Biomedical subjects

Michael J Strube

Publications and source records attributed to Michael J Strube.

15 recordsLinked to original sources

PubMed2006

SNOOP:a program for demonstrating the consequences of premature and repeated null hypothesis testing.

The ease with which data can be collected and analyzed via personal computer makes it potentially attractive to "peek" at the data before a target sample size is achieved. This tactic might seem appealing because data collection could be stopped early, which would save valuable resources, if a peek revealed a significant effect. Unfortunately, such data snooping comes with a cost. When the null hypothesis is true, the Type I error rate is inflated, sometimes quite substantially. If the null hypothesis is false, premature significance testing leads to inflated estimates of power and effect size. This program provides simulation results for a wide variety of premature and repeated null hypothesis testing scenarios. It gives researchers the ability to know in advance the consequences of data peeking so that appropriate corrective action can be taken.

Computer Simulation↗

PubMed2005

Personality traits in captive lion-tailed macaques (Macaca silenus).

Personality influences an individual's perception of a situation and orchestrates behavioral responses. It is an important factor in elucidating variation in behavior both within and between species. The major focus of this research was to test a method that differs from those used in most previous personality studies, while investigating the personality traits of 52 captive lion-tailed macaques from four zoos. In this study, data from behavioral observations, a P-type principal components analysis (PCA), and bootstrapped confidence intervals as criteria for judging the significance of factor loadings were used rather than subjective ratings, R-type factor analyses, and arbitrary rules of thumb to determine significance. We investigated the relationships among individual component scores and sex, hormonal status, and dominance rank (controlling for age and social group) using a multiple regression analysis with bootstrapped confidence intervals. Three personality dimensions emerged from this analysis: Component 1 contained Extraversion-like behaviors related to sociability and affiliativeness. The higher mean Component score for females suggests that they are more "extraverted" than males. Only agonistic behaviors were significantly related to component 2. High-ranking individuals exhibited higher mean Component 2 scores than mid- or low-ranked individuals. Bold and cautious behaviors both loaded positively on Component 3, suggesting a dimension related to curiosity. The mean Component 3 score for females was higher than the mean score for males. The method used in this study should facilitate intraspecific and general interspecific comparisons. Developing a standardized trait term list that is applicable to many species, and collecting trait term data in the same manner and concurrent with behavioral observations (and physiologic measures when feasible) could prove useful in primate research and should be explored.

Animals↗

PubMed2005

Efficacy of brief telephone psychotherapy with callers to a suicide hotline.

The efficacy of two types of theapy conducted exclusively over the telephone was studied. Clients (N=55) were recruited from a pool of callers to a suicide hotline and were randomly assigned to a waiting list control (WC) or Solution Focused Brief Therapy (SFBT) or Common Factors Therapy (CFT). It was hypothesized that improvements would be significantly higher in the two therapy conditions compared to the waitlist control and SFBT would be significantly more efficacious than CFT. Results confirmed that improvement was significantly higher in the two treatment conditions compared to the waitlist control, but no difference in improvement was found between SFBT and CFT. The implications of these findings for suicide hotlines are discussed.

Adult↗

PubMed2005

Effect of Achilles tendon lengthening on ankle muscle performance in people with diabetes mellitus and a neuropathic plantar ulcer.

BACKGROUND AND PURPOSE: The effect of a tendo-Achilles lengthening (TAL) procedure on ankle muscle performance has not been clearly established. The purpose of this study was to compare the effects of TAL and total-contact casting (TCC) with TCC alone on ankle muscle performance in subjects with diabetes mellitus (DM) and a neuropathic plantar ulcer. SUBJECTS: Subjects were randomly assigned to either a TAL group (3 female and 12 male subjects) or a TCC group (4 female and 10 male subjects). METHODS: Muscle performance measurements were obtained using an isokinetic dynamometer. RESULTS: Concentric plantar-flexor peak torque decreased 31% after TAL but returned to the baseline level after 8 months. Dorsiflexor peak torque did not change in either group. Plantar-flexor passive torque at 0 degrees of dorsiflexion decreased after TAL but increased to 60% of the baseline level after 8 months. Maximal dorsiflexion angle increased 11 degrees after TAL and remained increased at 8 months. DISCUSSION AND CONCLUSION: The TAL resulted in an increase in ankle dorsiflexion range of motion and a temporary reduction in concentric plantar-flexor peak torque and passive torque at 0 degrees of dorsiflexion. If TAL is being considered for people with DM and a neuropathic forefoot ulcer, the initial compromise in plantar-flexor muscle performance should be addressed.

