Hysterical Deafness in Microsoft Office

Generation Quick Response Code in Microsoft Office Hysterical Deafness

It is possible to distinguish hysterical and feigned deafness from that due to structural disease in several ways In the case of bilateral deafness, the distinction can be made by observing a blink (cochleo-orbicular re ex) or an alteration in skin sweating (psychogalvanic skin re ex) in response to loud sound Unilateral hysterical deafness may be detected by an audiometer, with both ears connected, or by whispering into the bell of a stethoscope attached to the patient s ears, closing rst one and then the other tube without the patient s knowledge The elicitation of the rst several waves of the brainstem auditory evoked potentials provides indisputable evidence that sounds are reaching the receptive auditory structures and that the patient should be capable of hearing sounds It should be kept in mind that a brief episode of deafness with fully preserved consciousness may rarely be caused by seizure activity in one temporal lobe (epileptic suppression of hearing)

Dizziness and other sensations of imbalance are, along with headache, back pain, and fatigue, the most frequent complaints among medical outpatients (Kroenke and Mangelsdorff) The signi cance of these complaints varies greatly For the most part they are benign, but always there is the possibility that they signal the presence of an important neurologic disorder Diagnosis of the underlying disease demands that the complaint of dizziness be analyzed correctly the nature of the disturbance of function being determined rst and then its anatomic localization This classic approach to neurologic diagnosis is nowhere more valuable than in the patient whose main complaint is dizziness The term dizziness is applied by the patient to a number of different sensory experiences a feeling of rotation or whirling as well as nonrotatory swaying, weakness, faintness, light-headedness, or unsteadiness Blurring of vision, feelings of unreality, syncope, and even petit mal or other seizure phenomena may be called dizzy spells Hence a close questioning of the patient as to how he is using the term becomes a necessary rst step in clinical study Essentially, the physician must determine whether the symptoms have the speci c qualities of vertigo which in this chapter refers to all subjective and objective illusions of motion or position or whether they are more properly categorized as light-headedness or nonrotatory pseudovertigo The distinction between these two groups of symptoms is elaborated after a brief discussion of the factors involved in the maintenance of equilibrium

Several mechanisms are responsible for the maintenance of a balanced posture and for awareness of the position of the body in relation to its surroundings Continuous afferent impulses from the eyes, labyrinths, muscles, and joints inform us of the position of different parts of the body In response to these impulses, the adaptive movements necessary to maintain equilibrium are carried out Normally we are unaware of these adjustments, since they operate largely at a re ex level The most important of the afferent impulses are the following: 1 Visual impulses from the retinae and possibly proprioceptive ones from the ocular muscles, which enable us to judge the distance of objects from the body This information is coor-

dinated with sensory information from the labyrinths and neck (see below) to stabilize gaze during movements of the head and body 2 Impulses from the labyrinths, which function as highly specialized spatial proprioceptors and register changes in the velocity of motion (either acceleration or deceleration) and position of the body The cristae of the three semicircular canals sense angular acceleration of the head (side-to-side or rotary), and the maculae of the saccule and utricle sense linear acceleration and gravity In each of these structures, displacement of sensory hair cells is the effective stimulus In the semicircular canals, this is accomplished by movement of the endolymphatic uid, which, in turn, is induced by rotation of the head and results in an illusion of rotation In the utricle and saccule, the hairs are displaced in response to the force of gravity on the otoliths, giving rise to a sensation of linear displacement or tilt In either case, the movement generates an electrical charge in the hair cells, causing depolarization of the nerve terminals and thereby initiating impulses in the vestibular nerve, with the production of two main re ex responses: the vestibulo-ocular, which stabilizes the eyes, and the vestibulospinal, which stabilizes the position of the head and body 3 Impulses from the proprioceptors of the joints and muscles are essential to all re ex, postural, and volitional movements Those from the neck are of special importance in relating the position of the head to the rest of the body The sense organs listed above are connected with the cerebellum and with certain ganglionic centers and pathways in the brainstem, particularly the vestibular nuclei, and, via the medial longitudinal fasciculi, with the ocular motor nuclei These cerebellar and brainstem structures are the important coordinators of the sensory data and provide for postural adjustments and the maintenance of equilibrium They are the basis of what is called the space constancy mechanisms, whereby the perceptions of one s self (the body schema) and one s surroundings (the environmental schema) are matched Conversely, any disease that disrupts these neural mechanisms may give rise to vertigo and disequilibrium The interdependence of the two schemata (self and environment) is ascribed to the fact that the various sense organs retinal, labyrinthine, and proprioceptive are usually activated simultaneously by any body movement Through a process of learning, we come to see objects as stationary while we are moving and moving objects as having motion when we are either moving or stationary At times, especially when our own sensory information is incomplete, we mistake movement of our surroundings for movements of our own body A well-known example is the feeling of movement that one experiences in a stationary train when a neighboring train is moving In this frame of reference, the orientation of the body to its surroundings depends on the maintenance of an orderly relationship between the bodily schema and the schema of the surround; as a result, disorientation in space, or disequilibrium, occurs when this relationship is upset Yet another factor that in uences equilibrium is the effect of aging (pages 106 and 521) Old people may lose their balance on extending the neck, and their peripheral sensory afferents are often impaired, as are the protective postural mechanisms, making falls more frequent A destructive lesion of one or both labyrinths may