Orit Shechtman

Comparison of Driving Errors Between On-the-Road and Simulated Driving Assessment: A Validation Study

Objective: Driving simulation provides a convenient and safe method for assessing driving behaviors. Many authors, however, agree that validation is a key component of any study that utilizes simulators to assess driving performance. The purpose of this study was to test driver response validity by discerning whether behavioral responses of drivers, as expressed by type and number of errors, are similar on the road and in the simulator. Methods: We replicated real-world intersections in our driving simulator (STISIM M500W; Systems Technology Inc.) and assessed the number and type of driving errors committed by the same 39 participants while negotiating a right and a left turn both on the road and in the simulator. Results: We found no significant interactions between the type of vehicle (road vs. simulator) and the type of turn (right versus left) for any of the driving errors, indicating that the same trends exist between driving errors made on the road and in the simulator and thus suggesting relative validity of the simulator. We also found no significant differences between the road and the simulator for lane maintenance, adjustment to stimuli, and visual scanning errors, indicating absolute validity for these types of errors. Conclusions: The findings suggest early support for external validity for our driving simulator, indicating that the results of assessing driving errors when negotiating turns in the simulator can be generalized or transferred to the road under the same testing conditions. A follow-up study with larger sample size is needed to establish whether driving performance in the simulator is predictive of driving performance on the road.

Reliability of motor cortex transcranial magnetic stimulation in four muscle representations

OBJECTIVE Motor cortex plasticity may underlie motor recovery after stroke. Numerous studies have used transcranial magnetic stimulation (TMS) to investigate motor system plasticity. However, research on the reliability of TMS measures of motor cortex organization and excitability is limited. We sought to test the reliability of these TMS measurements. METHODS Twenty healthy volunteers were tested twice over a two-week period using TMS to determine motor threshold, map topography, and stimulus-response curves for first dorsal interosseous (FDI), abductor pollicis brevis (APB), extensor digitorum communis (EDC), and flexor carpi radialis (FCR) muscles. RESULTS We found moderate to good test-retest reliability TMS measurements of motor threshold (ICC=0.90-0.97), map area (ICC=0.63-0.86) and location (ICC=0.69-0.86), and stimulus-response curves (ICC=0.60-0.83). CONCLUSIONS TMS assessments of motor representation size, location, and excitability are generally reliable measures, although their reliability may vary according to the muscle under investigation. SIGNIFICANCE These results suggest that TMS measurements of motor cortex function are reliable enough to be potentially useful in investigation of motor system plasticity.

Useful Field of View as a Reliable Screening Measure of Driving Performance in People With Parkinson's Disease: Results of a Pilot Study

Purpose: To determine the correlations of the Useful Field of View (UFOV), compared to other clinical tests of Parkinsons disease (PD); vision; and cognition with measures of on-road driving assessments and to quantify the UFOVs ability to indicate passing/failing an on-road test in people with PD. Methods: Nineteen randomly selected people with idiopathic PD, mean age = 74.8 (6.1), 14 (73.7%) men, 18 (94.7%) Caucasians, were age-matched to 104 controls without PD. The controls had a mean age of 75.4 (6.4), 59 (56.7%) men, 96 (92.3%) Caucasians. Both groups were referred for a driving evaluation after institutional review board approval. Results: Compared to neuropsychological and clinical tests of vision and cognition, the UFOV showed the strongest correlations (r > .75, p < 0.05) with measures of failing a standardized road test and number of driving errors. Among PD patients, the UFOV Risk Index score of 3 (range 1–5) was established as the optimal cutoff value for passing the on-road test, with sensitivity 87 percent and specificity 82 percent, AUC = 92 percent (SE 0.61, p = .002). Similarly, the UFOV 2 (divided attention) optimum cutoff value is 223 ms (range 16–500 ms), sensitivity 87.5 percent, specificity 81.8 percent, AUC = 91 percent (SE 0.73, p = .003). The UFOV 3 (selected attention) optimal cutoff value is 273 ms (range 16–500 ms), sensitivity 75 percent, specificity 72.7 percent, AUC = 87 percent (SE 0.81, p = .007). Conclusion: In this pilot study among PD patients, the UFOV may be a superior screening measure (compared to other measures of disease, cognition, and vision) for predicting on-road driving performance but its rigor must be verified in a larger sample of people with PD.

Reliability and validity of the BTE-Primus grip tool.

