Cerebrovascular hemodynamics, gait, and falls in an elderly population: MOBILIZE Boston Study

OBJECTIVE

To determine whether alterations in cerebral blood flow regulation are associated with slow gait speed and falls in community-dwelling elderly individuals.

METHODS

The study sample consisted of 419 individuals from the MOBILIZE Boston Study (MBS) who had transcranial Doppler ultrasound measures of cerebral blood flow velocity. The MBS is a prospective cohort study of a unique set of risk factors for falls in seniors in the Boston area. We measured beat-to-beat blood flow velocity in the middle cerebral artery in response to 1) changes in end-tidal CO(2) (cerebral vasoreactivity) and 2) blood pressure changes during a sit-to-stand protocol (cerebral autoregulation). Gait speed was measured during a 4-meter walk. Falls were tracked by monthly calendars, and demographic and clinical characteristics were assessed at baseline.

RESULTS

A multivariate linear regression analysis showed that cerebral vasoreactivity was cross-sectionally related to gait speed (p = 0.039). Individuals in the lowest quintile of vasoreactivity had lower gait speeds as compared to those in the highest quintile (p = 0.047). In a negative binomial regression analysis adjusted for relevant covariates, the relationship between cerebral vasoreactivity and fall rate did not reach significance. However, when comparing individuals in the lowest to highest quintile of cerebral vasoreactivity, those in the lowest quintile had a higher fall rate (p = 0.029).

CONCLUSIONS

Impaired cerebral blood flow regulation, as measured by cerebral vasoreactivity to CO(2), is associated with slow gait speed and may lead to the development of falls in elderly people.

The yield of head CT in syncope: a pilot study

Although head CT is often routinely performed in emergency department (ED) patients with syncope, few studies have assessed its value.

OBJECTIVES

To determine the yield of routine head CT in ED patients with syncope and analyse the factors associated with a positive CT.

METHODS

Prospective, observational, cohort study of consecutive patients presenting with syncope to an urban tertiary-care ED (48,000 annual visits).

INCLUSION CRITERIA

age >or=18 and loss of consciousness (LOC). Exclusion criteria included persistent altered mental status, drug-related or post-trauma LOC, seizure or hypoglycaemia. Primary outcome was abnormal head CT including subarachnoid, subdural or parenchymal haemorrhage, infarction, signs of acute stroke and newly diagnosed brain mass.

RESULTS

Of 293 eligible patients, 113 (39%) underwent head CT and comprise the study cohort. Ninety-five patients (84%) were admitted to the hospital. Five patients, 5% (95% CI=0.8%-8%), had an abnormal head CT: 2 subarachnoid haemorrhage, 2 cerebral haemorrhage and 1 stroke. Post hoc examination of patients with an abnormal head CT revealed focal neurologic findings in 2 and a new headache in 1. The remaining 2 patients had no new neurologic findings but physical findings of trauma (head lacerations with periorbital ecchymoses suggestive of orbital fractures). All patients with positive findings on CT were >65 years of age. Of the 108 remaining patients who had head CT, 45 (32%-51%) had signs or symptoms of neurologic disease including headache, trauma above the clavicles or took coumadin. Limiting head CT to this population would potentially reduce scans by 56% (47%-65%). If age >60 were an additional criteria, scans would be reduced by 24% (16%-32%). Of the patients who did not have head CT, none were found to have new neurologic disease during hospitalisation or 30-day follow-up.

CONCLUSIONS

Our data suggest that the derivation of a prospectively derived decision rule has the potential to decrease the routine use of head CT in patients presenting to the ED with syncope.

Noise and poise: Enhancement of postural complexity in the elderly with a stochastic-resonance-based therapy

Pathologic states are associated with a loss of dynamical complexity. Therefore, therapeutic interventions that increase physiologic complexity may enhance health status. Using multiscale entropy analysis, we show that the postural sway dynamics of healthy young and healthy elderly subjects are more complex than that of elderly subjects with a history of falls. Application of subsensory noise to the feet has been demonstrated to improve postural stability in the elderly. We next show that this therapy significantly increases the multiscale complexity of sway fluctuations in healthy elderly subjects. Quantification of changes in dynamical complexity of biologic variability may be the basis of a new approach to assessing risk and to predicting the efficacy of clinical interventions, including noise-based therapies.

Predicting cerebral blood flow response to orthostatic stress from resting dynamics: effects of healthy aging

The transfer function relating arterial pressure (AP) to cerebral blood flow velocity (CBFV) during resting conditions has been used to predict the CBFV response to hypotension. We hypothesized that this approach could predict the CBFV response to posture change in elderly individuals if impaired autoregulation allowed changes in AP to be passively transferred to CBFV. AP (Finapres) and CBFV (middle cerebral artery transcranial Doppler) were measured in 10 healthy young (age 24 +/- 1 yr) and 10 healthy elderly (age 72 +/- 3 yr) subjects during 5 min of quiet sitting and 1 min of active standing while breathing was paced at 0.25 Hz. Transfer functions between AP and CBFV changes during sitting were estimated from each full waveform in both low-frequency (LF; 0.05-0.2 Hz) and heartbeat-frequency (HBF; 0.7-1.4 Hz) ranges. The impulse-response function was used to compute changes in CBFV during posture change. The LF transfer function did not predict orthostatic changes in CBFV in either group, suggesting normal cerebral autoregulation. In the HBF range, the prediction was high in elderly (R = 0.65 +/- 0.23) but not young subjects (R = 0.19 +/- 0.35; P < 0.003, young vs. elderly). Thus rapidly acting regulatory mechanisms that reduce the transmission of beat-to-beat changes in AP to CBFV may be engaged during posture change in young but not elderly subjects.

Estrogen replacement therapy improves baroreflex regulation of vascular sympathetic outflow in postmenopausal women

BACKGROUND

Menopausal estrogen loss has been associated with increased cardiovascular disease in postmenopausal women. However, the link between estrogen and cardiovascular disease remains unclear. Some data suggest estrogen mediates its effect through changes in arterial pressure and its regulation. However, the data available in older women are equivocal regarding estrogen's ability to reduce resting arterial pressure or to improve its regulation.

METHODS AND RESULTS

We studied 11 healthy, postmenopausal women before and after 6 months of estrogen administration. Arterial pressure was measured by brachial auscultation and finger photoplethysmography. Vascular sympathetic nerve activity was measured in the peroneal nerve by microneurography, and the slope of the relations between changes in heart period, sympathetic activity, and arterial pressure caused by bolus infusions of nitroprusside and phenylephrine were used as an index of baroreflex gain. Estrogen therapy did not change systolic pressure (128+/-2 versus 123+/-2 mm Hg) or cardiac-vagal baroreflex gain (6.6+/-0.9 versus 6.7+/-0.7 ms/mm Hg). However, vascular sympathetic baroreflex gain was increased (-4.6+/-0.6 versus -7.4+/-1.0 arbitrary integrated units/mm Hg; P=0.02).

CONCLUSION

These findings suggest long-term estrogen replacement therapy has effects on cardiovascular regulation that may not be reflected in resting arterial pressures.

Intra-individual postural blood pressure variability and stroke in elderly nursing home residents

Orthostatic hypotension (OH) is a potential risk factor for adverse cardiovascular events, but OH is highly variable and may not be detected on a single occasion. To assess the relation between intra-individual variability of systolic orthostatic blood pressure change (DeltaSBP) and cardiovascular outcomes, an algorithm was developed to identify DeltaSBP instability using repeated supine and standing BP measurements. A cohort of 673 nursing home residents underwent baseline postural BP measurements (supine to 1 minute of standing, four times in a single day) and were followed for up to 2 years. Two groups (stable vs. unstable) were identified based on an analysis of DeltaSBP variance components. Differences in outcomes were compared via Cox survival analysis. At baseline 12.6% were unstable, defined as a one standard deviation difference of at least 20.2 mmHg between DeltaSBP readings. Unstable subjects were more likely to have OH on at least one measurement (systolic BP drop of 20 mmHg or more; 85% vs. 36%, respectively) and to be on psychotropic medication at baseline (47% vs 35%) (P-values <0.001). Other characteristics (including previous stroke) did not differ. During a mean follow-up of 10.3 months, stroke incidence was higher in unstable subjects (13.1% vs. 4.9%; P = 0.012), but ischemic heart disease and mortality rates were not significantly different (respectively, 13.5% vs. 7.4%, P = 0.115; 14.8% vs. 10.7%, P = 0.178). Survival analyses (adjusted for age, sex, psychotropic medications, body mass index, ischemic heart disease, and supine systolic pressure) confirmed a higher risk of stroke in unstable subjects (relative risk = 3.7, 95% CI: 1.6-8.4). Highly variable orthostatic BP measures may reflect impaired BP regulatory mechanisms in elders with occult cerebrovascular disease, or may directly affect cerebral blood flow. Orthostatic BP variability may be a better indicator of future stroke than a single supine or orthostatic change measure.

