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Evaluation of a theory-based nutrition intervention for older adults with diabetes mellitus.

OBJECTIVE: To evaluate an intervention to improve food label knowledge and skills in diabetes management among older adults with diabetes mellitus. DESIGN: A randomized pretest-posttest control group design was used. SUBJECTS/SETTING: Participants (48 experimental, 50 control) were aged 65 years and older with type 2 diabetes for 1 year or longer; 93 participants (95%) completed the study, conducted in an outpatient setting. INTERVENTION: The intervention included 10 weekly group sessions led by a dietitian. Information processing, learning theory, and Social Cognitive Theory principles were used in program development and evaluation. MAIN OUTCOME MEASURES: Participants' knowledge, outcome expectations (expected results of behavior), self-efficacy, and decision-making skills were assessed. Instrument validity and reliability were established before program evaluation. STATISTICAL ANALYSES PERFORMED: Factor analysis identified underlying factor structures. Analysis of covariance with pretest score as covariate was used to compare groups at posttest. Paired t tests compared results within groups. RESULTS: Two factors were identified for outcome expectations (positive and negative) and for self-efficacy (promoters of and barriers to diabetes management). The experimental group had greater improvement in total knowledge scores (mean +/- standard error of the mean: 7.8+/-0.7) than the control group (0.2+/-0.7) (P < .0001), positive outcome expectations (0.59+/-0.15 vs 0.06+/-0.15, P = .01), promoters of diabetes management (0.83+/-0.12 vs -0.09+/-0.18, P < or = .001) and decision-making skills (5.1+/-0.5 vs 0.3+/-0.5, P < .0001) and greater reduction in barriers to diabetes management (1.1+/-0.16 vs 0.34+/-0.16, P < .01). No significant difference in negative outcome expectations occurred between groups at posttest. APPLICATIONS/CONCLUSIONS: Older adults with diabetes can benefit from nutrition education designed to improve knowledge and skills necessary for diabetes management.

Aged↗

Evaluation of a food label nutrition intervention for women with type 2 diabetes mellitus.

OBJECTIVE: To evaluate an educational intervention about the food label designed specifically for women with type 2 diabetes mellitus. DESIGN: A pretest-posttest control group design. Participants received random group assignment. SUBJECTS/SETTING: Forty-three women aged 40 to 60 years with type 2 diabetes living in a rural community in Pennsylvania participated. Forty participants (93%) completed the program. INTERVENTION: Nine weekly group sessions were developed on the basis of findings from previous research among this sample. Principles from Ausubel's learning theory were also incorporated into program design and evaluation. MAIN OUTCOME MEASURES: The effectiveness of the food label education program on participants' knowledge was determined using a multiple-choice test designed to measure declarative and procedural knowledge. A skills inventory assessed participants' perceived confidence in using the food label. The validity and reliability of the instruments had been established previously. STATISTICAL ANALYSES: Analysis of variance was performed to compare groups. Paired t tests compared pretest and posttest results. RESULTS: The experimental group showed a greater gain than the control group in total knowledge (P < .001), declarative knowledge (P < .001), and procedural knowledge (P < .01) at posttest. Posttest data showed a significant increase (P < .01) in experimental participants' perceived confidence in using the food label. CONCLUSIONS: Women with diabetes need more education about the food label. This intervention is an effective outpatient education program. Participant knowledge and perceived confidence in using the food label improved significantly as a result of the intervention. Future research should assess retention of knowledge gained and the impact of the intervention on metabolic measures of diabetes management and control.

Adult↗

Noninvasive strategies for the estimation of cardiac risk in stable chest pain patients. The Economics of Noninvasive Diagnosis (END) Study Group.

