Word sound deafness resolved?

This paper reports a longitudinal study of a patient (B.C.R.) who was initially diagnosed as ‘pure word deaf’ (word sound deaf). Her performance, and change over time, on tests of speech perception and environmental sound discrimination are reported. The study demonstrates that recovery of word sound deafness can occur despite the presence of bilateral lesions. B.C.R. performed abnormally in both auditory and visual time estimation tasks. We tentatively suggest that the slow operation of an ‘internal clock’ that regulates perception across modalities underlies her difficulties. This clock may also regulate the timing of motor production (Ivry and Keele 1989) and thus account for the association between word sound deafness and phonological errors in speech production in all reported cases.