Gillian Z. Heller

Exercise for falls prevention in Parkinson disease: A randomized controlled trial

Objective: To determine whether falls can be prevented with minimally supervised exercise targeting potentially remediable fall risk factors, i.e., poor balance, reduced leg muscle strength, and freezing of gait, in people with Parkinson disease. Methods: Two hundred thirty-one people with Parkinson disease were randomized into exercise or usual-care control groups. Exercises were practiced for 40 to 60 minutes, 3 times weekly for 6 months. Primary outcomes were fall rates and proportion of fallers during the intervention period. Secondary outcomes were physical (balance, mobility, freezing of gait, habitual physical activity), psychological (fear of falling, affect), and quality-of-life measures. Results: There was no significant difference between groups in the rate of falls (incidence rate ratio [IRR] = 0.73, 95% confidence interval [CI] 0.45–1.17, p = 0.18) or proportion of fallers (p = 0.45). Preplanned subgroup analysis revealed a significant interaction for disease severity (p < 0.001). In the lower disease severity subgroup, there were fewer falls in the exercise group compared with controls (IRR = 0.31, 95% CI 0.15–0.62, p < 0.001), while in the higher disease severity subgroup, there was a trend toward more falls in the exercise group (IRR = 1.61, 95% CI 0.86–3.03, p = 0.13). Postintervention, the exercise group scored significantly (p < 0.05) better than controls on the Short Physical Performance Battery, sit-to-stand, fear of falling, affect, and quality of life, after adjusting for baseline performance. Conclusions: An exercise program targeting balance, leg strength, and freezing of gait did not reduce falls but improved physical and psychological health. Falls were reduced in people with milder disease but not in those with more severe Parkinson disease. Classification of evidence: This study provides Class III evidence that for patients with Parkinson disease, a minimally supervised exercise program does not reduce fall risk. This study lacked the precision to exclude a moderate reduction or modest increase in fall risk from exercise. Trial registration: Australian New Zealand Clinical Trials Registry (ACTRN12608000303347).

Determining the Distribution of Maintenance Categories: Survey versus Measurement

In 1978, Lientz, Swanson, and Tompkins published the results of a survey on software maintenance. They found that 17.4% of maintenance effort was categorized as corrective in nature, 18.2% as adaptive, 60.3% as perfective, and 4.1% was categorized as other. We refer to this as the “LST” result. We contrast this survey-based result with our empirical results from the analysis of data for the repeated maintenance of three software products: a commercial real-time product, the Linux kernel, and GCC. For all three products and at both levels of granularity we considered, our observed distributions of maintenance categories were statistically very highly significantly different from LST. In particular, corrective maintenance was always more than twice the LST value. For the summed data, the percentage of corrective maintenance was more than three times the LST value. We suggest various explanations for the observed differences, including inaccuracies on the part of the maintenance managers who responded to the LST survey.

A Post-Hospital Home Exercise Program Improved Mobility but Increased Falls in Older People: A Randomised Controlled Trial

Background Home exercise can prevent falls in the general older community but its impact in people recently discharged from hospital is not known. The study aimed to investigate the effects of a home-based exercise program on falls and mobility among people recently discharged from hospital. Methods and Findings This randomised controlled trial (ACTRN12607000563460) was conducted among 340 older people. Intervention group participants (n = 171) were asked to exercise at home for 15–20 minutes up to 6 times weekly for 12 months. The control group (n = 169) received usual care. Primary outcomes were rate of falls (assessed over 12 months using monthly calendars), performance-based mobility (Lower Extremity Summary Performance Score, range 0–3, at baseline and 12 months, assessor unaware of group allocation) and self-reported ease of mobility task performance (range 0–40, assessed with 12 monthly questionaries). Participants had an average age of 81.2 years (SD 8.0) and 70% had fallen in the past year. Complete primary outcome data were obtained for at least 92% of randomised participants. Participants in the intervention group reported more falls than the control group (177 falls versus 123 falls) during the 12-month study period and this difference was statistically significant (incidence rate ratio 1.43, 95% CI 1.07 to 1.93, p = 0.017). At 12-months, performance-based mobility had improved significantly more in the intervention group than in the control group (between-group difference adjusted for baseline performance 0.13, 95% CI 0.04 to 0.21, p = 0.004). Self-reported ease in undertaking mobility tasks over the 12-month period was not significantly different between the groups (0.49, 95% CI −0.91 to 1.90, p = 0.488). Conclusions An individualised home exercise prescription significantly improved performance-based mobility but significantly increased the rate of falls in older people recently discharged from hospital. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12607000563460

