Standing balance of vehicle passengers: The effect of vehicle motion, task performance on post-drive balance.

BACKGROUND: Motion platforms and driving simulators have been shown to contribute to motion sickness and a short-term increase in standing postural sway. However, no studies to date have investigated how the motion of a passenger vehicle and the performance of a task during a drive on a closed test track affects post-drive standing balance. RESEARCH QUESTIONS: What are the effects of (1) a continuous, scripted drive on a closed test track, and (2) the performance of a handheld tablet-based task during the scripted drive, on post-drive standing balance? METHODS: Fifty adults (23 males, 27 females; 40.0 ± 20.6 yr) rode in the front passenger seat of a midsized sedan on a scripted drive. Participants were assigned to one of the acceleration levels (Low, Moderate) and completed both Task and No-Task test conditions, involving a visual-based task on a handheld tablet device. Before and after each scripted drive, participants completed two standing balance exercises: 1) feet tandem, eyes open, on firm support, and 2) feet together, eyes closed, on foam support. An inertial measurement unit (IMU) captured estimates of postural trunk sway. Root-mean-square (RMS) of angular position and velocity in the anteroposterior (A/P) and mediolateral (M/L) directions, and elliptical fit and path length of sway trajectory were computed. A nonparametric analysis was performed on the balance metrics. RESULTS: Exposure to a scripted drive in a vehicle affected participants' postural sway, especially after using a handheld device during the drive. M/L RMS sway velocity and path length increased for both exercises following the scripted drive with task. Additionally, M/L RMS sway increased for the more challenging balance exercise, during which participants stood with feet together on foam support with eyes closed. SIGNIFICANCE: This study is the first to explore balance following a scripted drive on a closed test track. Changes in post-drive balance introduces potential risks to vehicle passengers; concurrent performance of a task on a handheld device further increases the likelihood that post-drive balance will be negatively affected.

Correlating motor performance with surgical error in laparoscopic cholecystectomy.

BACKGROUND: Analysis of motor performance in minimally invasive surgery (MIS) is a new field with applications in surgical training, surgical simulators, and robotics. Force/torque and derivatives of tool tip position (velocity, acceleration, and jerk) are examples of measures of motor performance (MMPs). Few studies have measured MMPs or have correlated MMPs with surgical performance during MIS on humans. The objectives of this study were to determine the feasibility of a novel multimodal system to quantify MMPs in laparoscopic cholecystectomy and to attempt to correlate MMPs with the magnitude of error as a measure of surgical performance. METHODS: Novice and expert surgeons performed laparoscopic cholecystectomies in two groups of three patients each. MMPs were obtained using a combination of optical and electromagnetic tool tip tracking and a force/torque sensor on a modified Maryland dissector. Error scores for laparoscopic cholecystectomy were calculated using a previously validated system. Novice and expert measurements were compared, and correlations were made between error scores and MMPs. RESULTS: Error scores were similar between novices and experts. Novice surgeons had a significantly greater mean velocity (566 +/- 83 vs 85 +/- 32 mm/s, p = 0.006) and acceleration (2,600 +/- 760 vs 440 +/- 174 mm/s2, p = 0.050) compared to expert surgeons. Force (16.5 +/- 4.6 vs 18.3 +/- 6.0 N, p = 0.829), position (121 +/- 25 vs 135 +/- 72 mm, p = 0.863), and jerk (19,600 +/- 7,410 vs 2,430 +/- 367 mm/s3, p = 0.138) were similar between groups. A positive correlation was found in novice surgeons between error score and jerk (Pearson correlation, 0.999; p = 0.035). CONCLUSIONS: It is feasible to quantify MMPs in laparoscopic cholecystectomy. Novice and expert surgeons can be differentiated by MMPs; moreover, there may be a positive correlation between jerk and error score in novice surgeons.

A Conceptual Framework for the Progression of Balance Exercises in Persons with Balance and Vestibular Disorders.

There is little information in peer-reviewed literature to specifically guide the choice of exercise for persons with balance and vestibular disorders. The purpose of this study is to provide a rationale for the establishment of a progression framework and propose a logical sequence in progressing balance exercises for persons with vestibular disorders. Our preliminary conceptual framework was developed by a multidisciplinary team of physical therapists and engineers with extensive experience with people with vestibular disorders. Balance exercises are grouped into six different categories: static standing, compliant surface, weight shifting, modified center of gravity, gait, and vestibulo-ocular reflex (VOR). Through a systematized literature review, interviews and focus group discussions with physical therapists and postural control experts, and pilot studies involving repeated trials of each exercise, exercise progressions for each category were developed and ranked in order of degree of difficulty. Clinical expertise and experience guided decision making for the exercise progressions. Hundreds of exercise combinations were discussed and research is ongoing to validate the hypothesized rankings. The six exercise categories can be incorporated into a balance training program and the framework for exercise progression can be used to guide less experienced practitioners in the development of a balance program. It may also assist clinicians and researchers to design, develop, and progress interventions within a treatment plan of care, or within clinical trials. A structured exercise framework has the potential to maximize postural control, decrease symptoms of dizziness/visual vertigo, and provide "rules" for exercise progression for persons with vestibular disorders. The conceptual framework may also be applicable to persons with other balance-related issues.

A prospective audit of wound infection rates after caesarean section in five West Yorkshire hospitals.

A three month prospective audit of wound infection following emergency and elective caesarean section was carried out in five West Yorkshire hospitals. Among 4076 women undergoing delivery in the five obstetric departments, the caesarean rate was 15.4%. The overall infection rate was 45/628 (7.2%) with a range of 2.5-17.2% between the five centres. The infection rate was 14/226 (6.2%) when antibiotics were used compared with 31/402 (7.7%) without antibiotics. The use of prophylactic antibiotics made no significant difference to the infection rate, which did not correlate with duration of labour or of ruptured membranes. The number of vaginal examinations correlated with the infection rate. In conclusion, the caesarean section rate observed was higher than that estimated for the UK as a whole, but was distorted by one centre with a high rate. For the other four hospitals the caesarean rate was unexceptional. The ratio of emergency to elective operations was comparable with recently reported values in the UK and the wound infection rate was within the widely varying limits found in previous studies. In view of the relatively low infection rate recorded without antibiotics, in the interests of cost effectiveness, prophylaxis may be limited in future to selected women at high risk. Because this was an audit rather than a randomized study we cannot exclude that this is already happening on an empirical basis.