bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison of several methods used to quantify prepulse inhibition of eyeblink responding
Authors: Blumenthal Terry D. , Elden Aake , Flaten Magne Arve 
Published: February 2004

AbstractSeveral methods of quantifying prepulse inhibition (PPI) of eyeblink responding were compared in adult volunteers. Blink‐eliciting stimuli were noise bursts at 85 or 100 dB, and prepulses were also noise bursts, at 55 or 70 dB and lead intervals of 60 or 120 ms. PPI was evaluated by comparing reactivity on prepulse and control trials within participants using the following methods: (1) difference between reactivity on prepulse and control trials; (2) reactivity on prepulse trials divided by that on control trials (proportion of control); (3) difference between reactivity on prepulse and control trials, divided by that on control trials (proportion of the difference from control); (4) range correction (maximum minus minimum reactivity, divided by the range of reactivity), across all control and prepulse trials; (5) z scores across all prepulse and control trials. Prepulses inhibited eyeblink response magnitude in all cases. Proportion of difference was the method least affected by differences in control reactivity, and is the preferred method to use when quantifying PPI, both from a practical and a neurophysiological perspective.
Is motor inhibition during laughter due to emotional or respiratory influences?
Authors: Overeem Sebastiaan , Taal Walter , Öcal Gezici E. , Lammers Gert Jan , Van Dijk J. Gert 
Published: February 2004

AbstractWe compared the effects of laughter and several respiratory movements on spinal motor excitability to unravel their respective influences. We measured H‐reflexes in 13 healthy volunteers during 10 different tasks (including laughter, simulated laughter, and various respiratory movements). We compared the percentage that remained of the initial H‐reflex during each task with that during a neutral task. H‐reflex percentage differed between the neutral task (79.4±16.1%), true laughter (43.7±17.9%), and simulated laughter (66.6±24.3%), and between the two latter tasks. Coughing also resulted in H‐reflex suppression, but not as deeply as true laughter. During the other respiratory maneuvers, the H‐reflex increased compared to the neutral task. Our finding that true laughter evoked more H‐reflex depression than simulated laughter suggests that mirth on its own depresses the H‐reflex. This mechanism may also be involved in the pathophysiology of cataplexy, the main symptom of narcolepsy.
Thinking and hallucinating: Reciprocal changes in sleep
Authors: Fosse Roar , Stickgold Robert , Hobson J. Allan 
Published: February 2004

AbstractInternal deliberations (focused thoughts) and endogenous percepts (hallucinations) vary in a reciprocal manner across the states of waking and sleep, paralleling changes in regional brain activation. As subjects go from waking through sleep onset to NREM sleep and then to REM sleep, they report progressively more hallucinoid imagery and progressively less thinking. We have investigated whether this reciprocity in cognition between NREM and REM is maintained throughout the night. To do so, we analyzed 229 REM and 165 NREM reports collected with the Nightcap sleep monitoring system from 16 participants in their homes over 14 nights. The reports were scored for the presence of hallucinations and directed thinking by external judges. As predicted, hallucinations were more frequent in REM than in NREM for each segment of the night, and directed thinking was more frequent in NREM in the first 5 h of the night. Late in the night, directed thinking was equally infrequent in NREM and REM. At the same time, hallucinations increased within both NREM and REM as the night progressed, whereas directed thinking decreased in NREM and remained at a stable, low level in REM. These findings suggest that a reciprocal shift in focused thinking and hallucinating is a general property of cognitive activity across the wake–sleep cycle. Biological evidence supports the hypothesis that these cognitive changes are governed by specific state regulatory and neurocognitive processes at several levels of the brain.
The stability of resting frontal electroencephalographic asymmetry in depression
Authors: Allen John J. B. , Urry Heather L. , Hitt Sabrina K. , Coan James A. 
Published: February 2004

