The mediator effect of cognition on the relationship between brain lesion location and dysphagia in patients with stroke: Applying a structural equation model.

Abstract

Cognitive status is important for performing the assessment and treatment of dysphagia. Nonetheless, the cognitive neuropsychological profile of patients with stroke and dysphagia is not studied as deeply enough as it should be. On the one hand, focal and non-focal brain lesions may lead to dysphagia and cognitive disorders, and on the other hand, the cognitive status possibly affects swallowing. In this study, cognition is supposed to be a mediator between brain lesion and swallowing disorder (dysphagia). The role of cognition and attention as mediators between brain lesion and dysphagia was evaluated via three causal models in which the causal mechanisms of swallowing were explained. Eighty-eight patients with their first stroke (34 women and 54 men) in the acute phase (mean: 3.5days after stroke; SD: 2.7) participated in this research. The data of dysphagic and non-dysphagic patients were entered into structural equation models. Two relationships were estimated: a direct relationship between brain lesion and dysphagia and an indirect association between brain lesion and dysphagia through cognition and attention. The goodness-of-fit indices confirmed the three models. Our first model proved a good fit [CFI=1.00; TLI=1.00]. The second model revealed an appropriate goodness of fit [CFI=1.00; TLI=1.00]. Our third model also showed a good fit [CFI=1.00; TLI=1.00]. It is suggested that in the assessment and treatment of dysphagia, cognition is better to be considered as a mediator along with physical aspects of dysphagia.