Autonomic and neurohumoral control of postprandial blood pressure in healthy aging.

Background: Postprandial hypotension (PPH) is a common and morbid problem in elderly people that is associated with an impaired vascular response to meal digestion. Healthy aging in the absence of blood pressure elevation is associated with autonomic and neurohumoral changes that may influence the vascular response to meal ingestion. However, it is not known whether these age-related changes are associated with the development of PPH.

Dynamic regulation of middle cerebral artery blood flow velocity in aging and hypertension.

Background And Purpose: Although aging and hypertension may predispose hypertensive elderly subjects to cerebral hypoperfusion during orthostatic stress, their effects on the acute cerebral autoregulatory response to hypotension are not known.

Methods: Continuous middle cerebral artery blood flow velocity (BFV) (transcranial Doppler ultrasound) and mean arterial pressure (MAP, Finapres) were measured in response to (1) acute hypotension during standing, (2) steady-state sitting and standing, and (3) hypercarbia during CO(2) rebreathing in 10 healthy young subjects (age 24+/-1 years), 10 healthy elderly subjects (age 72+/-3 years), and 10 previously treated hypertensive elderly (age 72+/-2 years) subjects. CO(2) reactivity was computed as the slope of cerebrovascular conductance (CVC=BFV/MAP) versus end-expiratory CO(2).

Development of constipation in nursing home residents.

Purpose: Constipation is a common complaint among geriatric patients and may result in significant morbidity, especially among nursing home residents. The prevalence of constipation increases with advancing age and may be a result of the aging process, but the exact cause is unknown. The aim of this study was to describe the prevalence of constipation and to determine risk factors for the development of constipation in a large population of nursing home residents.

Dimensions of the Mini-Mental State Examination among community dwelling older adults.

Background: Little work has been published on the internal structure of the Mini-Mental State Examination (MMSE), one of the most widely used instruments for grading cognitive status in clinical settings and field research.

Methods: MMSE responses from a sample of older adults (50-98 years) in five US sites (N = 8556) were analysed.

Results: A five-factor solution was found to be most appropriate.

Serum CTX: a new marker of bone resorption that shows treatment effect more often than other markers because of low coefficient of variability and large changes with bisphosphonate therapy.

Serum CrossLaps is a new assay for measuring carboxy-terminal collagen crosslinks (CTX) in serum. This measurement is reported to be more specific to bone resorption than other measurements. However, the utility of this and other markers in monitoring patients on antiresorptive therapy depends on how often changes anticipated with therapy exceed changes attributable to random variability.

Effects of postprandial walking exercise on meal-related hypotension in frail elderly patients.

The purpose of this study was to assess the hemodynamic effects of a postmeal walk in frail elderly patients with postprandial hypotension. We demonstrated that frail elderly patients with postprandial hypotension are able to increase their blood pressure and heart rate in response to a postmeal walking exercise, but this effect is limited to the exercise period only and is not sustained during subsequent rest.

Nursing rehabilitation and exercise strategies in the nursing home.

Background: The purpose of this study was to evaluate how weight training or nursing-based rehabilitative care programs in nursing homes impact on resident performance of Activities of Daily Living (ADL) and objectives tests of physical performance.

Methods: This study involved a quasi-experimental control, longitudinal comparison of functional status over a 10-month period, where baseline status was adjusted through a weighting procedure based on functional status, cognitive status, and age. All residents from six residential care nursing home facilities were eligible except those with a terminal prognosis, a projected stay of less than 90 days, or with health complications that prohibited contact.

Neural mechanisms of delirium: current hypotheses and evolving concepts.

The purpose of this article is to review current knowledge regarding potential neural mechanisms of delirium. A MEDLINE search for relevant English language articles was undertaken using various combinations of delirium (including cognitive disorders, encephalopathy, and confusion) with pathogenesis and pathophysiology. These articles were scanned for content related to hypotheses concerning the neurobiology of delirium.

Effects of age and gender on autonomic control of blood pressure dynamics.

