The Impact of Type 2 Diabetes on Peripheral and Cerebral Hemodynamic Responses to Active Stand.

BACKGROUND: Although type 2 diabetes mellitus (T2DM) is an established risk factor for cognitive impairment, the underlying mechanisms remain poorly explored. One potential mechanism may be through effects of T2DM on cerebral perfusion. The current study hypothesized that T2DM is associated with altered peripheral and central hemodynamic responses to orthostasis, which may in turn be associated with cognitive impairment in T2DM. METHODS: A novel use of function-on-scalar regression, which allows the entire hemodynamic response curve to be modeled, was employed to assess the association between T2DM and hemodynamic responses to orthostasis. Logistic regression was used to assess the relationship between tissue saturation index (TSI), T2DM, and cognitive impairment. All analyses used cross-sectional data from Wave 3 of The Irish Longitudinal Study on Ageing (TILDA). RESULTS: Of 2 984 older adults (aged 64.3 ±â€…8.0; 55% female), 189 (6.3%) had T2DM. T2DM was associated with many features that are indicative of autonomic dysfunction including a blunted peak heart rate and lower diastolic blood pressure. T2DM was associated with reduced TSI and also with greater odds of impaired performance on the Montreal Cognitive Assessment (odds ratio [OR]: 1.62; confidence interval [CI: 1.07, 2.56]; p = .019). Greater TSI was associated with lower odds of impaired performance (OR: 0.90, CI [0.81-0.99]; p = .047). CONCLUSIONS: T2DM was associated with impaired peripheral and cerebral hemodynamic responses to active stand. Both T2DM and reduced cerebral perfusion were associated with impaired cognitive performance. Altered cerebral perfusion may represent an important mechanism linking T2DM and adverse brain health outcomes in older adults.

Safety and feasibility of transcutaneous vagus nerve stimulation in mild cognitive impairment: VINCI-AD study protocol.

BACKGROUND: Over 55 million adults are living with dementia globally, which is projected to reach 157 million by 2050. Mild cognitive impairment (MCI), a syndrome of memory impairment with intact activities of daily living, may precede dementia by several years. Around 5-15% of individuals with MCI convert to dementia annually. Novel treatments which delay progression of MCI to dementia are urgently needed. Transcutaneous vagal nerve stimulation (tVNS) is a non-invasive neuromodulation technique that targets the vagus nerve. Importantly, tVNS has been shown to improve cognition in healthy volunteers, but has not been extensively examined as a potential therapeutic approach in MCI. VINCI-AD will examine the safety and feasibility of tVNS in older adults with MCI. DESIGN: VINCI-AD is an investigator-led, single-site, single-blind, sham-controlled crossover pilot study which aims to assess the safety and feasibility of tVNS in 40 participants with amnestic MCI. All participants will attend for three consecutive study visits during which they will be randomised to receive no stimulation (baseline), active tVNS stimulation (stimulation at cymba conchae of left ear) or sham tVNS stimulation (at earlobe). Safety will be primarily assessed by ascertainment of adverse events. Further safety assessment will examine the impact of acute tVNS on subjective (orthostatic symptoms), peripheral (finometry-based blood pressure) and central (assessed via Near Infrared Spectroscopy [NIRS]) haemodynamic responses to active stand. Feasibility will be determined using a custom-designed occupational assessment of device usability. Exploratory secondary analysis in VINCI-AD will examine the potential impact of acute tVNS on associative memory, spatial memory and inhibitory control to inform sample size estimates for future trials of tVNS in older adults with MCI. DISCUSSION: VINCI-AD will report on the safety (adverse events/haemodynamic responses to active stand) and feasibility of tVNS as a potential therapeutic option in MCI. Detailed reporting of study eligibility and completion rates will be reported. Exploratory analysis will examine the potential cognitive benefits of acute tVNS on cognitive function in MCI to report potential effect sizes that may inform future clinical trials in this cohort. TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT05514756 . Trial Registration Number NCT05514756 (24th August 2022 for this protocol, version 1.0.).

Cerebral Oxygenation Responses to Standing in Young Patients with Vasovagal Syncope.

