DEAFNESS

n. Deaf'neas. Gr., K<i<fxofia, t<i(f)<ris. Lat., surd it as. Fr., surdite. Ger., Taubheit. It., sorditd. Sp., sordera. The state of being deaf. Clang-d. That form of defect of the sense of hearing in which, although the loudne and other gro qualities of sounds are perceived correctly, their more delicate hysteria and independent of any the ear. [F.] Intellectual d. See Psychical d. Malarial d. D. sometimes met with in aggravated cases of malarial poisoning. It is supposed to be due to a lesion of the auditory nerve or of its nucleus, and may be a ociated with a lo of power in the optic nerve, and with lo of sensation in other nerves. [F.] Nervous d. Fr., surdite nerve use. Ger., nervose Taubheit. It., sorditd nervosa. Sp., sordera nerviosa. That form of d. in which the cause lies in a primary affection of the auditory nerve or of the labyrinth or of both. [F, 34.] Psychical d. Lat., amnesia (seu akamathesia) acustica. Ger., Seelentaubheit. A condition in which, although sounds are heard, their significance is not recognized; observed in cases of lesion of the gyrus infra marginal is. [R. Arndt (A, 319).] Throat-d. D. induced by some obstruction in the throat, as from enlarged tonsils, or due to some inflammatory affection starting in the pharynx and involving the Eustachian tubes. [F.] Vascular d. Fr., surdite d'origine vascula ire. Of R. T. Cooper, a variety of impaired hearing due to " a basic aural dyscrasia." A condition of ill health hi which a diffuse irritability attacks the walls of the blood-ve els, and which, left untreated, very often settles in the ears, giving rise to two prominent ear symptoms. One of these is enfeebled hearing power, divided into obstructive and non-obstructive. The latter variety Cooper terms " vascular d." [F.] Word-d. FT., aphemie auditive. Ger.,sinnliche Aphasie. It., sordita di parol a (o verbale). Sp., sordera de palabras. Syn.: sensory aphasia. Of Ku maul, that variety of psychical d. in which, while impre ions of sound can still be perceived, spoken words can not be understood. It is attributed to some pathological change in the cortex of the left temporal lobe of the brain (the seat of Wernicke's centre for the sense of hearing, where the impre ions received by the auditory nerves are united to form sound-pictures and the acoustic representation of words). [F.] [s. 512]