Functional auditory disorders

There are a number of auditory symptom syndromes that can develop without an organic basis. Some of these, such as nonorganic hearing loss, affect populations similar to those presenting with functional somatosensory and motor symptoms, while others, such as musical hallucination, affect populations with a significantly different demographic and require different treatment strategies. Many of these conditions owe their origin to measurably abnormal peripheral sensory pathology or brain network activity, but their pathological impact is often due, at least in part, to overamplification of the salience of these phenomena. For each syndrome, this chapter briefly outlines a definition, demographics, investigations, putative mechanisms, and treatment strategies. Consideration is given to what extent they can be considered to have a functional basis. Treatments are in many cases pragmatic and rudimentary, needing more work to be done in integrating insights from behavioral and cognitive psychology to auditory neuroscience. The audiology literature has historically equated the term functional with malingering, although this perception is, thankfully, slowly changing. These disorders transcend the disciplines of audiology, otorhinolaryngology, neurology and psychiatry, and a multidisciplinary approach is often rewarding

The oviduct in chaos

The unilateral avian oviduct is divisible into five functional regions which, moving distally, include the infundibulum, magnum, isthmus, tubular shell gland and shell gland pouch. Each region subserves a variety of functions, which through their interaction give rise to the multilayered albumen, shell membranes and the organichnorganic complex, which comprises the shell. The sequential activity of these structurally diverse regions is a necessary prerequisite for "normal" egg formation. The reproductive effort can be influenced by a number of disease processes either directly by virtue of the fact that they alter the ability of the lining cells to synthesise their integral components or indirect by generally compromising bird health. Notable amongst the former are Infectious Bronchitis, Newcastle Disease and Egg Drop Syndrome. All change the quality of the final product in terms of the shape and texture of the shell. In recent years it has become evident that environmental stress has an equally, if not more, important role to play in oviduct disfunction. In the absence of large areas of functional surface epithelium, the eggs laid were structurally defective at all levels from the mammillary layer outwards. As the epithelial layers regenerated, shell quality approximated normality, but never returned to the pre-stress condition. The process of candling signals amongst other internal defects a variety of inclusions variously classified as blood and meat spots. They are quite specific in their locations; thus blood spots originating from the rupture of ovarian blood vessels at ovulation, are invariably confined to the periphery of the yolk mass, while meat spots now classified according to their composition are confined to albumen. Within the latter they are recognised as tissue rich deposits, the result of oviduct breakdown and/or calcium rich fragments. The latter implies a breach in the barrier provided by the soft shell membranes