Vasovagal syncope (VVS) is common in young adults and is attributed to cerebral hypoperfusion. However, during active stand (AS) testing, only peripheral and not cerebral hemodynamic responses are measured. We sought to determine whether cerebral oxygenation responses to an AS test were altered in young VVS patients when compared to the young healthy controls. A sample of young healthy adults and consecutive VVS patients attending a Falls and Syncope unit was recruited. Continuous beat-to-beat blood pressure (BP), heart rate, near-infrared spectroscopy (NIRS)-derived tissue saturation index (TSI), and changes in concentration of oxygenated/deoxygenated Δ[O2Hb]/Δ[HHb] hemoglobin were measured. BP and NIRS-derived features included nadir, peak, overshoot, trough, recovery rate, normalized recovery rate, and steady-state. Multivariate linear regression was used to adjust for confounders and BP. In total, 13 controls and 27 VVS patients were recruited. While no significant differences were observed in the TSI and Δ[O2Hb], there was a significantly smaller Δ[HHb] peak-to-trough and faster Δ[HHb] recovery rate in VVS patients, independent of BP. A higher BP steady-state was observed in patients but did not remain significant after multiple comparison correction. Young VVS patients demonstrated a similar cerebral circulatory response with signs of altered peripheral circulation with respect to the controls, potentially due to a hyper-reactive autonomic nervous system. This study sets the grounds for future investigations to understand the role of cerebral regulation during standing in VVS.

Asymptomatic orthostatic hypotension and risk of falls in community-dwelling older people.

INTRODUCTION: Many older people with orthostatic hypotension (OH) may not report typical symptoms of dizziness, light-headedness or unsteadiness. However, the relationships between OH and falls in the absence of typical symptoms are not yet established. METHODS: Continuous orthostatic blood pressure (BP) was measured during active stand using a Finometer at Wave 1 of The Irish Longitudinal Study on Ageing in participants aged ≥ 70 years.OH, with and without dizziness, was defined as a sustained drop in systolic BP ≥ 20 and/or diastolic BP ≥ 10 mm Hg at 30, 60 and 90 seconds post-standing.The association between symptoms of dizziness and orthostatic BP was assessed with multi-level mixed-effects linear regression; logistic regression models assessed the longitudinal relationship between OH and falls at 6-year follow-up (Waves 2-5). RESULTS: Almost 11% (n = 934, mean age 75 years, 51% female) had OH, two-thirds of whom were asymptomatic.Dizziness was not associated with systolic BP drop at 30 (ß = 1.54 (-1.27, 4.36); p = 0.256), 60 (ß = 2.64 (-0.19, 5.47); p = 0.476) or 90 seconds (ß = 2.02 (-0.91, 4.95); p = 0.176) after standing in adjusted models.Asymptomatic OH was independently associated with unexplained falls (odds ratio 2.01 [1.11, 3.65]; p = 0.022) but not explained falls (OR 0.93 [0.53, 1.62]; p = 0.797) during follow-up. CONCLUSIONS: Two-thirds of older people with OH did not report typical symptoms of light-headedness. Dizziness or unsteadiness after standing did not correlate with the degree of orthostatic BP drop or recovery. Participants with asymptomatic OH had a significantly higher risk of unexplained falls during follow-up, and this has important clinical implications for the assessment of older people with falls.

Design and Haemodynamic Analysis of a Novel Anchoring System for Central Venous Pressure Measurement.