Reduced hip extension during walking: healthy elderly and fallers versus young adults

OBJECTIVES

To test the hypothesis that reduced hip extension range during walking, representing a limiting impairment of hip tightness, is a consistent dynamic finding that (1) occurs with increased age and (2) is exaggerated in elderly people who fall.

DESIGN

Using a 3-dimensional optoelectronic motion analysis system, we compared full sagittal plane kinematic (lower extremity joint motion, pelvic motion) data during walking between elderly and young adults and between elderly fallers and nonfallers. Comparisons were also performed between comfortable and fast walking speeds within each elderly group.

SETTING

A gait laboratory.

PARTICIPANTS

Twenty-three healthy elderly subjects, 16 elderly fallers (otherwise healthy elderly subjects with a history of recurrent falls), and 30 healthy young adult subjects.

MAIN OUTCOME MEASURES

All major peak joint angle and pelvic position values.

RESULTS

Peak hip extension was the only leg joint parameter measured during walking that was both significantly lower in elderly nonfallers and fallers than in young adult subjects and was even lower in elderly fallers compared with nonfallers (all p <.05). Peak hip extension +/- standard deviation during comfortable walking speed averaged 20.4 degrees +/- 4.0 degrees for young adults, 14.3 degrees +/- 4.4 degrees for elderly nonfallers, and 11.1 degrees +/- 4.8 degrees for elderly fallers. Peak hip extension did not significantly improve when elderly subjects walked fast.

CONCLUSION

An isolated and consistent reduction in hip extension during walking in the elderly, which is exaggerated in fallers, implies the presence of functionally significant hip tightness, which may limit walking performance. Overcoming hip tightness with specific stretching exercises is worthy of investigation as a simple intervention to improve walking performance and to prevent falls in the elderly.

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.

METHODS

We measured hemodynamic (blood pressure, heart rate, and forearm vascular resistance), autonomic (power spectral analysis of heart rate and blood pressure variability), and neurohumoral (plasma norepinephrine, renin, aldosterone, and endothelin) responses to a mixed 425 kilocalorie (kcal) meal in 89 rigorously screened healthy subjects aged 20-39, 40-59, and 60-83 years.

RESULTS

After the meal, supine mean arterial blood pressure fell significantly only in the middle-aged group by 5.4 +/- 7.9 mm Hg at 30 minutes (p = .02). Forearm vascular resistance fell after the meal in all age groups ( p = .0001). Older groups had higher plasma norepinephrine (p = .02), lower heart rate (p = .03), lower cardiovagal activity (p = .0001), and lower sympathetic vasomotor (p = .000) activity, but there was no difference in the response of these variables to a meal.

CONCLUSION

Healthy aging, in the absence of blood pressure elevation, alters the level of autonomic activity without further impairing the ability to maintain blood pressure during meal digestion. Hemodynamic, autonomic, and neurohumoral responses to meal ingestion remain unchanged in very healthy, normotensive elderly adults.

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). Coherence, transfer magnitudes, and phases between low-frequency MAP and BFV signals were computed from their autospectra during 5 minutes of sitting and standing.

RESULTS

MAP fell to a similar extent in all groups by an average of 21 to 26 mm Hg (22% to 26%) within 30 seconds of standing. Mean BFV also fell in all subjects but significantly less in the older subjects (-4.7+/-0. 7 cm/s in hypertensives and -5.3+/-1.2 cm/s in normotensives, P=NS) compared with younger subjects (-10.1+/-1.1 cm/s, P<0.05). CO(2) reactivity was greater in the young subjects (0.19+/-0.01) compared with normotensive (0.14+/-0.01, P<0.05) and hypertensive elderly subjects (0.11+/-0.02, P<0.05) (P=NS between elderly groups). Fewer hypertensive subjects had coherence between MAP and BFV signals; for subjects with coherence, there were no significant group differences in phase or transfer magnitudes in either sitting or standing positions.

CONCLUSIONS

Despite reduced CO(2) reactivity, elderly normotensive and previously treated hypertensive subjects retain cerebral autoregulatory capacity in response to acute orthostatic hypotension.

Large neutral amino acid changes and delirium in febrile elderly medical patients

A hypothesized but unexplored mechanism for delirium in older persons is that changes in plasma large neutral amino acid (LNAA) concentrations alter brain serotonin levels, result in neurotoxicity, or both. Therefore we performed a prospective study of 21 acutely febrile long-term-care residents to study the relationship between LNAA changes and delirium. Plasma LNAA concentrations were evaluated during illness and 1 month later. Delirium was diagnosed by using the Confusion Assessment Method. Other data included age, body mass index, cognitive impairment, comorbidity, gender, maximum temperature, and medication use. Seven subjects (33%) were delirious during febrile illness. Although the phenylalanine (PHE)/LNAA ratio was higher during illness in both delirious and nondelirious groups, a two-sample t test demonstrated that delirium was associated with a higher illness PHE/LNAA ratio (p = .03). The amount of change in PHE/LNAA from illness to recovery was not different between the delirious and nondelirious groups. Tryptophan/LNAA was not associated with delirium during illness or at recovery. These findings identify another potentially fruitful area of investigation for the prevention and treatment of delirium in older persons.

A cross-national survey of tube-feeding decisions in cognitively impaired older persons

OBJECTIVES

Many factors affect the decision to institute long-term tube-feeding in older persons. The objectives of this cross-national survey are to examine the tube-feeding decision-making process for cognitively impaired older persons from the perspective of the substitute decision-makers (SDM) and to contrast this process in US and Canadian healthcare settings.

DESIGN

Survey.

SETTING

Chronic care facilities in Ottawa and nursing homes in Boston.

PARTICIPANTS

Patients more than age 65 who were tube-fed for at least 2 months and who were unable to make their own healthcare decisions at the time of tube placement were identified at both sites. The SDMs of 46 patients in Ottawa and 48 patients in Boston were surveyed.

MEASUREMENTS

The survey asked questions relating to the following categories: health status of the patient, advance directives, communication with the healthcare team, perceived goals of tube-feeding, decision satisfaction, and sociodemographic data.

RESULTS

Tube-fed patients in Boston were more likely to have a diagnosis of dementia than those in Ottawa (60.4% vs 10.9%, P < .001) and were less likely to have had an acute neurological event (35.4% vs 71.7%, P < .001). There was a greater likelihood in Boston than in Ottawa (68.7% vs 6.5%, P < .001) for tube-feeding decisions to be made in a nursing home (vs an acute hospital). In the combined cohort, 19.1% of patients had a living will, and only 47.9% of SDMs felt confident that the patients would want to have a feeding tube. The majority of SDMs at both sites felt they understood the benefits (83.0%), but not the risks (48.9%), of tube-feeding. The most commonly perceived reasons for tube-feeding were to "prolong life" (84.0%) and to "prevent aspiration" (67.0%). Approximately half of all SDMs felt they had received adequate support from the healthcare team. A minority of SDMs (38.3%) at both sites stated that they would want a feeding tube for themselves, and only 40% of SDMs felt the feeding tube had improved the patients' quality of life.

