Using mobile eye tracking to measure cognitive load through gaze behavior during walking in lower limb prosthesis users: A preliminary assessment.

BACKGROUND: Lower limb amputation does not affect only physical and psychological functioning but the use of a prosthetic device can also lead to increased cognitive demands. Measuring cognitive load objectively is challenging, and therefore, most studies use questionnaires that are easy to apply but can suffer from subjective bias. Motivated by this, the present study investigated whether a mobile eye tracker can be used to objectively measure cognitive load by monitoring gaze behavior during a set of motor tasks. METHODS: Five prosthetic users and eight able-bodied controls participated in this study. Eye tracking data and kinematics were recorded during a set of motor tasks (level ground walking, walking on uneven terrain, obstacle avoidance, stairs up and ramp down, as well as ramp up and stairs down) while the participants were asked to focus their gaze on a visual target for as long as possible. Target fixation times and increase in pupil diameters were determined and correlated to subjective ratings of cognitive load. FINDINGS: Overall, target fixation time and pupil diameter showed strong negative and positive correlations, respectively, to the subjective rating of cognitive load in the able-bodied controls (-0.75 and 0.80, respectively). However, the individual correlation strength, and in some cases, even the sign, was different across participants. A similar trend could be observed in prosthetic users. INTERPRETATION: The results of this study showed that a mobile eye tracker may be used to estimate cognitive load in prosthesis users during locomotor tasks. This paves the way to establish a new approach to assessing cognitive load, which is objective and yet practical and simple to administer. Nevertheless, future studies should corroborate these results by comparing them to other objective measures as well as focus on translating the proposed approach outside of a laboratory.

Impact of age on indication for chemotherapy in early breast cancer patients: results from 104 German institutions from 2008 to 2017.

PURPOSE: Today, the decision to treat patients with chemotherapy for early breast cancer (EBC) is made based on the patient's individual risk stratification and tumor biology. In cases with chemotherapy indication, the neoadjuvant application (NACT) is the preferred option in comparison with primary surgery and adjuvant chemotherapy (ACT). Age remains a relevant factor in the decision-making process. The aim of the present study was to illustrate the impact of age on the use of systemic therapy in clinical routine. METHODS: The study separately analyzed chemotherapy use among six age cohorts of EBC patients who had been treated at 104 German breast units between January 2008 and December 2017. RESULTS: In total, 124,084 patients were included, 46,279 (37.3%) of whom had received chemotherapy. For 44,765 of these cases, detailed information on treatment was available. Within this cohort, chemotherapy was administered as NACT to 14,783 patients (33.0%) and as ACT to 29,982 (67.0%) patients. Due to the higher prevalence of unfavorable tumor subtypes, younger patients had a higher rate of chemotherapy (≤ 29y: 74.2%; 30-39y: 71.3%) and a higher proportion of NACT administration ( ≤ 29y: 66.9%; 30-39y: 56.0%) in comparison with elderly patients, who had lower rates for overall chemotherapy (60-69y: 37.5%; ≥ 70y: 17.6%) and NACT (60-69y: 25.5%; ≥ 70y: 22.8%). Pathologic complete response was higher in younger than in older patients (≤ 29y: 30.4% vs. ≥ 70y: 16.7%), especially for HER2- subtypes. CONCLUSION: The data from the nationwide German cohort reveal relevant age-dependent discrepancies concerning the use of chemotherapy for EBC.

Measuring the Time to Deterioration for Health-Related Quality of Life in Patients With Metastatic Breast Cancer Using a Web-Based Monitoring Application: Longitudinal Cohort Study.