This study was designed to examine the reliability and validity of the newly designed grip tool of the Baltimore Therapeutic Equipment (BTE)-Primus and to investigate the effects of body position (sit versus stand), handedness, and fatigue on grip strength. The subjects performed maximal grip strength tests using the Jamar dynamometer and the BTE-Primus. Intraclass correlation coefficients were calculated for test-retest reliability and criterion-related validity. A repeated measures analysis of covariance was conducted to reveal differences in grip strength between instruments, body positions, hands, and sessions. The BTE-Primus grip tool was found to be reliable (r = 0.97 to 0.98) and valid (r = 0.95 to 0.96). There were no significant differences in grip strength scores between the Jamar and the BTE-Primus or between sitting and standing. Grip strength scores of the right hand were significantly greater than those of the left hand, and grip strength scores in the first session were significantly greater than those in the second session. The results of this study indicate that clinicians can use the BTE-Primus grip attachment at the second handle setting and know that is reliable, valid, and comparable to the second-handle setting of the Jamar dynamometer.

Clinical Predictors of Older Driver Performance on a Standardized Road Test

Objectives. To determine the relationship between clinical variables (demographics, cognitive testing, comorbidities, and medications) and failing a standardized road test in older adults. Methods. Analysis of on-the road studies performed in optimal weather conditions, between January 1, 2005, and May 1, 2007. The standardized testing was held at the National Older Driver Research and Training Center (NODRTC), Florida, and included 127 adults aged 65 and older with current driver licenses, recruited by advertisement from the Gainesville, Florida, community. Measurements consist of demographics, self-reported medications and medical conditions, cognitive testing including Trail Making Part B, global rating score (pass/fail), and driver maneuver score (0–273, with 273 indicating perfect driving or zero errors). Results. A total of 127 older adults completed the protocol. Mean age was 74.8 years (SD = 6.3); 46.5% females. Mean time for Trail Making Part B was 114.3 seconds (SD of 83). Among the 127 drivers, the mean Sum of Maneuvers Score was 238.9 (SD of 25.0) and 24 (19%) failed the driver test. Odds ratio estimates for failing the test included advanced age (6.7, 95% CI 2.2 to 19.8), presence of a neurological disease (2.8, 95% CI 1.2 to 6.5), and prolonged time to complete the Trail Making Part B cognitive test (2.5, 95% CI 1.0 to 5.9). Conversely, odds ratio estimates lowering the risk of failure included taking a non-diabetic hormonal medications (e.g., thyroid and estrogen drugs; 0.3, 95% CI .09 to 0.7) and having a musculoskeletal diagnosis (0.3, 95% CI .1 to 0.7). Conclusions. To our knowledge, this is the first study to examine the medical predictors of failing a standardized road test. Advanced age and prolonged time on Trail Making Part B were the two major predictors of test failure and a lower Sum of Maneuvers Score. Our study also found that having a neurological diagnosis (primarily cerebrovascular and Parkinsons disease) predicted test failure. Medications from neurological class also predicted a lower Sum of Maneuvers Score. Further study needs to be done to explain the apparent protective effect of musculoskeletal conditions and hormonal medications.

Validity, Reliability, and Responsiveness of a Digital Version of the Visual Analog Scale

UNLABELLED The design used in this study was a prospective cohort. Pain intensity levels recorded by the digital version of the visual analog scale (VAS-D) are easy to both score and share with other health care professionals. The purpose of the study was to examine the test-retest reliability, concurrent validity, and responsiveness of the VAS-D. Thirty-three people with upper extremity injuries reported pain intensity levels before and after performing four maximal grip contractions (pre- and postgripping). Our version of the VAS-D had high test-retest reliability (r=0.96) and good concurrent validity (r=0.84-0.97) with both the paper version of the VAS (VAS-P) and the verbal numerical rating scale (NRS-V). Responsiveness of the VAS-D was indicated by a significant increase in pain levels from pre- to postgripping. Similar responsiveness to that of the VAS-P and NRS-V was indicated by similar effect size coefficients and analysis of variance of pain change scores. In conclusion, the VAS-D is a reliable, valid, and responsive measure of pain intensity for people with upper extremity injuries. However, differences in accuracy (resolution) among the VAS-D, VAS-P, or NRS-V may render the three pain scales not fully compatible. LEVEL OF EVIDENCE Not applicable.