CONCLUSIONS

A greater proportion of patients have feedings tubes inserted because of a degenerative dementia in Boston compared with an acute neurological event in Ottawa. Despite the difference in diagnostic indication for tube-feeding, the substitute decision-making process was seriously limited at both sites by poor implementation of the principle of substituted judgement, a need for broader advance directives, and improved transfer of knowledge between clinicians and decision-makers.

The association between orthostatic hypotension and recurrent falls in nursing home residents

PURPOSE

Orthostatic hypotension is common among the elderly, but its relation to falls is not certain. We determined whether orthostatic hypotension, including its timing and frequency, was associated with falls in elderly nursing home residents.

SUBJECTS AND METHODS

We conducted a prospective study of 844 elderly (60 years of age and older), long-stay residents at 40 facilities that were part of a multistate nursing home chain. All subjects were able to maintain weight-bearing for at least 1 minute. Orthostatic hypotension was defined as a 20 mm Hg or greater decrease in systolic blood pressure from supine to standing, as measured after 1 or 3 minutes of standing on four occasions (before or after breakfast, or before or after lunch). The outcome was any subsequent fall during a mean of 1.2 years of follow-up.

RESULTS

Orthostatic hypotension was present (at least on one measurement) in 50% of the subjects but was not associated with subsequent falls. However, among subjects with a history of previous falls in the past 6 months, those with orthostatic hypotension had an increased risk of recurrent falls [adjusted relative risk (RR) = 2.1; 95% confidence interval (CI), 1.4 to 3.1 ]. The risk of subsequent falls was greatest in previous fallers who had orthostatic hypotension at two or more measurements (RR = 2.6; 95% CI, 1.7 to 4.6). The association between orthostatic hypotension and recurrent falls was independent of measured demographic or clinical risk factors for falls. The timing of orthostatic hypotension (before or after meals) did not affect the risk of falls.

CONCLUSIONS

Orthostatic hypotension is an independent risk factor for recurrent falls among elderly nursing home residents. Although the benefit of treating orthostatic hypotension will require further study, it may be prudent to identify high-risk residents and institute precautionary measures.

Effects of angiotensin-converting enzyme inhibitors and digoxin on health outcomes of very old patients with heart failure. SAGE Study Group. Systematic Assessment of Geriatric drug use via Epidemiology

BACKGROUND

Randomized trials have shown that angiotensin-converting enzyme (ACE) inhibitors reduce mortality and morbidity, and improve symptoms and exercise tolerance in selected patients with congestive heart failure (CHF). There is, however, no evidence on the effectiveness of ACE inhibitors in the typical, very old and frail patients with CHF.

OBJECTIVE

To compare the effects of ACE inhibitors and digoxin on 1-year mortality, morbidity, and physical function among patients aged 85 years.

METHODS

We conducted a retrospective cohort study using the SAGE database, a long-term care database linking patient information with drug utilization data. Among 64637 patients with CHF admitted to all nursing homes in 5 states between 1992 and 1995, we identified 19492 patients taking either an ACE inhibitor (n = 4911) or digoxin (n = 14890). Record of date of death was derived from Medicare enrollment files, and we used the part A Medicare files to identify hospital admissions and discharge diagnoses. As a measure of physical function, we used a scale for activities of daily living performance. The effect of ACE inhibitors was estimated using Cox proportional hazards models with digoxin users as the reference group.

RESULTS

The overall mortality rate among ACE inhibitor recipients was more than 10% less than that of digoxin users (relative rate, 0.89; 95% confidence interval, 0.83-0.95). Mortality was equally reduced regardless of concomitant cardiovascular conditions and baseline physical function. Treatment with ACE inhibitors was associated with a tendency toward reduced hospital admissions that was more evident among patients with greater functional impairment. The adjusted relative rate for hospitalization for any reason was 0.96 (95% confidence interval, 0.91-1.01). The rate of functional decline was greatly reduced among ACE inhibitor recipients (relative rate, 0.74; 95% confidence interval, 0.69-0.80), and this effect was consistent and independent of background comorbidity and baseline physical function.

CONCLUSIONS

These data suggest that survival and functional benefits of ACE inhibitor therapy extend to patients with CHF 85 years and older, and mostly women, both systematically underrepresented in randomized trials. Alternatively, digoxin has a detrimental effect in this population.

Management of heart failure among very old persons living in long-term care: has the voice of trials spread? The SAGE Study Group

BACKGROUND

Increasing prevalence, use of health services, and number of deaths have made congestive heart failure (CHF) a new epidemic in the United States. Yet there are no adequate data to guide treatment of the more typical and complex cases of patients who are very old and frail.

METHODS

Using the SAGE database, we studied the cases of 86,094 patients with CHF admitted to any of the 1492 long-term care facilities of 5 states from 1992 through 1996. We described their clinical and functional characteristics and their pharmacologic treatment to verify agreement with widely approved guidelines. We evaluated age- and sex-related differences, and we determined predictors of receiving an angiotensin-converting enzyme (ACE) inhibitor by developing a multiple logistic regression model.

RESULTS

The mean age of the population was 84.9 +/- 8 years. Eighty percent of the patients 85 years of age or older were women. More than two thirds of patients underwent frequent hospitalizations related to CHF in the year preceding admission to a long-term care facility. Coronary heart disease and hypertension were the most common causes. Half of the patients received digoxin and 45% a diuretic, regardless of background cardiovascular comorbidities. Only 25% of patients had a prescription for ACE inhibitors. The presence of cardiovascular comorbidity, already being a recipient of a large number of medications, a previous hospitalization for CHF, and admission to the facility in recent years were associated with an increased likelihood of receiving an ACE inhibitor. The presence of severe physical limitation was inversely related to use of ACE inhibitors, as were a series of organizational factors related to the facilities.

CONCLUSIONS

Patients in long-term care who have CHF little resemble to those enrolled in randomized trials. This circumstance may explain, at least in part, the divergence from pharmacologic management consensus guidelines. Yet the prescription of ACE inhibitors varies significantly across facilities and depends on organizational characteristics.

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.

Correlates and management of nonmalignant pain in the nursing home. SAGE Study Group. Systematic Assessment of Geriatric drug use via Epidemiology

OBJECTIVE

Nonmalignant pain is a common problem among older people. The prevalence of pain in the nursing home is not well studied. We looked at the association between nonmalignant pain, psychological and functional health, and the practice patterns for pain management in the nursing home.

DESIGN

A cross-sectional study.

SETTING

Nursing Home in four US states.

PARTICIPANTS

A total of 49,971 nursing home residents from 1992 to 1995.

MEASUREMENTS

We used the SAGE database (Systematic Assessment of Geriatric drug use via Epidemiology), which linked information from the Minimum Data Set and nursing home drug utilization data. The MDS items measured included pain, activities of daily living (ADL) function, mood, and time involved in activities. The use of analgesics, anxiolytics, and antidepressants was also documented.

RESULTS

Daily pain was reported in 26% of nursing home residents. The prevalence was lower among men, persons more than age 85, and racial minorities. Persons suffering pain daily were more likely to have severe ADL impairment, odds ratio (OR) (2.47 (95% CI, 2.34-2.60)), more depressive signs and symptoms (OR 1.66 (95% CI, 1.57-1.75)), and less frequent involvement in activities (OR 1.35 (95% CI, 1.29-1.40)). Approximately 25% of persons with daily pain received no analgesics. Residents who were more than 85 years old (OR 1.15 (95% CI 1.02-1.28)), cognitively impaired, (OR 1.44 (95% CI, 1.29-1.61)), of male gender (OR 1.17 (95% CI, 1.06-1.29)), or a racial minority (OR 1.69 (95% CI, 1.40-2.05) and OR 1.56 (95% CI, 0.70-1.04) for blacks and Hispanics, respectively) were at greater risk of not receiving analgesics. Approximately 50% of those in pain used physical and occupational therapies, which was more than two times higher (OR 2.44 (95% CI, 2.34-2.54)), than use for those not in pain.