Achilles Tendon↗

PubMed2005

What didTriplett really find? A contemporary analysis of the first experiment in social psychology.

In 1898, Norman Triplett published was has been called the first experiment in social psychology and sports psychology. Claiming to demonstrate "the dynamogenic factors in pacemaking and competition," this oft-cited article began the serious investigation of social facilitation. This area of research now numbers in the hundreds of published works, includes the study of humans and other animials, and encompasses basic research and applied settings. But what did Triplett really find? I examine Triplett's original data and show that very little evidence existed for the social facilitation of the simple task he investigated. These analyses indicate the need to correct contemporary accounts of Triplett's work and underscore the differences in how research was evaluated at that time compared with today.

History, 19th Century↗

PubMed2004

Impact of achilles tendon lengthening on functional limitations and perceived disability in people with a neuropathic plantar ulcer.

OBJECTIVE: An Achilles tendon-lengthening (ATL) procedure is effective at reducing ulcer recurrence in patients with diabetes, peripheral neuropathy, and a plantar ulcer, but its effects on functional limitations and perceived disability are unknown. The purpose of this study is to report the effects of an ATL and total contact casting (TCC) on the functional limitations and perceived disability of patients with neuropathic plantar ulcers. RESEARCH DESIGN AND METHODS: Twenty-eight subjects with a mean age of 55 +/- 10 years and a BMI of 33 +/- 6 kg/m(2) participated. All subjects had a history of diabetes, loss of protective sensation, limited ankle motion, and a recurrent forefoot ulcer. Subjects were randomized into two groups: an ATL group (n = 14), who received treatment of ATL, and TCC and a TCC group (n = 14), who received TCC only. Subjects completed a modified physical performance test (PPT) and the SF-36 Health Survey before treatment, after primary treatment and healing of the plantar forefoot ulcer, and 8 months after initial ulcer healing. RESULTS: There were no significant changes in functional limitations as measured by the PPT between groups or over time. The physical summary score of the SF-36 decreased slightly from before treatment to 8 months after initial ulcer healing in the ATL group (35 +/- 7 to 31 +/- 6), whereas the TCC group score increased during this time (34 +/- 8 to 39 +/- 11; P < 0.05). CONCLUSIONS: The ATL resulted in no measurable change in functional limitations, but patients receiving an ATL and TCC reported lower physical functioning at 8 months after initial ulcer healing than subjects receiving TCC alone and may require additional physical therapy to address this perceived disability.

Achilles Tendon↗

PubMed2003

Hypnosis, attention, and time cognition.

This study examined the influence of hypnotic susceptibility (high vs. low), hypnotic condition (hypnotic vs. nonhypnotic), and attentional demands (high vs. low) on the verbal estimates (N = 510 undergraduates) of 30- and 60-second time intervals under both prospective (aware of timing) and retrospective (unaware of timing) paradigms. It was expected that prospective judgments would be greater than retrospective judgments across all factors. Consistent with existing literature, strong support was found for this hypothesis. Hypotheses generated within the trait-state paradigm were not supported. No effects were found for hypnotic susceptibility in any form. Partial support was found for the sociocognitive model. The hypnotic context, independent of level of susceptibility, apparently utilizes the attentional resources of participants and as a by-product leads to underestimation of time. Longer time intervals (60 s) were also underestimated in comparison to shorter intervals (30 s).

Adult↗

PubMed2003

Statistical analysis and interpretation in a study of prelingually deaf children implanted before five years of age.

This article describes the major statistical analyses used in a large-scale study of prelingually deaf children implanted before 5 yr of age. Two major challenges posed by the data were the need to reduce the number of outcome measures to a reasonable number while retaining the important information underlying the multiple measures, and the need to determine the unique contributions of multiple sets of predictor variables. The approach taken-principal components analysis of the outcome measures followed by hierarchical multiple regression-provided a compromise between statistical complexity and ease of interpretation.

Child↗

PubMed2003

Effect of Achilles tendon lengthening on neuropathic plantar ulcers. A randomized clinical trial.

