Semantic Function in Mild Cognitive Impairment

Abstract

It is well-established that semantic deficits are observed in mild cognitive impairment (MCI). However, the extent of impairment in different aspects of semantic function remains unclear, and may be influenced by the tasks used to assess performance. In the present study, people with MCI and cognitively healthy older adults completed a series of tasks assessing lexical access, retrieval, and recognition of semantic information, using different input and output modalities. Control participants outperformed people with MCI in almost all tasks, with the greatest deficits observed in picture naming tasks. This finding is interpreted as reflecting greater deficits in lexical access and/or access to the phonological and orthographic lexicon, and less severe deficits in retrieval and recognition of semantic feature and associative knowledge. In a subset of tasks, relatively greater impairment was also observed in biological compared to man-made items. From a clinical perspective, these results suggest that, while it is preferable that a full semantic battery be included in neuropsychological assessment, in cases where shorter testing time is necessary, picture naming is the task most likely to reveal deficits in people with MCI.

Speech pause distribution as an early marker for Alzheimer’s disease

“…Our picture description task [106] does not exert the same level of demand on recent anterograde memory while still managing to capture fluency impairments in a-mdMCI patients, in line with previous studies also implementing picture description tasks [59,83,60,64]. In light of this evidence and considering the well documented constellation of semantic and lexical processing deficits in AD [126,127,128,129,130], our results suggest a generalised, more profound deterioration of the memory system from the preclinical stages of Alzheimer's disease. Our elicitation task successfully taps onto these emerging deficits by imposing a controlled lexicosemantic setting that is also demanding on working memory for discourse building and task maintenance, testing other dimensions of memory in addition to episodic anterograde memory and verbal learning, -which are clearly impaired in these patients-avoiding thus circularity in their diagnosis, which is already based on verbal memory assessment.…”

Clinical study of central cholinergic pathway damage in two mild cognitive impairment patients

“…[23] Taler [24] evaluated the functions of word acquisition, retrieval, and semantic information recognition in MCI patients and in elderly individuals with normal cognition, and found that the control group was superior to the MCI group in all tests, especially in the task of picture naming. Therefore, Taler believed that the picture naming test was the most likely language test item to reveal language defects in MCI patients.…”

Using a Discourse Task to Explore Semantic Ability in Persons With Cognitive Impairment

“…At present, there is no gold standard regarding what tasks to use to evaluate language function in persons at risk of developing dementia. However, what is known is that language deficits in general and specifically semantic difficulties are seen early on McCullough et al ( 2019 ), and multiple evaluation methods might be needed to assess changes in language ability (Taler et al, 2020 ).…”