Training with cognitive sequences improves syntactic comprehension in agrammatic aphasics

A major open question in cognitive neuroscience concerns the modularity of language: does human language rely, in part, on neural processes that are not language specific? Such reliance would predict that learning should transfer between non-linguistic and linguistic domains via this common neural basis. To test this prediction, we studied effects of non-linguistic cognitive sequence training on syntactic comprehension of six left-hemisphere damaged aphasic patients. Syntactic comprehension impairment was quantified before and after 10 weeks of training on a non-linguistic sequence processing task. This task used a transformational rule specifically corresponding to the transformation required for understanding a particular type of sentence referred to as relativised. Non-linguistic sequencing improved significantly with training (day effect: F(9,45)=3.7, p<0.005). Moreover, a significant transfer of this improvement was observed for relativised, but not active nor passive sentences (pre-post x type interaction: F(2,10)=4.72, p < 0.05). The specificity of this transfer indicates that language relies partially on functional and neural processes that are not language specific.