Effective allocation of medical resources in stable chest pain patients requires the accurate diagnosis of coronary artery disease and the stratification of future cardiac risk. We studied the relative predictive value for cardiac death of 3 commonly applied noninvasive strategies, clinical assessment, stress electrocardiography, and myocardial perfusion tomography, in a large, multicenter population of stable angina patients. The multicenter observational series comprised 7 community and academic medical centers and 8,411 stable chest pain patients. All patients underwent pretest clinical screening followed by stress (exercise 84% or pharmacologic 16%) electrocardiography and myocardial perfusion tomography. Risk-adjusted multivariable Cox proportional hazards models were developed to predict cardiac death. Kaplan-Meier rates of time to cardiac catheterization were also computed. Cardiac mortality was 3% during the 2.5 +/- 1.5 years of follow-up. The number of infarcted vascular territories and pretest clinical risk factors were strong predictors of cardiac mortality, whereas the number of ischemic vascular territories gained increasing importance when determining post-test resource use requirements (i.e., the decision to perform cardiac catheterization). Exertional ST-segment depression in a population with a high frequency of electrocardiographic abnormalities at rest was not a significant differentiator of cardiac death risk. Stable chest pain patients are accurately identified as being at high risk for near-term cardiac events by both physicians' screening clinical evaluation and by the results of stress myocardial perfusion imaging. Disease management strategies for stable chest pain patients aimed at risk reduction should incorporate knowledge of relevant end points in treatment and guideline development.

Aged↗

Prognostic significance of normal dobutamine-atropine stress sestamibi scintigraphy in women with chest pain.

To evaluate the prognostic value of normal dobutamine-atropine technetium-99m sestamibi single-photon emission computed tomography (SPECT) perfusion imaging in women with chest pain and inability to perform an adequate exercise test, 80 women with a normal scintigram were followed up for 23 +/- 13 months. Mean age of the patients was 61 +/- 12 years. Nine patients (11%) had a low probability (< 10%) of coronary artery disease, 43 (54%) had an intermediate probability (10% to 80%) of disease, and 28 (35%) had a high probability (>80%) of disease (including 19 patients with known coronary artery disease). During follow-up, no major cardiac events (cardiac death or nonfatal myocardial infarction) occurred. One patient with known coronary disease underwent coronary bypass surgery after 3 months, and 1 patient with a 91% pretest likelihood of coronary disease underwent coronary angioplasty after 7 months. Thus, the overall incidence of (soft) cardiac events during the follow-up period was 2 of 80 patients, or 1.3%/year. It is concluded that normal dobutamine-atropine technetium-99m sestamibi SPECT perfusion imaging in women with chest pain implies an excellent prognosis, even in women with high pretest likelihood of coronary disease.

Adult↗

Comparison of patients with syncope of unknown cause having negative or positive tilt-table tests.

Many patients without an identified cause of syncope have negative tilt tests. We hypothesized that many of these might be falsely negative tilt tests. If so, then patients with negative and positive tilt tests should have similar pretest clinical characteristics, post-test probabilities of remaining free of syncope, and similar risk factors for syncope recurrence after the tilt-table test. Demographic characteristics and historic features were compared between 153 syncope patients with a positive tilt test, and 74 syncope patients with a negative tilt test and no obvious cause of syncope. Patients with negative and positive tests had similar numbers of syncopal spells, durations of symptoms, frequency of spells, and peak heart rate during tilt test, but patients with negative tests were older (48 +/- 19 vs 39 +/- 20 years). The actuarial probabilities of remaining free of syncope were very similar, with 2-year risks of syncope of 41% and 37% in patients with negative and positive tests, respectively. The regression coefficients of risk factors predicting syncope recurrence were similar for both populations, and the confidence intervals of all regression coefficients decreased when the populations were combined. The outcome of tilt testing did not predict the clinical outcome of patients. Patients with syncope and either negative or positive tilt tests share many pretest and post-test clinical characteristics, suggesting that they may be part of the same population.

Aged↗

Comparison of ramp versus step protocols for exercise testing in patients > or = 60 years of age.

