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Biomedical subjects

Dennis L Hart

Publications and source records attributed to Dennis L Hart.

13 recordsLinked to original sources
PubMed2006

Simulated computerized adaptive test for patients with lumbar spine impairments was efficient and produced valid measures of function.

OBJECTIVE: To equate physical functioning (PF) items with Back Pain Functional Scale (BPFS) items, develop a computerized adaptive test (CAT) designed to assess lumbar spine functional status (LFS) in people with lumbar spine impairments, and compare discriminant validity of LFS measures (theta(IRT)) generated using all items analyzed with a rating scale Item Response Theory model (RSM) and measures generated using the simulated CAT (theta(CAT)). METHODS: We performed a secondary analysis of retrospective intake rehabilitation data. RESULTS: Unidimensionality and local independence of 25 BPFS and PF items were supported. Differential item functioning was negligible for levels of symptom acuity, gender, age, and surgical history. The RSM fit the data well. A lumbar spine specific CAT was developed that was 72% more efficient than using all 25 items to estimate LFS measures. theta(IRT) and theta(CAT) measures did not discriminate patients by symptom acuity, age, or gender, but discriminated patients by surgical history in similar clinically logical ways. theta(CAT) measures were as precise as theta(IRT) measures. CONCLUSION: A body part specific simulated CAT developed from an LFS item bank was efficient and produced precise measures of LFS without eroding discriminant validity.

Activities of Daily Living↗
PubMed2006

A 37-item shoulder functional status item pool had negligible differential item functioning.

OBJECTIVE: Measures of shoulder function may differ by dominance of affected shoulder, surgical history, gender, or race. We present a technique for determining whether observed differences in function between groups are due to biased test items or real differences in function. STUDY DESIGN AND SETTING: Four hundred patients who were receiving rehabilitation for a variety of shoulder impairments completed a survey of shoulder function. Thirty-seven items measuring shoulder function were analyzed for differential item functioning (DIF) related to demographic characteristics using an ordinal logistic regression (OLR) and item response theory (IRT) approach. When DIF was identified in an item, we modified the IRT analysis to calibrate item parameters separately in appropriate demographic groups. We compared adjusted and unadjusted patient ability measures in each demographic group. RESULTS: Several items were found to have a modest amount of DIF related to the different demographic characteristics, especially gender; however, adjusting measures for DIF had little impact on overall measures of shoulder function and made almost no difference in average shoulder function across demographic groups. CONCLUSION: In this pool of shoulder function items, adjustment for DIF made almost no difference in measures of function across demographic groups.

Activities of Daily Living↗
PubMed2006

State regulation and the delivery of physical therapy services.

OBJECTIVE: The study purpose was to examine the relationship between state regulations of physical therapists (PT) and three dependent variables: physical therapist assistant (PTA) utilization more than 50 percent of the time during the treatment episode (high PTA utilization), number of visits, and patient self-reported functional health status (FHS) at discharge. We evaluated regulations governing licensure of PTAs, PT/PTA ratio, frequency of PT re-evaluation, and PTA supervision. DATA SOURCE: The analytic sample included 63,900 patients from 38 states drawn from 395 clinics who participated in the Focus on Therapeutic Outcomes Inc. (Knoxville, TN) database in 2000 and 2001. STUDY DESIGN: Using a Bayesian modeling approach with the Markov Chain Monte Carlo estimation method, we fitted separate multilevel multivariate regression models predicting high PTA utilization, number of visits, and discharge FHS. DATA COLLECTION METHODS: Patients completed FHS surveys at intake and discharge. Clinicians recorded the number of visits and percentage of time a patient spent with each provider. PRINCIPAL FINDINGS: After controlling for patient, therapist, and clinic characteristics, the presence of state regulations regarding PTA supervision was not associated with the likelihood of high PTA utilization. High PTA utilization and regulations requiring full-time onsite supervision were associated with more visits, whereas regulation of PT/PTA ratio was associated with fewer visits. Supervisory regulations were associated with better discharge FHS. High PTA utilization and use of therapy aides were associated with more visits per episode and lower discharge FHS. CONCLUSIONS: The use of care extenders in place of PTs is likely to result in less efficient and lower quality care in outpatient rehabilitation.

Adult↗
PubMed2005

Simulated computerized adaptive test for patients with shoulder impairments was efficient and produced valid measures of function.

