Function In Older Subjects Research Articles

Left Atrial Enlargement and Reduced Physical Function During Aging

Diastolic dysfunction, often seen with increasing age, is associated with reduced exercise capacity and increased mortality. Mortality rates in older individuals are linked to the development of disability, which may be preceded by functional limitations. The goal of this study was to identify which echocardiographic measures of diastolic function correlate with physical function in older subjects. A total of 36 men and women from the Louisiana Healthy Aging Study, age 62-101 yr, received a complete echocardiographic exam and performed the 10-item continuous-scale physical-functional performance test (CS-PFP-10). After adjustment for age and gender, left atrial volume index (ρ = -0.59; p = .0005) correlated with the total CS-PFP-10 score. Increased left atrial volume index may be a marker of impaired performance of activities of daily living in older individuals.

Tai Chi, arterial compliance, and muscle strength in older adults

Aerobic exercise can alleviate the declines in arterial compliance common in older adults. However, when combined with strength training, aerobic exercise may not reduce arterial compliance. Tai Chi practice has been found to improve muscle strength and cardiopulmonary function in older subjects, but whether or not it improves arterial compliance is not known. The primary aim of this study was to investigate whether Tai Chi practitioners have better arterial compliance and muscle strength. Twenty-nine older Tai Chi practitioners (73.7 ± 4.5 years) and 36 healthy control subjects (71.4 ± 6.6 years) participated in this cross-sectional study. The participants were independent in their daily living activities. They were screened for apparent cardiovascular disease and underwent arterial compliance testing and isokinetic knee muscle strength testing at 30°/s. Tai Chi practitioners showed significantly better haemodynamic parameters than the controls as indexed by larger and small artery compliance. They also demonstrated greater eccentric muscle strength in both knee extensors and flexors. The findings of better muscle strength without jeopardizing arterial compliance suggests that Tai Chi could be a suitable exercise for older persons to improve both cardiovascular function and muscle strength.

Abstract 18029: Left Ventricular Systolic Strain in Older Subjects with No Known Cardiac Disease

Introduction: It is known that with increasing age impaired myocardial relaxation increases, while systolic function is preserved. We hypothesize that there is, in fact, subclinical left ventricular (LV) systolic dysfunction in older subjects. We test this hypothesis by assessing LV systolic strain using velocity vector imaging in older subjects with no known cardiac disease. Methods: One-hundred and ninety consecutive subjects with no known cardiac disease had their echocardiograms analyzed by VVI after excluding patients with a left ventricular ejection fraction(LVEF) <55%, grade 2 and above diastolic dysfunction and QRS duration > 120ms. Subjects were divided into 2 groups based on age; older (> 60 years) and younger (< 60 years). Demographic, clinical and echocardiographic data were collected. Time to peak longitudinal and circumferential strain were calculated from apical 4-chamber, 2-chamber and short axis views. The above collected data were compared between groups. Results: The final cohort consisted of 136 subjects (46 were older). Mean age was 55 + 16 years, 32% were female and mean LVEF was 60 + 8%. The older group had a higher LVEF (63 + 9% vs. 59 + 6%; p=0.03), smaller LV diastolic dimension (4.4 + 0.5cm vs. 4.7 + 0.5cm; p<0.01) and higher occurrences of diastolic dysfunction (84% vs. 59%; p<0.01) and hypertension (85% vs. 63%; p=0.02), when compared to the younger group. There were no significant differences in the longitudinal and circumferential strain (even with cut-off ages of 50 or 75 years). Conclusions: Contrary to our hypothesis, older subjects with no known cardiac disease had a better LVEF than their younger counterparts. There were no significant differences in the longitudinal and circumferential myocardial strain between the older and younger groups. Therefore, impaired myocardial relaxation does not appear to have a direct influence on the myocardial contractility or systolic function in older subjects.