CONCLUSIONS

Daily nonmalignant pain is prevalent among nursing home residents and is often associated with impairments in ADL, mood, and decreased activity involvement. Even when pain was recognized, men, racial minorities, and cognitively impaired residents were at increased risk for undertreatment. More education and research is necessary to improve the recognition and management of pain in the nursing home, remembering that attention should be paid to populations at increased risk for underrecognition and undertreatment.

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. Additional references were obtained from a manual search of the bibliography of these articles. A secondary MEDLINE search of delirium with the mechanism in question (i.e., serotonin, acetylcholine, etc.) was then undertaken. Literature review was last updated as of April 1998. Despite being a common problem among elderly patients, the mechanisms of delirium are poorly understood. Delirium is a syndrome that may occur as the result of multiple complex interacting neurotransmitter systems and pathologic processes. The neurotransmitters acetylcholine and serotonin may play particularly important roles in common medical and surgical delirium. Other neurotransmitters such as dopamine and gamma-aminobutyric acid each may be involved in the development of delirium under special conditions. Other neurobiologic factors such as cytokines, cortisol abnormalities, and oxygen free radicals will require further study to define their role in delirium. Distinct neuropathologic processes leading to delirium are beginning to be defined. Such mechanisms may differ in various clinical settings. There is probably no final common pathway to delirium, but rather, delirium is the final common symptom of multiple neurotransmitter abnormalities. Further situation-specific studies of delirium pathophysiology should lead to more effective prevention and treatment strategies.

Assessing muscle stiffness from quiet stance in Parkinson's disease

In previous studies, we developed a postural stiffness measure that is extracted from foot center-of-pressure (COP) trajectories from quietly standing individuals and is based on an analytical mechanical model of posture control. Here we apply this measure to patients with Parkinson's disease (PD). We correlated the postural stiffness measure with different clinical rating scales, obtained from patients. Kendall's rank correlation was highly significant between the stiffness measure and rigidity, bradykinesia, posture impairment, gait, and leg agility, respectively, as rated by the Unified Parkinson's Disease Rating Scale. These results provide further evidence that a higher intrinsic muscle stiffness may contribute to the aforementioned clinically defined symptoms. From a clinical standpoint, this work indicates that the proposed postural stiffness measure may be useful as an assessment tool for the evaluation of PD patients subsequent to pharmacological and surgical treatment.

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 (0.25 Hz) in 89 carefully screened healthy subjects (41 men, 48 women, aged 20 to 83 years). Data were analyzed by gender (age adjusted) and by age group (gender adjusted). During tilt, women had greater decreases in systolic BP than men (-10.2+/-2 versus -1.2+/-3 mm Hg; P=0.02) and smaller increases in low-frequency (sympathetically mediated) BP power (P=0.02). Upright plasma norepinephrine was lower in women (P=0.02). Women had greater supine high-frequency R-R interval power than men (P=0.0001). In elderly subjects, the tilt-induced increase in low-frequency BP power was also diminished (P=0.01), despite higher supine (P=0.02) and similar upright norepinephrine levels compared with younger subjects. Thus, healthy women have less sympathetic influence on BP and greater parasympathetic influence on R-R interval than men. Elderly subjects also have reduced sympathetic influence on BP, but this appears to be more consistent with a reduction in vasomotor sympathetic responsiveness.

Blood pressure behavior in the nursing home: implications for diagnosis and treatment of hypertension

OBJECTIVES

To determine patterns of elevated blood pressure (BP) behavior, their clinical correlates, and the relationship to diagnosis and management of hypertension.

DESIGN

A cross-sectional, prevalence survey.

SETTING

Forty-five nursing homes owned or managed by a large national chain.

PARTICIPANTS

A total of 857 older residents (mean age = 84 years).

MEASUREMENTS

Supine and standing (1 and 3 minutes) BP and heart rate, taken four times in one day (before and after breakfast, and before and after lunch) by trained nurses using a random zero sphygmomanometer; medication profile; active medical diagnoses; functional status; sociodemographics.

RESULTS

The prevalence of a single, elevated, supine systolic pressure (> or = 160 mm Hg) was 14.3%, and of two to four elevated measures was 14.9%. The pre-breakfast reading was consistently the highest, and mean systolic pressures decreased after breakfast. Compared with those not treated, older residents taking antihypertensive medications had higher systolic pressures at all times and showed the same pattern of decline after breakfast. Isolated diastolic hypertension was uncommon (0.9%). Cardiovascular disease, orthostatic hypotension, diabetes, and use of angiotensin converting enzyme inhibitors or calcium channel blockers were more prevalent among older residents who had elevated pressures on multiple occasions (P < .03). Successful antihypertensive treatment was associated with a lower prevalence of orthostatic hypotension. Diuretic use was more likely to be associated with blood pressure control.

CONCLUSION

The diagnosis of hypertension in frail older people would benefit from multiple, within-day measures, including postural BP, taken before and after meals. Diuretic use alone, or in conjunction with ACE inhibitors or calcium channel blockers, was more likely to be associated with normalized blood pressures.

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. Delirium was diagnosed using the Confusion Assessment Method. Serum anticholinergic activity was determined using a previously described radionuclide competitive-binding assay.

RESULTS

Delirium was present during illness in 8 of 22 subjects (36%), and had resolved by 1-month follow-up in all but one resident. Serum anticholinergic activity levels were significantly higher during illness than at 1-month follow-up in both the delirious (0.69 +/- 0.85 nM atropine equivalents/200 microL sample versus 0.10 +/- 0.16; p = .06) and non-delirious (0.65 +/- 0.51 nM atropine equivalents/200 microL sample versus 0.08 +/- 0.12; p < .001) groups. Medication changes did not seem to be related to changes in serum anticholinergic activity.

CONCLUSIONS

In older nursing home residents with a fever, serum anticholinergic activity appears to be elevated during illness, and declines following recovery from illness. This effect does not seem to be specific to those residents with delirium, nor does it seem related to medication changes.

Nursing home characteristics and the development of pressure sores and disruptive behaviour

OBJECTIVE

To determine how nursing home characteristics affect pressure sores and disruptive behaviour.

METHOD

Residents (n = 5518, aged > or =60 years) were selected from 70 nursing homes in the National Health Care chain. Homes were classified as high- or low-risk based on incidence tertiles of pressure sores or disruptive behaviour (1989-90). Point-prevalence and cumulative incidence of pressure sores and disruptive behaviour were examined along with other functional and service variables.

RESULTS

The overall incidence of pressure sores was 11.4% and the relative risk was 4.3 times greater in high- than low-risk homes; for disruptive behaviour, the incidence was 27% and the relative risk was 7.1 times greater in the high-risk group. At baseline, fewer subjects in homes with a high risk of pressure sores were white or in restraints, but more had received physician visits monthly and had had problems with transfers and eating. High-risk homes also had fewer beds and used less non-licensed nursing staff time. At follow-up (1987-90), 52% of homes in the low-risk group and 35% of those in the high-risk group had maintained their risk status; low-risk homes were more likely to have rehabilitation and maintenance activities. Having multiple clinical risk factors was associated with more pressure sores in high- (but not low-) risk homes, suggesting a care-burden threshold. By logistic regression, the best predictor of pressure sores was a home's prior (1987-88) incidence status. Interestingly, 67% of homes with a high risk of pressure sores were also high-risk for disruptive behaviour, while only 27% of homes with a low risk of pressure sores were high-risk for disruptive behaviour. A threshold effect was also observed between multiple risk factors and behaviour. More homes with a high risk of disruptive behaviour (68%) remained at risk over 4 years, and the best predictor of outcome was a home's previous morbidity level.

CONCLUSION

Nursing-home characteristics may have a greater impact than clinical factors on pressure sores and disruptive behaviour in long-stay, institutionalized elders.

Age-related changes in the initiation of gait: degradation of central mechanisms for momentum generation

OBJECTIVE

To investigate cross-sectionally age-related changes in the expression and biomechanical efficiency of the gait-initiation motor program.

DESIGN

Case-control study.

PARTICIPANTS AND SETTING

Twenty healthy young research subjects and 20 healthy elderly subjects who volunteered from the community participated in this study at a university research laboratory.

