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Biomedical subjects

T M Gill

Publications and source records attributed to T M Gill.

At least 19 recordsLinked to original sources
PubMed2006

The ethanol self-administration context as a reinstatement cue: acute effects of naltrexone.

A major difficulty in treating alcohol addiction is the high rate of relapse even after prolonged abstinence. Relapse can be triggered by several factors, including stress, re-exposure to the drug, conditioned discrete stimuli and exposure to the context in which alcohol consumption occurred. The present study investigated the role played by the environmental context on ethanol relapse using an extinction/reinstatement animal model: rats were trained to self-administer ethanol in a distinctive context, and extinction occurred in a setting that differed by visual, tactile and olfactory properties; reinstatement was tested by placing the animals into the ethanol-associated context in the absence of ethanol. We found that re-exposure to the ethanol-associated context significantly increased responses on the ethanol-paired lever. The increase in responding required the presence of the complete configuration of the multimodal context. The non-selective opioid receptor antagonist naltrexone (0.3 mg/kg) administered 20 min prior to the reinstatement test significantly attenuated context-induced reinstatement of lever press responding, compared with saline-treated subjects. These data indicate that the environmental context associated with ethanol availability influences ethanol-seeking behavior in the rat, and that endogenous opioids are involved in this process. Our findings are in accordance with clinical reports demonstrating naltrexone efficacy in the treatment of alcohol relapse in humans, and indicate that the context-induced reinstatement model described here may be useful to investigate the biological mechanisms underlying alcohol relapse.

Alcohol Drinking↗
PubMed2001

Restricted activity among community-living older persons: incidence, precipitants, and health care utilization.

BACKGROUND: Restricted activity is a potentially important indicator of health and functional status. Yet, relatively little is known about the incidence, precipitants, or health care utilization associated with restricted activity among older persons. OBJECTIVE: To more accurately estimate the rate of restricted activity among community-living older persons, to identify the health-related and non-health-related problems that lead to restricted activity, and to determine whether restricted activity is associated with increased health care utilization. DESIGN: Prospective cohort study. SETTING: New Haven, Connecticut. PARTICIPANTS: 754 nondisabled members of a large health plan, 70 years of age or older, who were categorized according to their risk for disability (low, intermediate, or high). MEASUREMENTS: Occurrence of restricted activity (defined as having stayed in bed for at least half a day or having cut down on one's usual activities because of an illness, injury, or another problem), problems leading to restricted activity, and health care utilization were ascertained during monthly telephone interviews for up to 2 years. RESULTS: In median follow-up of 15 months, 76.6% of participants reported restricted activity during at least 1 month and 39.3% reported restricted activity during 2 consecutive months. The rates of restricted activity per 100 person-months were 19.0 episodes for all participants and 16.9, 27.3, and 22.7 episodes for participants at low, intermediate, and high risk for disability, respectively. Of the 24 prespecified health-related and non-health-related problems, the rates per 100 person-months of restricted activity ranged from 0.1 episode for "problem with alcohol" to 65.5 episodes for "been fatigued." On average, participants identified 4.5 different problems as a cause for their restricted activity. Health care utilization was substantially greater during months with restricted activity than months without restricted activity. The corresponding rates per 100 person-months were 63.8 and 45.1 for physician office visits, 12.5 and 1.0 for emergency department visits, 14.1 and 0.3 for hospital admissions, and 67.6 and 45.1 for any health care utilization (P < 0.001 for each pairwise comparison). CONCLUSIONS: Restricted activity is common among community-living older persons, regardless of risk for disability, and it is usually attributable to several concurrent health-related problems. Although restricted activity is associated with a substantial increase in health care utilization, older persons with restricted activity often do not seek medical attention.

Activities of Daily Living↗
PubMed2001

Two recruitment strategies for a clinical trial of physically frail community-living older persons.

