Electrophysiological resting state brain network and episodic memory in healthy aging adults.

Recent studies have emphasized the changes in large-scale brain networks related to healthy aging, with the ultimate purpose to aid in differentiating normal neurocognitive aging from neurodegenerative disorders that also arise with age. Emerging evidence from functional Magnetic Resonance Imaging (fMRI) indicates that connectivity patterns within specific brain networks, especially the Default Mode Network (DMN), distinguish those with Alzheimer's disease from healthy individuals. In addition, disruptive alterations in the large-scale brain systems that support high-level cognition are shown to accompany cognitive decline at the behavioral level, which is commonly observed in the aging populations, even in the absence of disease. Although fMRI is useful for assessing functional changes in brain networks, its high costs and limited accessibility discourage studies that need large populations. In this study, we investigated the aging-effect on large-scale networks of the human brain using high-density electroencephalography and electrophysiological source imaging, which is a less costly and more accessible alternative to fMRI. In particular, our study examined a group of healthy subjects in the age range from middle- to older-aged adults, which is an under-studied range in the literature. Employing a high-resolution computation model, our results revealed age associations in the connectivity pattern of DMN in a consistent manner with previous fMRI findings. Particularly, in combination with a standard battery of cognitive tests, our data showed that in the posterior cingulate / precuneus area of DMN higher brain connectivity was associated with lower performance on an episodic memory task. The findings demonstrate the feasibility of using electrophysiological imaging to characterize large-scale brain networks and suggest that changes in network connectivity are associated with normal aging.

Amplitude of fNIRS Resting-State Global Signal Is Related to EEG Vigilance Measures: A Simultaneous fNIRS and EEG Study.

Recently, functional near-infrared spectroscopy (fNIRS) has been utilized to image the hemodynamic activities and connectivity in the human brain. With the advantage of economic efficiency, portability, and fewer physical constraints, fNIRS enables studying of the human brain at versatile environment and various body positions, including at bed side and during exercise, which complements the use of functional magnetic resonance imaging (fMRI). However, like fMRI, fNIRS imaging can be influenced by the presence of a strong global component. Yet, the nature of the global signal in fNIRS has not been established. In this study, we investigated the relationship between fNIRS global signal and electroencephalogram (EEG) vigilance using simultaneous recordings in resting healthy subjects in high-density and whole-head montage. In Experiment 1, data were acquired at supine, sitting, and standing positions. Results found that the factor of body positions significantly affected the amplitude of the resting-state fNIRS global signal, prominently in the frequency range of 0.05-0.1 Hz but not in the very low frequency range of less than 0.05 Hz. As a control, the task-induced fNIRS or EEG responses to auditory stimuli did not differ across body positions. However, EEG vigilance plays a modulatory role in the fNIRS signals in the frequency range of less than 0.05 Hz: resting-state sessions of low EEG vigilance measures are associated with high amplitudes of fNIRS global signals. Moreover, in Experiment 2, we further examined the epoch-to-epoch fluctuations in concurrent fNIRS and EEG data acquired from a separate group of subjects and found a negative temporal correlation between EEG vigilance measures and fNIRS global signal amplitudes. Our study for the first time revealed that vigilance as a neurophysiological factor modulates the resting-state dynamics of fNIRS, which have important implications for understanding and processing the noises in fNIRS signals.

Sleep-Disordered Breathing and Cerebral Oxygenation During Sleep in Adults With Mild Cognitive Impairment.

The current study examined relationships between laterality in cerebral oxygenation (L-COX), sleep-disordered breathing (SDB), and daytime function in 16 adults with mild cognitive impairment (MCI). All participants underwent two nights of diagnostic polysomnography. Using dual-cerebral oximetry, L-COX was defined by differences ≥4% in right- versus left-sided percent cerebral oxyhemoglobin saturation. Eight patients had SDB. L-COX was found in five patients, but only on nights with SDB. Greater L-COX was associated more severe SDB: higher frequency of apneas + hypopneas per hour (r = 0.66, p < 0.01), desaturations per hour (r = 0.73, p < 0.01), and percent time with oxygen saturation <88% (r = 0.65, p < 0.01). Greater laterality, but not severity of SDB, was associated with poorer functional ability (Lawton Instrumental Activities of Daily Living Scale: r = -0.83, p = 0.02), lower cognitive function (Mini-Mental State Examination: r = -0.76, p = 0.03), and greater daytime sleepiness (Epworth Sleepiness Scale: r = 0.85, p < 0.001). L-COX associated with SDB suggests disruptions in cerebral autoregulation and need for aggressive treatment of SDB in individuals with MCI. [Res Gerontol Nurs. 2018; 11(6):282-292.].

