Quantitative Assessment of Children with Osteogenesis Imperfecta

Assessments of children with Osteogenesis Imperfecta (OI) are typically limited to a physical exam and observations from a clinician during a hospital visit. Often quantitative information such as bone mineral density and outcome questionnaires is obtained, but with the increasing prevalence of motion analysis and other performance type laboratories, there are many other tools available, which could be beneficial to this patient population. These laboratories can provide date supplementary to morphologic and radiographic data that is helpful in tracking changes in the patient’s functional abilities, recover from fracture, and treatment outcomes. This chapter will cover some useful evaluation methods for children with the most commonly seen types of OI and provide some examples of their test results

Analysis of Push-Off Power During Locomotion in Children with Type 1 Osteogenesis Imperfecta

Background/Purpose Children with type 1 osteogenesis imperfecta (OI) present with abnormal gait characteristics, including reduced power generation during pushoff. However, the exact biomechanical factors associated with reduced power generation are not clearly understood. The purpose of this study was to investigate the biomechanical factors associated with a reduction in ankle power generation in children with type 1 OI. Methods Twenty-four participants with type 1 OI (12.5 ± 3.6 years of age) and 24 typically developing children (12.4 ± 3.7 years of age) were evaluated. Three-dimensional gait analysis, isometric plantar flexion strength using dynamometry, and pedobarography were collected on each participant. Results were statistically compared between the groups and a correlation matrix analyzed the associations among the measures. Results Children with OI presented with weaker plantar flexors, reduced ankle power generation, and decreased sagittal plane ankle angular velocity during pushoff. However, they presented with similar moment arm distances and ground reaction force magnitudes as typically seen in developing children. There was a higher incidence of pes valgus, increased subarch angles, increased time spent loading the midfoot, and deceased time spent loading the forefoot in children with OI. Plantar flexion strength and the time spent at the midfoot and forefoot were most associated with ankle power generation. Conclusion The presence of pes valgus alone does not indicate a reduction of push-off power in children with type 1 OI, but those individuals who have both a flat foot and reduced time spent loading the forefoot during pushoff are the most likely to have reduced push-off power

Long-term Results of Comprehensive Clubfoot Release Versus the Ponseti Method: Which Is Better?

Background Clubfoot can be treated nonoperatively, most commonly using a Ponseti approach, or surgically, most often with a comprehensive clubfoot release. Little is known about how these approaches compare with one another at longer term, or how patients treated with these approaches differ in terms of foot function, foot biomechanics, or quality-of-life from individuals who did not have clubfoot as a child. Questions/purposes We compared (1) focused physical and radiographic examinations, (2) gait analysis, and (3) quality-of-life measures at long-term followup between groups of adult patients with clubfoot treated either with the Ponseti method of nonsurgical management or a comprehensive surgical release through a Cincinnati incision, and compared these two groups with a control group without clubfoot. Methods This was a case control study of individuals treated for clubfoot at two separate institutions with different methods of treatment between 1983 to 1987. One hospital used only the Ponseti method and the other mainly used a comprehensive clubfoot release. There were 42 adults (24 treated surgically, 18 treated with Ponseti method) with isolated clubfoot along with 48 healthy control subjects who agreed to participate in a detailed analysis of physical function, foot biomechanics, and quality-of-life metrics. Results Both treatment groups had diminished strength and motion compared with the control subjects on physical examination measures; however, the Ponseti group had significantly greater ankle plantar flexion ROM (p \u3c 0.001), greater ankle plantar flexor (p = 0.031) and evertor (p = 0.012) strength, and a decreased incidence of osteoarthritis in the ankle and foot compared with the surgical group. During gait the surgical group had reduced peak ankle plantar flexion (p = 0.002), and reduced sagittal plane hindfoot (p = 0.009) and forefoot (p = 0.008) ROM during the preswing phase compared with the Ponseti group. The surgical group had the lowest overall ankle power generation during push off compared with the control subjects (p = 0.002). Outcome tools revealed elevated pain levels in the surgical group compared with the Ponseti group (p = 0.008) and lower scores for physical function and quality-of-life for both clubfoot groups compared with age-range matched control subjects (p = 0.01). Conclusions Although individuals in each treatment group experienced pain, weakness, and reduced ROM, they were highly functional into early adulthood. As adults the Ponseti group fared better than the surgically treated group because of advantages including increased ROM observed at the physical examination and during gait, greater strength, and less arthritis. This study supports efforts to correct clubfoot with Ponseti casting and minimizing surgery to the joints, and highlights the need to improve methods that promote ROM and strength which are important for adult function. Level of Evidence Level III, prognostic study

Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914" (2016, ApJL, 826, L13)

This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Differential effects of 7-OH-DPAT on the development of behavioral sensitization to apomorphine and cocaine

The primary objective of this study was to determine whether concurrent treatments with a low dose of the dopamine D3-preferring receptor agonist 7-OH-DPAT would attenuate the development of behavioral sensitization to the indirect dopamine receptor agonist, cocaine, or the direct dopamine receptor agonist, apomorphine. In two experiments, male Wistar rats (250–350 g) were given seven daily injections of 7-OH-DPAT (0.05 mg/kg sc) or vehicle in combination with either cocaine (15 mg/kg ip), apomorphine (1.0 mg/kg sc), or vehicle. After the injections, the rats were tested for activity in photocell arenas for 40 min, and three measures of motor behavior (distance traveled, rearing, and stereotypy) were recorded at 10-min intervals. A total of 24 h after the last preexposure session, all rats were given a challenge injection of either cocaine (10.0 mg/kg ip, Experiment 1) or apomorphine (1.0 mg/kg sc, Experiment 2) and tested for activity. Major findings were as follows: (a) 7-OH-DPAT treatments alone suppressed all measures of locomotor activity and did not affect subsequent behavioral sensitivity to either cocaine or apomorphine; (b) cocaine treatments acutely increased all measures of activity, and repeated treatments produced behavioral sensitization to the horizontal locomotor-activating effects of cocaine; (c) apomorphine treatments alone increased horizontal activity and stereotypy but completely abolished rearing behavior; (d) like cocaine, repeated treatments with apomorphine induced behavioral sensitization; (e) concurrent treatments of 7-OH-DPAT with cocaine acutely attenuated cocaine-induced increases in motor behavior but enhanced the development of behavioral sensitization to cocaine; and (f) concurrent 7-OH-DPAT treatments did not significantly affect either the acute or chronic effects of apomorphine. It is evident from these results that concurrent treatment with 7-OH-DPAT does not block the development of behavioral sensitization to either cocaine or apomorphine. Moreover, the differential acute and chronic effects of 7-OH-DPAT on cocaine- and apomorphine-induced hyperactivity appear to be mediated by dopamine autoreceptor stimulation