OBJECTIVES: To compare the efficiency and cost of two distinct but complementary recruitment strategies for a clinical trial of physically frail, community-living persons, age 75 and older. DESIGN: In the first recruitment strategy, potential participants were identified and screened for physical frailty during office visits to their primary care physicians; in the second, potential participants were identified from the patient rosters of primary care physicians and were screened for physical frailty in their home. Physical frailty was defined on the basis of slow gait speed and inability to stand from a chair with one's arms folded. SETTING: General community in greater Bridgeport, Connecticut. PARTICIPANTS: Community-living persons, age 75 and older, who met criteria for physical frailty. MEASUREMENTS: Measures of efficiency included the number of persons screened for each participant randomized, the number of persons eligible for each participant randomized, and the refusal rate. Costs were calculated per randomized participant. RESULTS: One hundred eighty-eight participants, with a mean age of 83.2 years, were enrolled over 22 months. One hundred and one participants were enrolled via the office-based strategy; 87 were enrolled via the roster-based strategy. Participants in each group had considerable quadriceps weakness and performed poorly on objective measures of gait and upper- and lower-extremity function. For each participant randomized, the number of persons screened, number of persons eligible, and cost were 15.2, 1.2, and $868, respectively, for the office-based strategy and 11.6, 1.1, and $764, respectively, for the roster-based strategy. The corresponding refusal rates for the two strategies were 14.9% and 10.1%, respectively (P < .001). CONCLUSIONS: Although each recruitment strategy successfully identified older persons who were physically frail, the roster-based strategy was less expensive and performed modestly better on each measure of efficiency than the office-based strategy.

Aged↗
PubMed2001

Screening mammography: Is it suitably targeted to older women who are most likely to benefit?

OBJECTIVES: To determine whether screening mammography is suitably targeted to older women who are most likely to benefit. DESIGN: Prospective cohort study. SETTING: New Haven County, Connecticut. PARTICIPANTS: Eight hundred forty-four community-dwelling older women were interviewed as part of the 1990 New Haven Established Populations for the Epidemiologic Study of the Elderly (EPESE) program. MEASUREMENTS: Mammography use was ascertained from Medicare Part B claims data. A four-level prognostic mortality index was developed using items previously shown to be predictive of mortality. Mammography use and all-cause mortality were evaluated by prognostic stage over a 5-year period, January 1, 1991, to December 31, 1995. RESULTS: Five-year mortality increased steadily with each prognostic stage (12% to 68%, P = .001), whereas the 5-year mammography use rate declined (48% to 7%, P = .001). Over half the women (53%) in the most favorable prognostic group did not receive a mammogram, whereas 13% in the two worst prognostic groups received at least one mammogram. CONCLUSION: Screening mammography may be underutilized among older women who are the most likely to benefit and overutilized among those who are unlikely to benefit.

Activities of Daily Living↗
PubMed2000

Role of exercise stress testing and safety monitoring for older persons starting an exercise program.

While the benefits of physical activity and exercise among older persons are becoming increasingly clear, the role of exercise stress testing and safety monitoring for older persons who want to start an exercise program is unclear. Current guidelines regarding exercise stress testing likely are not applicable to the majority of persons aged 75 years or older who are interested in restoring or enhancing their physical function through a program of physical activity and exercise. In addition to being expensive and of unproven benefit, the current policy of routine exercise stress testing potentially could deter many older persons from participating in an exercise program. Research is needed to investigate current physician practices, evaluate the risk of adverse cardiac events, determine the role of pharmacological stress testing, and measure and compare absolute and relative exercise intensities. To assist clinicians, we offer a set of recommendations regarding precautions that can be taken to minimize the risk of adverse cardiac events among previously sedentary older persons who do not have symptomatic cardiovascular disease and are interested in starting an exercise program. JAMA. 2000;284:342-349

Aged↗
PubMed2000

Sustained visual attention performance-associated prefrontal neuronal activity: evidence for cholinergic modulation.