BACKGROUND: Health-related quality of life (HRQoL) is used to evaluate the treatment of metastatic breast cancer. In a long-term therapy setting, HRQoL can be used as an important benchmark for treatment success. With the help of digital apps, HRQoL monitoring can be extended to more remote areas and be administered on a more frequent basis. OBJECTIVE: This study aims to evaluate 3 common HRQoL questionnaires in metastasized breast cancer in terms of TTD in a digital, web-based setting. We further aim to examine the development of the HRQoL in different systemic treatment groups in each of these evaluation instruments. METHODS: A total of 192 patients with metastatic breast cancer were analyzed in this bicentric prospective online cohort study at two German university hospitals. Patients completed questionnaires on HRQoL (EuroQol Visual Analog Scale [EQ-VAS], EuroQol 5 Dimension 5 Level [EQ-5D-5L], European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 item [EORTC QLQ-C30]) via an online platform over a 6-month period. Treatment schedules and medical history were retrieved from medical records. Unadjusted Cox regression analysis on treatment-related factors was performed. We conducted subgroup analyses in regard to TTD events between different treatments. RESULTS: The EQ-VAS showed a higher rate of deterioration after 8 weeks (84/179, 46.9%) than the EQ-5D-5L (47/163, 28.8%) and EORTC QLQ-C30 (65/176, 36.9%). Unadjusted Cox regression revealed significant connections between known metastases in the liver (P=.03, HR 1.64, 95% CI 1.06-2.52) and pleura (P=.04, HR 0.42, 95% CI 0.18-0.96) in the EQ-VAS. Significant relations between EQ-VAS events and single EQ-5D-5L items and the EQ-5D-5L summary score were demonstrated. All treatment groups significantly differed from the CDK4/6 inhibition subgroup in the EQ-VAS. CONCLUSIONS: Compared to the EQ-5D-5L and QLQ-C30, the EQ-VAS showed a higher rate of deterioration after 8 weeks. Significant connections to certain metastatic locations were only detected in the EQ-VAS. The EQ-VAS is capable of reflecting the distinctive HRQoL profiles of different systemic treatments as well as the different aspects of HRQoL presented in the EQ-5D-5L. TTD with the EQ-VAS is an adequate mean of examining longitudinal development of HRQoL among breast cancer patients.

The impact of transfemoral socket adduction on pelvic and trunk stabilization during level walking - A biomechanical study.

BACKGROUND: It is common practice to align transfemoral prosthetic sockets in adduction, due to the physiologic, adducted femoral alignment in unimpaired legs. An adducted femoral and socket alignment helps tightening hip abductors to stabilize the pelvis and reduce pelvic and trunk related compensatory movements. RESEARCH QUESTION: How do different socket adduction conditions (SAC) of transfemoral sockets affect pelvic and trunk stabilization during level ground walking in the frontal plane? METHODS: Seven persons with transfemoral amputation with medium residual limb length participated in this study. The prosthetic alignment in the sagittal plane was performed according to established recommendations. SAC varied (0°, 3°, 6°, 9°). Kinematic and kinetic parameters were recorded in a gait laboratory with a 12-camera optoelectronic system and two piezoelectric force plates embedded in a 12-m walkway. The measurements were performed during level ground walking with self-selected comfortable gait speed. RESULTS: In the frontal plane, nearly all investigated kinematic and kinetic parameters showed a strong correlation with the SAC. The pelvis was raised on the contralateral side throughout the gait cycle with increasing SAC. During the prosthetic side stance phase, the mean shoulder obliquity and mean lateral trunk lean to the prosthetic side tended to be reduced with increased SAC. Prosthetic side hip abduction moment decreased with increasing SAC. SIGNIFICANCE: The results confirm that transfemoral SAC contributes to pelvic stabilization and reduced compensatory movements of the pelvis and trunk. Transfemoral SAC of 6 ± 1° for bench alignment seems adequate for amputees with medium residual limb length. However, the optimum value for the individual patient may differ slightly.

Do hospital type or caseload make a difference in chemotherapy treatment patterns for early breast cancer? Results from 104 German institutions, 2008-2017.

