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Scanning electron microscopy (SEM) permits a three-dimensional study of the surface morphology of the organ of Corti that is very useful in evaluating the condition of the apical end of the hair cells and the stereocilia. However, some laboratories have experienced problems with curling of the basilar membrane during critical point drying of cochlear specimens prepared For SEM evaluation using the Murakami or osmium thiocarbohydrazide-procedures. This curling of the basilar membrane can obstruct the view of the reticular lamina and the ciliary ends of the hair cells. We have used a dissection method, referred to as the anchor technique, to overcome basilar membrane curling. This technique removes all the structures above the reticular lamina but leaves the basilar membrane attached to the spiral ligament and the lateral bone to which the spiral ligament is anchored. Individual cochlear turns are dissected in this manner and mounted on the same examination stub For SEM evaluation. Maintenance of the lateral attachment of the basilar membrane requires additional dissection time but eliminates the problem of curling during critical point drying. An additional benefit is that mounting the individual turns on the same examination stub Facilitates evaluation and photomicroscopy of the surface morphology. The anchor technique has been used successfully on the guinea pig and should be appropriate for most mammalian cochleas.

Many investigations of noise-induced hearing loss have demonstrated a poor correlation between hearing threshold and hair cell loss. One reason for this is that more subtle changes in the hair cell, such as detailed morphological changes of stereocilia, have not been evaluated. However, examining such changes increases the problem of distinguishing experimental pathological changes from artefacts. Preparation of the specimen for scanning electron microscopy (SEM) may result in too many artefacts for an adequate quantification of defects due to noise exposure. One problem with some earlier studies seems to be lack of controls and/or statistical analysis for the purpose of eliminating the influence of artefacts and spontaneous degeneration. The aim of this study was to compare unexposed and noise-exposed cochleas examined with SEM in order to determine if subtle changes due to noise could be distinguished from preparation artefacts and from spontaneous deterioration. Ten different types of hair cell changes were found in exposed and control animals. By means of using controls for statistical comparison with noise-exposed animals two cell damage categories hair cell loss and missing stereocilia were found to be produced by exposure to noise.

This paper reports on a study investigating the impact of differences in the learning context on oral L2 fluency outcomes. The study specifically focuses on the effect of different levels of L1 and L2 prominence (as determined by their status, functions roles and domains of use) in the extracurricular context on the speed, breakdown and repair fluency of the L2 speech of German learners of English (ages 8–14). Controlled variation of L1 and L2 prominence is observed across 4 different authentic language learning contexts. The results demonstrate an effect of different levels of L2 prominence on L2 speed and breakdown fluency and grant support to a gradient operationalization of language prominence. We further suggest that L1 prominence is a relevant factor in the operationalization of context. The different dimensions of fluency (i.e., speed, breakdown and repair fluency) are affected differently by elements in the learning context, which confirms the multilayered approach to the construct.