BACKGROUND: Limited ankle dorsiflexion has been implicated as a contributing factor to plantar ulceration of the forefoot in diabetes mellitus. The purpose of this study was to compare outcomes for patients with diabetes mellitus and a neuropathic plantar ulcer treated with a total-contact cast with and without an Achilles tendon lengthening. Our primary hypothesis was that the Achilles tendon lengthening would lead to a lower rate of ulcer recurrence. METHODS: Sixty-four subjects were randomized into two treatment groups, immobilization in a total-contact cast alone or combined with percutaneous Achilles tendon lengthening, with measurements made before and after treatment, at the seven-month follow-up examination, and at the final follow-up evaluation (a mean [and standard deviation] of 2.1 +/- 0.7 years after initial healing). There were thirty-three subjects in the total-contact cast group and thirty-one subjects in the Achilles tendon lengthening group. There were no significant differences in age, body-mass index, or duration of diabetes between the groups. Outcome measures were time to healing of the ulcer, ulcer recurrence rate, range of dorsiflexion of the ankle, peak torque (strength) of the plantar flexor muscles, and peak plantar pressures on the forefoot. RESULTS: Twenty-nine (88%) of thirty-three ulcers in the total-contact cast group and all thirty ulcers (100%) in the Achilles tendon lengthening group healed after a mean duration (and standard deviation) of 41 +/- 28 days and 58 +/- 47 days, respectively (p > 0.05). (One patient in the Achilles tendon lengthening group died before treatment was completed.) In the first seven months of follow-up, sixteen (59%) of the twenty-seven patients in the total-contact cast group who were available for follow-up and four (15%) of the twenty-seven patients in the Achilles tendon lengthening group who were available for follow-up had an ulcer recurrence (p = 0.001). At the time of the two-year follow-up, twenty-one (81%) of the twenty-six patients in the total-contact cast group and ten (38%) of the twenty-six patients in the Achilles tendon lengthening group had ulcer recurrence (p = 0.002). Compared with the group treated with the total-contact cast, the group treated with Achilles tendon lengthening had increased dorsiflexion and it remained increased at seven months (p < 0.001). Plantar flexor peak torque also decreased after Achilles tendon lengthening (p < 0.004), but it returned to baseline after seven months. Peak plantar pressures on the forefoot during barefoot walking were reduced (p < 0.0002) following Achilles tendon lengthening yet returned to baseline values within seven months after treatment. CONCLUSIONS: All ulcers healed in the Achilles tendon lengthening group, and the risk for ulcer recurrence was 75% less at seven months and 52% less at two years than that in the total-contact cast group. Achilles tendon lengthening should be considered an effective strategy to reduce recurrence of neuropathic ulceration of the plantar aspect of the forefoot in patients with diabetes mellitus and limited ankle dorsiflexion (</=5 degrees ).

Adult↗

PubMed1988

Meta-analysis of non-medical treatments for chronic pain.

A meta-analysis was conducted on 109 published studies which assessed the outcome of various non-medical treatments for chronic pain. Of these studies, 48 provided sufficient information to calculate effect sizes. The remainder were examined according to proportion of patients rated as improved. Studies were compared as a function of type of treatment, type of pain, and type of outcome variable. In general, effect sizes were positive and of modest magnitude indicating the short-term efficacy of most treatments for most types of pain. This finding suggests that the effectiveness of treatments may be attributable not to the differences between treatments, but to the features they have in common. Mood and number of subjective symptoms consistently showed greater responses to treatment than did pain intensity, pain duration, or frequency of pain, indicating the importance of using a multidimensional framework for pain assessment. This finding also suggests that the benefit of psychological approaches to pain management may lie in reducing the fear and depression associated with pain, rather than relieving the pain itself. The present study also highlights the advantages of meta-analytic reviews.

Adolescent↗

PubMed1986

Self-evaluation of abilities: accurate self-assessment versus biased self-enhancement.

Past research indicates that individuals are keenly aware of the diagnostic implications of their performance. Theories differ, however, in regard to how this awareness influences task choice. According to the self-assessment view, individuals choose tasks that are maximally informative of abilities, regardless of self-esteem implications. According to the self-enhancement view, task choice is often mediated by a concern for self-esteem protection. In the first study, subjects chose among eight forms of a cognitive abilities test that varied in their diagnosticity of success, diagnosticity of failure, and difficulty. In accordance with the self-assessment view, test choice was found to be positively related to diagnosticity of success and, to a lesser extent, diagnosticity of failure. Test choice was also dependent on the interaction of diagnosticity and difficulty in a manner that was more consistent with the self-assessment view. In a second study that provided more precise measurement of perceived diagnosticity and expected success, results indicated that the motives for self-assessment and self-enhancement were each reliably related to task preference. Of the two, self-assessment motivation was a stronger determinant of task preference. Taken together, these results suggest that task choice is governed largely by a concern for accurate self-appraisal. Additional results, however, indicate that current models may require revisions that take into account the less-than-accurate appraisal of diagnosticity.