Cortical cholinergic inputs are hypothesized to mediate attentional functions. The present experiment was designed to determine the single unit activity of neurons within the medial prefrontal cortex (mPFC) of rats performing a sustained visual attention task. Demands on attentional performance were varied by the presentation of a visual distractor. The contribution of cholinergic afferents of the mPFC to performance-associated unit activity within this area was determined by recording neuronal activity before and after unilateral cholinergic deafferentation using intracortical infusion of the immunotoxin 192 IgG-saporin. Presentation of the visual distractor resulted in a decrease in the detection of brief, unpredictable visual signals. As predicted, the unilateral loss of cholinergic inputs within the recording area of the mPFC did not affect sustained attentional performance. Cholinergic deafferentation, however, resulted in a decrease in the overall firing rate of medial prefrontal neurons and a substantial reduction in the proportion of neurons whose firing patterns correlated with specific aspects of behavioral performance. Furthermore, cholinergic deafferentation attenuated the frequency and amplitude of increased mPFC neuronal firing rates that were associated with the presentation of the visual distractor. The main findings from this experiment suggest that cholinergic inputs to the mPFC strongly influence spontaneous and behaviorally correlated single unit activity and mediate increases in neuronal activity associated with enhanced demands for attentional processing, all of which may be fundamental aspects in the maintenance of attentional performance.

Afferent Pathways↗
PubMed2000

Dizziness among older adults: a possible geriatric syndrome.

BACKGROUND: In previous studies of dizziness, the prevalence of specific causes has varied widely and either no or multiple causes have been identified. Dizziness might be better considered a geriatric syndrome that results from impairment or disease in multiple systems. OBJECTIVE: To determine the predisposing characteristics and situational factors associated with dizziness. DESIGN: Population-based, cross-sectional study. SETTING: Community. PARTICIPANTS: Probability sample of 1087 community-living persons in New Haven, Connecticut, who were at least 72 years of age. MEASUREMENTS: Episodes of dizziness that occurred for at least 1 month; manifestations of dizziness; and predisposing demographic, medical, neurologic, sensory, and psychological characteristics. RESULTS: 261 participants (24%) reported dizziness; 56% of dizzy persons described several sensations and 74% reported several triggering activities. The adjusted relative risks for characteristics associated with dizziness were 1.69 (95% CI, 1.24 to 2.30) for anxiety, 1.36 (CI, 1.02 to 1.80) for depressive symptoms, 1.27 (CI, 0.99 to 1.63) for impaired hearing, 1.30 (CI, 1.01 to 1.68) for five or more medications, 1.31 (CI, 0.92 to 1.87) for postural hypotension, 1.34 (CI, 0.95 to 1.90) for impaired balance, and 1.31 (CI, 1.00 to 1.71) for past myocardial infarction. The adjusted relative risk for dizziness was 1.38 (CI, 1.27 to 1.49) for each additional characteristic. CONCLUSIONS: The association among characteristics in multiple domains (cardiovascular, neurologic, sensory, psychological, and medication-related) and dizziness, coupled with the multiplicity of sensations and triggering activities, suggests that dizziness may be a geriatric syndrome, similar to delirium and falling. If so, an impairment reduction strategy, proven effective for other geriatric syndromes, may be effective in reducing the symptoms and disabilities associated with dizziness.

Aged↗
PubMed2000

Septohippocampal pathway as a site for the memory-impairing effects of ethanol.

Ethanol affects behavior by interacting with synaptic sites at many levels of the nervous system. However, it targets most readily and at the lowest concentrations those sites mediating higher cognitive functions such as attention and memory. The memory-impairing effects of ethanol are thought to involve the hippocampus, a structure particularly vulnerable to the effects ethanol at low concentrations and early in the rising phase of the blood ethanol concentration curve. One of the early, low-dose effects of ethanol is an interruption of the normal physiological regulation of the hippocampus by the ascending septohippocampal pathway originating in the medial septal area (MSA). Ethanol enhances GABAergic transmission in the MSA, thereby reducing the regularity and vigor with which rhythmically bursting neurons of the MSA drive the hippocampal theta rhythm. Disruption of septohippocampal activity also has consequences on the response of the hippocampus to cortical inputs. Ethanol produces a loss of hippocampal responsivity that reduces the ability of the hippocampus to encode and retrieve relevant stimulus information necessary for accurate memory. This paper examines the behavioral and neural evidence for hippocampal vulnerability to ethanol and explores the hypothesis that these effects are due to ethanol disrupting septohippocampal modulation of the hippocampus, resulting in impairments of memory.