BACKGROUND/OBJECTIVE: In recent years, treatment of heart failure patients has proved to benefit from implantation of pressure sensors in the pulmonary artery (PA). While longitudinal measurement of PA pressure profoundly improves a clinician's ability to manage HF, the full potential of central venous pressure as a clinical tool has yet to be unlocked. Central venous pressure serves as a surrogate for the right atrial pressure, and thus could potentially predict a wider range of heart failure conditions. However, it is unclear if current sensor anchoring methods, designed for the PA, are suitable to hold pressure sensors safely in the inferior vena cava. The purpose of this study was to design an anchoring system for accurate apposition in inferior vena cava and evaluate whether it is a potential site for central venous pressure measurement. MATERIALS AND METHODS: A location inferior to the renal veins was selected as an optimal site based on a CT scan analysis. Three anchor designs, a 10-strut anchor, and 5-struts with and without loops, were tested on a custom-made silicone bench model of Vena Cava targeting the infra-renal vena cava. The model was connected to a pulsatile pump system and a heated water bath that constituted an in-vitro simulation unit. Delivery of the inferior vena cava implant was accomplished using a preloaded introducer and a dilator as a push rod to deploy the device at the target area. The anchors were subjected to manual compression tests to evaluate their stability against dislodgement. Computational Fluid Dynamics (CFD) analysis was completed to characterize blood flow in the anchor's environment using pressure-based transient solver. Any potential recirculation zones or disturbances in the blood flow caused by the struts were identified. RESULTS: We demonstrated successful anchorage and deployment of the 10-strut anchor in the Vena Cava bench model. The 10-strut anchor remained stable during several compression attempts as compared with the other two 5-strut anchor designs. The 10-strut design provided the maximum number of contact points with the vessel in a circular layout and was less susceptible to movement or dislodgement during compression tests. Furthermore, the CFD simulation provided haemodynamic analysis of the optimum 10-strut anchor design. CONCLUSIONS: This study successfully demonstrated the design and deployment of an inferior vena cava anchoring system in a bench test model. The 10-strut anchor is an optimal design as compared with the two other 5-strut designs; however, substantial in-vivo experiments are required to validate the safety and accuracy of such implants. The CFD simulation enabled better understanding of the haemodynamic parameters and any disturbances in the blood flow due to the presence of the anchor. The ability to place a sensor technology in the vena cava could provide a simple and minimally invasive approach for heart failure patients.

"The Wandering Nerve Linking Heart and Mind" - The Complementary Role of Transcutaneous Vagus Nerve Stimulation in Modulating Neuro-Cardiovascular and Cognitive Performance.

The vagus nerve is the longest nerve in the human body, providing afferent information about visceral sensation, integrity and somatic sensations to the CNS via brainstem nuclei to subcortical and cortical structures. Its efferent arm influences GI motility and secretion, cardiac ionotropy, chonotropy and heart rate variability, blood pressure responses, bronchoconstriction and modulates gag and cough responses via palatine and pharyngeal innervation. Vagus nerve stimulation has been utilized as a successful treatment for intractable epilepsy and treatment-resistant depression, and new non-invasive transcutaneous (t-VNS) devices offer equivalent therapeutic potential as invasive devices without the surgical risks. t-VNS offers exciting potential as a therapeutic intervention in cognitive decline and aging populations, classically affected by reduced cerebral perfusion by modulating both limbic and frontal cortical structures, regulating cerebral perfusion and improving parasympathetic modulation of the cardiovascular system. In this narrative review we summarize the research to date investigating the cognitive effects of VNS therapy, and its effects on neurocardiovascular stability.

Increased multimorbidity is associated with impaired cerebral and peripheral hemodynamic stabilization during active standing.

BACKGROUND: Age-related morbidities and frailty are associated with impaired blood pressure (BP) and heart rate (HR) recovery after standing. Here we investigate how multimorbidity affects cerebral and peripheral hemodynamics during standing in a large sample of older patients. METHODS: Patients were recruited from a national Falls and Syncope Unit. They underwent an active stand test (5-10 min lying +3 min standing) with monitoring of continuous BP, HR, total peripheral resistance (TPR), stroke volume (SV), and a near-infrared spectroscopy (NIRS) derived cerebral tissue saturation index (TSI). A multimorbidity count was derived from a 26-item list of conditions. Features derived from the signals included: nadir, overshoot, value at 30 s, steady-state and recovery rate. Robust linear regression was used to assess the association between multimorbidity, TSI and peripheral hemodynamics while correcting for covariates. A p-value <0.05 was considered statistically significant. RESULTS: Multimorbidity was associated with poorer recovery of TSI at 30 s after standing (ß: -0.15, CI:[-0.25-0.06], p = 0.009) independent of all peripheral hemodynamics. Impaired diastolic BP (DBP) recovery at 30s (ß:-1.34, CI:[-2.29-0.40], p = 0.032), DBP steady-state (ß:-1.18, CI:[-2.04-0.32], p = 0.032), TPR overshoot-to-nadir difference (ß:-0.041, CI:[-0.070-0.013], p = 0.045), and SV at 30s (ß:1.30, CI:[0.45 2.15], p = 0.027) were also associated with increasing multimorbidity. After sex stratification, only females demonstrated impaired TSI with multimorbidity at overshoot (ß: -0.19, CI: [-0.32 -0.07], p = 0.009), 30 s (ß: -0.22 [-0.35-0.10], p = 0.005) and steady-state (ß: -0.20, CI:[-0.35-0.04], p = 0.023), independent of peripheral hemodynamics. CONCLUSIONS: Transient cerebral oxygenation and peripheral hemodynamic responses are impaired with multimorbidity (frailty) in older patients, particularly in females. This study demonstrates the feasibility of using NIRS in this clinical context and may inform the development of clinical management strategies targeting both cerebral oxygenation and blood pressure impairments in patients with faints and falls.

