Workplace Activity in Health Professionals Exposed to Chemotherapy Drugs: An Otoneurological Perspective

Introduction The manipulation of antineoplastic drugs presents high risk for accidents and occupational diseases. Objective To evaluate the auditory and vestibular systems of workers who are exposed to chemotherapeutic treatment in the University Hospital of Universidade Federal de Santa Maria, Brazil, and to identify the use of individual protection equipment, related to the obtained results. Methods This study is a cross-sectional study using a quantitative method. We evaluate 33 male and female workers, ranging from 21-60 years old, of the nursing and pharmacy sectors. The workers underwent conventional Audiologic Assessment; Transient Evoked Otoacoustic Emissions; and Computerized Vectoelectronystagmography. Results The majority of the sample was female (90.9%). Individual protection equipment was used by 90.9% of the workers. Complaints of dizziness were reported by 56.25% of nursing workers and 52.94% of pharmacy workers. Audiological and vestibular assessment results were within normal limits, 96.97% and 74.20%, respectively. However, audiometric configuration of notch type was identified in 75.75% of all workers. Audiometric notches (76%) and altered caloric test (100%) were often associated with decreased use of coal masks. Conclusion Among the workers evaluated, the vestibulocochlear system was within the normal limits. The presence of notch configuration indicates the need to use individual protection equipment.

Recording from two neurons: second-order stimulus reconstruction from spike trains and population coding

We study the reconstruction of visual stimuli from spike trains, representing the reconstructed stimulus by a Volterra series up to second order. We illustrate this procedure in a prominent example of spiking neurons, recording simultaneously from the two H1 neurons located in the lobula plate of the fly Chrysomya megacephala. The fly views two types of stimuli, corresponding to rotational and translational displacements. Second-order reconstructions require the manipulation of potentially very large matrices, which obstructs the use of this approach when there are many neurons. We avoid the computation and inversion of these matrices using a convenient set of basis functions to expand our variables in. This requires approximating the spike train four-point functions by combinations of two-point functions similar to relations, which would be true for gaussian stochastic processes. In our test case, this approximation does not reduce the quality of the reconstruction. The overall contribution to stimulus reconstruction of the second-order kernels, measured by the mean squared error, is only about 5% of the first-order contribution. Yet at specific stimulus-dependent instants, the addition of second-order kernels represents up to 100% improvement, but only for rotational stimuli. We present a perturbative scheme to facilitate the application of our method to weakly correlated neurons.