Phonological dyslexia without phonological impairment?

RG, a patient with probable Alzheimer's disease, showed a severe impairment in nonword reading. RG's word reading was intact, for example, as demonstrated by her scores in standardised reading tasks, which were comparable to those of normal controls. No phonological impairment was apparent in speech production and comprehension. Moreover, RG performed well in a series of phonological tasks (e.g., production of a rhyming word, phoneme identification) on which patients with a reading deficit selective for nonwords have been reported to encounter problems. RG's data severely constrain reading models proposing that nonword reading deficits are caused by phonological deficits. However, RG's data are compatible with dual-route reading models, which do not propose a link between nonword reading deficits and phonological impairment.