BACKGROUND: Over the past decade, chemotherapy has been used more selectively in early breast cancer (EBC) due to better risk stratification. Neoadjuvant chemotherapy (NACT) has evolved to the primary treatment option. The type and size of hospitals is known to have a substantial influence on the kinds of treatment they provide, and therefore on patient outcomes (e.g. rates for pathological complete response, pCR), but it is not yet known how this has affected delivery of chemotherapy for EBC in Germany. METHODS: This study analyzed chemotherapy use and pCR rates after NACT for EBC patients treated at 104 German institutions 2008-2017. Institutions were separated into associated hospital type (university hospital; teaching hospital; community hospital) and annual caseload (≤100; 101-250; >250 cases/year). RESULTS: Overall, 124,084 patients were included, of whom 11.6% were treated at university hospitals, 63.1% at teaching hospitals, and 25.3% at community hospitals. In total, 46,274 (37.3%) received chemotherapy, of whom 44,765 had information available about systemic treatment and surgery. From 2008 to 2017, chemotherapy use declined from 48.3% to 36.4% for university hospitals, from 40.7% to 30.3% for teaching hospitals, and from 42.4% to 33.7% for community hospitals. Furthermore, the proportion of NACT increased the most in university hospitals (from 32.0% to 68.1%); whereas, the rate of pCR (defined as ypT0 ypN0) increased irrespective of institutional type. Analyses regarding annual caseload did not show any differences. CONCLUSIONS: The results from this large, nationwide cohort reflect a more selective use of chemotherapy in Germany, irrespective of institutional type or case load.

Evaluating the influence of music at different sound pressure levels on medical students' performance of standardized laparoscopic box training exercises.

BACKGROUND: The influence of music on the performance of surgical procedures such as laparoscopy is controversial and methodologically difficult to quantify. Here, outcome measurements using laparoscopic box training tools under standardized conditions might offer a feasible approach. To date, the effect of music exposure at different sound pressure levels (SPL) on outcome has not been evaluated systematically for laparoscopic novices. METHODS: Between May 2017 and October 2018, n = 87 students (49 males, 38 females) from Heidelberg University Medical School performed three different laparoscopy exercises using the "Luebecker Toolbox" that were repeated twice under standardized conditions. Time was recorded for each run. All students were randomly assigned to four groups exposed to the same music compilation but at different SPLs (50-80 dB), an acoustically shielded (earplug) group, or a control group (no intervention). RESULTS: Best absolute performance was shown under exposure to 70 dB in all three exercises (a, b, c) with mean performance time of 121, 142, and 115 s (p < 0.05 for a and c). For the control group mean performance times were 157, 144, and 150 s, respectively. In the earplug group, no significant difference in performance was found compared to the control group (p > 0.05) except for exercise (a) (p = 0.011). CONCLUSION: Music exposure seems to have beneficial effects on training performance. In comparison to the control group, significantly better results were reached at 70 dB SPL, while exposure to lower (50 or 60 dB) or higher (80 dB) SPL as well as under acoustic shielding did not influence performance.

Challenges in Acceptance and Compliance in Digital Health Assessments During Pregnancy: Prospective Cohort Study.

BACKGROUND: Pregnant women are increasingly using mobile apps to access health information during the antenatal period. Therefore, digital health solutions can potentially be used as monitoring instruments during pregnancy. However, a main factor of success is high user engagement. OBJECTIVE: The aim of this study was to analyze engagement and factors influencing compliance in a longitudinal study targeting pregnant women using a digital health app with self-tracking. METHODS: Digitally collected data concerning demographics, medical history, technical aspects, and mental health from 585 pregnant women were analyzed. Patients filling out ≥80% of items at every study visit were considered to be highly compliant. Factors associated with high compliance were identified using logistic regression. The effect of a change in mental and physical well-being on compliance was assessed using a one-sample t test. RESULTS: Only 25% of patients could be considered compliant. Overall, 63% left at least one visit blank. Influential variables for higher engagement included higher education, higher income, private health insurance, nonsmoking, and German origin. There was no relationship between a change in the number of physical complaints or depressive symptoms and study dropout. CONCLUSIONS: Maintaining high engagement with digital monitoring devices over a long time remains challenging. As cultural and socioeconomic background factors had the strongest influence, more effort needs to be directed toward understanding the needs of patients from different demographic backgrounds to ensure high-quality care for all patients. More studies need to report on compliance to disclose potential demographic bias.

