The neuropsychology of lipreading.

Lipreading presents a unique glimpse of the intersection of sensory processes with modular, cognitive ones. It presents speech to the eye in an automatic and natural way, whether performed silently or in conjunction with heard speech. It therefore allows us to examine closely claims concerning the relation between input modality and cognitive function. In this paper I consider some of the ways in which the investigation of single neuropsychological cases casts light on this; such cases show us that lipreading can dissociate from other aspects of face perception and recognition, and from auditory speech perception and reading, too. Furthermore, different cognitive components of lipreading itself can be inferred from dissociations on different lipreading tasks. This leads to closer consideration of the boundaries of the necessary cognitive (and possibly anatomical) structures that subserve these functions.