Association of Obstructive Sleep Apnea and Auditory Dysfunctions in Older Subjects

Determine the association between obstructive sleep apnea (OSA) and auditory dysfunction in older subjects. Cross-sectional study. Hospital volunteer helpers undergoing questionnaire, morphometry measurement, auditory examinations, and polysomnography between 2008 and 2009. In total, 224 subjects older than 50 years were randomly sampled for above evaluation and testing. The effects of OSA on the peripheral auditory function, represented by averaged pure-tone threshold of low frequencies (PTA-low) and high frequencies (PTA-high), and central auditory function, shown by pitch pattern sequence (PPS scores), were analyzed. The mean ± SD age was 61.2 ± 6.7 years. OSA was confirmed in 6 of 98 women (6.1%) and 28 of 126 men (22.2%). After adjusting for age, gender, and other variables, OSA did not show a significant positive association with PTA-low or PTA-high for all subjects. Conversely, there was a significant negative association between OSA and PPS scores for all subjects, even after adjusting for age, gender, and other variables. When OSA and central obesity together were taken into account in the multivariate linear regression analysis, OSA still showed significant association with PPS score for all subjects. OSA is independently associated with poorer central auditory function in older subjects.

Temporal Relationship between Depressive Symptoms and Cognitive Impairment: The Italian Longitudinal Study on Aging

The temporal relationship between depression and cognitive decline has not been extensively investigated in prospective population-based studies, and most of these have only looked in one direction. We estimated the bidirectional temporal relationship between depressive symptoms and cognitive function in older subjects, excluding subjects with a clinical diagnosis of dementia or mild cognitive impairment (MCI). In a total of 2,963 individuals from the Italian Longitudinal Study on Aging, depressive symptoms, global cognitive function, and episodic memory were measured. Dementia, Alzheimer's disease, vascular dementia, and MCI were classified using current clinical criteria. Depressive symptoms at baseline were associated with an accelerated global cognitive function decline and an accelerated rate of episodic memory delayed recall decline in a 3.5-year follow-up. Finally, an accelerated increase with time of depressive symptoms during the same follow-up period was not associated with global cognitive function and episodic memory (immediate and delayed recall). In older subjects non-cognitively impaired, depressive symptoms at baseline predicted change over time of global cognitive decline and episodic memory delayed recall. Global cognitive function and episodic memory at baseline were not associated with the course of depressive symptoms during the follow-up.

Lungenfunktion im Alter: Brauchen wir neue Referenzwerte?

The structure of our aging population has significantly changed in the last three decades as have also the anthropometric data. Therefore, the question arises as to whether or not the largely accepted reference values for ventilatory lung function, which were suggested by the European Community for Coal and Steel (EGKS), may still be used today, since these values were obtained in the 1960s from subjects in a limited age range. For the elderly, the measured values are deduced by extrapolation beyond the range of reference equations which had been obtained in a different population. Therefore decisions concerning elderly and smaller subjects concerning remuneration due to impaired lung function after industrial exposure on the basis of EGKS values are questionable. We have examined lung function using pneumotachography for recording static lung volumes and flow-volume curves in 176 asymptomatic non-smoking males, aged 20 to 90 years, and correlated the results to the reference values of the EGKS, SAPALDIA and LuftiBus. The age dependence of respiratory parameters (VC, FVC, FEV (1), FEV (1) %FVC, PEF, MEF (75,50,25)) for the healthy subjects can be described with a linear function (y = - m x age + n). The forced expiratory volume in one second, FEV (1), is calculated by FEV (1) = - 0.046 x age + 6.11; r = 0.88. Mean FEV1 for younger subjects was found to be 108 +/- 9.9 % of the EGKS reference values, 105 +/- 13.7 % in the middle-aged group and 97.3 +/- 12.4 % in the older subjects. All measured parameters concerning lung function can be described as linear functions of age which are steeper than those described by the EGKS reference values. The steeper slope in age dependency was also seen in other investigated parameters. The correlation of lung function parameters to height largely follows the EGKS predictions. Measured lung function values of healthy younger and elderly subjects showed a close correlation to the extrapolated reference values of the EGKS. Our results relating to normal lung function justify an extrapolation of the reference equations beyond the common ranges of age while applying the same limitations as described for subjects in the middle-age range. Our results permit an extrapolation of EGKS values beyond the range of the reference values and can be used for the classification of impaired lung function in older subjects. The alternatively discussed reference equations of the SALPADIA Study, of NHANES and partially of the LuftiBus Study are higher, but do not cover all the necessary parameters and/or age ranges. A multicentric study for contemporary reference values should be performed in order to solve the problems concerning valid reference values.

