Differentiating amnestic from non-amnestic mild cognitive impairment subtypes using graph theoretical measures of electroencephalography

Kim, Jae-Gyum; Kim, Hayom; Hwang, Ji Hyeon; Kang, Sung Hoon; Lee, Chan Nyoung; Woo, JunHyuk; Kim, Chanjin; Han, Kyungreem; Kim, Ho Jin; Park, Kun-Woo

doi:10.1038/s41598-022-10322-9

Cited by 12 publications

(4 citation statements)

References 43 publications

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“…Amnestic MCI is characterised by impaired episodic memory and is more likely to progress to AD dementia than other subtypes of MCI 8 and has therefore been considered a precursor of AD dementia. 9 The use of biomarkers can provide further evidence for the underlying aetiology of MCI and assist in determining the likelihood of progression to dementia. Many biomarkers directly reflect AD pathology (e.g.…”

Section: Is a Syndrome Characterised By Objective Cognitive Declinementioning

confidence: 99%

“…Subtypes of MCI have been described according to whether multiple or single domains of cognition are impaired, and whether episodic memory loss is a predominant symptom. Amnestic MCI is characterised by impaired episodic memory and is more likely to progress to AD dementia than other subtypes of MCI 8 and has therefore been considered a precursor of AD dementia 9 . The use of biomarkers can provide further evidence for the underlying aetiology of MCI and assist in determining the likelihood of progression to dementia.…”

Section: Introductionmentioning

confidence: 99%

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Neural markers of reduced arousal and consciousness in mild cognitive impairment

Estarellas,

Huntley,

Bor

2024

Int J Geriat Psychiatry

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ObjectivesPeople with Alzheimer's Disease (AD) experience changes in their level and content of consciousness, but there is little research on biomarkers of consciousness in pre‐clinical AD and Mild Cognitive Impairment (MCI). This study investigated whether levels of consciousness are decreased in people with MCI.MethodsA multi‐site site magnetoencephalography (MEG) dataset, BIOFIND, comprising 83 people with MCI and 83 age matched controls, was analysed. Arousal (and drowsiness) was assessed by computing the theta‐alpha ratio (TAR). The Lempel‐Ziv algorithm (LZ) was used to quantify the information content of brain activity, with higher LZ values indicating greater complexity and potentially a higher level of consciousness.ResultsLZ was lower in the MCI group versus controls, indicating a reduced level of consciousness in MCI. TAR was higher in the MCI group versus controls, indicating a reduced level of arousal (i.e. increased drowsiness) in MCI. LZ was also found to be correlated with mini‐mental state examination (MMSE) scores, suggesting an association between cognitive impairment and level of consciousness in people with MCI.ConclusionsA decline in consciousness and arousal can be seen in MCI. As cognitive impairment worsens, measured by MMSE scores, levels of consciousness and arousal decrease. These findings highlight how monitoring consciousness using biomarkers could help understand and manage impairments found at the preclinical stages of AD. Further research is needed to explore markers of consciousness between people who progress from MCI to dementia and those who do not, and in people with moderate and severe AD, to promote person‐centred care.

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Section: Is a Syndrome Characterised By Objective Cognitive Declinementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Neural markers of reduced arousal and consciousness in mild cognitive impairment

Estarellas,

Huntley,

Bor

2024

Int J Geriat Psychiatry

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“…CDR 0 was defined as SCD, CDR 0.5 as MCI, and CDR 1 as AD 29 , 30 . Compared to the age and education norms, MCI patients with in-memory domain scores below − 1.0 SD were classified as aMCI and otherwise, as naMCI 31 , 32 . Detailed values of the cognitive test scores for each group are presented in Table 2 .…”

Section: Methodsmentioning

confidence: 99%

Electroencephalography-based classification of Alzheimer’s disease spectrum during computer-based cognitive testing