Animals↗
PubMed2000

Environmental hazards and the risk of nonsyncopal falls in the homes of community-living older persons.

BACKGROUND: Identifying and eliminating environmental hazards in the home has high face validity but little empirical support for fall prevention. OBJECTIVE: The objective of this study was to determine whether environmental hazards increase the risk of nonsyncopal falls in the homes of community-living older persons. RESEARCH DESIGN: This was a prospective cohort study. PARTICIPANTS: The study included 1,088 men and women from a probability sample of 1,103 persons > or =72 years of age. MEASURES: A room-by-room assessment for 13 potential trip or slip hazards was completed at baseline and 1 year later by a trained research nurse using a standard instrument. Falls were ascertained monthly for 3 years using a fall calendar and follow-up phone calls. RESULTS: The numbers of participants with a nonsyncopal fall (by room) were as follows: 88 (kitchen), 144 (living room), 41 (hallway), 136 (bedroom), and 59 (bathroom). The risk of a nonsyncopal fall was significantly elevated for only 1 of the 13 trip or slip hazards. For exposure to > or =1 hazards per room, the relative risks adjusted for age, gender, and housing type were 0.91 (95% CI, 0.58-1.43) for the kitchen, 1.30 (95% CI, 0.92-1.83) for the living room, 1.73 (95% CI, 0.93-3.22) for the hallway, 1.29 (95% CI, 0.90-1.84) for the bedroom, and 0.57 (95% CI, 0.32-1.00) for the bathroom. No consistent association was found between the 13 trip or slip hazards and nonsyncopal falls, even after participants were categorized by impairments in vision, balance/gait, and cognition. CONCLUSIONS: Our findings do not support an association between environmental hazards and nonsyncopal falls.

Accidental Falls↗
PubMed2000

Health, functional, and psychological outcomes among older persons with chronic dizziness.

OBJECTIVE: The recommended clinical strategy for a health condition should depend both on the known causes of and outcomes associated with the condition. The aim of this study was to determine the range of adverse outcomes associated with chronic dizziness. DESIGN: Population-based prospective cohort study. SETTING AND PARTICIPANTS: A probability sample of 1087 persons, age 72 and older, living in the community. MEASUREMENTS: The following were measured: chronic dizziness, death, hospitalizations, falls, syncope, basic and instrumental activities of daily living, depressive symptoms, self-rated health, falls self-efficacy, and social activities. RESULTS: Of the 1087 participants, 261 (24%) reported chronic dizziness. Over 1 year of follow-up, chronic dizziness was not associated with mortality, hospitalization for any reason, or change in basic or instrumental activities of daily living, but was associated with risk of falling (unadjusted relative risk [RR] 1.35; 95% confidence interval [CI] 1.06-1.72) and with experiencing syncope (RR 2.31; 95% CI 1.24-4.30). After adjustment for baseline level, chronic dizziness also was associated with worsening of depressive symptoms, self-rated health, falls efficacy, and social activities. The relationship remained significant, after adjustment for potential confounding factors, for self-rated health (T-statistic -2.95, P = .003) and falls efficacy (T-statistic -2.68; P = .008), and was of marginal significance for depressive symptoms (T-statistic -1.73; P = .085). CONCLUSIONS: These results suggest that the goals of care for older persons with chronic dizziness should be redirected from solely identifying and treating discrete diseases--an often expensive and unrewarding task--toward reducing the symptoms of chronic dizziness and alleviating the resulting physical, psychological, and social disability.

Accidental Falls↗
PubMed2000

PTEVAL: a computerized home-based physical therapy intervention instrument.

The determination of physical therapy treatment protocols, based on an in-home evaluation of a patient, is a complex task. The specific rules for treatment indications are individually simple, but numerous and hence time-consuming and prone to error using pencil-and-paper methods. This paper describes PTEVAL, a computerized Point-of-Care instrument designed to support the intervention protocols of an ongoing clinical trial. With appropriate modifications and extensions, PTEVAL can be a model for instruments used in clinical practice.