To evaluate whether individualized ramp protocols may be better than step protocols in patients > or = 60 years of age referred for exercise testing, peak cardiopulmonary responses and accuracy in prediction of oxygen uptake (VO2) for individualized ramp and step protocols (Bruce or modified Bruce) were compared. Twenty-four subjects (67+/-3 years) with known or suspected coronary artery disease performed both tests in random order. Protocols were selected based on estimated exercise capacity using a pretest activity questionnaire. No differences were observed between peak VO2 (19.3+/-6.3 and 19.1+/-6.4 ml/kg/min), heart rate (127+/-15 and 126+/-16 beats/min), rate-pressure product (24.0+/-4.8 and 23.4+/-4.9 beats/min x mm Hg x 10(3)) and anaerobic threshold (16.6+/-3.7 and 16.0+/-4.7 ml/kg/min) for the ramp and step protocols, respectively. The relation between measured submaximal VO2 and American College of Sports Medicine (ACSM)-predicted VO2 during the ramp protocol is demonstrated by the regression coefficient (beta), where beta = 0.92 (95% confidence intervals [CI] 0.85 to 0.99) and for the step protocols where beta = 1.02 (95% CI 0.84 to 1.20). Peak cardiopulmonary responses in the elderly are similar during individualized ramp and step protocols when appropriately selected based on a pretest activity questionnaire. Both protocols appear to provide clinically reasonable estimates of VO2 when gas exchange analysis is not used.

Aged↗

Value of transthoracic echocardiography in the diagnosis of pulmonary embolism: results of a prospective study in unselected patients.

PURPOSE: Echocardiography is advocated by some as a useful diagnostic test for patients with suspected pulmonary embolism (PE), but its diagnostic accuracy is unknown. The present study was undertaken to determine prospectively the sensitivity and specificity of transthoracic echocardiography in the diagnosis of PE. SUBJECTS AND METHODS: We examined 110 consecutive patients with suspected PE. The study protocol included assessment of clinical probability, echocardiography, and perfusion lung scanning. Pulmonary angiography was performed in all patients with abnormal scans. As echocardiographic criteria to diagnose acute PE, we used the presence of any two of the following: right ventricular (RV) hypokinesis, RV end-diastolic diameter >27 mm (without RV wall hypertrophy), or tricuspid regurgitation velocity >2.7 m/sec. Clinical estimates of PE served as pretest probabilities in calculating, after echocardiography, the posttest probabilities of PE. RESULTS: Pulmonary angiography confirmed PE in 43 (39%) of 110 patients. Echocardiographic diagnostic criteria for PE yielded a sensitivity of 56% and a specificity of 90%. For pretest probabilities of 10%, 50%, and 90%, the posttest probabilities of PE conditioned by a positive echocardiogram were 38%, 85%, and 98%, respectively. The posttest probabilities of PE conditioned by a negative echocardiogram were 5%, 33%, and 81%, respectively. CONCLUSIONS: In unselected patients with suspected PE, transthoracic echocardiography fails to identify some 50% of patients with angiographically proven PE. Although echocardiographic findings of RV strain, paired with a high clinical likelihood, support a diagnosis of PE, the transthoracic echocardiography has to have a better sensitivity to be used as a screening test to rule out PE.

Adolescent↗

Clinical prediction of deep venous thrombosis using two risk assessment methods in combination with rapid quantitative D-dimer testing.

PURPOSE: The optimal approach to diagnosing deep venous thrombosis is not entirely clear. In this prospective cohort study, we aimed to evaluate the yield of two methods of assessing the pretest probability of deep venous thrombosis-the treating physician's implicit assessment and the Wells score, a validated prediction rule that incorporates signs, symptoms, and the presence or absence of an alternative diagnosis-used in isolation and in combination with D-dimer measurement. SUBJECTS AND METHODS: We studied 278 patients who were referred for suspicion of deep venous thrombosis. All patients were stratified into groups of low, moderate, or high risk of deep venous thrombosis on the basis of the clinical assessment and Wells score, and underwent rapid quantitative D-dimer testing (with a cutoff of 500 microg/mL), ultrasound examination, and follow-up for the occurrence of venous thromboembolism. RESULTS: Eighty-two patients (29%) had a deep venous thrombosis. The accuracy of both methods was good (area under the receiver operating characteristic curve = 0.72), despite only fair agreement at the level of individual patients (weighted kappa = 0.31; 95% confidence interval [CI]: 0.23 to 0.40). The negative predictive value of D-dimer measurement was 96% (95% CI: 91% to 100%). When restricted to patients with low pretest probability, the negative predictive value of D-dimer measurement was 100% (95% CI: 96% to 100%) with the use of the Wells score and 96% (95% CI: 88% to 100%) with the physician's assessment. Our results were unchanged in analyses restricted to patients with proximal deep venous thrombosis or outpatients. CONCLUSION: Clinical assessment to stratify a patient's likelihood of having deep venous thrombosis should be taught to physicians.