MAIN OUTCOME MEASURES

Participants performed gait-initiation trials at three speeds from a starting position on a force platform while ground reaction force data, 3-D motion analysis data, and electromyographic data were collected. Measures included: latency of tibialis anterior (TA) activation and soleus (SOL) and gastrocnemius (GA) inhibition, magnitude of center of pressure (COP) displacement, magnitude of momentum generated, and final walking velocity.

RESULTS

The expression of the central motor program governing gait initiation, as evidenced by the invariant timing between TA activation and SOL/GA inhibition, was seen in both the young and elderly populations, but the frequency was diminished in the latter group. The momentum-generating capacity of the COP shift mechanism was present but significantly diminished in the elderly population.

CONCLUSIONS

These findings suggest that the central nervous system uses stable, efficient mechanisms for dealing with the inherent instability of upright bipedalism and that the integrity of these mechanisms degrades with aging.

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. Baseline blood pressure, R-R, and ventilation were similar between syncope subjects and control subjects. Syncope subjects experienced an increase in tidal volume and decrease in BP beginning 3 minutes before impending syncope (systolic blood pressure <80 mm Hg) necessitated termination of tilt. Approximately 90 seconds before syncope there was a sudden prolongation of R-R interval and increase in amplitude of high and low frequency R-R interval variability, indicating an abrupt enhancement of vagal tone. The increase in respiratory amplitude between 180 and 90 seconds before syncope was not accompanied by changes in R-R interval or R-R variability, suggesting a dissociation between respiration and the respiratory sinus arrhythmia. The coherence analysis showed fewer syncope subjects with coherence between respiratory and R-R interval variabilities and lower transfer magnitudes in syncope subjects compared with control subjects. Nonsyncopal subjects had no change in respiratory, R-R interval, or blood pressure dynamics during matched time periods before the time of syncope.

CONCLUSIONS

Vasovagal syncope is preceded by a period of hyperpnea and cardiorespiratory decoupling followed by an abrupt increase in cardiovagal tone. Respiratory pumping without inspiratory cardiac slowing may partially counteract preload reduction until sudden bradycardia precipitates syncope.

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.

SETTING

Two hundred seventy-two nursing homes in the state of Washington.

PARTICIPANTS

A total of 18,855 residents who had a baseline assessment in 1991 and a follow-up assessment within the subsequent year.

MEASUREMENTS

Baseline Minimum Data Set items that could be potential risk factors for falling were considered as independent variables. The dependent variable was whether the resident fell as reported at the follow-up assessment. We estimated the extrinsic risk attributable to particular nursing home environments by calculating the annual fall rate in each nursing home and grouping them into tertiles of fall risk according to these rates.

RESULTS

Factors associated independently with falling were fall history, wandering behavior, use of a cane or walker, deterioration of activities of daily living performance, age greater than 87 years, unsteady gait, transfer independence, wheelchair independence, and male gender. Nursing home residents with a fall history were more than three times as likely to fall during the follow-up period than residents without a fall history. Residents in homes with the highest tertile of fall rates were more than twice as likely to fall compared with residents of homes in the lowest tertile, independent of resident-specific risk factors.

CONCLUSIONS

Fall history was identified as the strongest risk factor associated with subsequent falls and accounted for the vast majority of the predictive strength of the model. We recommend that fall history be used as an initial screener for determining eligibility for fall intervention efforts. Studies are needed to determine the facility characteristics that contribute to fall risk, independent of resident-specific risk factors.

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. Participants included 5,266 nursing home residents over the age of 65 with chewing and swallowing problems living in 272 Washington state nursing homes. Residents who had a feeding tube were identified. Baseline clinical characteristics and 12-month survival were compared for residents with and without feeding tubes. The proportion of tube-fed residents who became tube-free during the follow-up period was determined, and clinical features that predicted this outcome were examined.

RESULTS

Among the residents with chewing and swallowing problems, 10.5% had a feeding tube. After adjusting for potential confounding covariates, tube-fed residents had a significantly higher one-year mortality rate than those without feeding tubes (risk ratio, 1.44; 95% CI, 1.17-1.76). Of the 430 residents with feeding tubes who survived the follow-up period, 25.1% became free of a feeding tube. Age less than 87 years was associated with a significantly greater likelihood of becoming tube-free (odds ratio, 1.66; 95% CI, 1.03-2.6).

CONCLUSIONS

Residents selected for feeding tube placement have poorer survival after one year than residents who are not tube-fed. However, the feeding tubes are removed in a significant proportion of residents who survive one year. Residents with a potentially reversible condition, for whom the feeding tubes are a temporary intervention, need to be identified.

Biomechanical gait alterations independent of speed in the healthy elderly: evidence for specific limiting impairments

OBJECTIVES

It is not known whether changes in the biomechanics of elderly gait are related to aging per se, or to reduced walking speed in this population. The goals of the present study were to identify specific biomechanical changes, independent of speed, that might impair gait performance in healthy older people by identifying age-associated changes in the biomechanics of gait, and to determine which of these changes persist at increased walking speed.

DESIGN

Stereophotogrammetric and force platform data were collected. Differences in peak joint motion (kinematic) and joint moment and power (kinetic) values between healthy young and elderly subjects at comfortable and increased walking speed were measured.

SETTING

A gait laboratory.

SUBJECTS

Thirty-one healthy elderly (age 65 to 84 years) and 31 healthy young adult subjects (age 18 to 36 years), all without known neurologic, musculoskeletal, cardiac, or pulmonary problems.

MAIN OUTCOME MEASURES

All major peak kinematic and kinetic variables during the gait cycle.

RESULTS

Several kinematic and kinetic differences between young and elderly adults were found that did not persist when walking speed was increased. Differences that persisted at both comfortable and fast walking speeds were reduced peak hip extension, increased anterior pelvic tilt, and reduced ankle plantarflexion and ankle power generation.

CONCLUSION

Gait performance in the elderly may be limited by both subtle hip flexion contracture and ankle plantarflexor concentric weakness. Results of the current study should motivate future experimental trials of specific hip flexor stretching and ankle plantarflexor concentric strengthening exercises to preserve and potentially improve walking performance in the elderly.

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.

RESULTS

One hundred twelve articles met the inclusion criteria. The weighted mean (+/- SD) age for subjects in all trials was 62.2 +/- 3.9 years. Forty-two studies (37.5%) included subjects older than 75 years. However, in 31 articles (27.7%) it could not be determined if subjects older than 75 years were included. Among the 8 studies that provided the actual number of subjects within specific age groups, only 8 (5.5%) of 145 subjects were older than 75 years. Publication in the last decade was significantly associated with a decreased likelihood of including subjects older than 75 years (odds ratio, 0.19; 95% confidence interval, 0.06-0.62).

CONCLUSIONS

The relatively small number of subjects older than 75 years included in controlled trials of antiparkinsonian drugs seriously impedes our understanding of the efficacy and safety of these drugs in a large subgroup of frail patients for whom these products are prescribed. The tendency to exclude subjects of advanced age is highest in the most recently published articles that study new advances in pharmacotherapy. There is inadequate reporting of the age characteristics of subjects in clinical trials. This limitation hinders the synthesis of data regarding drug efficacy and toxicity relevant to older age groups.

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. Data were evaluated by power spectrum and transfer function analyses. During tilt, 27 subjects developed syncope or presyncope and 25 remained asymptomatic. Subjects with tilt-induced syncope had significantly greater increases in low-frequency (0.04-0. 15 Hz) systolic BP, diastolic BP, and HR power during tilt than the asymptomatic subjects (P </= 0.01). This difference was present during spontaneous but not paced breathing. However, average tidal volume, respiratory rate, minute ventilation, proportion of breaths below 0.15 Hz, and low-frequency respiratory power during tilt did not differ between syncopal and nonsyncopal subjects. Transfer magnitudes between low-frequency respiration and BP, and between BP and interbeat interval, were also similar between groups. Thus vasomotor instability before syncope is not related to alterations in respiration or the cardiovagal baroreflex but may reflect oscillating central sympathetic outflow to the vasculature.

