Movement and sound generation by the toadfish swimbladder

Although sound-producing (sonic) muscles attached to fish swimbladders are the fastest known vertebrate muscles, the functional requirement for such extreme speed has never been addressed. We measured movement of the swimbladder caused by sonic muscle stimulation in the oyster toadfish Opsanus tau and related it to major features of the sound waveform. The movement pattern is complex and produces sound inefficiently because the sides and bottom of the bladder move in opposite in and out directions, and both movement and sound decay rapidly. Sound amplitude is related to speed of swimbladder movement, and slow movements do not produce perceptible sound. Peak sound amplitude overlaps fundamental frequencies of the male's mating call because of muscle mechanics and not the natural frequency of the bladder. These findings suggest that rapid muscle speed evolved to generate sound from an inefficient highly damped system.

A comparison of mobility assessments in a geriatric day hospital

OBJECTIVE

To assess the sensitivity of the Elderly Mobility Scale (EMS) to detect improvements in mobility after physiotherapy in comparison with the Barthel Index (BI) and Functional Ambulation Category (FAC) in routine clinical day hospital practice.

SUBJECTS

Eighty-three patients who completed a course of physiotherapy were studied.

METHODS

Each was assessed by an independent physiotherapist before and after a programme of physiotherapy, using the EMS, BI and FAC.

RESULTS

The mean age was 79 years (SD 7.7). Fifty-three out of 83 (64%) patients were female and 92% were community dwelling. The median number of physiotherapy sessions undergone by each patient was 9 (range 3-51). All three scales detected an improvement in mobility with physiotherapy (p < 0.001). However, using the EMS, 68 out of 82 (83%) patients had a detectable improvement in mobility compared with only 34 out of 80 (42%) using the BI and 28 out of 81 (35%) using the FAC. Using a matched-pairs comparison, the EMS was significantly more likely to detect an improvement in mobility following physiotherapy within the study group than the BI (p < 0.001) or the FAC (p < 0.001).

CONCLUSION

Although all three scales detected improvements in mobility, the EMS detected mobility improvements in a significantly greater number of patients.

The association between antiulcer medication and initiation of cobalamin replacement in older persons

As chronic use of antiulcer medications might predispose older persons to cobalamin deficiency, we studied participants (> 65 years) in the clinical examination of the Canadian Study of Health and Aging to test the association between the use of an antiulcer medication (histamine-2 blocker or proton pump inhibitor) at baseline with initiation of cobalamin replacement during the 5 year follow-up period. Of 1054 eligible subjects, 125 (11.7%) were taking an antiulcer medication at baseline. At follow-up, 49 (4.6%) had started cobalamin replacement. Antiulcer medication use at baseline was significantly associated with the initiation of cobalamin therapy (odds ratio 2.56, 95% confidence interval 1.30-5.05), even after adjusting for age, gender and institutional residence (odds ratio 2.61, 95% confidence interval 1.31-5.23). There is an independent association between the use of antiulcer medication and initiation of cobalamin therapy. While the relationship is not unambiguously causal, this finding underscores the need for judicious prescribing of antiulcer medications for older persons.

Influence of bone densitometry results on the treatment of osteoporosis

BACKGROUND

Measurement of bone mineral density is widely used to diagnose osteoporosis. The objectives of this study are to determine how bone densitometry affects subsequent treatment of osteopenia and osteoporosis with either hormone replacement therapy or bisphosphonates and to examine clinical factors associated with starting either therapy after bone densitometry.

METHODS

We conducted a prospective study involving women over 50 years of age who were referred to a tertiary care hospital for the first time to undergo bone density measurement using dual-energy x-ray absorptiometry (DXA). Baseline clinical data were collected through face-to-face interviews before the test. Subsequently, the scans were reviewed and categorized as showing no bone loss, osteopenia or osteoporosis, based on World Health Organization criteria. Three months after DXA, subjects were contacted by telephone to determine their understanding of the test results and any new treatments started or recommended since the scan.