Adult↗

PubMed1986

Self-schematic representation of the type A and B behavior patterns.

Past research has established clear behavioral differences between Type A and B individuals. The purpose of our research was to examine how these behavioral differences are represented in the self-definitions of Type As and Bs. We investigated the existence of Type A and B self-schemata by using two tasks designed to measure the influence of these hypothetical structures on speed of processing and memory interference. During an initial task, Type As and Bs made self-relevant decisions (like me, not like me) in response to trait adjectives previously scaled as Type A, Type B, or neutral in content. Reaction times for the decisions were measured, and results indicated that both Type As and Bs made faster decisions for schema-compatible responses than for schema-incompatible responses. On a second task, Type As and Bs were tested for recognition memory after they attempted to memorize half of the aforementioned trait list. Memory errors were examined and indicated that Type As and Bs made more errors that were compatible with their respective self-schemata. Taken together, these results indicate that a Type A and B distinction forms a reliable organizing framework for the self-definitions of Type As and Bs. The existence of stable cognitive structures that parallel the behavioral differences between Type As and Bs has important implications for both theory and application.

Adult↗

PubMedDate not supplied

The efficacy of the Waterloo-Stanford Group Scale of hypnotic susceptibility: form C.

This study explored whether the Waterloo-Stanford Group Scale of Hypnotic Susceptibility Form: C (WSGC) approximates the predictive power of the individually administered Stanford Hypnotic Susceptibility Scale: Form C (SHSS: C). Seventy-one undergraduates were administered the WSGC in a group setting and then tested individually on the SHSS: C. The participants were then hypnotized and tested on four types of targeted hypnotic behaviors sampled from the Revised Stanford Profile Scale of Hypnotic Susceptibility: I & II (RSPSHS: I & II). The following four factors were chosen: (a) cognitive distortion; (b) positive hallucination; (c) negative hallucination, and (d) dreams and regression. The items from these factors were matched on difficulty level. A series of multiple regression and logistic regression analyses were performed. The Waterloo: C was found to match the SHSS: C on predictive power for only one of the four hypnotic factors: "dreams and regression." On the other three factors, the SHSS: C was clearly superior in predictive efficacy. These results mirror previous research (Kurtz & Strube, 1996) that examined other group scales of hypnotic susceptibility in relation to the individually administered SHSS: C. In general, group scales such as the WSGC are poor substitutes for the SHSS: C.

Adult↗

PubMedDate not supplied

A comparison of narratives told by younger and older adults.

The few studies that have examined verbal discourse in both young and older adults have yielded inconsistent results with respect to talkativeness and story quality. The disparity may arise from methodological differences. In this study the authors examined word count, irrelevant utterances, and ratings of quality of stories told by 24 young (mean age = 19.21) and 24 old (mean age = 72.13) adults. The authors found minimal age differences. A separate sample of 10 young and 10 older adults of ages similar to those of the storytellers read and rated all the stories. Raters were highly variable in their subjective evaluations of story quality, although satisfactory generalizability coefficients can be achieved with a sufficiently large number of raters. Most studies of discourse quality, however, use few raters, which produces unreliable measurement that can contribute to the inconsistent results reported in the literature.

Adult↗

PubMedDate not supplied

Weight changes, exercise, and dietary patterns during freshman and sophomore years of college.

Weight gain and behavioral patterns during college may contribute to overweight and obesity in adulthood. The aims of this study were to assess weight, exercise, and dietary patterns of 764 college students (53% women, 47% men) during freshman and sophomore years. Students had their weight and height measured and completed questionnaires about their recent exercise and dietary patterns. At the beginning of freshman year, 29% of students reported not exercising, 70% ate fewer than 5 fruits and vegetables daily, and more than 50% ate fried or high-fat fast foods at least 3 times during the previous week. By the end of their sophomore year, 70% of the 290 students who were reassessed had gained weight (4.1+/-3.6 kg, p < .001), but there was no apparent association with exercise or dietary patterns. Future research is needed to assess the contributions of fat, muscle, and bone mass to observed weight gain and to determine the health implications of these findings.

Adult↗