Language Dysfunction Could Aid in Earlier Identification of Dementia, Alzheimer Disease

New study findings suggest that language dysfunction could be used to identify cognitive decline and early signs of dementia in patients with Alzheimer disease (AD), according to findings published in Frontiers in Neurology.

Alzheimer illustration | Image credit: Orawan - stock.adobe.com

According to the study, efforts to decrease the cognitive decline and dementia in AD patients could be effective. Such efforts include monitoring of behavioral risk factors and multidomain interventions. If disease symptoms are detected in the early stage of AD, patients can begin treatment promptly, potentially resulting in more positive outcomes.

According to the authors, the early signs of amyloid β (Aβ) and tau aggregation can start to develop decades before AD symptoms appear. Importantly, amyloid deposition could accelerate tau pathology, which then leads to neurodegeneration. However, use of these biomarkers in practice is limited.

Language dysfunction is a common symptom that can be found early in AD. Recently, it has been discovered that Aβ has a greater impact on the language network in earlier stages of AD. Other studies have found that increased burden of pathological tau aggregates may be linked with declined capacity in name memorization, associated with primary progressive aphasia.

In the study, 272 elderly participants without dementia completed a neuropsychological assessment. The participants ranged from 54 to 89 years old. The assessments included the Boston naming test (BNT) and a semantic fluency animal test. A lower score implies a level of language dysfunction and those with lower scores were assigned to the clinical disease progression group to compare their manifestations over time with those who scored higher.

“We use linear models to further explore the independent influence of Aβ and tau pathologies on the baseline and change rate of semantic fluency and confrontation naming by including CSF (Aβ) and tau and the predictors in the multivariable model, controlling for the same covariables above,” the study authors wrote in the article.

The study confirmed that individuals who had worse language dysfunction had a higher risk for the clinical progression of cognitive impairments. Language dysfunction was confirmed as an identifier for preclinical AD detection.

“Our findings further confirmed the association between the change rates of semantic fluency and cognition and altered executive function. Before the onset of clinically significant cognitive dysfunctions, indicating that semantic fluency could be used as an imperative predictor for the disease progression rate,” the study authors wrote in the article.

The benefits of semantic fluency were also established as an accurate tool for screening of early dementia symptoms. Highlighting the change rates of semantic fluency and confrontation naming allowed a connection with the decline of memory and executive function.However, in the longitudinal findings, semantic fluency and confrontation naming confirmed greater decline among participants with differing profiles.

The findings suggest that utilizing longitudinal assessments of language impairment and clinical progression in patients with suspected dementia or AD could help identify challenges earlier, allowing for more effective treatment approaches and management.

Reference

Xiang C, Ai W, Zhang Y, Alzheimer’s Disease Neuroimaging Initiative. Language dysfunction correlates with cognitive impairments in older adults without dementia mediated by amyloid pathology. Front Neurol. 2023;14. doi:10.3389/fneur.2023.1051382