BACKGROUND AND OBJECTIVE: To test unidimensionality and local independence of a set of shoulder functional status (SFS) items, develop a computerized adaptive test (CAT) of the items using a rating scale item response theory model (RSM), and compare discriminant validity of measures generated using all items (theta(IRT)) and measures generated using the simulated CAT (theta(CAT)). STUDY DESIGN AND SETTING: We performed a secondary analysis of data collected prospectively during rehabilitation of 400 patients with shoulder impairments who completed 60 SFS items. RESULTS: Factor analytic techniques supported that the 42 SFS items formed a unidimensional scale and were locally independent. Except for five items, which were deleted, the RSM fit the data well. The remaining 37 SFS items were used to generate the CAT. On average, 6 items were needed to estimate precise measures of function using the SFS CAT, compared with all 37 SFS items. The theta(IRT) and theta(CAT) measures were highly correlated (r = .96) and resulted in similar classifications of patients. CONCLUSION: The simulated SFS CAT was efficient and produced precise, clinically relevant measures of functional status with good discriminating ability.

Activities of Daily Living↗
PubMed2005

Simulated computerized adaptive tests for measuring functional status were efficient with good discriminant validity in patients with hip, knee, or foot/ankle impairments.

BACKGROUND AND OBJECTIVE: To develop computerized adaptive tests (CATs) designed to assess lower extremity functional status (FS) in people with lower extremity impairments using items from the Lower Extremity Functional Scale and compare discriminant validity of FS measures generated using all items analyzed with a rating scale Item Response Theory model (theta(IRT)) and measures generated using the simulated CATs (theta(CAT)). METHODS: Secondary analysis of retrospective intake rehabilitation data. RESULTS: Unidimensionality of items was strong, and local independence of items was adequate. Differential item functioning (DIF) affected item calibration related to body part, that is, hip, knee, or foot/ankle, but DIF did not affect item calibration for symptom acuity, gender, age, or surgical history. Therefore, patients were separated into three body part specific groups. The rating scale model fit all three data sets well. Three body part specific CATs were developed: each was 70% more efficient than using all LEFS items to estimate FS measures. theta(IRT) and theta(CAT) measures discriminated patients by symptom acuity, age, and surgical history in similar ways. theta(CAT) measures were as precise as theta(IRT) measures. CONCLUSION: Body part-specific simulated CATs were efficient and produced precise measures of FS with good discriminant validity.

Activities of Daily Living↗
PubMed2005

Centralization: association between repeated end-range pain responses and behavioral signs in patients with acute non-specific low back pain.

OBJECTIVE: Tests and measures, if confounded by behavioral signs, cloud interpretation of physical test results during clinical examination. The purpose of this study was to determine whether common behavioral signs and pain responses (i.e. centralization and non-centralization) were associated during initial examination. DESIGN: Observational and designed to cross-tabulate pain responses to behavioral signs. PATIENTS: Data from 177 consecutive patients with acute work-related low back syndromes referred to physical therapy were analysed. METHODS: Patients were screened for 8 baseline behavioral signs. Pain responses during initial evaluation were determined from repeated end-range trunk movement tests or loading strategies following McKenzie assessment methods. Association between centralization and non-centralization and baseline behavioral signs were assessed. RESULTS: The physical sign of non-centralization was associated with non-organic signs, overt pain behaviors, fear of work activities, and somatization. Although depression, fear of physical activities, disability and pain intensity were not associated with non-centralization (p>0.05), upper bounds of odds ratios confidence intervals suggest that these behavioral signs may not be entirely independent of pain responses. CONCLUSION: Presence of non-centralization is associated with many behavioral signs, and therefore when present, clinicians should consider additional psychosocial screening during the initial evaluation.

Acute Disease↗
PubMed2004

Categorizing patients with occupational low back pain by use of the Quebec Task Force Classification system versus pain pattern classification procedures: discriminant and predictive validity.

