The first cochlear potentials were recorded from cats by Wever and Bray in 1930. 8 Since then cochlear potentials have been recorded in a number of other species. There has been difficulty in recording the potentials in man. In 1935 Fromm, Nylen, and Zotterman 3 tried to record cochlear potentials from man using headphones to evaluate their intensity. They observed a small response in two out of ten cases. Andreev, Arapova, and Gersuni 1 in 1939 reported studies of twenty subjects using a cathode ray oscilloscope to measure their potentials.Their records showed small potentials except in one instance when a 20 microvolt response to a tone of 200 cycles per second was recorded. The report stated that sound stimuli of such intensity were used that they were painful to the ears of the observers. In 1941 Perlman and Case 6 published the first picture of the human cochlear potential. This potential was obtained by placing an elec trode against the round window through a perforation in the tym panic membrane of an unanesthetized patient. The resulting response was small and just above the noise level of their amplifiers. Lempert, Wever, Lawrence, and Meitzer reported in 1947 and again in 1950 4,5 that in about one half of their cases they were able to achieve a coch lear potential of one microvolt.In 1959 observations in four individuals were reported from the
Sulitable electrical stimulaltion of the region of the decussation of the olivocochlear bundles, which supply efferent innervation to the organ of Corti, was found to abolish the response of the auditory cortex to a click, without changing the responses (N(1) and N(2)) of the eighth nerve in cats. At higher stimulation values the eighth nerve responses also were abolished, and at intermediate stimulus values responses at the medial geniculate and inferior colliculus were suppressed.
Studies were made on 100 pupils, recruited from occupational rehabilitation schools for the deaf in Kraków. They underwent general medical as well as specialist examinations. Deafness was found up to the age of 3 years in 75% of those examined. In 30% of the subjects, their vestibular system was paralysed, ophthalmological disorders were found in 95% of cases, neurological disturbances in 15% and pathological changes of the central nervous system in 65% of cases were recorded by EEG. We did not look for evidence that deafness causes anatomical changes in the central nervous system, but the disturbances observed nevertheless indicate a correlation with congenital or early acquired deafness.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.