AbstractAlthough resting frontal electroencephalographic (EEG) alpha asymmetry has been shown to be a stable measure over time in nonclinical populations, its reliability and stability in clinically depressed individuals has not been fully investigated. The internal consistency and test–retest stability of resting EEG alpha (8–13 Hz) asymmetry were examined in 30 women diagnosed with major depression at 4‐week intervals for 8 or 16 weeks. Asymmetry scores generally displayed good internal consistency and exhibited modest stability over the 8‐ and 16‐week assessment intervals. Changes in asymmetry scores over this interval were not significantly related to changes in clinical state. These findings suggest that resting EEG alpha asymmetry can be reliably assessed in clinically depressed populations. Furthermore, intraclass correlation stability estimates suggest that although some traitlike aspects of alpha asymmetry exist in depressed individuals, there is also evidence of changes in asymmetry across assessment occasions that are not closely linked to changes in depressive severity.
Attention allocation in the dual‐task paradigm as measured through behavioral and psychophysiological responses
Authors: Karatekin Canan , Couperus Jane W. , Marcus David J. 
Published: February 2004

AbstractWe investigated attention allocation in a dual‐task paradigm using behavioral and pupillary measures. We used an auditory digit span (DS) and a simple visual response time (RT) task. Participants were administered four conditions in which they performed neither task (no‐task), a single task (DS or RT only), or both tasks (dual). Dependent variables were DS accuracy, RT, and task‐evoked pupillary responses (TEPRs) to digits as estimates of mental effort. Participants maintained almost the same level of DS accuracy on dual as on DS only and sacrificed speed on the RT task. As expected, TEPRs increased linearly with memory load in both DS only and dual. Although TEPRs were initially higher in dual than in DS only, the slope of the increase was shallower in dual. Results suggest that TEPRs can elucidate mechanisms of attention allocation by distinguishing between effectiveness (level of behavioral performance) and efficiency (the costs of that performance in mental effort).
Staring at one side of the face increases blood flow on that side of the face
Authors: Drummond Peter D. , Mirco Nadia 
Published: February 2004

AbstractTo investigate the effect of observation on blushing, an experimenter sat next to 28 participants and looked closely at one cheek while the participant sang (embarrassing) or read aloud (not embarrassing). Increases in cheek temperature were greater on the observed than the unobserved side during both tasks. Changes in cheek temperature were symmetrical when the experimenter sat next to another 23 participants and looked straight ahead, as well as when the experimenter stared at one side of the participant's face through a glass window while the participant sang. However, increases in cutaneous blood flow were greater on the observed than the unobserved side of the forehead during singing. These findings suggest that staring at one side of the face triggers an ipsilateral increase in facial blood flow.
Context dependence of the event‐related brain potential associated with reward and punishment
Authors: Holroyd Clay B. , Larsen Jeff T. , Cohen Jonathan D. 
Published: February 2004

AbstractThe error‐related negativity (ERN) is an event‐related brain potential elicited by error commission and by presentation of feedback stimuli indicating incorrect performance. In this study, the authors report two experiments in which participants tried to learn to select between response options by trial and error, using feedback stimuli indicating monetary gains and losses. The results demonstrate that the amplitude of the ERN is determined by the value of the eliciting outcome relative to the range of outcomes possible, rather than by the objective value of the outcome. This result is discussed in terms of a recent theory that holds that the ERN reflects a reward prediction error signal associated with a neural system for reinforcement learning.
The functional relationship between visual backward masking and prepulse inhibition
Authors: Wynn Jonathan K. , Dawson Michael E. , Schell Anne M. 
Published: February 2004

AbstractThis experiment demonstrated a relationship between prepulse inhibition (PPI) of the startle eyeblink and visual backward masking in college students. It was hypothesized that recovery from backward masking effects is due in part to sensory gating, as assessed by auditory and visual PPI. Visual presentations of letters served as targets or visual prepulses in an intermixed session of backward masking and PPI. Backward masking and PPI (both auditory and visual) were assessed at stimulus onset asynchronies of 30, 45, 60, 120, and 150 ms. A repeated‐measures regression revealed that there was a relationship between backward masking and PPI for both visual and auditory PPI, with higher levels of PPI being associated with greater recovery from backward masking. The data are consistent with the hypothesis that recovery from backward masking effects is affected by sensory gating acting in part to gate out the interruptive effects of the mask.
Visual encoding differentially affects auditory event‐related potentials during working memory retrieval
Authors: Golob Edward J. , Starr Arnold 
Published: February 2004