Facilitating skilled right hand motor function in older subjects by anodal polarization over the left primary motor cortex

Healthy ageing is accompanied by limitations in performance of activities of daily living and personal independence. Recent reports demonstrated improvements in motor function induced by noninvasive anodal direct current stimulation (tDCS) of the primary motor cortex (M1) in young healthy adults. Here we tested the hypothesis that a single session of anodal tDCS over left M1 could facilitate performance of right upper extremity tasks required for activities of daily living (Jebsen-Taylor hand function test, JTT) in older subjects relative to Sham in a double-blind cross-over study design. We found (a) significant improvement in JTT function with tDCS relative to Sham that outlasted the stimulation period by at least 30 min, (b) that the older the subjects the more prominent this improvement appeared and (c) that consistent with previous results in younger subjects, these effects were not accompanied by any overt undesired side effect. We conclude that anodal tDCS applied over M1 can facilitate performance of skilled hand functions required for activities of daily living in older subjects.

The tendency to altered perception of airflow resistance in aged subjects might be due mainly to a reduction in diaphragmatic proprioception

Elderly patients with asthma, particularly those above the age of 80 years, appear less able to detect early worsening of their airflow resistance and hence might not take 'rescue' bronchodilator medication promptly. No consistent explanation for the observation has been posited. We hypothesize that deterioration in the sensitivity and accuracy of inspiratory (mainly diaphragmatic) proprioception is a plausible mechanism. This contention is supported by observations that indicate the central role of afferent phrenic nerve fibres arising from mechanoreceptors in diaphragmatic muscle and entheses in the ability to sense changes in intrathoracic pressure and volume. Other sensory afferent sources appear less important in this context because the ability to detect intrathoracic pressure and volume changes is preserved in patients with heart-lung transplants (parenchymal and airway denervation), topically anaesthetized upper airways and spinal cord transection below C4 (intact phrenic function) but not cord transection above C2 (phrenic function absent) if the airways are simultaneously anaesthetized. Further support for the hypothesis comes from demonstration of reduced integrated proprioceptive function in older subjects, such as increased postural sway, reduced ability to judge changes in joint position and slower recovery from eye and hand perturbation. In the context of asthma, the detection of a change in airflow resistance depends mainly on the subconscious detection of a mismatch between the inspiratory effort and the volume change achieved; the resulting discrepancy between length (volume) and tension (muscular effort) is felt as a sensation of obstructed breathing, resulting in greater effort to breath and conscious actions such as self-medication. Our hypothesis proposes that a reduced ability to detect accurately the volume change during tidal breathing delays the sensing of the obstruction in older subjects.

Evidence of preserved endothelial function and vascular plasticity with age

We sought to identify the relationship between shear stimuli and flow-mediated vasodilation and to determine whether small muscle mass exercise training could provoke limb-specific improvements in endothelial function in older subjects. In five young (22 +/- 1 yr old) and six old (71 +/- 2 yr old) subjects, ultrasound Doppler measurements were taken in the arm (brachial artery) and leg (deep and superficial femoral arteries) after suprasystolic cuff occlusion with and without ischemic exercise to evaluate flow-mediated dilation (FMD) in both limbs. Older subjects were reevaluated after 6 wk of single-leg knee extensor exercise training. Before the training, a significant FMD was observed in the arm of young (3 +/- 1%) but not old (1 +/- 1%) subjects, whereas a significant leg FMD was observed in both groups (5 +/- 1% old vs. 3 +/- 1% young). However, arm vasodilation was similar between young and old when normalized for shear rate, and cuff occlusion with superimposed handgrip exercise provoked additional shear, which proportionately improved the FMD response in both groups. Exercise training significantly improved arm FMD (5 +/- 1%), whereas leg FMD was unchanged. However, ischemic handgrip exercise did not provoke additional arm vasodilation after training, which may indicate an age-related limit to shear-induced vasodilation. Together, these data demonstrate that vascular reactivity is dependent on limb and degree of shear stimuli, challenging the convention of diminished endothelial function typically associated with age. Likewise, exercise training improved arm vasodilation, indicating some preservation of vascular plasticity with age.

