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Biomedical subjects

K J Ottenbacher

Publications and source records attributed to K J Ottenbacher.

At least 19 recordsLinked to original sources
PubMed2001

Single subject research designs for disability research.

PURPOSE: The objective of this article is to offer an overview of single subject designs and provide clinicians with information regarding the components of single subject designs and how they can be used in clinical and other rehabilitation environments. METHOD/RESULT: Three basic designs in single subject research are presented, with corresponding examples illustrating each design. A review of visual and statistical analysis techniques commonly used in single subject designs is provided, and the advantages and limitations of each are noted. CONCLUSION: Single subject designs are ideally suited for research in the rehabilitation practice environment. If properly applied, these designs can help establish the efficacy of rehabilitation practice and contribute to rehabilitation science.

Clinical Trials as Topic↗
PubMed2001

Comparison of logistic regression and neural networks to predict rehospitalization in patients with stroke.

CONTEXT: Rehospitalization following inpatient medical rehabilitation has important health and economic implications for patients who have experienced a stroke. OBJECTIVE: Compare logistic regression and neural networks in predicting rehospitalization at 3-6-month follow-up for patients with stroke discharged from medical rehabilitation. DESIGN: The study was retrospective using information from a national database representative of medical rehabilitation patients across the US. SETTING: Information submitted to the Uniform Data System for Medical Rehabilitation from 1997 and 1998 by 167 hospital and rehabilitation facilities from 40 states was examined. PARTICIPANTS: 9584 patient records were included in the sample. The mean age was 70.74 years (SD = 12.87). The sample included 51.6% females and was 77.6% non-Hispanic White with an average length of stay of 21.47 days (SD = 15.47). MAIN OUTCOME MEASURES: Hospital readmission from 80 to 180 days following discharge. RESULTS: Statistically significant variables (P <.05) in the logistic model included sphincter control, self-care ability, age, marital status, ethnicity and length of stay. Area under the ROC curves were 0.68 and 0.74 for logistic regression and neural network analysis, respectively. The Hosmer-Lemeshow goodness-of-fit chi-square was 11.32 (df = 8, P = 0.22) for neural network analysis and 16.33 (df = 8, P = 0.11) for logistic regression. Calibration curves indicated a slightly better fit for the neural network model. CONCLUSION: There was no statistically significant or practical advantage in predicting hospital readmission using neural network analysis in comparison to logistic regression for persons who experienced a stroke and received medical rehabilitation during the period of the study.

Aged↗
PubMed2001

Characteristics of persons rehospitalized after stroke rehabilitation.

OBJECTIVE: To develop classification models for risk of hospital readmission 80 to 180 days after discharge based the demographic and functional characteristics of persons discharged from acute inpatient rehabilitation after stroke. DESIGN: Retrospective, using information from US facilities subscribing to the Uniform Data System for Medical Rehabilitation (UDS(MR)). SETTING: Information submitted to the UDS(MR) from 1994 through 1996 by 167 hospital and rehabilitation facilities from 40 states was examined. PARTICIPANTS: A total of 15,992 records of patients (mean age +/- standard deviation, 70.97 +/- 12.19yr) with a diagnosis of stroke were included in the final sample. The sample included 52.7% women and was 80% non-Hispanic white with an average length of stay (LOS) of 25.31 +/- 14.72 days. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Six subscales of the FIM instrument (self-care, sphincter control, transfers, locomotion, communication, social cognition), total FIM, and other predictor variables for regression analysis (gender, age, ethnicity, marital status, prehospital living setting, LOS, primary payer source, level of function-related group). RESULTS: A logistic regression model included the following statistically significant variables (p <.05): ethnicity, sphincter control, self-care ability, gender, and LOS. The greatest variability occurred among men. Exactly 18.1% of non-Hispanic white men and 17.9% of African-American men were rehospitalized. In contrast, only 10.1% of Hispanic men and 11.4% of Asian men were rehospitalized. The odds of rehospitalization were lowest for Hispanic men. CONCLUSION: As prospective payment systems are introduced for postacute care, it is important that the relationship among functional abilities, demographic characteristics, and incidence of hospital readmission following medical rehabilitation be examined.