Activities of Daily Living↗
PubMed1999

Home-based multicomponent rehabilitation program for older persons after hip fracture: a randomized trial.

OBJECTIVE: To determine whether a home-based systematic multicomponent rehabilitation strategy leads to improved outcomes relative to usual care. DESIGN: A randomized controlled trial with 12 months of follow-up. SETTING: General community; 27 home care agencies. PARTICIPANTS: Three hundred four nondemented persons at least 65 years of age who underwent surgical repair of a hip fracture at two hospitals in New Haven, CT, and returned home within 100 days. INTERVENTION: Systematic multicomponent rehabilitation strategy addressing both modifiable physical impairments (physical therapy) and activities of daily living (ADL) disabilities (functional therapy) versus usual care. MAIN OUTCOME MEASURES: A battery of self-report and performance-based measures of physical and social function. RESULTS: There was no significant difference in the proportion of participants in the two groups who recovered to prefracture levels in self-care ADL at 6 months (71% vs 75%) or 12 months (74% in both groups) or in home management ADL at 6 months (35% vs 44%) or 12 months (44% vs 48%). There also was no difference between the two groups in social activity levels, two timed mobility tasks, balance, or lower extremity strength at either 6 or 12 months. Compared with participants who received usual care, those in the multicomponent rehabilitation program showed slightly greater upper extremity strength at 6 months (p = .04) and a marginally better gait performance (p = .08). CONCLUSIONS: The systematic multicomponent rehabilitation program was no more effective in promoting recovery than usual home-based rehabilitation. Compared with previous cohorts, however, participants randomized to usual care in our study received more rehabilitative and home care services and experienced a higher rate of recovery. This finding is important given the current pressures to reduce home services. The challenge is to determine the composition and duration of rehabilitation and home services that will ensure optimal functional recovery most efficiently in older persons after hip fracture.

Activities of Daily Living↗
PubMed1999

The combined effects of baseline vulnerability and acute hospital events on the development of functional dependence among community-living older persons.

BACKGROUND: Many older persons who are highly vulnerable do not develop functional dependence, whereas some older persons with low vulnerability do develop functional dependence. We conducted this study to determine the combined effects of baseline vulnerability and precipitating events on the development of functional dependence. METHODS: We analyzed data from two prospective, population-based cohort studies. The development cohort included 799 community-living persons, 72 years of age and older, who were independent in their activities of daily living (ADLs). The validation cohort included 1,051 comparable persons. Participants were classified by baseline vulnerability, defined on the basis of physical performance, cognitive status, and age, and by exposure to potential precipitating events, determined from information gathered from acute care hospital admissions. The primary outcome was the onset of functional dependence, defined as a new disability in one or more of the seven ADLs at the 1-year follow-up interview or admission to a skilled nursing facility prior to the 1-year interview. RESULTS: Functional dependence developed in 109 (13.6%) participants in the development cohort and in 100 (9.3%) participants in the validation cohort. The rates of functional dependence for the low, intermediate, and high vulnerability groups were 7.1%, 17.2%, and 40.1% (p<.001) in the development cohort and 4.8%, 15.0%, and 28.0% (p<.001) in the validation cohort. For the four categories (none, mild, moderate, severe) of precipitating events, the rates of functional dependence were 9.0%, 19.4%, 27.3%, and 53.2% (p<.001 ) in the development cohort and 5.1%, 12.0%, 28.2%, and 53.3% (p<.001) in the validation cohort. For both cohorts, when baseline vulnerability and precipitating events were analyzed in cross-stratified format, the rate of functional dependence increased progressively from low-risk to high-risk groups in all directions (double-gradient phenomenon). The contributions of baseline vulnerability and precipitating events to the development of functional dependence were independent and statistically significant. CONCLUSIONS: Among community-living older persons, baseline vulnerability and precipitating hospital events contribute independently to the development of functional dependence and should each be targeted for intervention when developing strategies aimed at forestalling the onset of functional dependence.

Activities of Daily Living↗
PubMed1999

Mismatches between the home environment and physical capabilities among community-living older persons.