BACKGROUND AND PURPOSE: Quebec Task Force Classification (QTFC) and pain pattern classification (PPC) procedures, including centralization and noncentralization, are common classification procedures. Classification was done to estimate validity of data obtained with QTFC and PPC procedures for differentiating patient subgroups at intake and for use in predicting rehabilitation outcomes at discharge and work status at 1 year after discharge from rehabilitation. SUBJECTS: Patients (n=171, 54% male; mean age=37 years, SD=10, range=18-62) with acute work-related low back pain referred for physical therapy were analyzed. METHODS: Patients completed pain and psychosocial questionnaires at initial examination and discharge and pain diagrams throughout intervention. Physical therapists classified patients using QTFC and PPC data at intake. Patients were classified again at discharge by PPC (time-dependent PPC). RESULTS: Analysis of variance of showed QTFC and PPC data could be used to differentiate patients by pain intensity or disability at intake. Analysis of covariance showed that intake PPC predicted pain intensity and disability at discharge, but QTFC did not. Logistic regression showed that PPC predicted work status at 1 year, but QTFC did not. Classifying patients over time using time-dependent PPC data reduced the false positive rate by 31% and increased percentage of change in pretest-posttest probability of return to work by 16% compared with classifying patients at intake. DISCUSSION AND CONCLUSION: Results support the discriminant validity of the QTFC data at intake and predictive validity of the PPC data at intake. Tracking PPC over time increases predictive validity for 1-year work status.

Acute Disease↗
PubMed2003

Discriminant validity and relative precision for classifying patients with nonspecific neck and back pain by anatomic pain patterns.

STUDY DESIGN: Secondary analysis of a previously described cohort of prospective, consecutive patients with acute neck or low back pain referred to outpatient rehabilitation was performed. OBJECTIVE: To estimate discriminant validity and relative precision of two classification procedures (first visit vs multiple visit) in discriminating short-term pain intensity and perceived disability outcomes. SUMMARY OF BACKGROUND DATA: Centralization and noncentralization are pain responses used to classify patients and predict outcomes. Different time frames have been proposed for operationally defining these responses, which are problematic for comparing outcomes across clinical trials. Classifying patients according to pain response observed from initial examination (first visit) and over time (multiple visits) influences prevalence within categories and interpretation of classification usefulness, which merits further investigation. METHODS: Patients with acute onset of nonspecific neck or low back pain referred to two outpatient physical therapy clinics completed body pain diagrams, pain intensity ratings, and disability questionnaires at initial evaluation, during each visit, and at discharge. Therapists collected data enabling patient classification on initial examination and throughout treatment. Differences in pain and disability from intake to discharge from rehabilitation across classification categories were used to assess discriminant validity. Relative precision was estimated by determining ratios of analysis of covariance F values between classification procedures for pain and disability. RESULTS: Both classification procedures discriminated categories for change in pain and disability. The multiple-visit classification procedure was more precise for discriminating outcomes than the first-visit classification procedure. CONCLUSION: Multiple-visit classification of patients into specific pain pattern subgroups is recommended when pain intensity and disability outcomes are of interest.

Adult↗
PubMed2003

Test-retest reliability of an abbreviated self-report overall health status measure.

STUDY DESIGN: Test-retest reliability study. OBJECTIVE: To assess test-retest reliability and estimate minimal detectable change of an overall measure and 2 summary measures of patient self-report of health status. BACKGROUND: Change in patient self-report of health status is a common outcome measure following rehabilitation. Because collection of health status data takes time and clinicians are required to be productive, selected items from reliable instruments were used to form a new, abbreviated instrument of health status relevant to patients in outpatient rehabilitation. There are no test-retest reliability statistics of these health status measures in this population. METHODS AND MEASURES: A convenience sample of 71 patients (mean age +/- SD, 41.9 +/- 17.9 years; age range, 15-83 years; sex, 35% male), with a variety of orthopaedic diagnoses, seeking rehabilitation in 2 outpatient facilities, volunteered. Patients completed health status questionnaires at initial evaluation and at 24 to 72 hours following evaluation. Intraclass correlation coefficients (ICC2.1) were used to estimate test-retest reliability and to estimate measurement error and minimal detectable changes. RESULTS: ICCs with a 1-sided lower limit 95% confidence intervals (CI) of the Overall Health Status measure and the Physical and Mental Component Summary measures for patients with chronic symptoms were 0.92 (0.85), 0.82 (0.68), and 0.85 (0.74), respectively. Minimal detectable changes (90% CI) were +/-12 (scale range, 100), +/- 9 (scale range, 60), and +/- 9 (scale range, 60) scale points, respectively, for the same measures. CONCLUSIONS: Results support the test-retest reliability of the Overall Health Status measure and summary measures for patients with chronic symptoms and demonstrate ability of the Overall Health Status and Physical Summary Scale measures to detect improvement of patient self-report of health status within the first few days of rehabilitation.

Adolescent↗
PubMed2003

Using clinical outcomes to identify expert physical therapists.

