Abstract
The author studied the audiograms of 957 patients with hearing difficulty, who were examined in the Tohoku University Hospital.
Symmetry of bilateral audiograms were found in high percentage in the cases with strepto-mycin deafness, acoustic trauma, familialy deafness, (chronic progressive labyrinthine deafness), presbyacusis, deafness following febrile diseases and few others.
Except familialy deafness, all these have been considered to be acquired deafness, so that it was contrary to the Langenbeck's Symmetry low that the Symmetry of bilateral audiograms indicate the hereditary diseases.
Considering the clinical evidences, the author concluded that these findings were due to congenital vulnerability of ears and were not contrary to Langenbeck's Symmetry law.