Both age and gender influence cardiovascular autonomic control, which in turn may influence the ability to withstand adverse cardiac events and respond to orthostatic stress. The purpose of this study was (1) to quantify age- and gender- related alterations in autonomic control of blood pressure (BP) and (2) to examine the impact of these autonomic alterations on BP response to orthostatic stress. We measured continuous BP and R-R intervals and vasoactive peptide levels in the supine and 60 degrees head-up tilt positions during paced respiration (0.

Serum anticholinergic activity changes with acute illness in elderly medical patients.

Background: Elevated serum anticholinergic activity levels have been associated with delirium in cross-sectional studies of ill older persons. This study used serial measures of serum anticholinergic activity levels to determine whether these levels change following illness resolution, and if such changes are specific to those with delirium.

Methods: Twenty-two nursing home residents with a febrile illness had serum specimens drawn and were evaluated for the presence of delirium during the acute illness and at 1-month follow-up.

Complex demodulation of cardiorespiratory dynamics preceding vasovagal syncope.

Background: The dynamic autonomic processes leading to vasovagal syncope are poorly understood.

Methods And Results: We used complex demodulation to continuously assess changes in respiration, R-R interval, and arterial pressure (blood pressure) variability during 60 degree head-up tilt in 25 healthy subjects with tilt-induced vasovagal syncope and 25 age-matched nonsyncopal control subjects. Coherence and transfer function analyses were used to examine the relation between respiration and R-R interval variability before syncope.

Lack of an association between insulin-like growth factor-I and body composition, muscle strength, physical performance or self-reported mobility among older persons with functional limitations.

Objective: The hypothesis that decreased growth hormone (GH) secretion contributes to the functional decline that occurs with aging is far from substantiated. There have been few studies addressing the distribution and correlates of IGF-I, an indicator of GH activity, in nonclinical populations. As part of a growth hormone intervention trial, we examined the cross-sectional relations between IGF-I levels and multiple measures of physical function, body composition, and strength in a group of older men and women exhibiting mild to moderate reductions in measured physical performance.

Does artificial enteral nutrition prolong the survival of institutionalized elders with chewing and swallowing problems?

Background: There is a lack of prognostic data regarding tube feeding of institutionalized elderly people. The objective of this study was to determine the impact of feeding tubes on the survival of nursing home residents with chewing and swallowing problems, and to follow the course of the tube-fed residents over one year.

Methods: We conducted a cohort study with 12-month follow-up using Minimum Data Set resident assessments from 1991.

Identifying nursing home residents at risk for falling.

Objectives: To develop a fall risk model that can be used to identify prospectively nursing home residents at risk for falling. The secondary objective was to determine whether the nursing home environment independently influenced the development of falls.

Design: A prospective study involving 1 year of follow-up.

Exclusion of elderly subjects from clinical trials for Parkinson disease.

Objectives: To determine whether subjects older than 75 years are included in the randomized controlled trials of antiparkinsonian medications conducted during the last 30 years and to identify study characteristics that are associated with the exclusion of patients of advanced age.

Methods: A systematic search was conducted on MEDLINE from January 1966 until September 1996 of all randomized controlled trials of drugs used to treat the motor symptoms of Parkinson disease. Articles were abstracted for the age of subjects date of publication, geographic location, drug class studied, stage of Parkinson disease of subjects, and the number of subjects in each trial.

Vasomotor instability preceding tilt-induced syncope: does respiration play a role?

This study aimed to determine whether alterations in cardiovascular dynamics before syncope are related to changes in spontaneous respiration. Fifty-two healthy subjects underwent continuous heart rate (HR), arterial blood pressure (BP), and respiratory measurements during 10-min periods of spontaneous and paced breathing (0.25 Hz) in the supine and 60 degrees head-up tilt positions.

The risk factors and impact on survival of feeding tube placement in nursing home residents with severe cognitive impairment.

Background: The provision of artificial enteral nutrition to an aged person with severe cognitive impairment is a complex dilemma in the long-term care setting.

Objective: To determine the risk factors and impact on survival of feeding tubes in nursing home residents with advanced cognitive impairment.