Kim,

Kim

et al. 2024

Sci Rep

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Alzheimer’s disease (AD) is a progressive disease leading to cognitive decline, and to prevent it, researchers seek to diagnose mild cognitive impairment (MCI) early. Particularly, non-amnestic MCI (naMCI) is often mistaken for normal aging as the representative symptom of AD, memory decline, is absent. Subjective cognitive decline (SCD), an intermediate step between normal aging and MCI, is crucial for prediction or early detection of MCI, which determines the presence of AD spectrum pathology. We developed a computer-based cognitive task to classify the presence or absence of AD pathology and stage within the AD spectrum, and attempted to perform multi-stage classification through electroencephalography (EEG) during resting and memory encoding state. The resting and memory-encoding states of 58 patients (20 with SCD, 10 with naMCI, 18 with aMCI, and 10 with AD) were measured and classified into four groups. We extracted features that could reflect the phase, spectral, and temporal characteristics of the resting and memory-encoding states. For the classification, we compared nine machine learning models and three deep learning models using Leave-one-subject-out strategy. Significant correlations were found between the existing neurophysiological test scores and performance of our computer-based cognitive task for all cognitive domains. In all models used, the memory-encoding states realized a higher classification performance than resting states. The best model for the 4-class classification was cKNN. The highest accuracy using resting state data was 67.24%, while it was 93.10% using memory encoding state data. This study involving participants with SCD, naMCI, aMCI, and AD focused on early Alzheimer’s diagnosis. The research used EEG data during resting and memory encoding states to classify these groups, demonstrating the significance of cognitive process-related brain waves for diagnosis. The computer-based cognitive task introduced in the study offers a time-efficient alternative to traditional neuropsychological tests, showing a strong correlation with their results and serving as a valuable tool to assess cognitive impairment with reduced bias.

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“…Amnestic mild cognitive impairment (aMCI) constitutes an intermediate stage, both symptomatically and pathologically, between aging and AD ( 36 , 37 ). Older adults with aMCI do not meet the diagnostic criteria of dementia but are at a greater risk to later develop AD ( 38 , 39 ).…”

Section: Introductionmentioning

confidence: 99%

Mitochondria-sequestered Aβ renders synaptic mitochondria vulnerable in the elderly with a risk of Alzheimer disease

Jia,

Tian,

Wang

et al. 2023

JCI Insight

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Mitochondria are critical for neurophysiology, and mitochondrial dysfunction constitutes a characteristic pathology in both brain aging and Alzheimer disease (AD). Whether mitochondrial deficiency in brain aging and AD is mechanistically linked, however, remains controversial. We report a correlation between intrasynaptosomal amyloid β 42 (Aβ42) and synaptic mitochondrial bioenergetics inefficiency in both aging and amnestic mild cognitive impairment, a transitional stage between normal aging and AD. Experiments using a mouse model expressing nonmutant humanized Aβ (humanized Aβ-knockin [hAβ-KI] mice) confirmed the association of increased intramitochondrial sequestration of Aβ42 with exacerbated synaptic mitochondrial dysfunction in an aging factor- and AD risk–bearing context. Also, in comparison with global cerebral Aβ, intramitochondrial Aβ was relatively preserved from activated microglial phagocytosis in aged hAβ-KI mice. The most parsimonious interpretation of our results is that aging-related mitochondrial Aβ sequestration renders synaptic mitochondrial dysfunction in the transitional stage between normal aging and AD. Mitochondrial dysfunction in both brain aging and the prodromal stage of AD may follow a continuous transition in response to escalated intraneuronal, especially intramitochondrial Aβ, accumulation. Moreover, our findings further implicate a pivotal role of mitochondria in harboring early amyloidosis during the conversion from normal to pathological aging.

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Differentiating amnestic from non-amnestic mild cognitive impairment subtypes using graph theoretical measures of electroencephalography

Cited by 12 publications

References 43 publications

Neural markers of reduced arousal and consciousness in mild cognitive impairment

Neural markers of reduced arousal and consciousness in mild cognitive impairment

Electroencephalography-based classification of Alzheimer’s disease spectrum during computer-based cognitive testing

Mitochondria-sequestered Aβ renders synaptic mitochondria vulnerable in the elderly with a risk of Alzheimer disease

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