Preliminary evidence for the evolution in complexity of heart rate dynamics during autonomic maturation in neonatal swine

Previous studies suggest that the autonomic nervous system plays an important role in the generation of complex heart rate dynamics. Therefore, we hypothesized that the complexity (irregularity) of cardiac interbeat intervals would evolve with the maturation of autonomic innervation to the heart. Twelve healthy newborn piglets were implanted with ECG transmitters and studied at one or more different ages up to 33 days of age, the period during which pigs develop functional sympathetic innervation of the heart from the stellate ganglia. Three animals underwent right stellate ganglionectomy, two a left stellate ganglionectomy, two a right cardiac vagotomy and five a sham procedure. The statistic, approximate entropy (ApEn), was used to quantify the regularity of interbeat interval fluctuations. Sham-operated animals showed an increase in the standard deviation (SD) and irregularity (ApEn) of cardiac interval fluctuations with increasing age. Right stellate ganglionectomized piglets had lower interbeat interval ApEn values, but similar SD's by 26-27 days of age compared to sham-operated animals. Left stellate ganglionectomy, which affects cardiac inotropy rather than chronotropy, had no effect on cardiac interval irregularity, while vagotomy had an indeterminant effect. The increasing irregularity of interbeat interval dynamics during autonomic maturation and the apparent attenuation of heartbeat irregularity when right stellate ganglion innervation is interrupted, provides empirical support for the notion that complex heartbeat dynamics in the mature animal are the result of a network of autonomic neural pathways that enables an organism to adapt to stress.

Syncope in the elderly

Age-related physiologic changes and disease-related abnormalities predispose older adults to syncope. It is important to know the physiologic changes that occur with normal aging to understand better their interaction with disease processes and to facilitate better evaluation and treatment of syncope when it occurs. Attention to situational stresses, such as posture changes, meals, or medications, is also likely to increase the diagnostic yield and improve therapeutic strategies that can reduce morbidity and potential mortality of recurrent episodes. Therapy should be directed toward minimizing multiple factors that contribute to syncope, avoiding iatrogenic medication effects, and treating specific contributory diseases.

Patterns of orthostatic blood pressure change and their clinical correlates in a frail, elderly population

OBJECTIVES

To determine patterns of within-day orthostatic blood pressure (BP) changes and clinical factors correlated with them in frail, elderly nursing home residents.

DESIGN

Prevalence study of orthostatic BP change.

SETTING

Sample of 45 nursing homes.

PARTICIPANTS

A total of 911 long-stay residents, aged 60 years or older, able to stand for at least 1 minute.

MAIN OUTCOME MEASURES

Supine and 1-minute and 3-minute standing BP measurements and heart rates, taken by a random-zero sphygmomanometer before and after breakfast and before and after lunch, symptoms upon standing, medication use, and clinical and functional assessments.

RESULTS

Four orthostatic hypotension (OH) groups were defined based on the frequency of a 20 mm Hg or greater orthostatic BP decline during any of 8 postural change measures: no OH group (48.5%); isolated OH group (only once, 18.3%); variable OH group (2-3 times, 19.9%); and persistent OH group (> or =4 times, 13.3%). Orthostatic hypotension was most prevalent before breakfast, especially 1 minute after standing (21.3%), and least prevalent after lunch after 3 minutes of standing (4.9%) (P=.001). A regression approach to repeated measures analysis (method of general estimating equations) showed the following to be significantly associated with OH (P< or =.05): elevated supine systolic BP before breakfast, dizziness/light-headedness on standing, male sex, medication for Parkinson disease, time of day (particularly before breakfast), greater independence in activities of daily living, and low body mass index.

CONCLUSIONS

Orthostatic hypotension occurs in more than half of frail, elderly nursing home residents, but is highly variable over time. It is most prevalent in the morning when subjects first arise and when supine BP is highest. The relationship of OH with elevated BP, but not antihypertensive medication use, suggests that the treatment of hypertension may improve postural BP regulation.

Short-term functional outcomes of long-term care residents with pneumonia treated with and without hospital transfer

OBJECTIVE

To determine 2-month mortality and functional status outcomes after resolution of pneumonia in older long-term care facility (LTCF) patients treated with and without hospital transfer.

DESIGN

Retrospective cohort study.

SETTING

Hebrew Rehabilitation Center for Aged, a 725-bed LTCF affiliated with an academic medical center, whose residents are cared for by staff physicians and geriatric fellows.

PATIENTS

LTCF residents with an acute episode of pneumonia, defined as a new respiratory sign or symptom and a new infiltrate on chest radiograph.

MEASUREMENTS

Functional decline or death in the 2 months after the resolution of pneumonia.

RESULTS

Of 312 cases of pneumonia, 246 (79%) were treated in the LTCF and 66 (21%) were treated in the hospital. Equal proportions of patients died of their pneumonia (13% vs 12%), but a larger proportion of those hospitalized had either worsening in their functional status or had died at 2 months (P = .005, Mantel-Haenszel trend test). In a logistic regression model controlling for differences between patients treated at the two sites, hospital treatment remained associated with poorer 2-month outcome (AOR 3.02, 95% CI 1.32, 7.22), with a significant interaction between respiratory rate and treatment site. LTCF treatment was associated with better 2-month outcomes only among patients with a lower respiratory rate. For these patients, the difference in outcome between LTCF treatment and hospital treatment was greatest for patients who were independent or mildly dependent at baseline.

CONCLUSIONS

In this academic LTCF, treatment for pneumonia without hospital transfer resulted in better 2-month outcomes compared with hospital treatment. Although the difference in outcome may be explained in part by differences between patients treated with and without hospital transfer, it persisted after correcting for these differences. The benefits of LTCF treatment appear to be greatest for those with less severe pneumonia and more independent functional status.

Effects of central muscarinic-1 receptor stimulation on blood pressure regulation

Stimulation of central nervous system muscarinic-1 (M1) receptors in animals increases blood pressure, heart rate, and sympathetic outflow. In Alzheimer's disease, stimulation of central M1 receptors is reduced. When the oral formulation of the selective M1 agonist xanomeline was tested for the treatment of Alzheimer's disease, an increased incidence of syncope was observed. Therefore, we used Alzheimer's disease as a model of relative M1 deficiency to determine the effect of M1 receptor stimulation on blood pressure regulation in humans. Eight Alzheimer's patients and 6 healthy age- and sex-matched subjects underwent blood pressure, heart rate, forearm vascular resistance, plasma norepinephrine, and heart rate variability measurements during 90 minutes after ingestion of xanomeline or placebo, then during 45 minutes of head-up tilt. Alzheimer's patients were studied on three occasions: after placebo, the first dose of xanomeline, and 3 days of xanomeline. Normal subjects were studied after placebo and the first dose of xanomeline. A subset of 5 Alzheimer's patients was studied with the peripheral muscarinic antagonist methscopolamine. Oral xanomeline increased supine systolic and diastolic blood pressures in normal subjects and heart rate and plasma norepinephrine in all subjects. During the placebo tilt, 0 of 8 Alzheimer's patients and 2 of 6 healthy subjects developed near-syncope, and during the first-dose xanomeline tilt, 4 of 8 Alzheimer's patients and 3 of 6 healthy subjects had near-syncope. The maximal decrease in systolic blood pressure during tilt was greater with xanomeline than placebo in both groups (P<.03). Methscopolamine did not prevent xanomeline-induced hypotension. Central M1 receptor stimulation with the oral formulation of xanomeline in humans is associated with sympathetic stimulation under supine conditions and impaired baroreflex compensation during tilt. Alzheimer's patients, who presumably lack M1 receptor activity, may have a reduced risk of tilt-induced syncope compared with normal subjects. Both groups, however, have enhanced susceptibility to hypotension and syncope when M1 receptor activity is pharmacologically increased.

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. Residents within this population who underwent feeding tube placement were identified. Clinical characteristics and survival for a period of 24 months were compared for residents who were and were not tube fed.