Open-Source Change Logs

A recent editorial in Empirical Software Engineering suggested that open-source software projects offer a great deal of data that can be used for experimentation. These data not only include source code, but also artifacts such as defect reports and update logs. A common type of update log that experimenters may wish to investigate is the ChangeLog, which lists changes and the reasons for which they were made. ChangeLog files are created to support the development of software rather than for the needs of researchers, so questions need to be asked about the limitations of using them to support research. This paper presents evidence that the ChangeLog files provided at three open-source web sites were incomplete. We examined at least three ChangeLog files for each of three different open-source software products, namely, GNUJSP, GCC-g++, and Jikes. We developed a method for counting changes that ensures that, as far as possible, each individual ChangeLog entry is treated as a single change. For each ChangeLog file, we compared the actual changes in the source code to the entries in the ChangeLog> file and discovered significant omissions. For example, using our change-counting method, only 35 of the 93 changes in version 1.11 of Jikes appear in the ChangeLog file—that is, over 62% of the changes were not recorded there. The percentage of omissions we found ranged from 3.7 to 78.6%. These are significant omissions that should be taken into account when using ChangeLog files for research. Before using ChangeLog files as a basis for research into the development and maintenance of open-source software, experimenters should carefully check for omissions and inaccuracies.

Quality Impacts of Clandestine Common Coupling

The increase in maintenance of software and the increased amounts of reuse are having major positive impacts on the quality of software, but are also introducing some rather subtle negative impacts on the quality. Instead of talking about existing problems (faults), developers now discuss “potential problems,” that is, aspects of the program that do not affect the quality initially, but could have deleterious consequences when the software goes through some maintenance or reuse. One type of potential problem is that of common coupling, which unlike other types of coupling can be clandestine. That is, the number of instances of common coupling between a module M and the other modules can be changed without any explicit change to M. This paper presents results from a study of clandestine common coupling in 391 versions of Linux. Specifically, the common coupling between each of 5332 kernel modules and the rest of the product as a whole was measured. In more than half of the new versions, a change in common coupling was observed, even though none of the modules themselves was changed. In most cases where this clandestine common coupling was observed, the number of instances of common coupling increased. These results provide yet another reason for discouraging the use of common coupling in software products.

Maintainability of the kernels of open-source operating systems: A comparison of Linux with FreeBSD, NetBSD, and OpenBSD

We compared and contrasted the maintainability of four open-source operating systems: Linux, FreeBSD, NetBSD, and OpenBSD. We used our categorization of common coupling in kernel-based software to highlight future maintenance problems. An unsafe definition is a definition of a global variable that can affect a kernel module if that definition is changed. For each operating system we determined a number of measures, including the number of global variables, the number of instances of global variables in the kernel and overall, as well as the number of unsafe definitions in the kernel and overall. We also computed the value of each our measures per kernel KLOC and per KLOC overall. For every measure and every ratio, Linux compared unfavorably with FreeBSD, NetBSD, and OpenBSD. Accordingly, we are concerned about the future maintainability of Linux.

