The impact of Cognitive Training on Brain Electrophysiology and Divided Attention in Healthy Older Adults

Aging impacts older adults’ ability to divide their attention. Research has shown that cognitive training techniques are promising in improving divided attention. Investigating the effects of training on electrophysiological brain activity might elucidate the mechanisms underlying improvements and allow better training method selection. Electroencephalography (EEG) is ideal for studying divided attention as switching attention is a dynamic process that takes place within milliseconds and requires high temporal resolution. All participants (mean age 69.5 years, SD=6.42) performed a visual detection task and an alphanumeric equation task under single and dual-task conditions. Afterwards, participants were randomly assigned to three groups: The single task training group (STT, N=13) practiced the two tasks separately; the fixed attention training group (FAT, N=12) was trained to assign equal attention to both tasks concurrently; the variable-attention training group (VAT, N=14) was trained to flexibly vary their attention while performing the tasks concurrently. After training, participants were tested again. EEG measures were taken pre- and post-training. Training led to behavioural improvements in all of our participants, with the VAT group displaying the greatest benefits and a reduction in dual-task costs. The N1 component was less pronounced after training while P2 was enhanced, suggesting more efficient processing. Functional connectivity measures indicated an increase in theta band coherence between fronto-parietal and fronto-occipital regions in the VAT group, suggesting improved cognitive control. Our results suggest that variable attentional allocation training incurred behavioural benefits with an electrophysiological profile distinct from single task practice and equal priority dual-task training

Auditory-cognitive Associations in Older Adults: Differential Effects of Sex, Test Modality, and Hearing Measures

Auditory-cognitive associations in older adults: Differential effects of sex, test modality, and hearing measures Faisal Al-Yawer, Ph.D. Concordia University, 2022 This dissertation presents findings that address auditory-cognitive associations in older adults with hearing loss (HL), particularly with regards to sex-related differences in said associations. Manuscript I (Chapter 2) reports the psychometric properties of the Montreal Cognitive Assessment scale (MoCA) when hearing-related items are excluded from scoring (MoCAModified). This involved a cross-sectional analysis of the original MoCA validation study data in healthy older adults, older adults with mild cognitive impairment (MCI), and older adults with mild Alzheimer’s disease (AD). Our findings showed that, compared to the original MoCA, MCI sensitivity was substantially reduced when all auditory subtests were omitted, with the biggest contribution to the reduction coming from the delayed recall subtest. This Chapter highlights the contribution that hearing-dependent subtests have on the accuracy of the MoCA. Manuscript II (Chapter 3) examines sex-related differences in the associations between MoCA scores and pure-tone average (PTA) in healthy older adults. MoCA-Modified scores were also calculated for all participants to assess the contribution of hearing-dependent items. Results showed that women with normal hearing were more likely to pass the MoCA compared to their counterparts with HL. In contrast, no associations were observed in men. Regression analysis showed an interaction between sex and PTA in the worse ear. PTAs were significantly correlated with both MoCA and MoCA-Modified scores in women, but not in men. This suggests significant sex-related differences in auditory-cognitive associations even when hearing-related test items are omitted. Manuscript III (Chapter 4) examines sex-related differences in auditory-cognitive associations in a sample of individuals with MCI. In this cross-sectional analysis, we examined sex-related differences in hearing, as measured by both PTA and the Canadian Digit Triplet Test (CDTT), and cognition, as measured by the MoCA, Rey Auditory Verbal Learning (RAVLT), and the Brief Visuospatial memory test (BVMT-R). Women with better hearing on either measure outperformed their worse hearing counterparts on the MoCA. Women with normal hearing showed correlations between CDTT SRTs and MoCA and RAVLT scores. Men but not women showed an effect of hearing on the BVMT-R. Generally, this dissertation points to the existence of sex-related differences in auditory-cognitive associations and discusses potential mechanisms that underly these observations, including the common cause and information degradation hypotheses

Correlations of morphological (macroscopic and microscopic) parameters of placenta with maternal age and parity

