Hand-held dynamometry in patients with haematological malignancies: measurement error in the clinical assessment of knee extension strength

BACKGROUND: Hand-held dynamometry is a portable and inexpensive method to quantify muscle strength. To determine if muscle strength has changed, an examiner must know what part of the difference between a patient's pre-treatment and post-treatment measurements is attributable to real change, and what part is due to measurement error. This study aimed to determine the relative and absolute reliability of intra and inter-observer strength measurements with a hand-held dynamometer (HHD). METHODS: Two observers performed maximum voluntary peak torque measurements (MVPT) for isometric knee extension in 24 patients with haematological malignancies. For each patient, the measurements were carried out on the same day. The main outcome measures were the intraclass correlation coefficient (ICC +/- 95%CI), the standard error of measurement (SEM), the smallest detectable difference (SDD), the relative values as % of the grand mean of the SEM and SDD, and the limits of agreement for the intra- and inter-observer ;3 repetition average; and the ;highest value of 3 MVPT; knee extension strength measures. RESULTS: The intra-observer ICCs were 0.94 for the average of 3 MVPT (95%CI: 0.86-0.97) and 0.86 for the highest value of 3 MVPT (95%CI: 0.71-0.94). The ICCs for the inter-observer measurements were 0.89 for the average of 3 MVPT (95%CI: 0.75-0.95) and 0.77 for the highest value of 3 MVPT (95%CI: 0.54-0.90). The SEMs for the intra-observer measurements were 6.22 Nm (3.98% of the grand mean (GM) and 9.83 Nm (5.88% of GM). For the inter-observer measurements, the SEMs were 9.65 Nm (6.65% of GM) and 11.41 Nm (6.73% of GM). The SDDs for the generated parameters varied from 17.23 Nm (11.04% of GM) to 27.26 Nm (17.09% of GM) for intra-observer measurements, and 26.76 Nm (16.77% of GM) to 31.62 Nm (18.66% of GM) for inter-observer measurements, with similar results for the limits of agreement. CONCLUSION: The results indicate that there is acceptable relative reliability for evaluating knee strength with a HHD, while the measurement error observed was modest. The HHD may be useful in detecting changes in knee extension strength at the individual patient level

Role of Trichomes in Plant Stress Biology

In this chapter, we will examine the role of trichomes in plant stress biology. Trichomes have been long studied as the first line of defense against herbivores. We review the studies that have examined the structure, classification, and diversity of trichomes in flowering plants, followed by their modes of action against abiotic and biotic stressors. We also review the studies on herbivore X trichome interactions and how trichomes play a role in both direct and indirect plant defenses. Next, we use results from our research to highlight the importance of trichomes as an effective measure of plant defense and how genetic variation affects trichome-mediated defenses. And, finally we propose some exciting new areas of research on trichomes and trichome-mediated defenses for future work

Genetic research on sleep, sleep disturbances and associated difficulties

Sleep is a fundamental state. We spend approximately one third of our lives asleep and our dedication to this activity is likely to reflect its profound significance in many areas of our functioning and well-being. Whereas sleep is often taken for granted and berated by those who are keen to achieve more in their waking hours; its disruption can be profound. Indeed, any new parent can testify to the draining effects of sleep loss; and those suffering from insomnia can often spend many desperate hours lying awake. Those who have been touched by horrific accidents caused by someone “falling asleep on the job” know of the sometimes catastrophic effects of its disruption