hundred weeks. This study suggests that distinct mechanisms are at work in visuospatial neglect recovery.
Lastly this series of painting offer a visual narrative of the patient’s visuospatial neglect recovery journey but a posteriori raise the question of whether the act of painting itself contributed to his recovery. The frame around the canvas offers a unique form of feedback revealing the disparity between intention to cover the whole canvas and the final, asymmetric outcome, thereby providing a concrete depiction of mental representations. The painting therefore projects the person into a new spatiality that contributes to recovery of action, attention and finally spatial symmetry. Using the words of the French philosopher Merleau-Ponty: “aesthetic perception in turn opens a new spatiality, and the painting as a work of art is no longer in the space that it inhabits as a physical thing or as a coloured canvas”(ref 34). The painting is not only a representation of mental objects (memories or images of a landscape) or material objects (the landscape seen by the patient), it is also an intentionality, defined as a “skilful bodily responsiveness and spontaneity in direct engagement with the world 35”(ref 35), the perceiver is engaged in the world and what they can act upon depends on what they perceive.