Speech perception, real-ear measurements and self-perceived hearing impairment after remote and face-to-face programming of hearing aids: A randomized single-blind agreement study.

INTRODUCTION: Current literature does not provide strong evidence that remote programming of hearing aids is effective, despite its increasing use by audiologists. We tested speech perception outcomes, real-ear insertion gain, and changes in self-perceived hearing impairment after face-to-face and remote programming of hearing aids in a randomized multicentre, single-blind crossover study. METHODS: Adult experienced hearing aid users were enrolled during routine follow-up visits to audiology clinics. Hearing aids were programmed both face to face and remotely, then participants randomly received either the face-to-face or remote settings in a blinded manner and were evaluated 5 weeks later. Participants then received the other settings and were evaluated 5 weeks later. RESULTS: Data from 52 out of 60 participants were analysed. We found excellent concordance in performance of hearing aids programmed face to face and remotely for speech understanding in quiet (phonetically balanced kindergarten test - intraclass correlation coefficient of 0.92 (95% confidence interval: 0.87-0.95)), and good concordance in performance for speech understanding in noise (phonetically balanced kindergarten +5 dB signal-to-noise ratio - intraclass correlation coefficient of 0.71 (95% confidence interval: 0.55-0.82)). Face-to-face and remote programming took 10 minutes (±2.9) and 10 minutes (±2.8), respectively. Real-ear insertion gains were highly correlated for input sound at 50, 65 and 80 dB sound pressure levels. The programming type did not affect the abbreviated profile of hearing aid questionnaire scores. CONCLUSIONS: In experienced hearing aid users, face-to-face and remote programming of hearing aids give similar results in terms of speech perception, with no increase in the time spent on patients' care and no difference in self-reported hearing benefit. CLINICALTRIALS.GOV IDENTIFIER: NCT02589561.

Ignition study of acetone/air mixtures by using laser-induced spark.

The breakdown and the laser-induced spark ignition of acetone-air mixtures were experimentally studied using a nanosecond pulse at 1064 nm from a Q-switched Nd:YAG laser. The breakdown was first characterized for different mixtures with acetone and air. This part of the work highlighted the wide variation in the energy absorbed by the plasma during a breakdown. We also demonstrated that the presence of acetone in air tends to reduce the energy required to obtain a breakdown. Next, the ignition of acetone-air mixtures in the equivalence ratio range 0.9-2.4 was investigated. The probabilities of ignition were calculated in function to the laser energy. However, according to the variability of energy absorption by the plasma, we preferred to present the result according to the energy absorbed by the plasma. The minimum ignition energies were also provided. The minimum ignition energy was obtained for an equivalence ratio of 1.6 and an absorbed energy of 1.15 mJ. Finally the characteristics of the plasma (absorption coefficient and kernel temperature) were calculated for the experiments corresponding to minimum ignition energies.