RESULTS

Of 383 women recruited at the time of their DXA, 335 (87.5%) completed the 3-month follow-up. Among those reached at follow-up, DXA results showed no bone loss in 119 (35.5%), osteopenia in 137 (40.9%) and osteoporosis in 79 (23.6%). The proportion of subjects with osteoporosis receiving either hormone replacement therapy or bisphosphonate therapy was 15.2% before the test, increasing to 63.3% after the scan. The following factors were independently associated with the initiation of either therapy: actual DXA result showing osteoporosis (odds ratio [OR] 7.2; 95% confidence interval [CI] 1.7-30.3), compared with a normal scan; subjects' perception that their scan showed bone loss (osteopenia, or osteoporosis) (OR 13.5; 95% CI 4.0-45.5) or that they were unclear about the results (OR 5.4; 95% CI 1.6-18.8), compared with the perception that the results were normal; and discussion of the DXA results with a physician (OR 5.5; 95% CI 1.9-16.0).

INTERPRETATION

The proportion of women with osteoporosis receiving hormone replacement therapy or bisphosphonate therapy increases after diagnosis with densitometry. However, communication by physicians so that patients understand their test results is a critical component in the initiation of therapy after bone densitometry.

A decision aid for long-term tube feeding in cognitively impaired older persons

OBJECTIVE

To describe the development and evaluation of a decision aid for long-term tube feeding in cognitively impaired older people.

DESIGN

Before-and-after study.

SETTING

Acute care hospitals in Ottawa, Canada.

PARTICIPANTS

Substitute decision makers for 15 cognitively impaired inpatients 65 years and older being considered for placement of a percutaneous endoscopic gastrostomy tube.

MEASUREMENTS

Questionnaires were used to compare the substitute decision makers' knowledge, decisional conflict, and predisposition regarding feeding tube placement before and after exposure to the decision aid. The acceptability of the decision aid was also assessed.

RESULTS

Substitute decision makers significantly increased their knowledge (P = .004) and decreased their decisional conflict (P = .004) regarding long-term tube feeding after using the decision aid. The impact of the decision aid on predisposition toward the intervention was greatest for those who were unsure of their preferences at baseline. All substitute decision makers found the decision aid helpful and acceptable despite very difficult and emotional circumstances.

CONCLUSIONS

A decision aid improves the decision-making process for long-term tube feeding in cognitively impaired older patients by decreasing decisional conflict and by promoting decisions that are informed and consistent with personal values. There are particular challenges for developing and evaluating these tools in the context of end-of-life decisions.

A cross-national comparison of institutionalized tube-fed older persons: the influence of contrasting healthcare systems

OBJECTIVE

Different health care settings may influence the type of patients selected for long-term tube-feeding. Clinical characteristics of older, tube-fed institutionalized subjects living in Ontario, Canada were compared with those in the United States (US).

DESIGN

A cross-sectional cohort study Setting: Nursing homes in the states of Mississippi, Texas, and Vermont (US) and chronic care facilities in Ontario.

PARTICIPANTS

Tube-fed residents older than age 65 living in facilities in the US between January 1, 1996, and March 31, 1997 (n = 859), and in institutions in Ontario between January 1, 1996, and December 31, 1997 (n = 913).

MEASUREMENTS

Data were obtained from Minimum Dataset assessments at both sites. Demographic and clinical characteristics were compared between tube-fed subjects living in the US and those in Canadian facilities.

RESULTS

In a logistic regression model, the following characteristics were significantly more likely to be found among tube-fed subjects in the US than in those in Ontario: greater impairment of cognitive performance, cardiopulmonary disease, a diagnosis of dementia, female, and age greater than 80 years. Characteristics that were significantly less likely to be present among the US tube-fed subjects included: recurrent lung aspirations, a chewing or swallowing problem, do not resuscitate status, restraint use, weight loss, and stroke.

CONCLUSIONS

Clinical characteristics differ between older, institutionalized tube-fed subjects in Ontario and in US nursing homes. In order to put these differences into context, consideration must be given to how the contrasting healthcare systems in these two countries may drive decision-making for long-term tube-feeding.

Survival after percutaneous endoscopic gastrostomy placement in older persons

BACKGROUND

The prolongation of life is an important consideration in the decision to initiate long-term tube feeding. This report critically synthesizes the evidence regarding the impact of percutaneous endoscopic gastrostomy (PEG) tube placement on survival in older persons.

