Spontaneous recovery of impaired memory span: does comprehension recover?

We have previously described a patient, T.B., who had a memory span of two digits and a sentence span of three words. He showed no evidence of effects of either phonological similarity or word length on span and his deficit was interpreted as reflecting the impaired functioning of the phonological loop component of working memory. Analysis of his language comprehension indicated normal processing of short sentences, together with a marked deficit in understanding long sentences, whether these were presented visually or auditorily (Baddeley and Wilson, 1988). When re-tested after several years, T.B.'s memory span had increased to nine digits, and showed clear effects of phonological similarity and word length. His performance on a series of language comprehension tests indicated a complete recovery, although he continued to show impairment on two tests of phonological awareness. These results are consistent with the proposed link between phonological working memory and language comprehension. In addition, they indicate a dissociation between short-term phonological memory and phonological awareness.