BACKGROUND AND PURPOSE: Previous studies of expert physical therapists have sampled therapists based on years of clinical experience or reputation, not on their patients' clinical outcomes. The purposes of this study were to identify expert physical therapists by using patient self-reported outcomes and to describe the characteristics of clinicians whose patients with lumbar spine syndromes reported higher health-related quality of life (HRQL) following rehabilitation. METHODS: Retrospective data were analyzed on 24276 patients (mean age=47.8 years, SD=16, range=14-97) with lumbar spine syndromes treated by 930 physical therapists participating in the Focus On Therapeutic Outcomes database in 1999-2000. Physical therapists and staff answered questions concerning years of experience and practice setting when starting their participation in the outcomes system. Patient self-report HRQL data were collected at intake and discharge from outpatient rehabilitation. Discharge HRQL data were risk adjusted using patient characteristics. Data were aggregated by physical therapist. Risk-adjusted discharge HRQL scores were used to classify physical therapists whose patients reported mean HRQL improvement above the 90th percentile as experts and physical therapists whose patients reported mean HRQL improvement between the 45th and 55th percentiles as average. RESULTS: Therapists classified as expert had fewer patients in the database than did therapists classified as average (mean SD) (19 +/-17 versus 29 +/-22). Mean treatment duration was different between groups (32 +/- 11 days for the expert group versus 31+/-8 days for the average group). DISCUSSION AND CONCLUSION: The results challenge assumptions that extensive clinical experience is necessary to achieve superior patient outcomes, and they provide information about the relationship between therapist characteristics and patient outcomes.

Adolescent↗
PubMed2002

Development of an index of physical functional health status in rehabilitation.

OBJECTIVE: To describe (1) the development of an index of physical functional health status (FHS) and (2) its hierarchical structure, unidimensionality, reproducibility of item calibrations, and practical application. DESIGN: Rasch analysis of existing data sets. SETTING: A total of 715 acute, orthopedic outpatient centers and 62 long-term care facilities in 41 states participating with Focus On Therapeutic Outcomes, Inc. PATIENTS: A convenience sample of 92,343 patients (40% male; mean age +/- standard deviation [SD], 48+/-17y; range, 14-99y) seeking rehabilitation between 1993 and 1999. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Patients completed self-report health status surveys at admission and discharge. The Medical Outcomes Study 36-Item Short-Form Health Survey's physical functioning scale (PF-10) is the foundation of the physical FHS. The Oswestry Low Back Pain Disability Questionnaire, Neck Disability Index, Lysholm Knee Questionnaire, items pertinent to patients with upper-extremity impairments, and items pertinent to patients with more involved neuromusculoskeletal impairments were cocalibrated into the PF-10. RESULTS: The final FHS item bank contained 36 items (patient separation, 2.3; root mean square measurement error, 5.9; mean square +/- SD infit, 0.9+/-0.5; outfit, 0.9+/-0.9). Analyses supported empirical item hierarchy, unidimensionality, reproducibility of item calibrations, and content and construct validity of the FHS-36. CONCLUSIONS: Results support the reliability and validity of FHS-36 measures in the present sample. Analyses show the potential for a dynamic, computer-controlled, adaptive survey for FHS assessment applicable for group analysis and clinical decision making for individual patients.

Adolescent↗
PubMed2002

Relationships among lifting ability, grip force, and return to work.

BACKGROUND AND PURPOSE: The relationship between functional capacity evaluation (FCE) data and work disability has not been studied. The validity of FCE testing results in terms of subsequent return to work (RTW) was the focus of this exploratory study. SUBJECTS AND METHODS: Six hundred fifty adults of working age were evaluated as part of a standardized FCE. Clients were contacted by telephone 6 months after the FCE to determine their work status. Predictor variables were gender, age, time off work, maximum safe loads during 3 dynamic lifts, and isometric grip force. Other variables measured were whether or not the client returned to work (RTW-Y/N) and level of return to work (RTW level). RESULTS: A multivariate logistic regression analysis demonstrated that the more time a worker was away from work, the less likely was RTW. Male subjects were less likely to return to work than female subjects. The more weight lifted from floor to waist, the more likely was RTW. The logistic regression equation correctly classified 80.3% of the subjects who returned to work and 56.6% of the subjects who did not return to work. Each of the 3 lift tests was related to RTW level, whereas the grip force tests were not related to either RTW-Y/N or RTW level. DISCUSSION AND CONCLUSION: Time off work and gender were the strongest predictors of RTW, but certain FCE subtests of lifting were related to RTW and RTW level for people with work-related chronic symptoms. Grip force was not related to RTW.

Adult↗