RESULTS

Among the residents with recent progression to severe cognitive impairment, 9.7% underwent placement of a feeding tube. Factors independently associated with feeding tube placement included age younger than 87 years (odds ratio [OR], 1.85; 95% confidence interval [CI], 1.25-2.78), aspiration (OR, 5.46; 95% CI, 2.66-11.20), swallowing problems (OR, 3.00; 95% CI, 1.81-4.97), pressure ulcer (OR, 1.64; 95% CI, 1.23-2.95), stroke (OR, 2.12; 95% CI, 1.17-2.62), less baseline functional impairment (OR, 2.07; 95% CI, 1.27-3.36), no do-not-resuscitate order (OR, 3.03; 95% CI, 1.92-4.85), and no dementia (OR, 2.17; 95% CI, 1.43-3.22). Survival did not differ between groups of residents with and without feeding tubes even after adjusting for independent risk factors for feeding tube placement.

CONCLUSIONS

There are specific risk factors associated with feeding tube placement in nursing home residents with severe cognitive impairment. However, there is no survival benefit compared with similar residents who are not tube fed. These prognostic data are important for health care providers, families, and patients making decisions regarding enteral nutritional support in long-term care.

Factors influencing subject willingness to participate in clinical gerontologic research

To identify factors influencing willingness to participate (WTP) in clinical gerontologic research, a questionnaire containing descriptions of seven research projects with a corresponding set of questions about perceived intrusiveness (discomfort and inconvenience), stipend, and other incentive factors was sent to 1004 community-dwelling research subject registry members. There was an inverse relationship between perceived level of intrusiveness and WTP. The more intrusive the study, the greater the relative influence of a stipend on WTP. Male gender and a new experience with an opportunity to learn were independently related to WTP. Subject ratings of perceived intrusiveness for each study component were entered into a factor analysis to guide the development of a three-tier "Level of Intrusiveness" scale. Although prospective validation is necessary, the Level of Intrusiveness scale may be useful in predicting WTP, and determining when other incentives are needed to improve subject recruitment for clinical research.

Age-related alterations in the fractal scaling of cardiac interbeat interval dynamics

We postulated that aging is associated with disruption in the fractallike long-range correlations that characterize healthy sinus rhythm cardiac interval dynamics. Ten young (21-34 yr) and 10 elderly (68-81 yr) rigorously screened healthy subjects underwent 120 min of continuous supine resting electrocardiographic recording. We analyzed the interbeat interval time series using standard time and frequency domain statistics and using a fractal measure, detrended fluctuation analysis, to quantify long-range correlation properties. In healthy young subjects, interbeat intervals demonstrated fractal scaling, with scaling exponents (alpha) from the fluctuation analysis close to a value of 1.0. In the group of healthy elderly subjects, the interbeat interval time series had two scaling regions. Over the short range, interbeat interval fluctuations resembled a random walk process (Brownian noise, alpha = 1.5), whereas over the longer range they resembled white noise (alpha = 0.5). Short (alpha s)- and long-range (alpha 1) scaling exponents were significantly different in the elderly subjects compared with young (alpha s = 1.12 +/- 0.19 vs. 0.90 +/- 0.14, respectively, P = 0.009; alpha 1 = 0.75 +/- 0.17 vs. 0.99 +/- 0.10, respectively, P = 0.002). The crossover behavior from one scaling region to another could be modeled as a first-order autoregressive process, which closely fit the data from four elderly subjects. This implies that a single characteristic time scale may be dominating heartbeat control in these subjects. The age-related loss of fractal organization in heartbeat dynamics may reflect the degradation of integrated physiological regulatory systems and may impair an individual's ability to adapt to stress.

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.

METHODS

Twenty elderly subjects with stable coronary artery disease (age, 76 +/- 4 [SD] years) underwent a baseline evaluation followed by a double-blind, randomized crossover comparison of nicardipine (20 mg by mouth t.i.d.) versus isosorbide (20 mg by mouth t.i.d.). Doppler echocardiography and a 15-minute 60-degree head-up tilt test were conducted on no study medications and then after successive 3-week treatment periods with nicardipine or isosorbide. Blood pressure, heart rate, vascular resistance, cardiac output, and spectral characteristics of heart rate and blood pressure variability were measured before and during each tilt.

RESULTS

Isosorbide treatment was associated with a higher prevalence of symptoms of cerebral hypoperfusion and a failure to increase systemic vascular resistance during tilt. While taking isosorbide subjects were able to preserve cardiac output and maintain upright blood pressure through enhanced cardioacceleration. During nicardipine treatment systemic vascular resistance and low-frequency blood pressure variability were reduced, but the ability to increase systemic vascular resistance during tilt was preserved.

CONCLUSIONS

Although nicardipine may decrease vascular responsiveness to sympathetic activation, the baroreflex-mediated vasoconstrictor response to upright tilt remains intact. In contrast, isosorbide impairs the systemic vascular response to orthostatic stress in elderly patients with stable coronary artery disease.

Restrictive left ventricular filling patterns in very old patients with congestive heart failure: clinical correlates and prognostic significance

OBJECTIVES

In certain younger patients with congestive heart failure (CHF), Doppler/echocardiography has identified a "restrictive" pattern of early diastolic ventricular filling characterized by very rapid early filling and a steep deceleration slope. We asked whether a similar restrictive pattern can be identified in very old patients with CHF, and if so, what are its clinical correlates and prognostic implications.

DESIGN

Retrospective cohort with prospective follow-up.

SETTING

Academic long-term care facility.

PARTICIPANTS

Thirty-nine residents with clinical CHF (age 89 +/- 5 (SD) years)

MEASUREMENTS

Transmitral Doppler flow, clinical characteristics, recurrent CHF episodes, hospitalizations, and mortality were measured.

RESULTS

Fifteen (38%) of the subjects had restrictive filling patterns, characterized by a ratio of early to late flow (E/A) > 1.00 and 24 (62%) had nonrestrictive patterns. The restrictive pattern was associated with a longer duration of CHF, more angina, and higher rate of symptomatic recurrences of CHF.

CONCLUSION

A restrictive diastolic filling pattern may represent a late stage in the evolution of congestive heart failure when left ventricular filling pressure is markedly increased. The treatment of CHF in older patients may need to account for different patterns of diastolic filling.

The epidemiology, clinical characteristics, and natural history of older nursing home residents with a diagnosis of Parkinson's disease

OBJECTIVE

To determine the epidemiology, clinical characteristics and natural history of nursing home residents with a diagnosis of Parkinson's disease (PD).

DESIGN

A cohort study with 18-month follow-up utilizing resident assessments from the National HealthCorp 1991-1992 dataset.

SETTING

Seventy-one National HealthCorp nursing homes.

PARTICIPANTS

A total of 5020 nursing home residents older than age 55 were studied. Residents with primary and secondary diagnoses of PD were identified from the population using the International Classification of Diseases, Ninth Revision, Clinical Modification code 332.0.

MEASUREMENTS

Baseline demographic and clinical characteristics were compared for residents with and those without Parkinson's disease. Outcome measures over the course of 18 months included death and functional status.

RESULTS

The prevalence of a diagnosis of PD was 6.8%. Significant factors associated independently with PD included: younger age (79 +/- 7 vs 81 +/- 9 years; P < .001), male sex (32% vs 23%; P < .001), severe dependence in activities of daily living (OR = 1.26; 95% CI 1.08-1.46), impared body control (OR = 1.38; 95% CI 1.03-1.68), symptoms of depression (OR = 1.29; 95% CI 1.02-1.64), and the number of daily medications (OR = 1.23; 95% CI 1.08-1.44). Residents with a diagnosis of PD had a faster rate of functional decline over 18 months (P < .001) but did not have a higher mortality rate than residents without PD.

CONCLUSIONS

Parkinson's disease is a relatively common diagnosis among nursing home residents and is associated with increased functional disability. There are several potentially modifiable conditions associated with PD that may offer an opportunity to design specific interventions and health services to improve the quality of life and slow functional decline in this frail population.

