Initial Development and Validation of a Patient-Reported Symptom Survey for Small-Fiber Polyneuropathy

Small-fiber polyneuropathy (SFPN) affects unmyelinated and thinly myelinated peripheral axons. Several questionnaires have been developed to assess polyneuropathy from diabetes or chemotherapy, but none for SFPN from other or unknown causes. A comprehensive survey could help clinicians diagnose and assess treatment responses, define prevalence natural history and cures, and identify research subjects. Thus, we developed the 1-page Small-Fiber Symptom Survey, using input from patients and 21 medical/scientific experts. Participants comprised consenting consecutive patients evaluated for SFPN at the Massachusetts General Hospital plus normal control subjects. Participants SFPN status was stratified on the basis of the results of their objective diagnostic tests (distal leg skin biopsy and autonomic function testing). We measured internal consistency, test retest reliability, convergent validity, and performed a receiver operating curve analysis. The 179 participants averaged 46.6 ± 15.6 years old; they were 73.2% female and 92.2% Caucasian. Eighty-five had confirmed SFPN, mostly idiopathic. Principal component analysis revealed 5 symptom clusters. The questionnaire had good internal consistency (Cronbach α = .893), excellent test retest reliability (r = .927, P < .001) and good to fair convergent validity. Participants with confirmed SFPN had more severe symptoms than others (P = .009). The Small-Fiber Symptom Survey has satisfactory psychometric properties, indicating potential future utility for surveying patient-reported symptoms of SFPN regardless of its cause.

PERSPECTIVE

This article reports the initial development and early psychometric validation of a new patient-reported outcome measure intended to capture the wide range of multisystem symptoms of SFPN. When further developed, it could potentially help clinicians diagnose and monitor patients, and help advance research.

Experimental comparison of parametric versus nonparametric analyses of data from the cold pressor test

Parametric statistical methods are common in human pain research. They require normally distributed data, but this assumption is rarely tested. The current study analyzes the appropriateness of parametric testing for outcomes from the cold pressor test (CPT), a common human experimental pain test. We systematically reviewed published CPT studies to quantify how often researchers test for normality and how often they use parametric versus nonparametric tests. We then measured the normality of CPT data from 7 independent small to medium cohorts and 1 study of >10,000 subjects. We then examined the ability of 2 common mathematical transformations to normalize our skewed data sets. Lastly, we performed Monte Carlo simulations on a representative data set to compare the statistical power of the parametric t-test versus the nonparametric Wilcoxon Mann-Whitney test. We found that only 39% of published CPT studies (47/122) mentioned checking data distribution, yet 72% (88/122) used parametric statistics. Furthermore, among our 8 data sets, CPT outcomes were virtually always nonnormally distributed, and mathematical transformations were largely ineffective in normalizing them. The simulations demonstrated that the nonparametric Wilcoxon Mann-Whitney test had greater statistical power than the parametric t-test for all scenarios tested: For small effect sizes, the Wilcoxon Mann-Whitney test had up to 300% more power.

PERSPECTIVE

These results demonstrate that parametric analyses of CPT data are routine but incorrect and that they likely increase the chances of failing to detect significant between-group differences. They suggest that nonparametric analyses become standard for CPT studies and that assumptions of normality be routinely tested for other types of pain outcomes as well.

Self-control in postsecondary settings: students' perceptions of ADHD college coaching

OBJECTIVE

The objective of this study was to identify undergraduates' perceptions of the impact of ADHD coaching on their academic success and broader life functioning.

METHOD

One-on-one interviews were conducted with 19 students on 10 different U.S. campuses who comprised a purposive sample of gender, cumulative grade point average, and self-regulation skills variables as measured by the learning and study strategies inventory. Interview transcripts were coded using NVivo 8 software, and emergent themes were triangulated with students' descriptions of personal artifacts that symbolized coaching's influence on their lives.

RESULTS

Students reported that ADHD coaching helped them become more self-regulated, which led to positive academic experiences and outcomes. Students described ADHD coaching as a unique service that helped them develop more productive beliefs, experience more positive feelings, and engage in more self-regulated behaviors.

CONCLUSION

ADHD coaching helped participants enhance their self-control as they responded to the multifaceted demands of undergraduate life.

Measurement practices: methods for developing content-valid student examinations

Measurement experts generally agree that a systematic approach to test construction will probably result in an instrument with sound psychometric properties. One fundamental method is called the blueprint approach to test construction. A test blueprint is a tool used in the process for generating content-valid exams by linking the subject matter delivered during instruction and the items appearing on the test. Unfortunately, this procedure as well as other educational measurement practices is often overlooked A survey of curriculum administrators at 144 United States and international medical schools was conducted to assess the importance and prevalence of test blueprinting in their school. Although most found test blueprinting to be very important, few require the practice. The purpose of this paper is to review the fundamental principals associated with achieving a high level of content validity when developing tests for students. The short-term efforts necessary to develop and integrate measurement theory into practice will lead to long-term gains for students, faculty and academic institutions.

Perceived importance of self-determination factors by consumers in substance-abuse treatment

40 consumers (20 from 1993 and 20 from 1994) were randomly selected from about 450 residents of a midwestern urban free-standing residential substance-abuse treatment facility to participate in a study on factors relating to self-determination. Self-confidence, positive attitude, listening skills, and assuming responsibility were identified in both years as the most important factors. Role models, however, were not reported as being important.

Comparison of two tests useful in situations where treatment is expected to increase variability relative to controls

The type I error and power characteristics of the modified t test were compared with those of the generalized t test. Results suggested that, in contrast to the generalized t test, the modified t test can be seriously non-robust to departures from population normality, with such departures often producing anti-conservative results. Neither test held an absolute power advantage over the other when responses were from normal distributions, but the modified t test was generally more powerful for these conditions. In comparison with the pooled samples t test, both tests were usually much more efficient when treatment caused increases both in mean response and between-subject variance, and suffered only small disadvantages when between-subject variance was unchanged by treatment. Given these results and other considerations, recommendations for use of these recently devised tests are given.

A note on the operating characteristics of the modified F test

Brownie, Boos, and Hughes-Oliver (1990, Biometrics 46, 259-266) suggested a modification to the fixed-effects analysis of variance (ANOVA) F test for use in situations where treatments are likely to affect mean response while simultaneously increasing between-subject variability. These authors suggest that the modified test (1) is robust against departures from population normality, (2) is more powerful than its classical counterpart when the expected alternative form is encountered, and (3) will suffer only minor power losses relative to the usual test when alternatives are in the form of simple shifts in location. This study shows that the modified test is not generally robust when sampling is from nonnormal distributions and is likely to produce unacceptably high Type I error inflations when sampling is from heavy-tailed or skewed distributions. Some power results are also provided for the multisample situation to supplement those of Brownie et al., who generated results only for the two-sample case.

Effects of disability labels on teachers' perceptions of students' self-determination

Teachers' perceptions of their students' self-determination were significantly lower for students with disabilities ( n = 48) than for students without disabilities (n = 47), even though there was little difference in observed behaviors of these students.