Grip strength in the frail elderly

Shechtman O, Mann WC, Justiss MD, Tomita M: Grip strength in the frail elderly. Am J Phys Med Rehabil 2004;83:819–826. Objective:To explore the relationship of impairment types to grip strength in the live-at-home frail elderly. Design:All data in this cross-sectional study were collected in face-to-face interviews in subjects’ homes by a nurse or occupational therapist. A total of 832 elders with activity limitations, as determined by the FIM™ instrument, participated in the study. Subjects were divided into three age groups (60–69, 70–79, and 80+ yrs) and four impairment groups: (1) minimally impaired, (2) visually impaired, (3) motor impaired, and (4) cognitively impaired. The outcome measures included the average (in kilograms) of three grip-strength trials per hand measured with the Jamar dynamometer at the second handle setting. Results:There were significant differences in grip strength scores among all age groups, indicating that grip strength decreased with age. Among impairment groups, the minimally impaired and visually impaired groups had significantly greater grip strength scores than the motor-impaired and the cognitively impaired groups. There were no significant differences between the minimally impaired and visually impaired groups or between the motor-impaired and the cognitively impaired groups. Conclusions:Age and sex are not the only determining factors of grip strength in the frail elderly. The type of impairment affects grip strength as well. Thus, age-based norms may not be the only basis for interpreting evaluation data and establishing treatment goals with this population.

Using the Coefficient of Variation to Detect Sincerity of Effort of Grip Strength: A Literature Review

Many clinicians use the coefficient of variation (CV) to assess sincerity of effort, without understanding the premise on which it is based or its physiological and mathematical bases. Clinicians who use computerized evaluation systems that calculate the CV may not even be aware of the formula used to derive it. The wide use of the CV in detecting sincerity of effort of grip strength is puzzling, since it lacks empirical support in the literature. This paper examines the physiological rationale for using measures of variability to detect sincerity of effort, the mathematical basis on which the CV is founded, and the reliability and validity of the CV. The conclusions based on this literature review are that the CV is not an appropriate method for determining whether an effort is sincere and that CV values may be inflated in injured patients with compromised hand strength.

Prevention of cold-induced increase in blood pressure of rats by captopril

To assess the possibility that the renin-angiotensin system may play a role in the development of cold-induced hypertension, three groups of rats were used. Two groups were exposed to cold (5±2°C) while the remaining group was kept at 26±2°C. One group of cold-treated rats received food into which captopril (0.06% by weight) had been thoroughly mixed. The remaining two groups received the same food but without captopril. Systolic blood pressure of the untreated, cold-exposed group increased significantly above that of the warm-adapted, control group within 4 weeks of exposure to cold. In contrast, chronic treatment with captopril prevented the elevation of blood pressure. Rats were killed after 4 months of exposure to cold. At death, the heart, kidneys, adrenal glands, and interscapular brown fat pad were removed and weighed. Although captopril prevented the elevation of blood pressure in cold-treated rats, it did not prevent hypertrophy of the kidneys, heart, and interstitial brown adipose tissue that characteristically accompanies exposure to cold. Thus, chronic treatment with captopril prevented the elevation of blood pressure when administered at the time exposure to cold was initiated. It also reduced the elevated blood pressure of cold-treated rats when administered after blood pressure became elevated. This suggests that the renin-angiotensin system may play a role in the elevation of blood pressure during exposure to cold.

The use of the rapid exchange grip test in detecting sincerity of effort, part I: Administration of the test

A review of studies that utilize the rapid exchange grip (REG) test revealed that there is no standardized test protocol for administering the test. The purpose of this study was to investigate three factors that affect the result of the REG test: the hand switch rate, the number of grips performed during the test, and the comparative tests used in the interpretation of the REG test. The 146 uninjured subjects performed a series of randomized grip strength tests including the REG test, the maximal static grip test (MSGT), and the five-rung (5R) test while making maximal and submaximal efforts. Results revealed no significant differences in peak REG scores between hand switch rates of 45 and 60 rpm. Significant differences were found for peak REG scores obtained from three vs. five trials. Peak scores from the 5R test vs. the MSGT differed significantly for maximal efforts but not for submaximal efforts. These results led to the following recommendations for a standardized protocol for administering the REG test: 1) the REG maneuver may be administered at a rate of either 45 or 60 rpm; 2) at least five hand-grip exchanges must be performed; and 3) only one comparative test, either the MSGT or the 5R test, should be used consistently for comparison with the REG maneuver. The findings of the present study, however, did not verify which static grip test should be used for comparison with REG scores.