A longitudinal study of oculomotor function in normal older people

Cross-sectional studies have found declines in most measures of oculomotor function in older subjects compared to young controls, but no prior study has followed the same subjects over time. We measured saccade peak velocity, saccade delay time, smooth pursuit, optokinetic nystagmus (OKN), visual-vestibular-ocular-reflex (VVOR), fixation suppression of the vestibulo-ocular reflex (VOR-fix), and the vestibulo-ocular reflex in 53 subjects (older than 75 years) able to complete at least 9 yearly evaluations. In addition at each visit all patients underwent a complete history and examination, a gait and balance assessment, mini-mental status evaluation, and visual acuity testing. A subset of subjects completed 12 yearly evaluations (14 patients). Despite significant declines of most variables over time, smooth pursuit gain and saccade peak velocity remained stable during the duration of the study both in the 9-year group and the patients completing 12 years. Decline in OKN, VVOR, and VOR were significantly correlated ( P < 0.001) with decline in the Tinetti gait and balance score, even after controlling for age. In normal healthy older subjects, smooth pursuit and saccade peak velocity are relatively maintained while OKN, VVOR, and VOR function decline. The significant correlation between decline in oculomotor measures and gait and balance measures (even after controlling for age) suggests a common mechanism for the decline in both measures.

Effects of a Nap on Nighttime Sleep and Waking Function in Older Subjects

To examine, in older subjects, the effect on waking function of increasing 24-hour sleep amounts by providing a nap opportunity; to assess what effects an afternoon nap may have on subsequent nighttime sleep quality and composition. Two-session, within-subject laboratory design. The study was conducted in the Laboratory of Human Chronobiology at Weill Cornell Medical College. Thirty-two healthy men and women aged 55 to 85. Polysomnography (sleep electroencephalogram), cognitive and psychomotor performance, body core temperature. Napping had little effect on subsequent nighttime sleep quality or duration, resulting in a significant increase in 24-hour sleep amounts. Such increased sleep resulted in enhanced cognitive and psychomotor performance immediately after the nap and throughout the next day. A behavioral approach that adds daytime sleep to the 24-hour sleep quota seems worthy of consideration when presented with a situation in which physiological changes associated with aging may limit the duration of nighttime sleep.

What is the role of tests of lung function in the management of infants with lung disease?

This review considers whether there is a role for lung function tests in the clinical management of infants with lung disease. The purpose of testing lung function in older subjects, the tests available for infants, and the practical problems of testing lung function in infants are considered. After reviewing all the facts, we suggest that there are four situations in which lung function testing should be recommended for infants, as follows: (1) the infant who presents with unexplained tachypnea, hypoxia, cough, or respiratory distress in whom a definitive diagnosis is not apparent from physical examination and other, less difficult investigations; (2) the infant with severe, continuous, chronic obstructive lung disease who does not respond to an adequate clinical trial of combined corticosteroid and bronchodilator therapy; (3) the infant with known respiratory disease of uncertain severity in whom there is need to justify management decisions; and (4) research and development. A review of 62 recent publications to determine how lung function tests are being used at the present time showed that they are being used overwhelmingly for research. The role of lung function testing in the clinical management of infants has not been established, and research is needed to clarify this situation. We suggest that such studies should explore the role of lung function tests in infants with specific symptoms, signs, or diagnoses, taking into account information from other types of investigation and the cost/benefit/risk ratios.

Age-related changes in vestibular function: a longitudinal study.

The objective of this study was to identify age-related changes in the vestibulo-ocular reflex (VOR) in normal older subjects and patients complaining of disequilibrium followed serially over time. Cross-sectional studies have found decreases in vestibular function in older subjects compared to younger subjects, but no prior longitudinal studies have been made following the same older subjects over time. We measured VOR responses using step and sinusoidal stimuli in 110 normal subjects and 51 patients with disequilibrium of unknown cause. This report focuses on 57 normal subjects who were able to return for five yearly examinations and 7 patients who were found to have severe bilateral vestibulopathy on the initial examination. In the normal subjects, there was a significant shortening of the VOR time constant to step changes in angular velocity and an amplitude-dependent decrease in gain and increase in phase lead of low-frequency sinusoidal responses over the five examinations. There was also a decrease in the gain of visual-vestibular responses at low frequencies of sinusoidal stimulation over the five examinations. The patients with bilateral vestibulopathy showed relatively little change in vestibular function over the five years of follow-up. This is the first longitudinal study to show age-related decreases in vestibular responses in normal older subjects. The VOR changes identified were not associated with symptoms or signs of disequilibrium. A small subgroup of patients with disequilibrium of unknown cause had profound bilateral vestibulopathy that remained stable during follow-up. These patients likely had an underlying disease even though in most cases the disease process could not be identified.

Effect of an exercise-heat acclimation program on body fluid regulatory responses to dehydration in older men.

