Visual and cognitive demands of manual and voice-based driving mode implementations on smartphones.

Mobile phone apps and operating systems are increasingly adopting driving mode functions that attempt to reduce driver visual and cognitive demand by limiting functionality, using larger buttons and icons, and adding voice-based interactions. The present study assessed the visual and cognitive demands and the subjective level of distraction from two driving mode implementations (voice or manual) on an Android™ mobile phone using Google Assistant™, compared to a typical mobile phone operating system experience. While driving on a test track, participants performed several trials of five tasks on each of three interfaces: A mobile operating system interface, a manual driving mode interface, and a voice driving mode interface. Visual demand was measured with eye-gaze recordings, cognitive load was measured with the detection response task, and a Likert scale was used to rate the perceived level of distraction. The voice driving mode resulted in the lowest visual attention demand and lowest subjective ratings of distraction. The manual driving mode condition also reduced visual demand and subjective ratings of distraction relative to the mobile operating system condition. The cognitive load results were inconsistent across the task and interaction mode conditions. Overall, the results of this study provide positive evidence in support of voice-based driving mode implementations for reducing visual demand and subjective levels of distraction from mobile devices while driving. Moreover, the results suggest that manual driving mode implementations also have the potential to reduce visual demand and subjective levels of distraction, relative to the mobile operating system condition.

Magnetic induction spectroscopy (MIS)-probe design for cervical tissue measurements.

OBJECTIVE: Gradiometers have the advantage of increasing measuring sensitivity, which is particularly useful in magnetic induction spectroscopy (MIS) for bio-impedance measurements. Traditional gradiometers use a pair of field sensing coils equally distant and on opposite sides of a drive coil, which provides high immunity to interference. In this paper, a ferrite-cored coaxial gradiometer probe of 29 mm diameter has been developed for measuring the impedance spectra of cervical tissues in vivo. APPROACH: It consists of a ferrite rod with outer ferrite confinement screening in order to eliminate the signals from surrounding tissue. The magnetic screening efficiency was compared with an air-cored gradiometer probe. For both gradiometer probes, a drive coil and two sensing coils were wound on a borosilicate glass former aligned coaxially with two sensing coils equidistant from the drive coil. The signal sensitivity of those two MIS gradiometers has been measured using saline samples with a conductivity range between 0.1 and 1.1 S m-1. Finite element methods using COMSOL Multiphysics have been used to simulate the distribution of sensitivity to conductivity over the face of each probe and with depth. MAIN RESULTS: The ferrite-cored probe has a sensitivity confined to the volume defined by the gap between the ferrite core and outer tube of ferrite while the air-cored probe without any magnetic shielding had a wide sensitivity over the face and the side of the probe. Four saline samples and one of distilled water with conductivities from 0.1 to 1.1 S m-1 have been used to make conductivity measurements at frequencies of 50 kHz, 100 kHz, and 300 kHz. The measurement accuracy of the air-cored MIS probe was 0.09 S m-1 at 50 kHz, improving to 0.05 S m-1 at 300 kHz. For the ferrite-cored MIS probe, the measurement accuracy was 0.28 S m-1 at 50 kHz, improving to 0.04 S m-1 at 300 kHz. SIGNIFICANCE: In vivo measurements on human hand have been performed using both types of gradiometers and the conductivity is consistent with reported data.

In-hospital patients exposed to clopidogrel before coronary artery bypass graft surgery: a word of caution.

BACKGROUND: The aim of our study was to investigate the independent effect of preoperative exposure to aspirin, heparin, and clopidogrel on early clinical outcomes of in-hospital referral patients undergoing first time coronary artery bypass graft (CABG) surgery. METHODS: Outcomes for in-hospital referrals for CABG between January 2001 and January 2002 were prospectively recorded. Exposure to aspirin, heparin, and clopidogrel during the 5 days before surgery was recorded, and their effect on outcome was explored using multiple regression methods. The effect of clopidogrel given within 48 hours before surgery versus stopped at least 48 hours before the operation was also investigated. RESULTS: In-hospital referral patients represented 40% (473 of 1,185) of the total surgical population; 304 (64.7%) were prescribed aspirin, 116 (24.7%) heparin, 91 (19.4%) clopidogrel, and 133 (28.3%) had all anticoagulants stopped 5 days before surgery. In-hospital mortality was 2.3% (95% confidence interval [CI]: 1.1 to 4.1) and was highest among those exposed to clopidogrel (odds ratio 16.9, 95% CI: 2.10 to 136, p = 0.008). Seven of the 11 deaths occurred in patients given clopidogrel. Postoperative intraaortic balloon pump, arrhythmia, reintubation, and stroke were all significantly more common when clopidogrel was prescribed (relative risk estimates all greater than 1.5, p values all < or = 0.021). Blood loss was 37% higher in the patients given clopidogrel (95% CI: +3% to +82%, p = 0.033). Clopidogrel patients were more likely to need a reoperation for bleeding (p < 0.001) and require transfusions (p < or = 0.015). Intubation time and hospital stay were also longer (p = 0.021 and p = 0.019, respectively). Heparin was also associated with longer hospital stay (p < 0.001) and aspirin use with reduced stay (p = 0.041), but for all other outcomes, no association with aspirin or heparin use was found. Comparison of subgroups of clopidogrel patients suggested mortality was highest when clopidogrel was given in the 48 hours before surgery. CONCLUSIONS: Our study suggests that among in-hospital referral patients, preoperative exposure to clopidogrel within 5 days before CABG may increase early mortality and morbidity, and that the mortality risk is greatest when the drug is given within 48 hours of surgery.