OBJECTIVE: To determine whether environmental hazards related to transfers, balance, and gait are any less prevalent in the homes of older persons with specific deficits in physical capabilities than they are in the homes of older persons without the same deficits. DESIGN: Cross-sectional study of a population-based cohort. SETTING: The general community in New Haven, Connecticut. PARTICIPANTS: A total of 1088 persons, aged 72 years and older, who had an environmental assessment of their homes. MEASUREMENTS: Each participant underwent a physical performance assessment and comprehensive interview to document the presence of underlying deficits in physical capabilities. Items from the environmental assessment that were potentially hazardous for participants with specific deficits in transfers, balance, or gait were identified. RESULTS: With the exception of no grab bars in the tub/shower, environmental hazards were as prevalent in the homes of participants with specific deficits in physical capabilities as they were in the homes of participants without the same deficits, and, in many cases, they were actually more prevalent. Among participants with and without observed difficulty standing from a chair, for example, the prevalence of a low lying chair was 24% versus 14% (chi2 = 13.4; P < .001), respectively. Among participants with and without an observed deficit in turning, the prevalence of an obstructed pathway was 47% versus 37% (chi2 = 8.7; P = .003), respectively; and the prevalence of loose throw rugs was 72% in both groups. CONCLUSIONS: If the epidemiologic link between environmental hazards and adverse functional outcomes can be strengthened, then interventions designed to enhance the everyday function of frail, older persons should focus on the environment as well as the individual.

Accidental Falls↗
PubMed1999

A population-based study of environmental hazards in the homes of older persons.

OBJECTIVES: This study sought to estimate the population-based prevalence of environmental hazards in the homes of older persons and to determine whether the prevalence of these hazards differs by housing type or by level of disability in terms of activities of daily living (ADLs). METHODS: An environmental assessment was completed in the homes of 1000 persons 72 years and older. Weighted prevalence rates were calculated for each of the potential hazards and subsequently compared among subgroups of participants characterized by housing type and level of ADL disability. RESULTS: Overall, the prevalence of most environmental hazards was high. Two or more hazards were found in 59% of bathrooms and in 23% to 42% of the other rooms. Nearly all homes had at least 2 potential hazards. Although age-restricted housing was less hazardous than community housing, older persons who were disabled were no less likely to be exposed to environmental hazards than older persons who were nondisabled. CONCLUSIONS: Environmental hazards are common in the homes of community-living older persons.

Activities of Daily Living↗
PubMed1998

Difficulty and dependence: two components of the disability continuum among community-living older persons.

BACKGROUND: Although most epidemiologic studies have defined disability in basic activities of daily living (BADLs) as dependence, some investigators have argued that BADL disability should be defined as degree of difficulty. OBJECTIVE: To determine whether the responses to questions about difficulty and dependence provide complementary information that together can depict the continuum of disability more fully than the response to either question alone. SETTING: General community. PARTICIPANTS: 1065 persons 72 years of age and older. MEASUREMENTS: On the basis of self-reported information collected at baseline, participants were categorized into three BADL groups: independent without difficulty, independent with difficulty, and dependent. Additional baseline information was collected on several measures of higher-level function and physical performance. Follow-up information was collected on regular home care visits and BADL function at 1 and 3 years and on hospitalizations, admissions to skilled-nursing facilities, and deaths over a 4-year period. RESULTS: In a cross-sectional analysis, the proportion of participants with poor higher-level function and physical performance increased substantially across the three BADL groups. In a longitudinal analysis, the rates of hospitalization and regular home care visits for the independent without difficulty group, the independent with difficulty group, and the dependent group were 46%, 57%, and 72% (P < 0.001) and 17%, 30%, and 49% (P < 0.001), respectively; survival curves for admission to a skilled-nursing facility and death differed significantly for each pair-wise comparison. Among persons who were BADL independent, those with difficulty were significantly more likely to develop BADL dependence over a 3-year period than those without difficulty (31% compared with 18%; P < 0.001). CONCLUSIONS: In the assessment of BADL function in older persons, questions about difficulty and dependence provide complementary information that together can depict the continuum of disability more fully than either question alone.

Activities of Daily Living↗