AbstractPrevious working memory studies using auditory stimuli at both encoding and retrieval show amplitude decreases in event‐related potentials (N100 and late positive wave, LPW) at retrieval as a function of memory load. This study tested if these effects are associated with phonological or semantic coding by presenting visual stimuli at encoding and auditory stimuli at retrieval. We hypothesized that event‐related potentials associated with phonological but not semantic coding would be affected by modality differences at encoding and retrieval. Memory sets having one, three, or five visual digits were followed by auditory probes that subjects classified as present or absent from the set. Reaction time increased and LPW amplitudes decreased with increases in memory load, but there were no significant effects of memory load on N100 amplitude. Results suggest that with respect to brain activity that covaries with memory load, probe N100 amplitude is associated with phonological coding and LPW amplitude is associated with semantic coding.
Where to Q in PEP
Authors: Berntson Gary G. , Lozano David L. , Chen Yun‐Ju , Cacioppo John T. 
Published: February 2004

AbstractThe onset of ventricular depolarization defines the start of the preejection period (PEP), which is commonly used as an index of myocardial contractility and sympathetic control of the heart. Although the fiducial point for this onset has traditionally been the onset of the Q wave of the electrocardiogram, other measurement points have also been used in the literature, including the peak of the Q wave (i.e., the onset of the R wave). Conceptual, physiological, and empirical considerations addressing the reliability and validity of these alternative metrics support the application of the Q‐wave peak/R‐wave onset as the fiducial point for PEP measures.
Relationship of Nursing Home Staffing to Quality of Care
Authors: Schnelle John F. , Simmons Sandra F. , Harrington Charlene , Cadogan Mary , Garcia Emily , M. Bates‐Jensen Barbara 
Published: February 2004

Objective. To compare nursing homes (NHs) that report different staffing statistics on quality of care.Data Sources. Staffing information generated by California NHs on state cost reports and during onsite interviews. Data independently collected by research staff describing quality of care related to 27 care processes.Study Design. Two groups of NHs (n=21) that reported significantly different and stable staffing data from all data sources were compared on quality of care measures.Data Collection. Direct observation, resident and staff interview, and chart abstraction methods.Principal Findings. Staff in the highest staffed homes (n=6), according to state cost reports, reported significantly lower resident care loads during onsite interviews across day and evening shifts (7.6 residents per nurse aide [NA]) compared to the remaining homes that reported between 9 to 10 residents per NA (n=15). The highest‐staffed homes performed significantly better on 13 of 16 care processes implemented by NAs compared to lower‐staffed homes.Conclusion. The highest‐staffed NHs reported significantly lower resident care loads on all staffing reports and provided better care than all other homes.
A Longitudinal Examination of Hospital Registered Nurse Staffing and Quality of Care
Authors: Mark Barbara A. , Harless David W. , McCue Michael , Xu Yihua 
Published: February 2004

Objective. To evaluate previous research findings of the relationship between nurse staffing and quality of care by examining the effects of change in registered nurse staffing on change in quality of care.Data Sources/Study Setting. Secondary data from the American Hospital Association (AHA)(nurse staffing, hospital characteristics), InterStudy and Area Resource Files (ARF) (market characteristics), Centers for Medicare and Medicaid Services (CMS) (financial performance), and Healthcare Cost and Utilization Project (HCUP) (quality measures—in‐hospital mortality ratio and the complication ratios for decubitus ulcers, pneumonia, and urinary tract infection, which were risk‐adjusted using the Medstat® disease staging algorithm).Study Design. Data from a longitudinal cohort of 422 hospitals were analyzed from 1990–1995 to examine the relationships between nurse staffing and quality of care.Data Collection/Extraction Methods. A generalized method of moments estimator for dynamic panel data was used to analyze the data.Principal Findings. Increasing registered nurse staffing had a diminishing marginal effect on reducing mortality ratio, but had no consistent effect on any of the complications. Selected hospital characteristics, market characteristics, and financial performance had other independent effects on quality measures.Conclusions. The findings provide limited support for the prevailing notion that improving registered nurse (RN) staffing unconditionally improves quality of care.
The Impact of S‐CHIP Enrollment on Physician Participation in Medicaid in Alabama and Georgia
Authors: Bronstein Janet M. , Adams E. Kathleen , Florence Curtis S. 
Published: February 2004

