Auditory repetition priming is impaired in pure alexic patients

Alexia without agraphia, or "pure" alexia, is an acquired impairment in reading that leaves writing skills intact. Repetition priming for visually presented words is diminished in pure alexia. However, it is not possible to verify whether this priming deficit is modality-specific or modality independent because reading abilities are compromised. Hence, auditory repetition priming was assessed with lexical decision and word stem completion tasks in pure alexic patients with lesions in left inferior temporal-occipital cortex and the splenium. Perceptually based, modality-specific priming models predict intact auditory priming, since auditory association cortex is spared in the patients. Alternatively, modality-independent models, which suggest that priming reflects the temporary modification of an amodal system, might predict impairments. Baseline performance was matched in the patients and controls, although lexical decision priming measures showed an interaction between group and repetition lag. The patients showed intact immediate priming but significantly less priming than controls at longer delays. Furthermore, word stem completion priming was abolished in the patients. One explanation for the deficit is that left inferior temporal-occipital cortex supports amodal aspects of priming, as suggested by recent neuroimaging results. Another possibility is that long-term auditory priming relies on covert orthographic representations which were unavailable in the patients. The results provide support for interactive models of word identification.     

Phonological alexia with vowel-consonant dissociation in non-word reading

We present a patient with alexia secondary to cerebral lesion whose errors in the reading of non-words affect vowels more than consonants. The interest of the case resides in: (1) the documentation of a vowel-consonant dissociation selectively affecting the reading of non-words; and (2) the localization of the alteration in a specific stage of the perilexical reading pathway, that is, the blending of phonetic chains. The case contributes to the discussion on the nature of representations and the processing of vowels and consonants.