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Category-selective deficits are the exception and not the rule: Evidence from a case-series of 64 patients with ventral occipitotemporal cortex damage
Authors:
RICE, G.E., Kerry, S.J., Robotham, R.J., Leff, A.P., LAMBON RALPH, M.A., * Starrfelt, R.
Reference:
Cortex, 138, 266-281
Year of publication:
2021
CBU number:
8610
Abstract:
The organisational principles of the visual ventral stream are still highly debated, particularly
the relative association/dissociation between word and face recognition and the degree of
lateralisation of the underlying processes. Reports of dissociations between word and face
recognition stem from single case-studies of category selective impairments, and
neuroimaging investigations of healthy participants. Despite the historical reliance on single
case-studies, more recent group studies have highlighted a greater commonality between
word and face recognition. Studying individual patients with rare selective deficits misses (a)
important variability between patients, (b) systematic associations between task
performance, and (c) patients with mild, severe and/or non-selective impairments; meaning
that the full spectrum of deficits is unknown. The Back of the Brain project assessed the
range and specificity of visual perceptual impairment in 64 patients with posterior cerebral
artery stroke recruited based on lesion localization and not behavioural performance. Word,
object, and face processing were measured with comparable tests across different levels of
processing to investigate associations and dissociations across domains. We present two
complementary analyses of the extensive behavioural battery: (1) a data-driven analysis of
the whole patient group, and (2) a single-subject case-series analysis testing for deficits and
dissociations in each individual patient. In both analyses, the general organisational principle
was of associations between words, objects, and faces even following unilateral lesions. The
majority of patients either showed deficits across all domains or in no domain, suggesting a
spectrum of visuo-perceptual deficits post stroke. Dissociations were observed, but they
were the exception and not the rule: Category-selective impairments were found in only a
minority of patients, all of whom showed disproportionate deficits for words. Interestingly,
such selective word impairments were found following both left and right hemisphere lesions.
This large-scale investigation of posterior cerebral artery stroke patients highlights the
bilateral representation of visual perceptual function.
URL:
Data for this project is held by an external institution. Please contact the authors to request a copy.