El-La: The impact of degraded semantic representations on knowledge of grammatical gender in semantic dementia

Previous research on semantic dementia (SD) has demonstrated a link between conceptual representations and ability on a range of 'non-semantic' tasks, both verbal and nonverbal. In all cases, SD patients perform well on items that conform to the underlying statistical 'surface' structure of the domain in question but poor performance on items that are atypical with respect to these statistics. For such items, there is a strong tendency for the patients' erroneous responses to reflect the more typical pattern. To date, most research on this topic has been conducted with Englishspeaking patients, and where extended to non-English languages, directly comparable aspects of each language have been probed. In this study we tested the generalisation of this theory by probing performance on an aspect of Spanish with no analogue in English (grammatical gender). As predicted, Spanish SD patients provided the correct gender to high frequency words or where the phonology of the noun strongly predicted the gender. For low frequency, atypical nouns, however, the patients made many more errors (preferring the statistically typical gender). As expected, performance on nouns with atypical grammatical gender was strongly correlated with the degree of semantic impairment across the case-series of SD patients. The results not only provide another example of the critical relationship between semantic memory and 'non-semantic' cognition, but also indicate that this theoretical framework generalises to novel aspects of non-English languages - suggesting that the phenomenon is based on brain-general mechanisms.