Objective. To assess whether increasing enrollment in State Children's Health Insurance Programs (S‐CHIPs) has an impact on the number of office physicians participating in Medicaid and the extent of their participation. Effects are measured for a freestanding S‐CHIP program with an open provider panel and an S‐CHIP program that uses the state's Medicaid provider panel.Data Sources. Children's Medicaid claims data for primary care services were used to measure physician participation in the program; census and enrollment data were used to describe market area characteristics.Study Design. This is a time series study of communities in two states, measuring physician Medicaid participation quarterly between 1998 and 2001, controlling for changes in community characteristics and children's program enrollment as well as other factors by quarter.Data Collection/Extraction. Office physician participation is measured by practice site. Claims data are aggregated to the level of the community and reflect the number of limited practice sites, the ratio of Medicaid office sites to the number of primary care physicians in the community as reported by the American Medical Association (AMA), and the mean number of Medicaid office visits made to physician sites in the community in the quarter.Findings. In Alabama, the state with a freestanding S‐CHIP program, there is little association between increased S‐CHIP enrollment and physician participation in Medicaid. In Georgia, where the same provider network serves both programs, increases in S‐CHIP enrollment are associated with a decline in office‐based physician participation in Medicaid in urban areas.Conclusion. Linkage of S‐CHIP and Medicaid programs through the use of the same provider network, in the absence of market conditions that encourage the expansion of the network, can lead to a negative impact on access for Medicaid enrollees.
The Impact of Managed Care on Substance Abuse Treatment Services
Authors: Olmstead Todd , White William D. , Sindelar Jody 
Published: February 2004

Objective. To examine the impact of managed care on the number and types of services offered by substance abuse treatment (SAT) facilities. Both the number and types of services offered are important factors to analyze, as research shows that a broad range of services increases treatment effectiveness.Data Sources. The 2000 National Survey of Substance Abuse Treatment Services (NSSATS), which is designed to collect data on service offerings and other characteristics of SAT facilities in the United States. These data are merged with data from the 2002 Area Resource File (ARF), a county‐specific database containing information on population and managed care activity. We use data on 10,513 facilities, virtually a census of all SAT facilities.Study Design. We estimate the impact of managed care (MC) on the number and types of services offered by SAT facilities using instrumental variables (IV) techniques that account for possible endogeneity between facilities' involvement in MC and service offerings. Due to limitations of the NSSATS data, MC and specific services are modeled as binary variables.Principal Findings. We find that managed care causes SAT facilities to offer, on average, approximately two fewer services. This effect is concentrated primarily in medical testing services (i.e., tests for TB, HIV/AIDs, and STDs). We also find that MC increases the likelihood of offering substance abuse assessment and relapse prevention groups, but decreases the likelihood of offering outcome follow‐up.Conclusion. Our findings raise policy concerns that managed care may reduce treatment effectiveness by limiting the range of services offered to meet patient needs. Further, reduced onsite medical testing may contribute to the spread of infectious diseases that pose important public health concerns.
The Effects of HMO Penetration on Preventable Hospitalizations
Authors: Zhan Chunliu , Miller Marlene R. , Wong Herbert , Meyer Gregg S. 
Published: February 2004

