Cortical inhibition assessed using paired-pulse TMS-EEG is increased in older adults

Background

Alterations in inhibitory processes mediated by gamma-aminobutyric acid type B (GABA_B) receptors may contribute to age-related functional impairments. However, investigation of these circuits using conventional paired-pulse transcranial magnetic stimulation (TMS) at long interstimulus intervals (～100-200ms) have produced conflicting results in older adults, possibly due to the indirect nature of the TMS motor evoked potential (MEP).

Association of masticatory performance with age, gender, number of teeth, occlusal force and salivary flow in Japanese older adults: is ageing a risk factor for masticatory dysfunction?

Objective

In general, ageing is a risk factor for sensory and motor deterioration, with the rate of decline varying amongst individuals. Concerning masticatory function, missing teeth along with oral disease seem to accelerate the dysfunction. Here, we aimed to confirm whether masticatory dysfunction by ageing is inevitable. This study investigated the effect of age, gender, number of natural teeth, occlusal force and salivary flow on the masticatory performance in a large sample of elderly adults.

Design

The study sample consisted of 1288 independently living people aged 60–84 years. Masticatory performance was determined by the comminuted particles of test food. Bilateral maximal occlusal force in the intercuspal position was measured with pressure sensitive sheets. Stimulated whole saliva was collected.

Results

Masticatory performance was significantly correlated to age, number of residual teeth, occlusal force and stimulated salivary flow rate by Pearson's correlation test. The multiple linear regression analysis showed that, with other variables controlled, masticatory performance was significantly associated with the number of residual teeth (β = 0.456, P < 0.001), occlusal force (β = 0.244, P < 0.001) and stimulated salivary flow rate (β = 0.069, P = 0.003). Age was not related to masticatory performance (β = −0.007, P = 0.753).

Conclusions

Declines in the number of residual teeth, occlusal force and salivary flow were associated with a reduction of masticatory performance in older adults. If tooth loss is not considered as an attribute of physiological ageing, then ageing by itself may not be a risk factor for masticatory dysfunction.     

The impact of social support,unit cohesion,and trait resilience on PTSD in treatment-seeking military personnel with PTSD: The role of posttraumatic cognitions

BackgroundThe personal resources of social support, unit cohesion, and trait resilience have been found to be associated with posttraumatic stress disorder (PTSD) severity among military personnel. However, the underlying mechanisms of these relationships are unclear. We hypothesized that negative posttraumatic cognitions, which are associated with PTSD, mediate the relationships between these personal resources and PTSD.MethodsThe relationship between PTSD symptom severity and a latent factor comprised of social support, unit cohesion, and trait resilience was evaluated using cross-sectional data from 366 treatment-seeking active duty military personnel with PTSD following deployments to or near Iraq or Afghanistan. Structural equation modeling (SEM) was used to test whether posttraumatic cognitions mediated this relationship.ResultsThe SEM model indicated that (1) a robust latent variable named personal resources (indicated by social support, unit cohesion, and trait resilience) was negatively associated with PTSD severity; (2) personal resources were negatively associated with negative posttraumatic cognitions; (3) negative posttraumatic cognitions fully mediated the association between personal resources and PTSD severity. The final SEM mediation model showed a highly satisfactory fit [χ² (22) = 16.344, p = 0.798; χ²/df = 0.743; CFI = 1; RMSEA = 0.000].ConclusionsThese findings suggest that among active duty military personnel seeking treatment for PTSD, personal resources (social support, unit cohesion, and trait resilience) may mitigate PTSD severity by reducing negative posttraumatic cognitions.     

轻度认知功能障碍筛查量表研究进展

轻度认知功能障碍(MCI)患者是老年性痴呆(SD)的高危人群。痴呆的发病率随着世界人口老龄化的加剧而迅速攀升,中晚期痴呆的治疗效果欠佳,而对MCI的早期筛查和干预可延缓痴呆病程的进展。文中对国内外MCI筛查量表的研究分析得出,记忆与执行筛查(MES)量表、Dem Tect、中文修订版轻度认知功能障碍测试(CAMCI)和阿尔茨海默病调查问卷(AQ)4种筛查量表可作为MCI筛查的首选筛查量表。     

The long-term association of adverse childhood experiences with C-reactive protein and hair cortisol: Cumulative risk versus dimensions of adversity

BackgroundExposure to adverse childhood experiences (ACEs) may lead to stress-induced upregulation of inflammatory and neuroendocrine processes. However, it remains unclear whether such effects persist into later life, and which dimensions of ACEs might have the strongest impact on these biological mechanisms. Therefore, this study investigated the effects of ACEs on C-reactive protein (CRP) and hair cortisol in a large sample of older adults, distinguishing between cumulative exposure and dimensions of ACEs.MethodsWe utilised data from the English Longitudinal Study of Ageing. ACEs were assessed through retrospective reports at wave 3(2006/07). CRP (N = 4198) was measured at waves 4(2008/09) and 6(2012/13), and hair cortisol (N = 3357) at wave 6. The effects of ACEs cumulative exposure were examined using linear and ordinal logistic regression analysis. ACEs dimensions (i.e. threat, household dysfunction, low parental bonding, and loss of an attachment figure) were identified using explorative and confirmatory factor analysis with cross-validation. All analyses were adjusted for relevant confounders.ResultsParticipants with three or more ACEs had higher CRP levels at wave 4 and an elevated risk of high CRP concentrations across waves 4 and 6 compared with those who did not experience any ACEs. The four ACEs dimensions were all positively associated with both CRP outcomes and had similar effect sizes. In contrast, neither the cumulative score nor the dimensions of ACEs were significantly related to hair cortisol. However, there was a positive, yet small, interaction effect between ACEs and age on hair cortisol.ConclusionOlder adults who retrospectively reported three or more ACEs had chronically elevated CRP levels and exhibited a slightly steeper increase in hair cortisol with age. Different dimensions of ACEs had similar associations with the biomarkers.     