Aged↗

Development of physical examination skills in a third-year surgical clerkship.

BACKGROUND: Previous studies have revealed deficiencies in physical examination (PE) skills of third-year medical students. The purpose of this study was to determine if formal teaching of PE skills and more supervised experiences with clinical faculty would increase the competency of these skills. METHODS: Forty-nine third-year medical students were assigned to one of two groups: group A was given formal instruction on PE skills at the beginning of the clerkship, and group B received the same instruction at the midpoint of the clerkship. The two groups received an assessment of the PE skills before, in the middle, and at the end of clerkship, utilizing a physician-developed checklist. RESULTS: Group A had a pretest score of 57.7%. Group B scored 59.8% on the pretest. Independent groups t tests were used to compare the two groups. At the midterm examination, group A increased their score to 71.0%, while group B decreased their score to 55.6%. From beginning to final, both groups had significant improvements in all areas, with group A scoring an overall mean of 75.1% (P = 0.0001), and group B scoring 75.5% (P = 0.0001). CONCLUSION: These findings show the effectiveness of structured learning situations for improving third-year surgery students' PE skills. There is also an indication that usual clerkship activities may not enhance learning of PE skills.

Clinical Clerkship↗

Learning preferences, computer attitudes, and test performance with computer-aided instruction.

BACKGROUND: Learning preference refers to how individuals choose to approach learning situations. Computer-aided instruction (CAI) permits the adaptation of educational content to individual student learning strategies. METHODS: To determine if learning preference and computer attitude influence the acquisition of knowledge using CAI materials, a prototype CAI program was developed that incorporated differing learning exercises. Students (n = 180) completed Rezler's Learning Preference Inventory (LPI) and a computer attitude survey (CAS). The LPI uses three sets of paired scales to characterize learning preference and choice of learning situation. The CAS assesses student attitudes toward computers in general (CAS-G), as well as the educational use of computers (CAS-E). After finishing the program students completed a program attitude survey (CAS-P). Immediate comprehension was assessed by pretests and posttests incorporated into the program. Retention was assessed by a repeat of the posttest 4 to 6 weeks after initial program review. RESULTS: Scores (mean +/- SEM) on the pretest, posttest, and late posttest were 38.1% +/- 1.35%, 70.9% +/- 1.24%, and 62.5% +/- 1.44%, respectively. There was no correlation between students' learning preferences or computer attitude and test performance. CONCLUSIONS: The data indicate that CAI provides a means of delivering educational content that results in an increase in knowledge that is not correlated with computer attitudes or learning preferences.

Angiography↗

International prospective evaluation of scintimammography with technetium-99m sestamibi: interim results.