Aged↗
PubMed2001

Levels of self-awareness after acute brain injury: how patients' and rehabilitation specialists' perceptions compare.

OBJECTIVE: To examine self-awareness regarding performance on 4 daily living tasks and to test theoretical predictions for a model of self-awareness in persons with acquired brain injury. DESIGN: A comparative design examining the level of self-awareness recorded by patients and actual patient performance as judged by rehabilitation clinicians. SETTING: A community-based residential center providing comprehensive rehabilitation services to persons with acquired brain injury. PARTICIPANTS: Fifty-five persons with acquired brain injury and the identified potential to return to independent function in the community. Ten subjects without brain injury provided comparison data. INTERVENTION: Information was collected by using patient self-report, clinician rating of patient performance, patient rating of non-brain-injured subjects, and clinician rating of non-brain-injured subjects. MAIN OUTCOME MEASURES: Three self-awareness criteria were examined: intellectual, emergent, and anticipatory. Self-awareness was rated for 3 tasks: dressing, meal planning, and money management. RESULTS: Statistically significant differences (p <.05) were found for all levels of self-awareness across the 3 tasks. Persons with brain injury judged their abilities higher than clinician ratings of actual performance. No statistical support was found for a hierarchy among intellectual, emergent, and anticipatory self-awareness. CONCLUSIONS: No evidence was found supporting a hierarchy among levels of self-awareness as defined and measured in the present study. New methods for operationally defining intellectual, emergent, and anticipatory self-awareness are necessary to examine the relationship between self-awareness and performance.

Activities of Daily Living↗
PubMed2001

Measures of central tendency in rehabilitation research: what do they mean?

Measures of central tendency including the mean, median, and mode are commonly reported in rehabilitation research. It is believed that the relationship among the mean, median, and mode changes in a specific way when the distribution being analyzed is skewed. A number of widely used textbooks were reviewed to determine how the relationship among the mean, median, and mode is presented in the health sciences and rehabilitation literature. We report a potential misinterpretation of the relationship between measures of central tendency that was identified in several research and statistical textbooks on the subject of rehabilitation. The misinterpretation involves measures of central tendency derived from skewed unimodal sample distributions. The reviewed textbooks state or imply that in asymmetrical distributions, the median is always located between the mode and mean. An example is presented illustrating the fallacy of this assumption. The mean and median will always be to the right of the mode in a positively skewed unimodal distribution and to the left of the mode in a negatively skewed distribution; the order of the mean and median is impossible to predict or generalize. The assumption that the median always falls between the mode and mean in the calculation of coefficients of skewness has implications for the interpretation of exploratory and confirmatory data analysis in rehabilitation research.

Data Interpretation, Statistical↗
PubMed2001

Virtual reality in the assessment of selected cognitive function after brain injury.

OBJECTIVE: To assess selected cognitive functions of persons with traumatic brain injury using a computer-simulated virtual reality environment. STUDY DESIGN: A computer-simulated virtual kitchen was used to assess the ability of 30 patients with brain injury and 30 volunteers without brain injury to process and sequence information. The overall assessment score was based on the number of correct responses and the time needed to complete daily living tasks. Identical daily living tasks were tested and scored in participants with and without brain injury. Each subject was evaluated twice within 7 to 10 days. A total of 30 tasks were categorized as follows: information processing, problem solving, logical sequencing, and speed of responding. RESULTS: Persons with brain injuries consistently demonstrated a significant decrease in the ability to process information (P = 0.04-0.01), identify logical sequencing (P = 0.04-0.01), and complete the overall assessment (P < 0.01), compared with volunteers without brain injury. The time needed to process tasks, representing speed of cognitive responding, was also significantly different between the two groups (P < 0.01). CONCLUSION: A computer-generated virtual reality environment represents a reproducible tool to assess selected cognitive functions and can be used as a supplement to traditional rehabilitation assessment in persons with acquired brain injury.

Activities of Daily Living↗
PubMed2001

Evidence-based practice: methods to evaluate individual patient improvement.