METHODS

A systematic search was conducted using MEDLINE from January 1980 until January 1999. Articles reporting survival data in older persons (mean or median age >65 years) after PEG tube placement were identified. The number and age of subjects, length of follow-up, setting, and survival data were extracted from all eligible studies. Mortality data at 1, 2, 6, and 12 months after PEG placement were quantitatively synthesized. Clinical characteristics associated with decreased survival among subjects with PEG tubes were identified.

RESULTS

Five cohort studies compared survival in patients with and without feeding tubes in nursing homes, but none demonstrated a survival benefit. Another cohort study reported increased survival for tube-fed patients with amyotrophic lateral sclerosis. The pooled proportion of all subjects surviving after PEG placement was as follows: 1 month = 0.81 (95% confidence interval [CI], 0.74-0.88), 2 months = 0.70 (95% CI, 0.65-0.74), 6 months = 0.56 (95% CI, 0.20-0.92), and 12 months = 0.38 (95% CI, 0.26-0.49). Advanced age and malignancy were the factors most often reported to be associated with poorer survival among subjects with PEG tubes.

CONCLUSIONS

The impact of PEG placement on survival is not known because the level of evidence is limited. PEG tubes may prolong life in selected populations. However, the majority of older patients selected for PEG placement will not survive 1 year after the procedure. Certain factors may identify those patients more likely to derive a survival benefit from long-term tube feeding. This information may offer some guidance to decision makers for whom prolongation of life is an important factor in the tube-feeding decision.

A retrospective comparison of abdominal muscle strength following breast reconstruction with a free TRAM or DIEP flap

Abdominal weakness is a known potential complication of breast reconstruction with a pedicled or free TRAM flap. It has been presumed that the DIEP flap, which involves no muscle resection, does not compromise abdominal muscle strength but little objective research exists to substantiate this. The aims of this retrospective study were to compare abdominal muscle strength following free TRAM flap and DIEP flap, to compare both groups with a control group and to establish the effect of both procedures on functional activities. Fifty women (23 with a DIEP flap, 27 with a free TRAM flap) plus 32 non-operated controls underwent assessment of their abdominal and back extensor muscle strength on a KIN COM isokinetic dynamometer. Two questionnaires were used to establish the impact on function. The TRAM flap group had significant weakness of the abdominal and back extensor muscles compared with the DIEP flap group and the control group. The trend was for the DIEP flap group to have weaker abdominal muscles than the control group. There was a higher level of abdominal pain and a greater number of reported functional difficulties in the TRAM flap group than in the DIEP flap group. This study demonstrates that whilst the DIEP flap can reduce the strength deficit caused by the free TRAM flap, abdominal weakness can still result from the DIEP flap. A randomised controlled trial is currently underway to investigate the effect of preoperative abdominal exercises in preventing/minimising postoperative abdominal muscle weakness in this group.

Migration of polyethylene particles around stable implants in an animal model

The aim of this study was to test the hypothesis that a tight seal between bone and implant will eliminate the avenue of particle migration around stable implants. Three types of implants were used in rabbits (polished press-fit Ti-6Al-4V or plasma-sprayed hydroxyapatite [HA]-coated Ti-6Al-4V) or doughy stage polymethyl methacrylate (PMMA). Implants were placed in the condylar notch. Each animal received an intra-articular injection of high density polyethylene (PE) particles (10(8) in 0.4 mL; mean size 4.7 microns) at 4 and 6 weeks postoperatively. Eight weeks postoperatively, peri-implant tissues were examined for PE particles and osteolysis. In all cases, intracellular PE particles were seen at the bone-implant interface and within marrow. No osteolysis was observed. Bone apposition was determined by computerized image analysis. There was no significant difference in the percentage of bone apposition (+/- SD) among the three groups of implants: Ti-6Al-4V (68% +/- 19%), HA-coated Ti-6Al-4V (70% +/- 10%), and PMMA (59% +/- 12%). These results indicate that a polished Ti-6Al-4V surface is as effective as PMMA or HA coating in limiting migration of PE particles around stable osseointegrated implants in rabbits.

Tracheal rupture associated with intubation in cats: 20 cases (1996-1998)

OBJECTIVE

To characterize clinical features of tracheal rupture associated with endotracheal intubation in cats and to evaluate the most appropriate treatment for this condition.

DESIGN

Retrospective study.

ANIMALS

20 cats with a history of endotracheal intubation that subsequently developed dyspnea or subcutaneous emphysema.