Background: Placenta is a chief cause of maternal and perinatal mortality and significant factor in fetal growth retardation. It undergoes different variations in weight, volume, structure, shape and function continuously throughout the gestation tosupport the prenatal life. Cautious examination of placenta can give information which can be useful in the management of complications in mother and the newborn. Objective: The present work has been attempted towards determination of the morphological ( macroscopic and microscopic) parameters of human full-term placentae and their relation with different parity and age group of mothers. Patients and Methods: A whole of 40  placentae were recently collected.They were divided into four  groups (10  women each); primigravida age35 years, multigravida 35years.Neonataland placental weights,placental thickness  and  number of cotyledons were measured.Tissue for histological examination wasobtained to study the parameters of  microscopic morphometry   (number of apoptotic cells, number of terminal villi, number of syncytial knots, number of fetal capillaries and thickness of trophoblastic basement  membrane). Results: Placental and  neonatal weights were within normal range. They were augmented with maternal age and parity. Number of cotyledons was higher than those reported by other authors in other populations but it was still within normal range and it was significantly decreased in multigravida> 35.Placental thickness was within normal range and it was significantly decreased in multigravida> 35. All microscopic parameters were increased with maternal age and parity.. Conclusion: There were correlations between microscopic and macroscopic parameters. Thelength of stem villi were less in multigravida> 35 since placental thickness was decreased in this group.  All microscopic parameters were increased with maternal age and parity.These variations may have some important bearing on the placental inadequacy in higher age group and parity of mother

Overcoming the challenges to develop the future of E-government in Iraq: a systematic literature review

Despite the early start that Iraq had in the e-government project and its launch in 2004, the pace of development is rather slow. This study aims to identify the main themes of the technical challenges hindering the development of e-government in Iraq. Systematic literature review was employed in this study to collect and analyse papers published on e-government in Iraq to reveal the main themes of the technical challenges in e-government projects. The result obtained from the systematic literature review revealed six themes of technical challenges. These identified challenges are important to be addressed to accelerate the progress of e-government in Iraq

Observations on the ultrastructure of a rat mammary gland treated with harmal and borage

Background : It had been indentified by histological, histochemical and morphometrical studies that peganum harmala is a mammogenic herb and borage officinalis is a lactogenic one . To complete our investigation about these two herbs , we performed electron microscopical study. Materials and methods : Rats were grouped according to their physiological status into three groups . Each group was subdivided in to three subgroups : one control and two experimental . The two experimental group were treated daily; the 1st one with an aqueous extract of peganum harmala seeds and the 2nd with an aqueous extract of borage officinalis flowers . After two weeks of treatment , mammary glands were employed for electron microscopical study. Results : In virgin rats , the epithelial and myoepithelial cells were partially differentiated when harmal was given and completely differentiated when borage was given . In pregnant rats , harmal and borage optimize mammary parenchymal growth and induce lactation when these herbs were given. In lactating rats ,these herbs exhibited a picture similar to control lactating group but the budding of lipid droplets and the swelling of secretary vesicles were markedly increased. Conclusion: Both harmal and borage stimulate the release of prolactin and induce galactogenesis during pregnancy and promote it during lactation

Effects of AL-Qutub (Tribulus terrestris) on the Spermatogenesis of the Mouse Testis: Histological, Histochemical and Morphometrical Studies

Backgrounds: Tribulus terrestris is one of the traditional herbs that have a revolutionary breakthrough in the management of erectile dysfunction and have become world –wide as an “instant treatment” Materials & Methods: Tribulus terrestris was given daily to mature male mouse in a dose of 2 mg /kg body weight for 14 days .10% formalin fixed paraffin sections were performed for histological, histochemical and morphometrical studies. Results: Histological and histochemical studies demonstrated a considerable increase in the number of spermatocytes, spermatids and sperms in parallel with an increase number of interstitial (Leydig) cells. Morphometrically, the thickness of seminiferous tubule is significantly increased together with a significant increase in the number of interstitial cells. Conclusions: Tribulus terrestris increases the number of Leydig cells, and the androgens produced by these cells are directly responsible for enhanced spermatogenesis

Visual Performance and Cortical Atrophy in Vision-Related Brain Regions Differ Between Older Adults with (or at Risk for) Alzheimer’s Disease