OBJECTIVE: The purpose of this study is to evaluate the validity and reliability of scintimammography with technetium-99m (99mTc)-labeled sestamibi as an adjunct radiodiagnostic agent in the diagnosis of breast cancer. METHODS: This is a multicenter prospective cohort clinical trial that was initiated in June 1999 and will terminate May 2001. All patients with a physical or mammographic finding visiting any of the participating clinics are enrolled in the study. Patients who are younger than 18 years, pregnant, not willing to sign the consent form, or who have undergone an invasive procedure on the breast 30 days or less before scintimammography are excluded. At the time of the first interim report, 633 patients had been recruited from six Canadian centers. To date complete data have been collected for 530 patients. RESULTS: The mean (SD) age of the patients is 56 (12) years with a range between 24 and 85. There were 122 (23%) of the women in the sample who were postmenopausal and 36 (7%) who were perimenopausal. Breast density was graded as dense for 127 (24%), normal for 260 (50%), and fatty for 138 (26%). Of the 530 women in the study 156 (29%) had a palpable mass at physical examination. The mammographic results were classified as 76 (14%) breast imaging reporting and data system (BIRADS) 5, 60 (11%) BIRADS 4, 70 (13%) BIRADS 3 and the remaining BIRADS 2 or 1. The scintimammography results were positive for 118 (23%) of the patients and negative for 412 (78%). The histopathology showed malignant breast disease for 66 (12.5%) of the patients in the sample. Sensitivity and specificity of scintimammography for the detection of breast cancer was estimated 90.9% and 87.5%, respectively. A positive predictive value (PPV) of 50.8% with a negative predictive value of 98.5% and an accuracy of 87.5% were calculated. The PPV is interpreted as the posttest probability of disease given a positive test result. In this sample the pretest probability of disease would be best estimated by the prevalence of disease, which is equal to 12.5%. A positive scintimammography result would change the estimated probability to 51%, which is equivalent to a 400% change from the pretest value. Therefore a positive scintimammography result significantly increases our ability to predict the presence of malignant disease in this population. CONCLUSION: The interim results of the present study suggest that scintimammography with 99mTc-sestamibi is accurate and potentially useful as an adjunct to mammography for the detection of breast cancer.

Adult↗

Intravenous catheter training system: computer-based education versus traditional learning methods.

BACKGROUND: Virtual reality simulators allow trainees to practice techniques without consequences, reduce potential risk associated with training, minimize animal use, and help to develop standards and optimize procedures. Current intravenous (IV) catheter placement training methods utilize plastic arms, however, the lack of variability can diminish the educational stimulus for the student. This study compares the effectiveness of an interactive, multimedia, virtual reality computer IV catheter simulator with a traditional laboratory experience of teaching IV venipuncture skills to both nursing and medical students. METHODS: A randomized, pretest-posttest experimental design was employed. A total of 163 participants, 70 baccalaureate nursing students and 93 third-year medical students beginning their fundamental skills training were recruited. The students ranged in age from 20 to 55 years (mean 25). Fifty-eight percent were female and 68% percent perceived themselves as having average computer skills (25% declaring excellence). The methods of IV catheter education compared included a traditional method of instruction involving a scripted self-study module which involved a 10-minute videotape, instructor demonstration, and hands-on-experience using plastic mannequin arms. The second method involved an interactive multimedia, commercially made computer catheter simulator program utilizing virtual reality (CathSim). RESULTS: The pretest scores were similar between the computer and the traditional laboratory group. There was a significant improvement in cognitive gains, student satisfaction, and documentation of the procedure with the traditional laboratory group compared with the computer catheter simulator group. Both groups were similar in their ability to demonstrate the skill correctly. CONCLUSIONS; This evaluation and assessment was an initial effort to assess new teaching methodologies related to intravenous catheter placement and their effects on student learning outcomes and behaviors. Technology alone is not a solution for stand alone IV catheter placement education. A traditional learning method was preferred by students. The combination of these two methods of education may further enhance the trainee's satisfaction and skill acquisition level.

Adult↗

Use of a paper-cut as an adjunct to teaching the Whipple procedure by video.

