Early visual deprivation affects the development of face recognition and of audio-visual speech perception

Purpose: The investigation of patients treated for bilateral congenital cataracts allows to study the development of visual and multisensory functions after a period of visual deprivation in early infancy. In the present study, cataract patients were tested for their capability to recognize faces and to integrate auditory and visual speech information. Methods: In Experiment 1, 12 cataract patients were tested with the Benton Facial Recognition Test. In Experiment 2, a McGurk paradigm was used that investigated audio-visual interaction and lip-reading capabilities. Here, fifteen cataract patients participated and were compared to normally sighted controls and to visually impaired controls. Results: In the Benton Facial Recognition Test, cataract patients' performance was unimpaired when target and test face were identical. By contrast, they performed worse than a normally sighted control group when head orientation and/or lighting conditions of the test faces were changed. In the McGurk paradigm, cataract patients displayed impaired lip-reading abilities and a reduced audio-visual interaction compared to normally sighted controls. The latter deficit prevailed even in a sub-group matched for lip-reading capacities with a normally sighted control sub-group. Conclusion: These results suggest that visual input in early infancy is a prerequisite for a normal development of visual and multisensory functions.