Relationship between the audiogram and the duration of the tone measuring the threshold

Summary In addition to the data on intensity-duration curves of the threshold tones, the threshold audiograms are constructed for the different durations of the threshold measuring tone. The durations 0.5; 2; 5; 20; 100 and 850 msec and frequencies 200, 500, 1000, 2000, 3000, and 5000 cps were used. Even when the duration of the testing tone is so short that this tone becomes a noise, the pattern of an audiogram in cases of normal hearing has some resemblance to the typical audiogram. But the great remoteness of the point for 1000 cps from the minimum zone draws attention. As the duration of the testing becomes longer, the audiogram of a person with normal hearing is gradually transforrned from a V-shaped curve with a sharp minimum into a typical curve with an elongated minimum zone, and the point for 1000 cps shifts from the left ascending branch of the audiogram to the center of the minimum zone. Several audiograms are obtained for 2 patients with a partial hearing loss, resulting from growing age, and 1 patient with a severe hearing loss of traumatic origin. Peculiar changes in these audiogram could be clearly seen at the least durations of the testing tone used. The diminishing of absolute threshold, when the tone duration is prolonged from 100 to 850 msec, is less for the listeners with impaired hearing.(Presented by Academician V. N. Chernigovskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 54, No. 10, pp. 21–26, October 1962.     

Topical organization of the projections of neurons of the substantia nigra and the ventral field of the tegmentum of the midbrain to the head of the caudate nucleus of the cat

Neuroscience and Behavioral Physiology -