Impaired autonomic function after incomplete revascularisation.

INTRODUCTION: Incomplete cardiac revascularisation (ICR) assessed by residual SYNTAX score (rSs) is associated with increased 5-year mortality. Furthermore, in the general population, our group has demonstrated that impaired autonomic function determined by heart rate recovery time between 10 and 20 s (HRR10-20) following an active stand is associated with increased all-cause mortality. PURPOSE: We hypothesised that ICR would be associated with impaired autonomic function determined by HRR10-20. METHODS: After ethical approval and informed consent, consecutive patients attending cardiac rehabilitation in a tertiary referral centre were enrolled. All patients had percutaneous coronary revascularisation. During an active stand, real-time heart rate, blood pressure and ECG recordings were taken using non-invasive digital photoplethysmography and HRR10-20 determined. Assessment of autonomic function was performed by determining speed of HRR10-20 post-orthostatic challenge.Patients with an rSs >0 were considered incompletely revascularised and those with an rSs of 0 fully revascularised. Demographic data were recorded and statistical analysis performed. RESULTS: Patients (n=53) comprised those with complete revascularisation (CR) (n=37) and ICR (n=16). In the ICR group, mean rSs was 9.4.HRR10-20 was impaired in the ICR group (-3±0.60) compared with the CR cohort (-6.56±0.52) (p<0.0001). Completeness of revascularisation was strongly associated with HRR10-20 (Pearson's correlation coefficient 0.529; p<0.0001). Baseline demographics did not differ significantly. Use of rate-limiting medication was similar between cohorts (beta blockers, calcium channel blockers, ivabradine). CONCLUSIONS: Our data confirm significant correlation between ICR and impaired autonomic function determined by speed of heart rate recovery. Thus, determining autonomic dysfunction post-ICR may identify those at increased mortality risk.

Fatigue following COVID-19 infection is not associated with autonomic dysfunction.

BACKGROUND: The long-term clinical and physiological consequences of COVID-19 infection remain unclear. While fatigue has emerged as a common symptom following infection, little is known about its links with autonomic dysfunction. SARS-CoV-2 is known to infect endothelial cells in acute infection, resulting in autonomic dysfunction. Here we set out to test the hypothesis that this results in persistent autonomic dysfunction and is associated with post-COVID fatigue in convalescent patients. METHODS: We recruited 20 fatigued and 20 non-fatigued post-COVID patients (median age 44.5 years, 36/40 (90%) female, median time to follow up 166.5 days). Fatigue was assessed using the Chalder Fatigue Scale. These underwent the Ewing's autonomic function test battery, including deep breathing, active standing, Valsalva manoeuvre and cold-pressor testing, with continuous electrocardiogram and blood pressure monitoring, as well as near-infrared spectroscopy-based cerebral oxygenation. 24-hour ambulatory blood pressure monitoring was also conducted, and patients completed the generalised anxiety disorder-7 questionnaire. We assessed between-group differences in autonomic function test results and used unadjusted and adjusted linear regression to investigate the relationship between fatigue, anxiety, and autonomic test results. RESULTS: We found no pathological differences between fatigued and non-fatigued patients on autonomic testing or on 24-hour blood pressure monitoring. Symptoms of orthostatic intolerance were reported by 70% of the fatigued cohort at the time of active standing, with no associated physiological abnormality detected. Fatigue was strongly associated with increased anxiety (p <0.001), with no patients having a pre-existing diagnosis of anxiety. CONCLUSIONS: These results demonstrate the significant burden of fatigue, symptoms of autonomic dysfunction and anxiety in the aftermath of COVID-19 infection, but reassuringly do not demonstrate pathological findings on autonomic testing.