PROCEDURE

Medical records of cats with a presumptive diagnosis of tracheal rupture associated with intubation were reviewed. Clinical and clinicopathologic data were retrieved.

RESULTS

Cats were evaluated 5 hours to 12 days after a surgical or medical procedure requiring general anesthesia with intubation had been performed. Fourteen (70%) cats were evaluated after dental prophylaxis. All cats radiographed had pneumomediastinum and subcutaneous emphysema. Eighteen of 19 cats were initially treated medically. Duration of medical treatment for cats that did not have surgery ranged from 12 to 72 hours. Cats that had surgery received medical treatment 3 to 24 hours prior to the surgical procedure. Medical treatment alone was administered to 15 cats that had moderate dyspnea, whereas surgical treatment was chosen for 4 cats that had severe dyspnea (open-mouth breathing despite treatment with oxygen) or worsening subcutaneous emphysema. Eighteen cats had improvement of clinical signs, 1 cat died after surgery, and 1 cat died before medical or surgical intervention.

CONCLUSIONS AND CLINICAL RELEVANCE

Most cats with tracheal rupture associated with intubation can be treated medically. Cats with worsening clinical signs (severe dyspnea, suspected pneumothorax, or worsening subcutaneous emphysema) should have surgery performed immediately to correct the defect.

The association between parkinsonism, Alzheimer's disease, and mortality: a comprehensive approach

BACKGROUND

The impact of parkinsonism on survival in older persons independent of dementia is not well understood.

METHODS

Participants in the clinical examination of the Canadian Study of Health and Aging who had parkinsonism and were older than age 65 were identified. The impact of parkinsonism on 5-year survival was determined for a combined cohort with and without dementia, and a stratified analysis was then conducted for the subgroups with Alzheimer's disease (AD) and those without dementia. Subjects with a previous diagnosis of Parkinson's disease and those prescribed drugs causing extrapyramidal side effects were excluded.

FINDINGS

A total of 721 subjects with AD and 1705 subjects without dementia were examined. After adjusting for age and residential status (community vs institution), parkinsonism was associated with poorer survival in the combined cohort (risk ratio 1.51; 95% CI, 1.22-1.85), in those with AD (risk ratio 1.34; 95% CI, 1.02-1.76), and those without dementia (risk ratio 1.54; 95% CI, 1.11-2.15). In the combined cohort, parkinsonism remained independently associated with higher mortality after adjusting for AD status (risk ratio 1.39; 95% CI, 1.13-1.72). In the subgroup with AD, parkinsonism remained associated with poorer survival after adjusting for severity of cognitive impairment (risk ratio 1.33; 95% CI. 1.04-1.74).

INTERPRETATION

Parkinsonism is significantly associated with poorer survival in older persons, regardless of whether they have dementia.

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.

Patterns of outcome measurement in Parkinson's disease clinical trials

The study examines the pattern of use and clinimetric properties of clinical endpoints used in randomized trials for Parkinson's disease (PD). Randomized drug trials for PD were identified through a Medline search conducted from January 1966 until August 1998. The endpoints used in these trials were abstracted. Reports examining the clinimetric properties of the disease-specific scales used in these trials were also abstracted. Data regarding the consistency, accuracy, discrimination and feasibility of scales used in at least 10% of trials were determined. One hundred and thirty-seven articles met the inclusion criteria; 70.8% of trials used some clinical scale for PD as an endpoint. The Unified Parkinson's Disease Rating Scale (UPDRS) was the most commonly used scale (32.8%). Factors independently associated with the use of the UPDRS included: the study location in the US, mean age of subjects over 62.7 years and publication after 1994. The UPDRS was more thoroughly studied and superior in most clinimetric domains compared to scales developed earlier. Few studies included generic health status (2.9%) or cognitive measures (16.8%) as secondary endpoints. There have been definite improvements in the area of disease-specific measurement in PD trials since the introduction of the UPDRS. The results of studies that used instruments with poor or unreported clinimetric properties should be critically interpreted.

Assessing the quality of newspaper medical advice columns for elderly readers

BACKGROUND

Medical advice columns in newspapers can provide a valuable service by educating the general public about important health-related issues. However, these columns may be harmful if the advice or information given in them is incomplete, inappropriate or misleading. The objective of this study was to assess the safety and appropriateness of advice given to elderly readers of newspapers in medical advice columns.

