Dissociating language switching from executive control in bilinguals with MCI

Area of Science:

• Cognitive Neuroscience
• Psycholinguistics
• Neurology

Background:

• Bilingual language control manages switching and interference between languages.
• Neurodegenerative conditions can impact bilingual abilities.
• The effect of mesial temporal neurodegeneration (MCI) on bilingual lexical retrieval is unclear.

Purpose of the Study:

• To investigate if Mild Cognitive Impairment (MCI) affects language switching and lexical retrieval in bilinguals.
• To determine if language control deficits in MCI are domain-specific or related to executive control (EC).

Main Methods:

• Assessed Catalan-Spanish bilinguals with MCI (n=28) and healthy older adults (n=40) using a language-switching task.
• Administered four non-linguistic executive control (EC) tasks: task switching, n-back, Spatial Stroop, and flanker task.
• Analyzed switch costs and mixing costs in language tasks and performance in EC tasks.

Main Results:

• MCI patients showed significantly larger switch costs than controls.
• MCI patients performed worse on the n-back task and slower on the task-switching task.
• No significant correlation was found between language switching performance and EC task performance.

Conclusions:

• MCI may independently affect reactive language control mechanisms.
• Language control deficits in MCI are not necessarily tied to executive control deficits.
• Bilingual language control and executive control may not entirely overlap in neurodegenerative conditions.