Systemic and cerebral circulatory adjustment within the first 60 s after active standing: An integrative physiological view.

Transient cardiovascular and cerebrovascular responses within the first minute of active standing provide the means to assess autonomic, cardiovascular and cerebrovascular regulation using a real-world everyday stimulus. Traditionally, these responses have been used to detect autonomic dysfunction, and to identify the hemodynamic correlates of patient symptoms and attributable causes of (pre)syncope and falls. This review addresses the physiology of systemic and cerebrovascular adjustment within the first 60 s after active standing. Mechanical factors induced by standing up cause a temporal mismatch between cardiac output and vascular conductance which leads to an initial blood pressure drops with a nadir around 10 s. The arterial baroreflex counteracts these initial blood pressure drops, but needs 2-3 s to be initiated with a maximal effect occurring at 10 s after standing while, in parallel, cerebral autoregulation buffers these changes within 10 s to maintain adequate cerebral perfusion. Interestingly, both the magnitude of the initial drop and these compensatory mechanisms are thought to be quite well-preserved in healthy aging. It is hoped that the present review serves as a reference for future pathophysiological investigations and epidemiological studies. Further experimental research is needed to unravel the causal mechanisms underlying the emergence of symptoms and relationship with aging and adverse outcomes in variants of orthostatic hypotension.

Orthostatic Hypotension, Cardiovascular Outcomes, and Adverse Events: Results From SPRINT.

Orthostatic hypotension (OH) is frequently observed with hypertension treatment, but its contribution to adverse outcomes is unknown. The SPRINT (Systolic Blood Pressure Intervention Trial) was a randomized trial of adults, age ≥50 years at high risk for cardiovascular disease with a seated systolic blood pressure (BP) of 130 to 180 mm Hg and a standing systolic BP ≥110 mm Hg. Participants were randomized to a systolic BP treatment goal of either <120 or <140 mm Hg. OH was defined as a drop in systolic BP ≥20 or diastolic BP ≥10 mm Hg 1 minute after standing from a seated position. We used Cox models to examine the association of OH with cardiovascular disease or adverse study events by randomized BP goal. During the follow-up period (median 3years), there were 1170 (5.7%) instances of OH among those assigned a standard BP goal and 1057 (5.0%) among those assigned the intensive BP goal. OH was not associated with higher risk of cardiovascular disease events (primary outcome: hazard ratio 1.06 [95% CI, 0.78-1.44]). Moreover, OH was not associated with syncope, electrolyte abnormalities, injurious falls, or acute renal failure. OH was associated with hypotension-related hospitalizations or emergency department visits (hazard ratio, 1.77 [95% CI, 1.11-2.82]) and bradycardia (hazard ratio, 1.94 [95% CI, 1.19-3.15]), but these associations did not differ by BP treatment goal. OH was not associated with a higher risk of cardiovascular disease events, and BP treatment goal had no effect on OH's association with hypotension and bradycardia. Symptomless OH during hypertension treatment should not be viewed as a reason to down-titrate therapy even in the setting of a lower BP goal. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT01206062.

A practical guide to active stand testing and analysis using continuous beat-to-beat non-invasive blood pressure monitoring.