Background: Visual impairment is associated with deficits in cognitive function and risk for cognitive decline and Alzheimer’s disease (AD). Objective: The purpose of this study was to characterize the degree of visual impairment and explore the association thereof with cortical atrophy in brain regions associated with visual processing in individuals with (or at risk for) AD. Methods: Using the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) dataset, we analyzed vision and brain imaging data from three diagnostic groups: individuals with subjective cognitive decline (SCD; N = 35), mild cognitive impairment (MCI; N = 74), and mild AD (N = 30). We used ANCOVAs to determine whether performance on reading acuity and contrast sensitivity tests differed across diagnostic groups. Hierarchical regression analyses were applied to determine whether visual performance predicted gray matter volume for vision-related regions of interest above and beyond group membership. Results: The AD group performed significantly worse on reading acuity (F(2,138) = 4.12, p < 0.01, ω2 = 0.04) compared to the SCD group and on contrast sensitivity (F(2,138) = 7.6, p < 0.01, ω2 = 0.09) compared to the SCD and MCI groups, which did not differ from each other. Visual performance was associated with volume in some vision-related structures beyond clinical diagnosis. Conclusion: Our findings demonstrate poor visual performance in AD and that both group membership and visual performance are predictors of cortical pathology, consistent with the idea that atrophy in visual areas and pathways contributes to the functional vision deficits observed in AD

Hearing loss is associated with gray matter differences in older adults at risk for and with Alzheimer’s disease

Using data from the COMPASS-ND study we investigated associations between hearing loss and hippocampal volume as well as cortical thickness in older adults with subjective cognitive decline (SCD), mild cognitive impairment (MCI), and Alzheimer’s dementia (AD). SCD participants with greater pure-tone hearing loss exhibited lower hippocampal volume, but more cortical thickness in the left superior temporal gyrus and right pars opercularis. Greater speech-in-noise reception thresholds were associated with lower cortical thickness bilaterally across much of the cortex in AD. The AD group also showed a trend towards worse speech-in-noise thresholds compared to the SCD group

Sex-Specific Interactions Between Hearing and Memory in Older Adults With Mild Cognitive Impairment: Findings From the COMPASS-ND Study

Objectives:  Hearing loss (HL) in older adults is associated with a decline in performance on cognitive tasks and the risk of developing dementia. However, very few studies have investigated sex-related effects on these associations. A previous study of cognitively healthy older adults showed an association between HL and lower cognitive performance in females only. In the present study, we examined the effects of sex and hearing on cognition in individuals with mild cognitive impairment (MCI). We predicted that females with HL would be more likely to show poorer performance on the cognitive measures compared to females with normal hearing (NH), while cognitive performance in males would not depend on hearing. We further predicted that these auditory-cognitive associations would not depend on test modality, and would thus be observed in females for both auditory and visual tests. Design:  Participants were 101 older adults with amnestic MCI (M = 71 years, 45% females) in the Canadian Consortium on Neurodegeneration in Aging (CCNA) COMPASS-ND study. Performance on the Montreal Cognitive Assessment (MoCA), Rey Auditory Verbal Learning (RAVLT), and Brief Visuospatial Memory Test-Revised (BVMT-R) was analyzed to investigate sex-related differences and/or hearing-related differences. Participants were categorized as having NH or HL using two different measures: pure-tone hearing screening results (normal based on a pure-tone threshold < 25 dB HL at 2000 Hz in the worse ear) and speech-in-noise speech reception thresholds (SRTs; normal < −10 dB SNR on the Canadian Digit Triplet Test [CDTT]). Results:  Males and female groups did not differ in age, years of education, or other relevant covariates. Yet, females with better hearing on either pure-tone or speech-in-noise measures outperformed their worse hearing counterparts on the MoCA total score. Additionally, females with better hearing were more likely to recall several words on the MoCA delayed recall trial relative to those with worse hearing. Females with NH showed significant correlations between CDTT SRTs and both MoCA and RAVLT scores, while no correlations were observed in males. In contrast, males but not females showed an effect of hearing group on BVMT-R test status. Conclusions:  There were sex-specific differences in auditory-cognitive associations in individuals with MCI. These associations were mostly observed in females and on auditory tests. Potential mechanisms and implications are discussed