Objective. To examine the effects of health maintenance organization (HMO) penetration on preventable hospitalizations.Data Source. Hospital inpatient discharge abstracts for 932 urban counties in 22 states from the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SID), hospital data from American Hospital Association (AHA) annual survey, and population characteristics and health care capacity data from Health Resources and Services Administration (HRSA) Area Resource File (ARF) for 1998.Methods. Preventable hospitalizations due to 14 ambulatory care sensitive conditions were identified using the Agency for Healthcare Research and Quality (AHRQ) Prevention Quality Indicators. Multiple regressions were used to determine the association between preventable hospitalizations and HMO penetration while controlling for demographic and socioeconomic characteristics and health care capacity of the counties.Principal Findings. A 10 percent increase in HMO penetration was associated with a 3.8 percent decrease in preventable hospitalizations (95 percent confidence interval, 2.0 percent–5.6 percent). Advanced age, female gender, poor health, poverty, more hospital beds, and fewer primary care physicians per capita were significantly associated with more preventable hospitalizations.Conclusions. Our study suggests that HMO penetration has significant effects in reducing preventable hospitalizations due to some ambulatory care sensitive conditions.
The Combined Effects of Participatory Styles of Elderly Patients and Their Physicians on Satisfaction
Authors: Xu K. Tom 
Published: February 2004

Objectives.To test whether concordance or discordance of patient participation between patients and physicians is associated with higher satisfaction, and to examine the effects of patients' and physicians' participatory styles on patients' satisfaction with their physicians.Data.Data collected in the Texas Tech 5000 Survey of elderly patients in West Texas were used. Patient satisfaction with their physicians was measured by a single item from the Consumer Assessment of Health Plans (CAHPS), representing patients' ratings of their physicians. Patient participation was measured by an index derived from a three‐item instrument and physicians' participatory decision‐making (PDM) style was measured by a three‐item instrument developed by the Medical Outcomes Study.Methods.An ordered logit multivariate regression was used to investigate the effects of patients' and physicians' participatory styles on satisfaction with physicians. The interaction between patients' participation and physicians' participatory styles was also included to examine the dependency of the two variables.Results.Controlling for confounding factors, a higher PDM score was associated with a higher rating of patient satisfaction with physicians. A higher patient participation score was related to a lower physician satisfaction rating. The combined effect of patients' and physicians' participation styles indicated that for a low patient participation score, a high PDM score was not needed to produce high satisfaction. The greater the discordance in this direction, the higher the satisfaction. However, with a high patient participation score, only an extremely high PDM score would produce relatively high satisfaction.Conclusions.The current study supports the discordance hypothesis. Participatory physicians and patient–physician communications concerning patient participation can promote higher satisfaction.
Delays in Initial Treatment Contact after First Onset of a Mental Disorder
Authors: Wang Philip S. , Berglund Patricia A. , Olfson Mark , Kessler Ronald C. 
Published: February 2004

Objective. To examine nationally representative patterns and predictors of delays in contacting a professional after first onset of a mental disorder.Data Sources. The National Comorbidity Survey, a nationally representative survey of 8,098 respondents aged 15–54.Study Design. Cross‐sectional survey.Data Collection. Assessed lifetime DSM‐III‐R mental disorders using a modified version of the Composite International Diagnostic Interview (CIDI). Obtained reports on age at onset of disorders and age of first treatment contact with each of six types of professionals (general medical doctors, psychiatrists, other mental health specialists, religious professionals, human services professionals, and alternative treatment professionals). Used Kaplan–Meier (KM) curves to estimate cumulative lifetime probabilities of treatment contact after first onset of a mental disorder. Used survival analysis to study the predictors of delays in making treatment contact.Principal Findings. The vast majority (80.1 percent) of people with a lifetime DSM‐III‐R disorder eventually make treatment contact, although delays average more than a decade. The duration of delay is related to less serious disorders, younger age at onset, and older age at interview. There is no evidence that delay in initial contact with a health care professional is increased by earlier contact with other non–health‐care professionals.Conclusions. Within the limits of recalling lifetime events, it appears that delays in initial treatment contact are an important component of the larger problem of unmet need for mental health care. Interventions are needed to decrease these delays.