PURPOSE: The average adult stands approximately 50-60 times per day. Cardiovascular responses evoked during the first 3 min of active standing provide a simple means to clinically assess short-term neural and cardiovascular function across the lifespan. Clinically, this response is used to identify the haemodynamic correlates of patient symptoms and attributable causes of (pre-)syncope, and to detect autonomic dysfunction, variants of orthostatic hypotension, postural orthostatic tachycardia syndrome and orthostatic hypertension. METHODS: This paper provides a set of experience/expertise-based recommendations detailing current state-of-the-art measurement and analysis approaches for the active stand test, focusing on beat-to-beat BP technologies. This information is targeted at those interested in performing and interpreting the active stand test to current international standards. RESULTS: This paper presents a practical step-by-step guide on (1) how to perform active stand measurements using beat-to-beat continuous blood pressure measurement technologies, (2) how to conduct an analysis of the active stand response and (3) how to identify the spectrum of abnormal blood pressure and heart rate responses which are of clinical interest. CONCLUSION: Impairments in neurocardiovascular control are an attributable cause of falls and syncope across the lifespan. The simple active stand test provides the clinician with a powerful tool for assessing individuals at risk of such common disorders. However, its simplicity belies the complexity of its interpretation. Care must therefore be taken in administering and interpreting the test in order to maximise its clinical benefit and minimise its misinterpretation.

Hemodynamic Mechanisms Underlying Initial Orthostatic Hypotension, Delayed Recovery and Orthostatic Hypotension.

OBJECTIVES: Continuous noninvasive blood pressure (BP) measurement enables us to observe rapid changes in BP and to study underlying hemodynamic mechanisms. This study aimed to gain insight into the pathophysiological mechanisms underlying short-term orthostatic BP recovery patterns in a real-world clinical setting with (pre)syncope patients. SETTING AND PARTICIPANTS: In a prospective cohort study, the active lying-to-standing test was performed in suspected (pre)syncope patients in the emergency department with continuous noninvasive finger arterial BP measurement. MEASURES: Changes in systolic BP, cardiac output (CO), and systemic vascular resistance (SVR) were studied in normal BP recovery, initial orthostatic hypotension, delayed BP recovery, and sustained orthostatic hypotension. RESULTS: In normal recovery (n = 47), ΔBP at nadir was -24 (23) mmHg, with a CO change of +10 (21%) and SVR of -23 (21%). In initial orthostatic hypotension (n = 7) ΔBP at nadir was -49 (17) mmHg and CO and SVR change was -5 (46%) and -29 (58%), respectively. Delayed recovery (n = 12) differed significantly from normal recovery 30 seconds after standing, with a ΔBP of -32 (19) vs 1 (16) mmHg, respectively. Delayed recovery was associated with a significant difference in SVR changes compared to normal recovery, -17 (26%) vs +4 (20%), respectively. There was no difference in CO changes. In sustained orthostatic hypotension (n = 16), ΔBP at 180 seconds after standing was -39 (21) mmHg, with changes in CO of -16 (31%) and SVR of -9 (20%). CONCLUSIONS/IMPLICATIONS: Hemodynamic patterns following active standing are heterogeneous and differ across orthostatic BP recovery patterns, suggesting that volume status, medication use, and autonomic dysfunction should all be taken into account when evaluating these patients. Moreover, results suggest that a delayed BP recovery is associated with an impaired increase in SVR in a significant proportion of individuals, implying that physicians treating older adults with hypertension should consider the possible negative effect of intensive hypertension treatment on initial orthostatic blood pressure control.

Impairments in Hemodynamic Responses to Orthostasis Associated with Frailty: Results from The Irish Longitudinal Study on Ageing (TILDA).

OBJECTIVES: To characterize the relationships between orthostatic blood pressure (BP) and heart rate recovery and frailty in an older population. DESIGN: Cross-sectional study. SETTING: Two health centers in the Republic of Ireland. PARTICIPANTS: The Irish Longitudinal Study on Ageing participants aged 50 and older (N=4,334). MEASUREMENTS: Continuous noninvasive BP responses during active standing were captured using digital photoplethysmography. Frailty was assessed using the Cardiovascular Health Study criteria. Linear mixed models (random intercept) with piecewise splines were used to model differences in rate of BP and heart rate recovery. RESULTS: Ninety-three (2.2%) participants were frail, and 1,366 (31.5%) were prefrail. Adjusting for age and sex, frailty was associated with a slower rate of systolic BP recovery 10 to 20 seconds after standing (frailty by time = -4.12, 95% confidence interval=-5.53 to -2.72) and with subsequent deficits in BP 20 to 50 seconds after standing. Similar results were seen for diastolic BP and heart rate. Further adjustment for health behaviors, morbidities, and medications reduced, but did not attenuate, these associations. Of the 5 frailty criteria, only slow gait speed was consistently related to impaired BP and heart rate responses in the full model. CONCLUSION: Frailty, particularly slow gait speed, was associated with slower rate of BP and heart rate recovery after active standing. Impaired BP recovery may be a marker of physiological frailty.