We examined if an exercise-heat acclimation program improves body fluid regulatory function in older subjects, as has been reported in younger subjects. Nine older (Old; 70 +/- 3 yr) and six younger (Young; 25 +/- 3 yr) male subjects participated in the study. Body fluid regulatory responses to an acute thermal dehydration challenge were examined before and after the 6-day acclimation session. Acute dehydration was produced by intermittent light exercise [4 bouts of 20-min exercise at 40% peak rate of oxygen consumption (VO(2 peak)) separated by 10 min rest] in the heat (36 degrees C; 40% relative humidity) followed by 30 min of recovery without fluid intake at 25 degrees C. During the 2-h rehydration period the subjects drank a carbohydrate-electrolyte solution ad libitum. In the preacclimation test, the Old lost approximately 0.8 kg during dehydration and recovered 31 +/- 4% of that loss during rehydration, whereas the Young lost approximately 1.2 kg and recovered 56 +/- 8% (P < 0.05, Young vs. Old). During the 6-day heat acclimation period all subjects performed the same exercise-heat exposure as in the dehydration period. Exercise-heat acclimation increased plasma volume by approximately 5% (P < 0.05) in Young subjects but not in Old. The body fluid loss during dehydration in the postacclimation test was similar to that in the preacclimation in Young and Old. The fractional recovery of lost fluid volume during rehydration increased in Young (by 80 +/- 9%; P < 0.05) but not in Old (by only 34 +/- 5%; NS). The improved recovery from dehydration in Young was mainly due to increased fluid intake with a small increase in the fluid retention fraction. The greater involuntary dehydration (greater fluid deficit) in Old was accompanied by reduced plasma vasopressin and aldosterone concentrations, renin activity, and subjective thirst rating (P < 0.05, Young vs. Old). Thus older people have reduced ability to facilitate body fluid regulatory function by exercise-heat acclimation, which might be involved in attenuation of the acclimation-induced increase in body fluid volume.

Effects of Exercise Training on -Adrenergic Mediated Pressor Responses and Baroreflex Function in Older Subjects

Endurance exercise training increases maximal O2 uptake (VO2max) in older subjects, and training also improves cardiac function in older men. Although the effects of training on beta-adrenergic responses have been investigated, little information is available regarding the effects of alpha-adrenergic responses and baroreflex function in older men and women. The purpose of the study was to determine whether endurance exercise training can affect alpha-adrenergic responses and baroreflex function in the elderly. We studied 13 men and women, 63 +/- 4 yrs old (mean +/- SE). VO2max was determined during treadmill exercise. Baroreflex function was determined from the change in heart rate (HR) relative to the change in systolic blood pressure (delta HR/delta SBP) during infusion of phenylephrine. VO2max was increased by 23% (1.9 +/- 0.16 vs 2.34 +/- 0.20 l/min; p < .01) in response to training. Maximal heart rate did not change, but HR during submaximal exercise at the same absolute exercise intensity was 17% lower after training. Resting heart rate was slower in the trained state. During alpha-adrenergic stimulation induced by graded doses of phenylephrine infusion, heart rate was lower after training because of training-induced bradycardia at rest. However, the elevation in systolic blood pressure (delta SBP) and mean blood pressure (delta MBP) from basal levels in response to a given dose of phenylephrine were significantly larger (delta SBP:18 +/- 3 vs 26 +/- 3 mmHg, p < .01; and delta MBP 10 +/- 2 vs 15 +/- 3 mmHg, p < .01) after than before training.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasticity in the Aging Brain

The course of idiopathic normal-pressure hydrocephalus was studied in a 78-year-old woman with a 4-year history of progressive dementia who underwent neuropsychologic testing, quantitative x-ray computed tomography, magnetic resonance imaging, and positron emission tomography with fludeoxyglucose F 18 to measure rates of regional cerebral glucose utilization. Preshunt cognitive testing demonstrated progressive deterioration during 2 years, and positron emission tomography showed significant reductions in regional cerebral glucose utilization of 34% to 49% as compared with age- and sex-matched control subjects in frontal, temporal, parietal, and whole brain regions. Periodic testing, carried out during a 2-year period after shunt surgery, showed steady improvement in clinical status. Parallel to the clinical changes, there was a significant reversal in neuropsychologic test scores with increased brain volume and increased regional cerebral glucose utilization in several brain regions. These results documented the considerable potential for recovery of compromised brain function in older subjects even after 4 years of progressive brain disease.