METHODS

Medical advice columns published in Canadian newspapers in 1995 were identified from a CD-ROM database. The articles that were selected were published in English and contained medical advice pertinent to elderly people about topics that could be found in a textbook of geriatric medicine. Fifty articles, randomly selected from the 109 articles that met these criteria, were independently assessed by 5 geriatricians. A scoring system was used to rate the ability to determine to which population the article applied, how well fact was distinguished from opinion, the degree to which critical issues were addressed, the safety and the appropriateness of the advice. When the kappa statistic for inter-rater agreement was 0.74 or less, a 2-stage Delphi process was used in an attempt to reach consensus.

RESULTS

Agreement (kappa > 0.74) was eventually achieved for 232 (92.8%) of the 250 ratings. In 4 (8%) of the articles there was a high probability that the advice given could be applied to the wrong patient population; in 7 (14%) there was a high probability that opinion might be interpreted as fact; and in 11 (22%) the major critical issues were not identified. Of greatest concern, however, the advice in 25 (50%) of the articles was judged to be inappropriate, and in 14 (28%) advice may have been dangerous and potentially life-threatening.

INTERPRETATION

Although medical advice columns have the potential to improve the health of elderly readers, a significant percentage of these articles contain inappropriate or even potentially dangerous advice.

Decision-making for long-term tube-feeding in cognitively impaired elderly people

BACKGROUND

The decision to start long-term tube-feeding in elderly people is complex. The process by which such decisions are made is not well understood. The authors examined the factors involved in the decision to start long-term tube-feeding in cognitively impaired older people from the perspective of the substitute decision-maker.

METHODS

A telephone survey was administered to the substitute decision-makers of tube-fed patients over 65 years old in chronic care facilities in Ottawa. Subjects were recruited from September 1997 to March 1998. Patients were incapable of making their own decisions about tube-feeding. Data were collected on sociodemographic factors, patients' health status, advance directives, communication between the substitute decision-maker and the health care team, and the decision-maker's perceived goals of tube-feeding and satisfaction with the decision regarding tube-feeding.

RESULTS

Among the 57 cases in which the patient was eligible for inclusion in the study, 46 substitute decision-makers agreed to participate. Most of the patients had not given advance directives, and only 26 substitute decision-makers (56.5%) were confident that the patient would want to be tube-fed. A physician spoke with the substitute decision-maker about tube-feeding for 15 minutes or less in 17 cases (37.0%) and not at all in 13 cases (28.3%). Most of the substitute decision-makers (39 [84.8%]) felt that they understood the benefits of tube-feeding, but less than half (21 [45.7%]) felt that they understood the risks. The prevention of aspiration and the prolongation of life were the medical benefits most often cited as reasons for tube-feeding. Just over half (24 [52.2%]) of the substitute decision-makers felt that they had received adequate support from the health care team in making the decision. Substitute decision-makers of patients less than 75 years old were more likely than those of older patients to feel supported (odds ratio [OR] 4.2, 95% confidence interval [CI] 1.0-17.9). Compared with the physician's making the decision independently, substitute decision-makers felt more supported if they primarily made the decision (OR 16.5, 95% CI 2.7-101.4) or if they made the decision together with the physician (OR 5.3, 95% CI 1.0-27.9). Most (20 [43.5%]) of the substitute decision-makers did not feel that tube-feeding improved the patient's quality of life, and less than half (21 [45.7%]) indicated that they would choose the intervention for themselves.

INTERPRETATION

The substitute decision-making process for tube-feeding in cognitively impaired elderly people is limited by a need for advance directives, lack of confidence in substituted judgement and poor communication of information to the substitute decision-maker by the health care team.

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.

Radiologic diagnosis and staging of head and neck squamous cell carcinoma

The predominant extracranial head and neck cancer in adults is squamous cell carcinoma. The purpose of this article is to discuss the radiographic evaluation of these patients with CT scans or MR imaging before therapeutic intervention. Specific focus is given to the efficacy of CT scans and MR imaging, as an adjunct to clinical staging for evaluation of the primary tumor, and metastatic adenopathy. MR imaging, because of its improved soft tissue contrast and multiplanar capability, is probably superior to CT scans for evaluation of the primary tumor in patients with squamous cell carcinoma. CT scans, however, remain the gold standard for identifying metastatic adenopathy and in most institutions remain the study of choice for evaluating this patient population.