Quantitative Ultrasound of the Mandible as a Novel Screening Approach for Osteoporosis.

This study used an axial transmission quantitative ultrasound (QUS) device to assess mandibular bone strength. The aim of the study was first to establish the precision and repeatability of the axial transmission QUS measurement for a range of mandibular anatomic sites, and second to investigate the ability of the modality to differentiate between osteoporotic subjects and a control group. Three groups of adult Caucasian women were recruited: (1) healthy premenopausal women (n = 26), (2) healthy postmenopausal women (n = 48), and (3) women with osteoporosis (n = 53). Subjects were excluded from groups 1 and 2 if they had any pre-existing bone conditions. Speed of sound (SOS) measurements were taken from the mandible using an OmniSense multisite QUS device. Group 3 had dual-energy X-ray absorptiometry scans of the lumbar spine and femur. The most suitable site on the mandible was determined by repeat SOS measurements in 10 healthy premenopausal subjects, at 5 different sites. The parasymphysis site had the lowest root mean squared coefficient of variation at 0.74%, and was chosen as the most suitable site for mandibular SOS measurements. Group 1 and group 2 had significantly higher mean SOS measurements than the osteoporotic subjects (group 3), with means of 3683 m/s (210), 3514 m/s (221), and 3312 m/s (264), respectively. A 1-way analysis of variance confirmed a statistically significant difference between mean SOS measurements from the 3 groups (p < 0.0001). Axial transmission QUS of the mandible can differentiate between subjects with osteoporosis and a healthy control group, and shows potential for use as a screening tool for osteoporosis.

Time to Refocus Assessment of Vision in Older Adults? Contrast Sensitivity but Not Visual Acuity Is Associated With Gait in Older Adults.

BACKGROUND: The relationship between measures of visual function and gait related risk factors for falls is unclear. In this study, we examine the relationship between visual function (visual acuity [VA] and contrast sensitivity [CS] at multiple spatial frequencies) and quantitative spatiotemporal gait, using a large, nationally representative sample of community dwelling older adults. METHODS: Participants aged 50 and over were recruited as part of The Irish Longitudinal Study on Ageing (TILDA). VA was measured with the LogMAR chart according to the Early Treatment of Diabetic Retinopathy Study protocol. CS was measured at five spatial frequencies ranging 1.5 to 18 cycles per degree (cpd) using the Functional Acuity Contrast Test. Gait speed, cadence, and stride length were measured using the GAITRite system. Multivariate analysis examined associations between gait and visual performance parameters adjusting for socioeconomic, physical, cognitive, and mental health covariates. RESULTS: Data from 4,678 participants were analyzed (age 61.7 ± 8.3 years, 54.1% woman). Poorer CS at 1.5 cpd and 3.0 cpd (low spatial frequency) was independently associated with decreased stride length (CS at 1.5 cpd: ß = .031; p = .001 and CS at 3.0 cpd: ß = .020; p = .001) but not cadence or gait speed. There was no evidence of an association between VA and any of the gait variables considered (p > .05). CONCLUSION: Reduced CS, at low spatial frequencies, is independently associated with shorter stride length, while VA is not associated with any gait measures. This evidence suggests that it may be necessary to consider refocus of the assessment of vision to include the most appropriate measures.

Impaired Orthostatic Blood Pressure Recovery Is Associated with Unexplained and Injurious Falls.