The expectations and demands associated with evidence-based practice in medical rehabilitation require the use of research procedures that are practice based and practitioner oriented. Traditional research methods, including randomized clinical trials, are powerful techniques for determining the efficacy of rehabilitation interventions; however, randomized clinical trials have some practical and ethical limitations when applied to many research questions important to the field of medical rehabilitation, and alternative methods are needed to fully examine the effectiveness of treatment techniques for individual patients and to document clinical accountability. This paper examines the use of single-system designs and N of 1 research strategies. The advantages and limitations of single-system methods are described, and examples relevant to the documentation of clinical outcomes in medical rehabilitation are presented.

Evidence-Based Medicine↗
PubMed2001

Satisfaction with medical rehabilitation in patients with cerebrovascular impairment.

OBJECTIVE: Overall satisfaction has important social and economic implications for patients who have received inpatient medical rehabilitation. We conducted this study to examine the overall satisfaction level at 3- to 6-mo follow-up for inpatients with cerebrovascular impairments discharged from medical rehabilitation. DESIGN: The study was retrospective using information from a national database representative of medical rehabilitation patients across the United States. Information submitted in 1997 and 1998 to the Uniform Data System for Medical Rehabilitation by 177 hospital and rehabilitation facilities from 40 states was examined. The final sample included 8,900 patient records. The main outcome measure was the level of satisfaction with medical rehabilitation at 80-180 days postdischarge follow-up. RESULTS: A logistic regression model including ten independent variables was used to predict satisfied vs. dissatisfied at follow-up. Three statistically significant variables were included in the final model and correctly classified 95.1% of the patients. Higher FIM instrument discharge scores were associated with increased satisfaction. Further analysis of the FIM instrument subscales indicated that higher ratings in transfers, social cognition, and locomotion were significantly associated with increased satisfaction. CONCLUSION: We identified several functional variables associated with increased satisfaction after medical rehabilitation in persons with stroke. The ability to objectively assess patient satisfaction is important as consumer-based outcome measures are integrated in accreditation and healthcare evaluation.

Activities of Daily Living↗
PubMed2001

Concurrent validity of the Functional Independence Measure for Children (WeeFIM) and the Pediatric Evaluation of Disabilities Inventory in children with developmental disabilities and acquired brain injuries.

The Functional Independence Measure for Children (WeeFIM) and the Pediatric Evaluation of Disability Inventory (PEDI) are the most commonly used measures of functional performance in children. The purpose of this study was to determine the concurrent validity of the instruments when used with children with developmental disabilities and acquired brain injury. The subjects were 41 children, age 1.3 to 9.5 years, who were receiving inpatient or outpatient services at a pediatric rehabilitation unit in Brisbane, Australia. Spearman correlation coefficients between the two tests were greater than 0.88 for self care, transportation/locomotion, and communication/social function. The high correlations indicate that the two tests measure similar constructs. Choosing between the tests depends on situational requirements and depth of information required.

Brain Injuries↗
PubMed2000

The WeeFIM instrument: its utility in detecting change in children with developmental disabilities.

OBJECTIVE: To examine the utility of the WeeFIM instrument ("WeeFIM") in detecting changes in the functional status of children with disability. DESIGN: Prospective longitudinal design with correlation and responsiveness analysis. SETTING: Three facilities providing services to children with developmental disabilities in western New York State. PARTICIPANTS: Two hundred five children (72 girls, 133 boys) with identified medical disabilities receiving special services were administered the WeeFIM. Subjects ranged in age from 11 to 87 months and came from diverse socioeconomic and ethnic backgrounds. Scores for 174 children were available for 3 administrations performed over a 1-year period. MAIN OUTCOME MEASURES: The responsiveness of the WeeFIM instrument was examined using 5 statistical procedures: Reliability Change Index, Proportional Change Index, effect size, standardized response means, and paired t tests. RESULTS: All 5 indexes of responsiveness indicated statistically significant (p < .05) or reliable changes over time. The transfer subscale of the WeeFIM showed a skewed distribution that affected the results for some responsiveness indexes. The advantage, limitations, and assumptions of the responsiveness indexes are described and graphic examples of change over time are presented to validate the responsiveness of the WeeFIM instrument. CONCLUSION: The WeeFIM instrument showed the ability to document change in functional abilities over a 1-year period in children with chronic disabilities.

