A hearing test used to investigate the middle ear in cases of conductive deafness.
resistance to the flow of electricity through the heart muscle during *defibrillation due to the thoracic structures lying between the defibrillation paddles and the heart. These structures include the skin and soft subcutaneous tissues, the ribs and sternum, the lungs, and the pericardium. The best way to reduce the impedance, and thus to deliver the maximum available current to the heart, is to use defibrillation gel pads (see coupling agents), to deliver the shock when the lungs are empty of air, or to press firmly down if using hand-held paddles. Transthoracic impedance is usually between 70 and 80 ohms.... transthoracic impedance
(visual reinforced audiometry, VRA) a behavioural test of hearing for children aged approximately 6 to 30 months in which the subject sits between two calibrated loudspeakers. A sound is generated from one loudspeaker. Children who turn towards the sound are rewarded by brief illumination of a toy adjacent to the loudspeaker. Older children can be tested with headphones, rather than using the loudspeakers, to enable each ear to be tested separately. The test can be adapted for use with older subjects who have learning disabilities.... visual reinforcement audiometry
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