BACKGROUND: Medical students often experience difficulty comprehending anatomic relationships of complex operations to which they are exposed during surgical clerkship. Pancreaticoduodenectomy, the Whipple procedure, is one such operation. Although video recordings are available to facilitate the learning of the Whipple procedure, commercially available tapes are not self-explanatory to the uninitiated. Since we have previously demonstrated that third-year medical students could learn the operative steps of inguinal herniorraphy by a paper-cutting exercise, we set out to determine whether an exercise of similar design could enhance a student's comprehension of the Whipple procedure. METHODS: Using Adobe Illustrator 5.5 for MacIntosh, an exercise was developed on a 8.5 x 11-inch paper that could be distributed to students for self-administration. The exercise was performed using a #15 scalpel or an iris scissors. Thirty-seven students were randomized into two groups. Each student received a pretest of questions focusing on the Whipple procedure. Group I was shown an 18-minute commercially available teaching video on the Whipple procedure. Group II was given the Whipple origami exercise, which required 20 minutes to complete. A first posttest was administered to each group. Next, the groups switched exercises, and a second posttest was administered. RESULTS: There was no significant difference between the groups' pretest scores (two-tailed t test, P = 0.290). Group I improved its score from an average of 64.21 (SD 14.27) to 67.89 (SD 13.16) after watching the video, and further to 77.89 (SD 14.37) after completing the paper-cut exercise. Group II improved from 60.00 (SD 9.43) to 78.95 (SD 11.00) after performing the paper-cut, but derived no additional measurable benefit from watching the video, average score 74.74 (SD 18.37). After the first exercise, students who performed the paper-cut showed a significantly greater improvement in test scores compared with students who saw the video (P = 0.0035 by Mann-Whitney U). After both groups had completed the exercises, the mean changes from baseline were no longer significantly different (P = 0.58 by Mann-Whitney U). CONCLUSION: As a single educational intervention, the paper-cut exercise was a more effective teaching device than the video in the given time frame. The origami model may be generalized to a variety of surgical procedures and appears to be a valuable adjunct to traditional teaching.

Audiovisual Aids↗

A virtual reality module for intravenous catheter placement.

BACKGROUND: Virtual reality (VR) is a potential tool for technical skills training. We tested the validity and instructional effectiveness of a prototype VR module for learning intravenous (i.v.) catheter placement. METHODS: First-year medical students (n = 37), third-year medical students (n = 14), and surgical residents (n = 9) attempted two pretest i.v.s into each other, used the VR module for 12 minutes, and subsequently attempted two posttest i.v.s. Success or failure were recorded for each attempt. For each successful attempt, time and global rating of i.v. insertion were also recorded. RESULTS: The pretest success rate was significantly different between groups (chi square = 28.71, P <0.01). VR success rate was not significantly different between groups (F(2,57) = 1.47, ns). Although there was improvement in all groups during VR training (F(2,114) = 44.16, P <0.01), this did not result in improvement in posttest performance. CONCLUSIONS: Significant differences between groups were observed in performance of i.v. insertion in physical reality. However, no significant difference was observed in performance in VR. Thus, performance in VR demonstrated neither construct nor concurrent validity. While performance improved in VR, transfer of skill from VR to physical reality was not observed. Additional development and testing of VR as a training tool is warranted before its widespread use can be recommended.

Catheterization↗

Modeling surgical expertise for motor skill acquisition.

BACKGROUND: This work is part of an ongoing effort to introduce an innovative medical teaching technique to assist the efficient acquisition of surgical hand skills required to perform an inguinal hernia repair with a McVay technique. The purpose was to determine the effect of expert cognitive modeling, auditory elaboration, and split-screen video analysis on the surgical hand movements required while performing inguinal hernia surgery on cadavers. PURPOSE: Six surgical residents were videotaped performing a McVay procedure inguinal hernia in a pretest-posttest control group design. The experimental group received expert cognitive modeling, auditory elaboration, and split-screen analysis after the pretest. RESULTS: A distinct advantage for surgical instrument control and manipulation was found for the experimental group on the posttest surgeries. Less time was required to perform the operation, and more purposeful movements were exhibited by the experimental group. CONCLUSION: The treatment condition favored mindfulness learning of the McVay technique for an inguinal hernia repair.

Cadaver↗

Wheelchair skills training program: A randomized clinical trial of wheelchair users undergoing initial rehabilitation.