Activities of Daily Living↗
PubMed2000

Length of stay and hospital readmission for persons with disabilities.

OBJECTIVES: Length of stay (LOS) and hospital readmission for persons receiving medical rehabilitation were examined. METHODS: A total of 96,473 patient records (1994-1998) were analyzed. Mean age of patients was 68.97 years; 61% were female and 83% were non-Hispanic White. RESULTS: A decrease in LOS of 6.07 days (SD = 3.23) and increase in hospital readmission were found across all impairment groups (P < .001). Readmission increases ranged from 6.7% for amputations to 1.4% for orthopedic conditions. LOS was longer (2.1 days) for readmitted patients (P < .01). Age was not a significant predictor of rehospitalization. CONCLUSIONS: Understanding variables associated with rehospitalization is important as prospective payment systems are introduced for postacute care.

Activities of Daily Living↗
PubMed1999

Measuring developmental and functional status in children with disabilities.

This study compared performance on the Functional Independence Measure for Children (WeeFIM), the Battelle Developmental Inventory Screening Test (BDIST), and the Vineland Adaptive Behavior Scales (VABS) in children with developmental disabilities. The three instruments were administered to 205 children with identified disabilities. All 205 children were tested using the WeeFIM instrument. The BDIST was administered to 101 children and the VABS to the remaining 104 children. Administration was counterbalanced and randomized across all three instruments. A proportional sampling plan was used to select the 205 children, who ranged in age from 11 to 87 months. A variety of medical diagnoses and levels of severity of motor, cognitive, and communication impairments were systematically included in the sample. Correlations (r) among subscales for all three instruments ranged from 0.42 to 0.92. Correlations for total scores ranged from 0.72 to 0.94. Analyses of potential moderator variables found no significant relation between age and severity of disability (r=0.05) or between socioeconomic status (SES) and severity of disability (r=0.21). Correlations with age were strongest for those subscale scores involving gross and fine motor skills. Correlations with SES and subscale scores ranged from 0.03 to 0.18. The three instruments provide important information regarding childhood performance in motor, self-care, communicative, cognitive, and social skills. The WeeFIM instrument requires less administration time and provides information directly relevant to evaluating functional outcomes for children with disabilities and their families.

Child↗
PubMed1998

Quantitative evaluation of multiplicity in epidemiology and public health research.

Epidemiologic and public health researchers frequently include several dependent variables, repeated assessments, or subgroup analyses in their investigations. These factors result in multiple tests of statistical significance and may produce type 1 experimental errors. This study examined the type 1 error rate in a sample of public health and epidemiologic research. A total of 173 articles chosen at random from 1996 issues of the American Journal of Public Health and the American Journal of Epidemiology were examined to determine the incidence of type 1 errors. Three different methods of computing type 1 error rates were used: experiment-wise error rate, error rate per experiment, and percent error rate. The results indicate a type 1 error rate substantially higher than the traditionally assumed level of 5% (p < 0.05). No practical or statistically significant difference was found between type 1 error rates across the two journals. Methods to determine and correct type 1 errors should be reported in epidemiologic and public health research investigations that include multiple statistical tests.

Bias↗
PubMed1998

The effect of autocorrelation on the results of visually analyzing data from single-subject designs.

OBJECTIVE: Single-subject research designs are used to conduct clinical research and outcome evaluation in occupational therapy. Confusion exists regarding the best method to analyze and interpret single-subject data. METHOD: One hundred graphs displaying the results of published single-subject research were examined to determine the influence of autocorrelation on the visual inferences made by the original investigators. The graphs were selected from 20 articles published over 10 years in seven rehabilitation journals. The data were extrapolated and lag 1 autocorrelation coefficients computed for both the baseline and treatment phases. RESULTS: Data analysis focused on two issues: (a) whether a relationship existed between the amount of autocorrelation present in a graph and the conclusion on the basis of visual analysis and (b) whether the amount of autocorrelation varied across different phases of the single-subject graphs. When a significant degree of autocorrelation was present, researchers using visual analysis were more likely to conclude that there was no clinically significant change in performance. Autocorrelation values were significantly higher in the treatment phases of the single-subject designs. CONCLUSION: Additional research is needed to establish a set of decision rules to assist clinicians in using visual analysis to evaluate the results of single-subject research.

