Pathological changes of hyperphonated cat vocal folds.

To investigate the pathological changes of hyperphonated vocal folds 15 cats were used and over-cry was induced by mechanical stimuli. The longest experiment time was 15 weeks. All of the larynges were taken and the vocal folds were examined grossly and microscopically. The results were as follows: 1) liquid exudate accumulation beneath the epithelium developed in all of the experimental animals; 2) thickening of the epithelium was noticed in cats which had hyperphonated for more than 4 weeks; 3) acute laryngitis occurred in three cats.