OBJECTIVE: To test the hypothesis that a brief, formalized period of additional wheelchair skills training is safe and results in significantly greater improvements in wheelchair skills performance than a standard rehabilitation program. DESIGN: Randomized controlled trial. SETTING: Rehabilitation center. PARTICIPANTS: Thirty-five wheelchair users (20 with musculoskeletal disorders, 15 with neurologic disorders) admitted for initial rehabilitation. Subjects' mean age +/- standard deviation (SD) was 59+/-18.3 years. INTERVENTION: Subjects randomly allocated to the treatment group participated in the Wheelchair Skills Training Program (WSTP), averaging 4.5+/-1.5 training sessions, each 30 minutes long. Subjects in the control group did not receive any wheelchair skills training beyond that given in a typical rehabilitation stay. MAIN OUTCOME MEASURES: Wheelchair Skills Test (WST), version 2.4, before and after training. Changes in total percentage WST score and individual skill scores were examined. RESULTS: There were no adverse incidents. The control group's mean percentage score +/- SD increased from 60.1%+/-14.4% to 64.9%+/-13.3%, an 8% improvement of the posttest relative to the pretest (P=.01). The WSTP group's mean score increased from 64.9%+/-9.4% to 80.9%+/-5.6%, a 25% improvement of the posttest relative to the pretest (P<.000). The WSTP group showed significantly greater improvements than the control group (P<.000). Among the specific skills, significantly greater improvements were seen in the WSTP group for the gravel and high-curb descent skills (P<.001). CONCLUSIONS: The WSTP is safe and practical and has a clinically significant effect on the independent wheeled mobility of new wheelchair users. These findings have implications for the standards of care in rehabilitation programs.

Adult↗

The chi-square test: its use in rehabilitation research.

OBJECTIVE: This report examines the impact of collecting and analyzing sequential data from the same sample using the chi-square test. Researchers in rehabilitation frequently analyze categorical data collected repeatedly from the same sample. DESIGN: Simulations were conducted using the chi-square test to analyze data with correlations between pretest and posttest ranging from .20 to .80. The simulations were analyzed using the standard chi-square based on a 2 x 2 contingency table. RESULTS: An incidence of type 1 errors of approximately .30 for an expected alpha of .05 was found when the correlation (serial dependence) between pretest and posttest was high (phi = .80). For simulations using an alpha = .01, the type 1 error rate was .18 for data with substantial correlation (phi = .80). CONCLUSION: Rehabilitation researchers who use the chi-square test with data collected repeatedly from the same sample risk committing a type 1 error and misinterpreting their results. Alternatives to the standard chi-square test, such as McNemar's test, should be considered when correlated data are analyzed using a 2 x 2 contingency table.

Chi-Square Distribution↗

Biofeedback effect on electromyography responses in patients with spinal cord injury.

OBJECTIVE: To determine if electromyography (EMG) biofeedback procedures using an operant conditioning paradigm could significantly increase voluntary EMG responses from the triceps muscles of long term cervical spinal cord injured individuals. DESIGN: Intervention study with before-after trial measurement with each subject as its own control. SETTING: University outpatient clinic. PARTICIPANTS: One hundred individuals with cervical spinal cord injuries C6 or higher that were greater than 1-year duration, and who had less than normal strength and recordable EMG activity from the triceps, and who had reached a plateau in return of function. The first 100 individuals meeting this criteria who presented sequentially for EMG testing and biofeedback were included. No subjects were deleted from the sample. INTERVENTION: Muscle strength and surface EMG recording during attempts at elbow extension were obtained. The EMG pretest data were derived from the highest average recorded voluntary EMG response from the triceps during elbow extension. One 45-minute treatment session of EMG biofeedback for the triceps in an operant conditioning paradigm was provided for each of the 100 subjects. Seventy-five subjects received an average of 3 additional biofeedback treatment sessions. The posttest EMG data were derived from EMG measurements of the triceps during attempts at elbow extension from the 45-minute biofeedback treatment session and from the last additional biofeedback treatment session in a similar manner to the pretest procedures. MAIN OUTCOME MEASURES: A significant increase in EMG activity occurred from the triceps (p < or = .001) after one biofeedback treatment session and further significant increases in EMG activity occurred after additional biofeedback treatment sessions (p < or = .001). Initial muscle strength and initial EMG levels were not determining factors for response to the biofeedback. CONCLUSIONS: The results suggest the efficacy of biofeedback for increasing voluntary EMG responses in long term spinal cord injury patients.

Adolescent↗