Speech perception in medico-legal assessment of hearing disabilities

OBJECTIVE

Examination of Danish data for medico-legal compensations regarding hearing disabilities. The study purposes are: (1) to investigate whether discrimination scores (DSs) relate to patients' subjective experience of their hearing and communication ability (the latter referring to audio-visual perception), (2) to compare DSs from different discrimination tests (auditory/audio-visual perception and without/with noise), and (3) to relate different handicap measures in the scaling used for compensation purposes in Denmark.

DESIGN

Data from a 15 year period (1999-2014) were collected and analysed.

STUDY SAMPLE

The data set includes 466 patients, from which 50 were omitted due to suspicion of having exaggerated their hearing disabilities.

RESULTS

The DSs relate well to the patients' subjective experience of their speech perception ability. By comparing DSs for different test setups it was found that adding noise entails a relatively more difficult listening condition than removing visual cues. The hearing and communication handicap degrees were found to agree, whereas the measured handicap degrees tended to be higher than the self-assessed handicap degrees.

CONCLUSIONS

The DSs can be used to assess patients' hearing and communication abilities. The difference in the obtained handicap degrees emphasizes the importance of collecting self-assessed as well as measured handicap degrees.

Sound exposure of symphony orchestra musicians

BACKGROUND

Assessment of sound exposure by noise dosimetry can be challenging especially when measuring the exposure of classical orchestra musicians where sound originate from many different instruments. A new measurement method of bilateral sound exposure of classical musicians was developed and used to characterize sound exposure of the left and right ear simultaneously in two different symphony orchestras.

OBJECTIVES

To measure binaural sound exposure of professional classical musicians and to identify possible exposure risk factors of specific musicians.

METHODS

Sound exposure was measured with microphones mounted on the musician's ears and recorded digitally. The recorded sound was analysed and the specific sound exposure of the left and the right ear was determined for the musicians. A total of 114 measurements covering 106 h were recorded in two symphony orchestras.

RESULTS

Sound exposure depends significantly on the specific instrument and the repertoire played by the exposed musician. Concerts, group rehearsals and individual practice were all significant contributors to the sound exposure. The highest L(Aeq) of 86 -98 dB was found among the brass players. High string players were exposed from 82 to 98 dBA and their left ear was exposed 4.6 dB more than the right ear. Percussionists were exposed to high sound peaks >115 dBC but less continuous sound exposure was observed in this group. Musicians were exposed up to L(Aeq8h) of 92 dB and a majority of musicians were exposed to sound levels exceeding L(Aeq8h) of 85 dB.

CONCLUSIONS

Binaural recording of the individual sound exposure showed that orchestra musicians could be exposed differently to the left and right ear and that they were primarily exposed from their own instruments. Specific repertoires as well as the specific instrument determine the level of exposure.

Negative specific heat in a quasi-2D generalized vorticity model

Negative specific heat is a dramatic phenomenon where processes decrease in temperature when adding energy. It has been observed in gravo-thermal collapse of globular clusters. We now report finding this phenomenon in bundles of nearly parallel, periodic, single-sign generalized vortex filaments in the electron magnetohydrodynamic model for the unbounded plane under strong magnetic confinement. We derive the specific heat using a steepest-descent method and a mean-field property. Our derivations show that as temperature increases, the overall size of the system increases exponentially and the energy drops. The implication of negative specific heat is a runaway reaction, resulting in a collapsing inner core surrounded by an expanding halo of filaments.

Sensitivity and stability of LiF thermoluminescence dosimeters

Three different batches of LiF TLD-100 rods were subjected to investigation of their radiation sensitivity and the stability of the sensitivity after subsequent cycles of irradiation readouts. An old batch (circular rods from 1985), R85, showed an initial sensitivity of approximately 720 (nC/Gy). A new batch of circular rods (R0059) had an initial sensitivity more than a factor of 2.5 higher than the old batch. A batch of square rods (S3720) had an even higher sensitivity; a factor of almost 4 higher than batch R85. Both batches of circular rods showed a statistically significant change in sensitivity with increasing cycles of irradiations and readouts. No significant change was observed for the batch S3720. Batch R85 showed an increasing sensitivity with increasing number of cycles, and a small reduction in the width of the sensitivity distribution within the batch. However, the newer batch (R0059), showed a marked decrease in sensitivity and a doubling of the broadening of the sensitivity distribution after 10 cycles. No significant change in the sensitivity distribution within the S3720 batch was observed after 10 cycles.