Intraindividual reproducibility of postprandial and orthostatic blood pressure changes in older nursing-home patients: relationship with chronic use of cardiovascular medications

OBJECTIVES

Although postprandial and orthostatic hypotension are commonly observed in nursing home residents, their reproducibility, relationship to each other, and association with chronic use of cardiovascular medications are poorly understood.

DESIGN

We examined blood pressure (BP) and heart rate (HR) before and after postural change, and before and after a 419-kcal meal in 22 nursing home residents (mean age 89 +/- 5 (SD) years), each on two occasions, to determine reproducibility changes. These studies were repeated in 17 residents, with and without previous administration of cardiovascular medications, in random order.

SETTING

Hebrew Rehabilitation Center for the Aged, an academic long-term care facility.

RESULTS

Systolic BP declined an average (+/- SE) of 16 +/- 4 mm Hg and 12 +/- 4 mm Hg during the first and second meal studies, respectively. Mean intra-class correlation of postprandial systolic BP values during the two studies was 0.88 (95% CI 0.85-0.97). Systolic BP increased significantly during the first posture test to a maximum of 8 +/- 6 mm Hg at 6 minutes. There was no significant difference over time in postural systolic BP between the two tests. Repeated postural studies showed a mean intra-class correlation of 0.72 (95% CI 0.62-0.92) for changes in systolic BP. Cardiovascular medications had no additional effect on postprandial or orthostatic BP and HR changes. During the first studies, 10 subjects had postprandial hypotension, and three subjects had orthostatic hypotension, but only two of 22 subjects had both.

CONCLUSIONS

Patterns of systolic BP response to meals or postural change are reproducible. BP responses to meals and postural change seem to be unaffected by potentially hypotensive medications in chronic users. Postprandial hypotension is distinct from orthostatic hypotension, occurring more commonly than orthostatic hypotension and infrequently together in the same patients.

Clinical and pathological correlates of apolipoprotein E epsilon 4 in Alzheimer's disease

Inheritance of the apolipoprotein E (apoE) epsilon 4 allele is associated with a high likelihood of developing Alzheimer's disease (AD). The pathophysiologic basis of this genetic influence is unknown. We reasoned that understanding the influence of apoE epsilon 4 on the clinical course and neuropathological features of AD may provide tests of potential mechanisms. We carried out a prospective longitudinal study to compare the age of onset, duration, and rate of progression of 359 AD patients to apoE genotype. Thirty-one of the individuals who died during the study were available for quantitative neuropathological evaluation. Statistically unbiased stereological counts of neurofibrillary tangles (NFTs) and A beta deposits were assessed in a high-order association cortex, the superior temporal sulcus. Analysis of clinical parameters compared with apoE genotype showed that the epsilon 4 allele is associated with an earlier age of onset but no change in rate of progression of dementia. Quantitative neuropathological assessment revealed that NFTs were strongly associated with clinical measures of dementia duration and severity but not with apoE genotype. A beta deposition, by contrast, was not related to clinical features but was elevated in association with apoE epsilon 4. These results indicate that apoE epsilon 4 is associated with selective clinical and neuropathological features of AD and support hypotheses that focus on an influence of apoE epsilon 4 on amyloid deposition.

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. Simultaneous heart rate and respiratory dynamics during 2.5 hours of sleep by fast Fourier transform analysis of beat to beat heart rate and of an electrocardiographically derived respiration signal.

RESULTS

All subjects had resting hypoxaemia at high altitude, with an average oxyhaemoglobin saturation of 81% (5%). There was no significant change in mean heart rate, but low frequency (0.01-0.05 Hz) spectral power was increased (P < 0.01) at high altitude. Time series analysis showed a complex range of non-linear sinus rhythm dynamics. Striking low frequency (0.04-0.06 Hz) heart rate oscillations were observed during sleep in eight subjects at high altitude. Analysis of the electrocardiographically derived respiration signal indicated that these heart rate oscillations correlated with low frequency respiratory oscillations.

CONCLUSIONS

These data suggest (a) that increased low frequency power during high altitude exposure is not simply attributable to increased sympathetic modulation of heart rate, but relates to distinctive cardiopulmonary oscillations at approximately 0.05 Hz and (b) that the emergence of periodic heart rate oscillations at high altitude is consistent with an unstable cardiopulmonary control system that may develop on acute exposure to hypoxaemic stress.

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. Six healthy premenopausal women were also studied. Continuous electrocardiographic and noninvasive radial artery blood pressure measurements and intermittent forearm blood flow recordings (by venous-occlusion plethysmography) were obtained before and after a 20-minute, 60 degrees head-up tilt and a 420-kcal meal during periods of spontaneous and metronomic breathing (at 0.25 Hz). Low-frequency (0.01- to 0.15-Hz) and high-frequency (0.15- to 0.50-Hz) heart rate and blood pressure spectral powers were compared with a fast Fourier transform. Cardiovascular and heart rate spectral power responses to upright tilt and meal digestion were the same in postmenopausal estrogen users and nonusers. However, during spontaneous breathing the blood pressure spectral power responses to upright tilt and meal ingestion were significantly different between the two groups of women. The low-frequency systolic pressure power response to upright tilt was smaller in estrogen users than nonusers (P = .01). After meal ingestion nonusers had an early postprandial fall (20 to 30 minutes after the meal) and late rise (50 to 60 minutes) in low-frequency systolic and diastolic pressure powers, which were significantly attenuated in estrogen users (P < .02).(ABSTRACT TRUNCATED AT 250 WORDS)

Depression in a long-term care facility: clinical features and discordance between nursing assessment and patient interviews

OBJECTIVE

Nurses commonly observe more depression than is diagnosed and treated in nursing homes. Accordingly, we aimed to describe the clinical features of untreated nursing home residents whom nurses identify as depressed and to compare nurse ratings of depressed nursing home residents with ratings from direct interviews and patient self-reports.

DESIGN

Cross-sectional survey followed by semi-structured diagnostic interviews of depressed patients and their nurses.

SETTING

A large academic, multi-level, long-term care facility.

PARTICIPANTS

Thirty-seven patients aged 74-99 (mean age 88.4) whom nurses identified as having daily symptoms of depression. Subjects had Mini-Mental State Exam (MMSE) scores > 10 (mean score 21.2), were not acutely or terminally ill, and were able to participate in an interview.

MEASUREMENTS

DSM-III-R mood diagnoses and separate ratings of interviews with nurses and patients using the Cornell Scale for Depression.

RESULTS

Nurses observed daily symptoms of depression in 110 of 495 (22%) long-term care residents on units not reserved for advanced dementia. Of these 110 patients, 58 (53%) were not receiving antidepressants. Of 37 patients eligible for interviews, nine met criteria for major depression, 20 met criteria for another non-major depression diagnosis, and eight did not have a diagnosable mood disorder. Cornell scale ratings derived exclusively from interviews of nurses were similar across the three diagnostic groups (12.5, 9.9, and 9.5, respectively; P = .31; mean 10.5), whereas Cornell scale ratings from patient interviews differed among groups (15.9, 6.9, and 4.1, respectively; P < .001; mean 8.4). Correlation between nurse Cornell ratings and patient Cornell ratings was poor (r = .27), especially for patients with non-major forms of depression (r = -.20). MMSE and Cumulative Illness Rating Scale (CIRS-G) scores were similar in the three groups.

CONCLUSIONS

Nurses frequently observed symptoms of depression in a long-term care setting, and many symptomatic patients were not being treated with antidepressants. In these patients, nurse-derived symptom ratings did not vary across DSM-III-R diagnostic categories and correlated poorly with ratings from direct patient interviews. These findings suggest that nurse caregivers may contribute important diagnostic information about non-major depression and raise questions about the application of standard diagnostic categories to late-life depression in the nursing home.

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. Mediolateral posturographic measures were also associated with a history of falls and poor performance on clinical measures of balance. It is hypothesized that the increase in mediolateral activity in subjects with IPD may reflect an attempt to maintain potentially stabilizing movements during quiet standing in the face of impaired movement in the anteroposterior direction. This study supports the notion that mediolateral instability is an important posturographic marker of functional balance impairment in the elderly.