Solidification Cracking Assessment of LTT Filler Materials by Means of Varestraint Testing and µCT.

Investigations of the weldability of metals often deal with hot cracking, as one of the most dreaded imperfections during weld fabrication. The hot cracking investigations presented in this paper were carried out as part of a study on the development of low transformation temperature (LTT) weld filler materials. These alloys allow to mitigate tensile residual stresses that usually arise during welding using conventional weld filler materials. By this means, higher fatigue strength and higher lifetimes of the weld can be achieved. However, LTT weld filler materials are for example, high-alloyed Cr/Ni steels that are susceptible to the formation of hot cracks. To assess hot cracking, we applied the standardized modified varestraint transvarestraint hot cracking test (MVT), which is well appropriate to evaluate different base or filler materials with regard to their hot cracking susceptibility. In order to consider the complete material volume for the assessment of hot cracking, we additionally applied microfocus X-ray computer tomography (µCT). It is shown that by a suitable selection of welding and MVT parameter the analysis of the complete 3D hot crack network can provide additional information with regard to the hot cracking model following Prokhorov. It is now possible to determine easy accessible substitute values (e.g., maximum crack depth) for the extent of the Brittleness Temperature Range (BTR) and the minimum critical strain P m i n .

Comparative biomechanical evaluation of two technologically different microprocessor-controlled prosthetic knee joints in safety-relevant daily-life situations.

Safety-relevant gait situations (walking on stairs and slopes, walking backwards, walking with small steps, simulated perturbations of swing phase extension) were investigated in a motion analysis laboratory with six unilateral transfemoral amputees using two different microprocessor-controlled prosthetic knee joints (Rheo Knee XC, C-Leg). A randomized crossover design was chosen. The study results imply that the performance and safety potential of a microprocessor-controlled knee joint can be associated with the individual control algorithms and the technological concepts that are implemented to generate motion resistances for controlling flexion and extension movements. When walking with small steps, advantages of the "default swing" concept used in the Rheo Knee XC were identified due to a highly reproducible swing phase release. However, when walking backwards, this concept may lead to an uncontrolled knee flexion which partly resulted in falls. When walking down stairs, walking on slopes or while recovering from a stumble after perturbations of the swing phase extension, the C-Leg demonstrated a reliable prosthetic side load-bearing capacity resulting in reduced loading on the residual body. In contrast, the Rheo Knee XC required increased compensatory movements of the remaining locomotor system in order to compensate for reduced load-bearing and safety reserves.

Combining metabolomic non-targeted GC×GC-ToF-MS analysis and chemometric ASCA-based study of variances to assess dietary influence on type 2 diabetes development in a mouse model.

Insulin resistance (IR) lies at the origin of type 2 diabetes. It induces initial compensatory insulin secretion until insulin exhaustion and subsequent excessive levels of glucose (hyperglycemia). A high-calorie diet is a major risk factor contributing to the development of this metabolic disease. For this study, a time-course experiment was designed that consisted of two groups of mice. The aim of this design was to reproduce the dietary conditions that parallel the progress of IR over time. The first group was fed with a high-fatty-acid diet for several weeks and followed by 1 week of a low-fatty-acid intake, while the second group was fed with a low-fatty-acid diet during the entire experiment. The metabolomic fingerprint of C3HeB/FeJ mice liver tissue extracts was determined by means of two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-ToF-MS). This article addresses the application of ANOVA-simultaneous component analysis (ASCA) to the found metabolomic profile. By performing hyphenated high-throughput analytical techniques together with multivariate chemometric methodology on metabolomic analysis, it enables us to investigate the sources of variability in the data related to each experimental factor of the study design (defined as time, diet and individual). The contribution of the diet factor in the dissimilarities between the samples appeared to be predominant over the time factor contribution. Nevertheless, there is a significant contribution of the time-diet interaction factor. Thus, evaluating the influences of the factors separately, as it is done in classical statistical methods, may lead to inaccurate interpretation of the data, preventing achievement of consistent biological conclusions.