Regression of left hyperschematia after prism adaptation: A single case study

Julie Di Marco, Marine Lunven, Patrice Revol, Laure Christophe, Sophie Jacquin-Courtois, Giuseppe Vallar, Gilles Rode

Research output: Contribution to journalArticlepeer-review


Prism adaptation (PA)is a promising treatment in the rehabilitation of post-stroke cognitive disorders such as unilateral spatial neglect or constructional deficits. Right brain damage can bring about another representational spatial disorder, termed «hyperschematia», and defined by a left-sided disproportionate expansion of drawings by copy and from memory, and by an overestimation of left lateral extent when a leftward movement is required. This case study aimed at evaluating the effect of PA induced by prismatic lenses creating a shift to the left on hyperschematia signs. A 63-year-old woman with left hyperschematia, consecutive to a right fronto-temporo-parietal hematoma, was exposed to a leftward optical deviation produced by prismatic lenses. An anatomical MRI studied topography of the brain lesion; the patient's lesion was then mapped onto tractography reconstructions of white matter pathways. Results showed that PA significantly reduced the left-sided expansion of drawing by copy and from memory, and the overestimation of left lateral extent, immediately after prism removal and 4 days later, indicating a persistent long lasting cognitive effect. MRI showed a right hemisphere disconnection of the posterior and long segments of the arcuate fasciculus, and of the inferior longitudinal and fronto-occipital fasciculi. Overall, these findings suggest that: i)PA is effective also in hyperschematia by re-orientating spatial attention towards the right side of space, with a relative rightward PA-induced unbalance, and re-setting the spatial representation to the left side of space, contralateral to the side of the lesion; ii)the left misrepresentation of lateral extent may be related to a disconnection between visual coordinates and attentional networks to the frontal lobe.

Original languageEnglish
Pages (from-to)128-140
Number of pages13
Publication statusPublished - Oct 2019


  • Bottom-up
  • Hyperschematia
  • Prism adaptation
  • Space representation

ASJC Scopus subject areas

  • Neuropsychology and Physiological Psychology
  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience


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