Semantic processing and neurobiology in Alzheimer's disease and Mild Cognitive Impairment

Almeida, Victor N.; Radanovic, Márcia

doi:10.1016/j.neuropsychologia.2022.108337

Cited by 11 publications

(4 citation statements)

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“…Future studies are needed to better localize these oscillatory changes within these semantic networks due to normal and pathological aging. Biochemical mechanisms of these oscillatory changes remain unclear, although it has been proposed that cholinergic and glutamatergic systems disrupted by the AD pathology could contribute to semantic memory deficits in MCI (Almeida & Radanovic, 2022).…”

Section: Discussionmentioning

confidence: 99%

“…In contrast, older adults with MCI and AD‐RD have semantic memory deficits that may go beyond word retrieval issues and can involve degradation of semantic knowledge (Dudas et al, 2005; Joubert et al, 2021). With disease progression from MCI to AD‐RD, there is more noticeable semantic memory deterioration (Almeida & Radanovic, 2022; Aschenbrenner et al, 2015; Pelgrim et al, 2021). The majority of this research has been conducted using naming tasks (e.g., confrontational naming, verbal fluency, associations).…”

Section: Introductionmentioning

confidence: 99%

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Differences in electroencephalography oscillations between normal aging and mild cognitive impairment during semantic memory retrieval

Chiang

Lydon

Kraut

et al. 2023

Eur J of Neuroscience

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Semantic memory remains relatively stable with normal cognitive aging and declines in early stages of neurodegenerative disease. We measured electroencephalography (EEG) oscillatory correlates of semantic memory retrieval to examine the effects of normal and pathological aging. Twenty‐nine cognitively healthy young adults (YA), 22 cognitively healthy aging adults (HA) and 20 patients with mild cognitive impairment (MCI) completed a semantic memory retrieval task with concurrent EEG recording in which they judged whether two words (features of objects) led to retrieval of an object (retrieval) or not (non‐retrieval). Event‐related power changes contrasting the two conditions (retrieval vs. non‐retrieval) within theta, alpha, low‐beta and high‐beta EEG frequency bands were examined for normal aging (YA vs. HA) and pathological aging effects (HA vs. MCI). With no behavioural differences between the two normal age groups, we found later theta and alpha event‐related power differences between conditions only in YA and a high‐beta event‐related power difference only in HA. For pathological aging effects, with reduced accuracy in MCI, we found different EEG patterns of early event‐related beta power differences between conditions in MCI compared with HA and an event‐related low‐beta power difference only in HA. Beta oscillations were correlated with behavioural performance only in HA. We conclude that the aging brain relies on faster (beta) oscillations during the semantic memory task. With pathological aging, retrieval accuracy declines and pattern of beta oscillation changes. The findings provide insights about age‐related neural mechanisms underlying semantic memory and have implications for early detection of pathological aging.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Differences in electroencephalography oscillations between normal aging and mild cognitive impairment during semantic memory retrieval

Chiang

Lydon

Kraut

et al. 2023

Eur J of Neuroscience

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“…Naming tasks permit clinicians to gauge the extent of lexical–semantic disintegration and confrontation with naming, thereby indicating that the disorders are not simply resulting from the age-associated decline in semantic and/or visuoperceptual knowledge ( 14 , 15 ). MCI patients have been found to retrieve names of famous persons or public figures, even after the deliverance of a semantic cue, which is shown as the major complaint among MCI and AD patients ( 16 ).…”

Section: Introductionmentioning

confidence: 99%

Language dysfunction correlates with cognitive impairments in older adults without dementia mediated by amyloid pathology

Xiang¹,

Ai²,

Zhang³

2023

Front. Neurol.

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BackgroundPrevious studies have explored the application of non-invasive biomarkers of language dysfunction for the early detection of Alzheimer's disease (AD). However, language dysfunction over time may be quite heterogeneous within different diagnostic groups.MethodPatient demographics and clinical data were retrieved from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database for the participants without dementia who had measures of cerebrospinal fluid (CSF) biomarkers and language dysfunction. We analyzed the effect of longitudinal neuropathological and clinical correlates in the pathological process of semantic fluency and confrontation naming. The mediation effects of AD biomarkers were also explored by the mediation analysis.ResultThere were 272 subjects without dementia included in this analysis. Higher rates of decline in semantic fluency and confrontation naming were associated with a higher risk of progression to MCI or AD, and a greater decline in cognitive abilities. Moreover, the rate of change in semantic fluency was significantly associated with Aβ deposition, while confrontation naming was significantly associated with both amyloidosis and tau burden. Mediation analyses revealed that both confrontation naming and semantic fluency were partially mediated by the Aβ aggregation.ConclusionIn conclusion, the changes in language dysfunction may partly stem from the Aβ deposition, while confrontation naming can also partly originate from the increase in tau burden. Therefore, this study sheds light on how language dysfunction is partly constitutive of mild cognitive impairment and dementia and therefore is an important clinical predictor.

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“…In contrast, older adults with MCI and AD-RD have semantic memory deficits that may go beyond word retrieval issues and can involve degradation of semantic knowledge (Dudas et al, 2005;Joubert et al, 2021). With disease progression from MCI to AD-RD, there is more noticeable semantic memory deterioration (Pelgrim et al, 2021;Aschenbrenner et al, 2015;Almeida & Radanovic, 2022). The majority of this research has been conducted using naming tasks (e.g., confrontational naming, verbal fluency, associations).…”

Section: Introductionmentioning

confidence: 99%

Differences in EEG oscillations between normal aging and mild cognitive impairment during semantic memory retrieval

Chiang

Lydon

Kraut

et al. 2022

Preprint

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Semantic memory remains relatively stable with normal cognitive aging and declines in early stages of neurodegenerative disease. We measured electroencephalography (EEG) oscillatory correlates of semantic memory retrieval to examine the effects of normal and pathological aging. Twenty-nine cognitively healthy young adults (YA), 22 cognitively healthy aging adults (HA), and 20 patients with mild cognitive impairment (MCI) completed a semantic memory retrieval task with concurrent EEG recording in which they judged whether two words (features of objects) led to retrieval of an object (retrieval) or not (non-retrieval). Event-related power changes contrasting the two conditions (retrieval vs. non-retrieval) within theta, alpha, low-beta, and high-beta EEG frequency bands were analyzed across time to examine normal aging (YA versus HA) and pathological aging effects (HA versus MCI). Though no behavioral differences between the cognitively healthy groups were observed, we found later theta and alpha power differences between conditions only in YA, and a high-beta power difference between conditions only in HA. For pathological aging effects, we found reduced accuracy in MCI. While we found different EEG patterns of early beta power differences between conditions in MCI compared to HA, a low-beta power difference between conditions was found only in HA. We conclude that the aging brain relies on faster (beta) oscillations during the semantic memory task. With pathological aging, retrieval accuracy declines and patterns of beta oscillation changes. The findings improve understanding on age-related neural mechanisms underlying semantic memory and have implications for early detection of pathological aging.

show abstract

Semantic processing and neurobiology in Alzheimer's disease and Mild Cognitive Impairment

Cited by 11 publications

References 344 publications

Differences in electroencephalography oscillations between normal aging and mild cognitive impairment during semantic memory retrieval

Differences in electroencephalography oscillations between normal aging and mild cognitive impairment during semantic memory retrieval

Language dysfunction correlates with cognitive impairments in older adults without dementia mediated by amyloid pathology

Differences in EEG oscillations between normal aging and mild cognitive impairment during semantic memory retrieval

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