OBJECTIVES: Cardiovascular disorders are recognized as important modifiable risk factors for falls. However, the association between falls and orthostatic hypotension (OH) remains ambivalent, particularly because of poor measurement methods of previous studies. The goal was to determine for the first time to what extent OH (and variants) are risk factors for incident falls, unexplained falls (UF), injurious falls (IF) and syncope using dynamic blood pressure (BP) measurements in a population study. DESIGN: Nationally representative longitudinal cohort study-The Irish Longitudinal Study on Ageing (TILDA)-wave 1 (2009-2011) with 2-year follow-up at wave 2 (2012-2013). SETTING: Community-dwelling adults. PARTICIPANTS: Four thousand one hundred twenty-seven participants were randomly sampled from the population of older adults aged ≥50 years resident in Ireland. MEASUREMENTS: Continuous BP recordings measured during active stands were analyzed. OH and variants (initial OH and impaired orthostatic BP stabilization OH(40)) were defined using dynamic BP measurements. Associations with the number of falls, UF, IF, and syncope reported 2 years later were assessed using negative binomial and modified Poisson regression as appropriate. RESULTS: Participants had a mean age of 61.5 (8.2) years (54.2% female). OH(40) was associated with increased relative risk of UF (RR: 1.52 95% CI: 1.03-2.26). OH was associated with all-cause falls (IRR: 1.40 95% CI: 1.01-1.96), UF(RR: 1.81 95% CI: 1.06-3.09), and IF(RR: 1.58 95% CI: 1.12-2.24). IOH was not associated with any outcome. CONCLUSION: With the exception of initial orthostatic hypotension, beat-to-beat measures of impaired orthostatic BP recovery (delayed recovery OH (40) or sustained orthostatic hypotension OH) are independent risk factors for future falls, unexplained falls, and injurious falls.

The accuracy of anatomical landmarks for locating the carotid sinus.

BACKGROUND: carotid sinus massage (CSM) is a valuable clinical test for carotid sinus syndrome (CSS) and relies on accurately locating the carotid sinus (CS). OBJECTIVE: in this study, we sought to examine the accuracy of using anatomical landmarks for locating the CS. METHODS: consecutive patients (n = 20) were recruited prospectively. Two clinicians, trained in CSM, were asked to locate the CS using anatomical landmarks. A point on the skin overlying the CS was then marked by a vascular technician using ultrasound. Accuracy of techniques was compared using intra-class correlation coefficients and Bland-Altman statistics. RESULTS: anatomical landmarks underestimated the CS location by 1.5 ± 1.3 cm. Error extremes ranged from 4 cm below to 2 cm above CS using anatomical landmarks. A moderate correlation between ultrasound and anatomical landmarks was found, r = 0.371 (P = 0.031). CONCLUSION: this is the first study to characterise the accuracy of standard anatomical landmarks used in CSM. Results suggest that the point of maximal pulsation has the lowest associated error. Future work should examine CSM yield across this and a range of other methodological factors.

Social Disadvantage and Social Isolation Are Associated With a Higher Resting Heart Rate: Evidence From The Irish Longitudinal Study on Ageing.

OBJECTIVES: A high resting heart rate (RHR) represents a major risk factor for cardiovascular disease and individuals from poorer backgrounds have a higher RHR compared with their more advantaged peers. This study investigates the pathways through which low socioeconomic status (SES) contributes to a higher RHR. METHOD: The sample involved data for 4,888 respondents who were participating in the first wave of The Irish Longitudinal Study on Ageing. Respondents completed a detailed interview at home and underwent a 5-min baseline electrocardiograph recording as part of a clinic-based health assessment. SES was indexed using household income. RESULTS: The mean difference in RHR between those at polarized ends of the income distribution was 2.80 beats per minute (bpm) (95% CI = 1.54, 4.06; p < .001), with the magnitude of the socioeconomic differential being greater for men (4.15 bpm; 95% CI = 2.18, 6.12; p < .001) compared with women (1.57 bpm; 95% CI = 0.04, 3.10; p < .05). Psychosocial factors including social network size and loneliness accounted for a sizeable proportion of the socioeconomic differential in RHR, particularly among men. DISCUSSION: The finding that poorer people have a higher RHR reinforces the need for additional research exploring the pathways through which social inequalities are translated into biological inequalities.