Menopausal symptom control and side-effects on continuous estrone sulfate and three doses of medroxyprogesterone acetate

OBJECTIVES To establish the optimum oral daily dose of micronized medroxyprogesterone acetate (MPA), given in combination with 1.25 mg of estrone sulfate for menopausal symptom control. METHODS This multicenter, randomized, double-blind study was conducted on 568 postmenopausal women who were randomized to take estrone sulfate 1.25 mg daily with 2.5, 5.0 or 10 mg of MPA daily for 2 years. The number of vasomotor symptoms and the severity of mood swings, lethargy, vaginal dryness and loss of libido as well as side-effects were recorded in a diary. Blood pressure and weight were recorded at each 3-month visit. RESULTS Vasomotor symptoms were reported by approximately 80% of subjects at month 1, 23% at month 3 but only 9% by month 24. Mood swings, lethargy and vaginal dryness improved rapidly in the initial 3 months of therapy. Decrease in libido had a slower response to therapy in all three treatment groups. Breast tenderness was the commonest side-effect with 22% of subjects complaining of this in the first 3 months of therapy, dropping to 13% by 6 months. Headache, depression, nausea, bloating and irritability showed a similar pattern of decline. There was no significant difference in the rate of decrease in menopausal symptoms or reported side-effects between the three treatment groups. There was a small but significant (p < 0.001) decrease in systolic and diastolic blood pressure over the study period. CONCLUSIONS All three treatment regimens provide adequate symptom control. Side-effects decreased markedly after the first 3 months, with no significant difference between the treatment groups.

A Pilot Study of Low-Power Laser Therapy in the Management of Chronic Neck Pain

Objective: This pilot study was undertaken to test techniques of application of laser therapy, appropriate outcome measures and to determine effect sizes in order to facilitate the performance of a larger, clinical trial of laser therapy in chronic neck pain. Methods: We conducted a randomized double-blind, placebo-controlled study of low level laser therapy in 20 patients with chronic neck pain. The primary outcome measure was change in a 10 cm Visual Analogue Scale [VAS] for pain. Other measures used included a Self-Reported Improvement in pain [SRI], measured by a VAS, Short-Form 36 Quality-of-Life questionnaire [SF-36], Northwick Park Neck Pain Questionnaire [NPNPQ] and the McGill Pain Questionnaire [MPQ]. Measurements were taken at baseline, at the end of 7 weeks treatment and at 12 weeks from baseline. Results: We found a positive, pain-relieving effect in the treated group compared with those given placebo using the VAS [P < 0.039], SRI [P < 0.001], NPNPQ [P < 0.002] and the MPQ [P < 0.009]. The results of the SF-36 did not differ significantly between the two groups. Patients in the treated group experienced an average pain score improvement of 66.7% compared with 16.6% in the placebo group. Conclusion: Low-power laser therapy, at the parameters used in this pilot study, may provide a non-invasive, non-pharmaceutical therapy for chronic neck pain for patients in general practice. Further study of this technique in a large-scale trial would be justified on the basis of the findings of this pilot study.

Believing Is Seeing II: Beliefs and Perceptions of Criminal Psychological Profiles

This study built upon previous research by Kocsis and Hayes (2004) by investigating whether a bias exhibited by police officers in their perception of profiles would replicate in a sample of nonpolice participants. Additionally, the relationship, if any, between the degree of belief harbored by an individual concerning the merits of profiling and their perceptions of a given profile was also investigated. The findings of this study add to the contention that the biases observed in Kocsis and Hayes’s previous study with regard to author label may be related to some intrinsic feature of the previously sampled police participants. Additionally, evidence was found to support the proposition that an individual’s degree of belief in profiling is related to their perceptions concerning the merits of a profile. Namely, the more an individual believes in the profiling technique, the greater the merit that will be perceived in a profile.

Mean and dispersion modelling for policy claims costs

A model for the statistical analysis of the total amount of insurance paid out on a policy is developed and applied. The model simultaneously deals with the number of claims (zero or more) and the amount of each claim. The number of claims is from a Poisson-based discrete distribution. Individual claim sizes are from a continuous right skewed distribution. The resulting distribution of total claim size is a mixed discrete-continuous model, with positive probability of a zero claim. The means and dispersions of the claim frequency and claim size distribution are modeled in terms of risk factors. The model is applied to a car insurance data set.