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.

Interaction of stress, smoking, and dietary restraint in women

Smoking cessation often results in weight gain but certain subtypes of smokers may be more likely than others to gain weight. Women high in dietary restraint ("restrainers") increase food intake and gain more weight than nonrestrainers during smoking cessation. Restrainers have also been reported to increase food intake following laboratory stressors. Therefore, the present study was designed to measure the influence of stress on food intake and subjective distress during acute smoking abstinence in restrained and nonrestrained women. Participants were 48 women, 18-40 years old, comprising six groups (n = 8 per group) in a 2 x 3 x 2 design. Groups consisted of two levels of restraint (restrained and nonrestrained) and three levels of smoking (ad lib. smokers, abstinent smokers, and nonsmokers), whereas the within-participant manipulation involved two sessions differing in stress (stress and control). Snack foods were available for consumption. Results showed that distress, measured by the Stress-Arousal Checklist and visual analogue measures of tension and anxiety, was higher in the stress session for all groups except for restrainers who smoked ad lib. Furthermore, distress was significantly higher in smoke-abstinent restrainers during the stress session than all other conditions. However, despite differences in distress, no effect was observed for food intake. Desire for a cigarette showed a sharper increase over the stress session for restrainers compared with nonrestrainers but did not differ in the control session. These data suggest that restrainers may use smoking to reduce distress and may increase smoking, but not eating, during stress.

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.

Increased gait unsteadiness in community-dwelling elderly fallers

OBJECTIVE

To test the hypothesis that quantitative measures of gait unsteadiness are increased in community-dwelling elderly fallers.

STUDY DESIGN

Retrospective, case-control study.

SETTING

General community.

PARTICIPANTS

Thirty-five community-dwelling elderly subjects older than 70 years of age who were capable of ambulating independently for 6 minutes were categorized as fallers (age, 82.2 +/- 4.9 yrs [mean +/- SD]; n = 18) and nonfallers (age, 76.5 +/- 4.0 yrs; n = 17) based on history; 22 young (age, 24.6 +/- 1.9 yrs), healthy subjects also participated as a second reference group.

MAIN OUTCOME MEASURES

Stride-to-stride variability (standard deviation and coefficient of variation) of stride time, stance time, swing time, and percent stance time measured during a 6-minute walk.

RESULTS

All measures of gait variability were significantly greater in the elderly fallers compared with both the elderly nonfallers and the young subjects (p < .0002). In contrast, walking speed of the elderly fallers was similar to that of the nonfallers. There were little or no differences in the variability measures of the elderly nonfallers compared with the young subjects.

CONCLUSIONS

Stride-to-stride temporal variations of gait are relatively unchanged in community-dwelling elderly nonfallers, but are significantly increased in elderly fallers. Quantitative measurement of gait unsteadiness may be useful in assessing fall risk in the elderly.

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.

Altered fractal dynamics of gait: reduced stride-interval correlations with aging and Huntington's disease

Fluctuations in the duration of the gait cycle (the stride interval) display fractal dynamics and long-range correlations in healthy young adults. We hypothesized that these stride-interval correlations would be altered by changes in neurological function associated with aging and certain disease states. To test this hypothesis, we compared the stride-interval time series of 1) healthy elderly subjects and young controls and of 2) subjects with Huntington's disease and healthy controls. Using detrended fluctuation analysis we computed alpha, a measure of the degree to which one stride interval is correlated with previous and subsequent intervals over different time scales. The scaling exponent alpha was significantly lower in elderly subjects compared with young subjects (elderly: 0.68 +/- 0.14; young: 0.87 +/- 0.15; P < 0.003). The scaling exponent alpha was also smaller in the subjects with Huntington's disease compared with disease-free controls (Huntington's disease: 0.60 +/- 0.24; controls: 0.88 +/-0.17; P < 0.005). Moreover, alpha was linearly related to degree of functional impairment in subjects with Huntington's disease (r = 0.78, P < 0.0005). These findings demonstrate that strike-interval fluctuations are more random (i.e., less correlated) in elderly subjects and in subjects with Huntington's disease. Abnormal alterations in the fractal properties of gait dynamics are apparently associated with changes in central nervous system control.