Accelerated vascular aging and persistent cognitive impairment in older female breast cancer survivors.

Advances in breast cancer treatment have markedly increased survivorship over the past three decades, with over 3.1 million survivors expected to live into their 70s and 80s. Without symptom relief interventions, nearly 35% of these survivors will have life-altering and distressing cognitive symptoms. This pilot study explored associations between serum markers of vascular aging, laterality in cerebral oxygenation, and severity of cognitive impairment in women, 12-18 months after chemotherapy for stage 2/3 invasive ductal breast cancer. Fifteen women (52-84 years) underwent a brief cognitive assessment (Montreal Cognitive Assessment [MOCA]) and blood draws to assess markers of vascular aging (interleukin-6 [IL-6], tumor necrosis factor alpha [TNF-α], C-reactive protein [CRP], and insulin growth factor-1 [IGF-1]). All underwent a computer-based test protocol that is known to increase blood flow within the frontal lobes. Percent cerebral oxyhemoglobin saturation (rcSO2) was recorded during and after testing. Laterality in rcSO2 was defined by ≥ 3% difference between left and right rcSO2 (|rcSO2 meanRIGHT - meanLEFT|). Eight participants had MOCA scores between 21 and 25 points, suggestive of mild cognitive impairment. Neither CRP (r = -.24) nor IL-6 (r = .34) nor TNF-α (r = .002) were associated with MOCA scores. Higher IL-6 was associated with greater laterality (r = .41). MOCA scores were significantly lower in subjects with laterality in rcSO2 than in those without laterality (F(1,14) = 13.5, p = 003). Lower IGF-1 was significantly associated with greater laterality (r = - .66, p = .007) and lower cognitive function (r = .58). These findings suggest that persistent cognitive impairment is associated with phenotypical changes consistent with accelerated vascular aging.

Expressive writing in early breast cancer survivors.

AIMS: This article is the report of a study aimed at determining whether or not expressive writing improves the quality-of-life of early breast cancer survivors. An additional aim is the investigation of whether or not the type of writing prompt makes a difference in results. BACKGROUND: The risk of distress can extend well beyond the time of a breast cancer diagnosis. Emotional expression may assist in dealing with this. DESIGN: Randomized controlled study. METHODS: Participants (n = 120) were randomized into one of four groups: a control group (no writing) or one of three expressive writing groups: breast cancer trauma, any self-selected trauma and facts related to breast cancer. Participants wrote 20 minutes a day for 4 consecutive days. Their quality-of-life was measured, using the 'Functional Assessment of Cancer Therapy-Breast Cancer Version', at baseline and at 1 month and 6 months after writing. Paired t-tests, multivariate analysis of variance and multiple regression were used to analyse the data of the 97 participants who completed the journaling assignment and at least the first assessment, collected in 2006. Intention-to-treat analysis was used. RESULTS/FINDINGS: Expressive writing about one's breast cancer, breast cancer trauma and facts related to breast cancer, significantly improved the quality-of-life outcome. CONCLUSION: Expressive writing, focusing the instructions on writing about one's living and dealing with a diagnosis of breast cancer, is recommended for early breast cancer survivors as a feasible and easily implemented treatment approach to improve quality-of-life.

Oligogenic combinations associated with breast cancer risk in women under 53 years of age.

Common, but weakly penetrant, functional polymorphisms probably account for most of the genetic risk for breast cancer in the general population. Current polygenic risk models assume that component genes act independently. To test for potential gene-gene interactions, single nucleotide polymorphisms in ten genes with known or predicted roles in breast carcinogenesis were examined in a case-control study of 631 Caucasian women diagnosed with breast cancer under the age of 53 years and 1,504 controls under the age of 53 years. Association of breast cancer risk with individual genes and with two- and three-gene combinations was analyzed. Sixty-nine oligogenotypes from 37 distinct two- and three-gene combinations met stringent criteria for significance. Significant odds ratios (ORs) covered a 12-fold range: 0.5-5.9. Of the observed ORs, 17% differed significantly from the ORs predicted by a model of independent gene action, suggesting epistasis, i.e., that these genes interact to affect breast cancer risk in a manner not predictable from single gene effects. Exploration of the biological basis for these oligogenic interactions might reveal etiologic or therapeutic insights into breast cancer and other cancers.