Differences in EEG Delta Frequency Characteristics and Patterns in Slow-Wave Sleep Between Dementia Patients and Controls

Bonanni, Enrica; Coscio, Elisa Di; Maestri, Michelangelo; Carnicelli, Luca; Tsekou, Hara; Economou, Nicholas-Tiberio; Paparrigopoulos, Thomas; Bonakis, Anastasios; Papageorgiou, Sokratis G.; Vassilopoulos, Dimitris; Soldatos, Constantin R.; Murri, Luigi; Ktonas, P.Y.

doi:10.1097/wnp.0b013e318246b56d

Cited by 20 publications

(14 citation statements)

References 25 publications

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“…A similar dissociation was reported during SWS in demented patients compared to normal elderly8. Albeit the relatively small sample size (but still the largest in the literature) and the heterogeneity of the dementia group, this study reported a decreased amplitude and incidence of slow delta waves (<1.6 Hz) and an increased incidence of fast delta waves (2–3.6 Hz).…”

Section: Discussionsupporting

confidence: 84%

“…Albeit the relatively small sample size (but still the largest in the literature) and the heterogeneity of the dementia group, this study reported a decreased amplitude and incidence of slow delta waves (<1.6 Hz) and an increased incidence of fast delta waves (2–3.6 Hz). Since KCs mostly correspond to slow delta frequency events and some evidence suggests that they may be considered as single instances of delta EEG activity that predominates in SWS161832, the observation by Bonanni and coworkers8 is coherent with the decreased incidence of KCs in dementia.…”

Section: Discussionmentioning

confidence: 93%

“…During REM sleep, it appears as an increase of delta and theta power, which is larger in the temporoparietal and frontal regions6, while in NREM it is evidenced by a parietal decrease of sigma power7 and an increase of high (1.6–3.6 Hz) delta power8.…”

Section: Slow-wave Activity (Swa)mentioning

confidence: 99%

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The Fall of Sleep K-Complex in Alzheimer Disease

Gennaro

Gorgoni

Reda

et al. 2017

Sci Rep

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Although a slowing of electroencephalographic (EEG) activity during wakefulness and –to some extent- sleep of Alzheimer disease (AD) patients (i.e., increased slow-frequency activity) was documented, recent findings in healthy elderly show a decreased 0.6–1 Hz slow wave activity (SWA) during NREM, which was associated to β-amyloid deposition and impaired hippocampal memory consolidation. We hypothesize that the apparent contradiction may be explained by the partial overlap between 0.6–1 Hz EEG activity and K-Complex (KC). According to this view, we studied both frontal KCs and SWA in 20 AD patients and 20 healthy age-matched controls (HC) during nightly sleep, under the hypothesis that KCs better discriminate patients from healthy elderly than ≤1 Hz SWA. A drastic decrease of KC density during stage 2 NREM was found in AD compared to HC. Patients show more than 40% reduction of the KC density, allowing a correct classification of 80%. On the other hand, ≤1 Hz SWA of AD patients is slightly (not significantly) higher in most cortical areas compared to HC. Although no significant changes of ≤1 Hz SWA are detectable over frontal areas in AD, KC density decreases over the same location, and its decrease is related to the cognitive decline.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 93%

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The Fall of Sleep K-Complex in Alzheimer Disease

Gennaro

Gorgoni

Reda

et al. 2017

Sci Rep

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“…() speculated that the consequences of cholinergic deficits for cortical activation may be more pronounced in REM sleep because cortical activation during this stage is mainly the result of the cholinergic system. Here, we found EEG slowing during N2 sleep, which is in line with a reported increase in NREM delta power in demented subjects (Bonanni et al., ). A recent study, on the other hand, found decreased NREM EEG delta power in a group of highly intelligent individuals as compared with those with average intelligence, suggesting that sleep EEG delta power reflects neural plasticity and cortical homeostatic processes (Pótári et al., ).…”

Section: Discussionsupporting

confidence: 92%

Sleep efficiency and neurophysiological patterns in middle‐aged men are associated with cognitive change over their adult life course

Waser

Lauritzen

Fagerlund

et al. 2018

Journal of Sleep Research

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Summary Disrupted sleep is a contributing factor to cognitive ageing, while also being associated with neurodegenerative disorders. Little is known, however, about the relation of sleep and the gradual cognitive changes over the adult life course. Sleep electroencephalogram (EEG) patterns are potential markers of the cognitive progress. To test this hypothesis, we assessed sleep architecture and EEG of 167 men born in the Copenhagen Metropolitan Area in 1953, who, based on individual cognitive testing from early (~18 years) to late adulthood (~58 years), were divided into 85 subjects with negative and 82 with positive cognitive change over their adult life. Participants underwent standard polysomnography, including manual sleep scoring at age ~58 years. Features of sleep macrostructure were combined with a number of EEG features to distinguish between the two groups. EEG rhythmicity was assessed by spectral power analysis in frontal, central and occipital sites. Functional connectivity was measured by inter‐hemispheric EEG coherence. Group differences were assessed by analysis of covariance (p < 0.05), including education and severity of depression as potential covariates. Subjects with cognitive decline exhibited lower sleep efficiency, reduced inter‐hemispheric connectivity during rapid eye movement (REM) sleep, and slower EEG rhythms during stage 2 non‐REM sleep. Individually, none of these tendencies remained significant after multiple test correction; however, by combining them in a machine learning approach, the groups were separated with 72% accuracy (75% sensitivity, 67% specificity). Ongoing medical screenings are required to confirm the potential of sleep efficiency and sleep EEG patterns as signs of individual cognitive progress.

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“…In healthy elderly subjects, a decreased frontal SWA has been associated with medial prefrontal cortex gray matter atrophy and impaired hippocampaldependent memory [39], whereas in amnestic MCI subjects a reduction of stage 2 sleep spindles and decreased delta and theta power has been described [18]. An impaired regulation of delta waves has been observed in AD NREM sleep [40,41]. Taken together, these data suggest that NREM sleep organization and microstructure are already impaired in preclinical stages of dementia, and parallel the cognitive decline, more pronounced in AD than in MCI.…”

Section: Discussionmentioning

confidence: 98%