Methods: We conducted a cohort study with 24-month follow-up using Minimum Data Set resident assessments on 1386 nursing home residents older than 65 years with recent progression to severe cognitive impairment in the state of Washington.

Cardiovascular adaptation to orthostatic stress during vasodilator therapy.

Background: Orthostatic hypotension is a dangerous problem in elderly patients, often exacerbated by vasodilator medications. Age- and disease-related impairments in cardioacceleration and diastolic ventricular function may make older patients particularly vulnerable to the hypotensive effects of these drugs. Therefore we aimed to determine mechanisms of postural blood pressure regulation in elderly patients with coronary artery disease and to compare the effects of isosorbide dinitrate and nicardipine hydrochloride on postural blood pressure homeostasis in these patients.

The effect of smoking at different life stages on bone mineral density in elderly men and women.

To assess the effect of smoking on bone mineral density (BMD) at different life stages, to examine whether the effect of smoking differs between men and women, and to discover whether its effect in women differs according to history of estrogen use, a cohort study was carried out with single cross-section measurement of BMD by single and dual photon absorptiometry. The setting was the Framingham Study, a population-based cohort study with over 40 years prospectively collected data on smoking. Subjects (n = 1164) consisted of cohort members participating in the 20th biennial Framingham examination (1988-1989).

Effects of chronic estrogen replacement therapy on beat-to-beat blood pressure dynamics in healthy postmenopausal women.

Recent data showing gender differences in autonomic control of heart rate and acute estrogen effects on vasodilatation suggest that estrogen may influence autonomic regulation of heart rate and blood pressure. We aimed to determine the effect of postmenopausal estrogen replacement therapy on autonomic control of beat-to-beat heart rate and blood pressure dynamics. Subjects included 20 healthy postmenopausal women aged 60 to 75 years with normal exercise tolerance tests, 10 of whom were taking oral estrogen for 13 +/- 3 (+/- SEM) years.

Heart rate and respiratory rhythm dynamics on ascent to high altitude.

Objective: To investigate the alterations in autonomic control of heart rate at high altitude and to test the hypothesis that hypoxaemic stress during exposure to high altitude induces non-linear, periodic heart rate oscillations, similar to those seen in heart failure and the sleep apnoea syndrome.

Subjects: 11 healthy subjects aged 24-64.

Main Outcome Measures: 24 hour ambulatory electrocardiogram records obtained at baseline (1524 m) and at 4700 m.

Open-loop and closed-loop postural control mechanisms in Parkinson's disease: increased mediolateral activity during quiet standing.

Stabilogram-diffusion analysis was used to gain insights into how idiopathic Parkinson's disease (IPD) affects the postural control mechanisms involved in maintaining erect stance. Twenty-two subjects with IPD and twenty-four healthy elderly subjects were studied under eyes-open, quiet-standing conditions. The postural control mechanisms in the parkinsonian subjects, compared to the healthy elderly, were characterized by an increase in the effective stochastic activity in the mediolateral direction.

The effects of analytic software and scan analysis technique on the comparison of dual X-ray absorptiometry with dual photon absorptiometry of the hip in the elderly.

As part of a longitudinal comparison of bone mineral density (BMD) results originally obtained using a Lunar dual photon absorptiometry (DPA) scanner and later, using a Lunar dual X-ray absorptiometry (DXA) scanner, we compared femur results between DPA and DXA according to DXA analytic software (versions 1.3y and 1.4), and according to the method of placement of the femoral neck box (software algorithm or operator placement according to the appearance of the pair of images) in 58 elderly men and women.

The outcomes of patients newly admitted to nursing homes after hip fracture.

Objectives: The outcomes of elderly, hospitalized patients discharged to nursing homes after hip fracture were examined.

Methods: For 2624 hip fracture patients admitted to any of 43 proprietary nursing homes between 1984 and 1988, admission assessments were examined in relation to 1-month outcomes.

Results: Mean patient age was 82 +/- 7 y; 85% of the sample were female.