Data Interpretation, Statistical↗
PubMed1997

Interrater agreement and stability of the Functional Independence Measure for Children (WeeFIM): use in children with developmental disabilities.

OBJECTIVE: Examination of the interrater agreement and stability of ratings obtained using the Functional Independence Measure for Children (WeeFIM) in a sample of children with developmental disabilities. DESIGN: A relational design was used in which two sets of WeeFIM scores were collected under four conditions: same rater-short interval; same rater-long interval; different rater-short interval; and different rater-long interval. SETTING: WeeFIM scores were collected in outpatient developmental rehabilitation centers, school programs, and the children's homes. PARTICIPANTS: Data were collected for 205 children ranging in age from 11 to 87 months. All children had a medical diagnosis of disability and were receiving habilitative-educational intervention or follow-along services including neurodevelopmental surveillance. INSTRUMENT: The WeeFIM instrument examines basic daily living and functional skills in children from birth to 7 years of age. The WeeFIM is modeled after the Functional Independence Measure (FIM) for adults and includes 18 items in the following subscales: self-care, sphincter control, transfers, locomotion, communication, and social cognition. RESULTS: Kappa values for items ranged from .44 to .82. Intraclass correlation coefficients (ICC) for the six subscales ranged from .73 to .98. Total WeeFIM ICC values were greater than .95 for all analyses. CONCLUSIONS: The WeeFIM ratings for the 205 children with developmental disabilities participating in this investigation were consistent across raters and time.

Activities of Daily Living↗
PubMed1997

Equivalence reliability of the functional independence measure for children (WeeFIM) administration methods.

OBJECTIVE: This study examined the equivalence reliability of two administration methods for the Functional Independence Measure for Children (WeeFIM). The two methods were direct observation of child performance and parental interview. METHOD: Thirty children between the ages of 19 months and 71 months with identified developmental disabilities were included in this study. The direct observation and interview methods were administered in random order to each subject within a 3-week period. The direct observation was completed in the educational setting, and the WeeFIM interview was obtained by either in-person interview or telephone interview with the parent. RESULTS: The intraclass correlation coefficient (ICC) for total WeeFIM ratings was .93, indicating consistency between the two administration methods. Analysis of the WeeFIM Motor (13 items) and Cognitive (5 items) domains yielded ICC values of .93 and .75, respectively, suggesting greater consistency for items measuring motor-related skills. CONCLUSION: The results demonstrate good agreement for total ratings when the WeeFIM is administered by direct observation and by interview with a parent. The findings establish the clinical usefulness of information collected by clinical interview.

Activities of Daily Living↗
PubMed1997

The use of microwave ovens by elderly persons with disabilities.

OBJECTIVE: This study examined the effectiveness of microwave ovens in assisting elderly persons with disabilities with cooking food. METHOD: The participants were five elderly persons who had gross motor, fine motor, or vision impairments but no cognitive impairments. Before the study, none of the participants owned or operated a microwave oven. In this single-subject design of four phases (ABAB), training in microwave oven use was provided between the first A (baseline) and first B (intervention) phases. Participants had access so the microwave oven in their homes only during the B phases. Each phase lasted for 3 weeks, for a total of 12 weeks. The frequency of using cooking appliances, the number of food items prepared, and the time spent preparing meals were recorded through daily self-reports. RESULTS: All participants showed an increase in the frequency of using cooking appliances for at least one of the two B phases, although they showed different patterns. The number of food items prepared increased in the B phases, except for two participants who were ill. With the introduction of the microwave oven, time spent preparing meals decreased for all five participants, and their participation in meal preparation increased. Although not measured as a study variable, results suggest that the quality of diet also improved with microwave oven use. CONCLUSION: Occupational therapy practitioners who serve elderly clients might consider recommending microwave ovens for those who do not have cognitive impairments but who are having difficulty with cooking because of vision impairments or physical disabilities.

Activities of Daily Living↗