Understanding the relationship of perceived social support to post-trauma cognitions and posttraumatic stress disorder

Poor social support in the aftermath of a traumatic event is a well-established risk factor for posttraumatic stress disorder (PTSD) among adult trauma survivors. Yet, a great deal about the relationship between social support and PTSD remains poorly understood. In this study, we analyzed data from 102 survivors of a serious motor vehicle accident (MVA) at 4 weeks (Time 1) and 16 weeks (Time 2) post-MVA. We assessed the role of perceived dyadic social support, positive dyadic interaction, and negative dyadic interaction in the development and maintenance of PTSD. In addition, we examined how these social support constructs work together with negative post-trauma cognitions to affect the maintenance of PTSD. Neither perceived social support nor the quality of social interaction (i.e., positive or negative) was associated with PTSD symptom severity at Time 1. However, among those with elevated PTSD symptom severity at Time 1, greater social support and positive social interaction and lower negative social interaction were each associated with reductions in PTSD symptom severity from Time 1 to Time 2. For social support and negative social interaction, this association ceased to be significant when jointly assessed with negative post-trauma cognitions, suggesting that perceived social support and negative dyadic interaction were associated with maintenance of PTSD symptom severity because of their association with negative post-trauma cognitions. These results provide support to models and treatments of PTSD that emphasize the role of negative post-trauma cognitions in maintenance of PTSD.     

Ageing affects event-related potentials and brain oscillations: a behavioral and electrophysiological study using a haptic recognition memory task

In this electrophysiological study, we investigated the effects of ageing on recognition memory for three-dimensional (3D) familiar objects presented to touch in a continuous paradigm. To examine changes in event-related potentials (ERPs) and brain oscillations, we recorded the EEGs of healthy groups of young (n = 14; mean age = 32.3 years) and older adults (n = 14; mean age = 65.1). Both age groups exhibited similar accuracy and exploration times when making old–new judgments. Young and older participants showed a marginally significant ERP old/new effect widely distributed over the scalp between 550–750 ms. In addition, the elders showed lower amplitude than younger participants within 1200–1500 ms. There were age-related differences in brain oscillations as measured by event-related spectral perturbation (ERSP). Older adults showed greater alpha and beta power reductions than young participants, suggesting the recruitment of additional neural resources. In contrast, the two age groups showed a reliable old/new effect in the theta band that temporarily overlapped the ERP old/new effect. The present results suggest that despite similar behavioral performance, the young and older adults recruited different neural resources to perform a haptic recognition task.     

Victim into sacrifice: The construction of the old as a symbolic type

Drawing on the conceptual framework of symbolic types, the paper analyses a case study of media presentation of the old in Israel. Being a T.V. based fund raising event, the motif of the role of the elderly as dependent, vulnerable and collective social victims was prominent. The paper argues that this symbolic position construction serves to impart cultural attributes to an unidentifiable phenomenon, while exonerating the non-aged viewer from assuming personal responsibility to his/her kith and kin by means of communal moral absolution. It is also maintained that the symbolic type generated helps to create a barrier between the living and the dead.An earlier version of this paper was presented at the XIIth International Congress of Anthropological and Ethnological Sciences, Zagreb, Yugoslavia, July 24–30, 1988.     

Periodontal histomorphometry and status of aged sheep subjected to ovariectomy, malnutrition and glucocorticoid application

Objective

Ageing, hypogonadism, malnutrition, and the application of glucocorticoids have adverse effects on skeletal homeostasis. Herein we determined to which extent the periodontium undergoes catabolic changes under these conditions in a sheep model.

Methods

Six old sheep with a mean age of 7.5 ± 1.0 years were subjected to ovariectomy, calcium/vitamin D-restricted diet, and intramuscular administration of approximately 2 g methylprednisolone. Six adult sheep with a mean age of 3.8 ± 0.9 years remained untreated and served as controls. First and second premolars of both jaws were subjected to histological analysis. The distances from the gingival margin (GM) and from the alveolar bone crest (ABC) to the cemento-enamel junction (CEJ) were determined. Periodontal attachment was given as the ratio between the dimension of the periodontal ligament and the alveolar bone. Clinical data were collected by counting the number of teeth missing, teeth with gingival recession, and teeth with a probing depth > 4 mm.

Results

We report that distance between GM and CEJ (2.1 ± 1.7 mm and 6.6 ± 2.6 mm maxilla; −0.4 ± 1.4 mm and 3.2 ± 1.5 mm mandible), and between ABC and CEJ (−3.4 ± 1.3 mm and 1.8 ± 2.7 mm maxilla; −3.5 ± 1.1 mm and −0.1 ± 1.4 mm mandible) are significantly lower in test than in control animals. In line with these findings, periodontal attachment was 67% in the maxilla and 86% in the mandible of the test group and almost completely preserved in the control group. Clinical evaluation showed that the overall number of teeth with recessions was significantly higher in the test compared to the control group (4.9 ± 2.4 and 2.3 ± 3.6), but not the number of teeth missing and teeth with a probing depth > 4 mm.

Conclusions

Together these findings suggest that in sheep, the cumulating effects of ageing, hypogonadism, malnutrition and glucocorticoid application can cause substantial catabolic changes of the periodontium.