Nervous and mental diseases . poral lobe, thedestruction of which produces word-deafness, or a loss of spoken-wordmemories. At its peripheral termination the auditory nerve enters thecribriform opening in the internal meatus. The auditory portion is dis-tributed to the cochlea and the organ of Corti. The labyrinthian portionis distributed to the vestibule and ampuUiS of the semicircular canals. Irritation of the auditory portion of the eighth nerve ismarked by auditory hyperesthesia, by increased acuteness of hearing {hijper-(icoiisis), and bv tinnitus. It must be understood that continued irr
Nervous and mental diseases . poral lobe, thedestruction of which produces word-deafness, or a loss of spoken-wordmemories. At its peripheral termination the auditory nerve enters thecribriform opening in the internal meatus. The auditory portion is dis-tributed to the cochlea and the organ of Corti. The labyrinthian portionis distributed to the vestibule and ampuUiS of the semicircular canals. Irritation of the auditory portion of the eighth nerve ismarked by auditory hyperesthesia, by increased acuteness of hearing {hijper-(icoiisis), and bv tinnitus. It must be understood that continued irrita-tion of the auditory apparatus may result in diminished or lost function,just as overstimulation of any tissue or organ finally produces weaknessand involution. It follows that tinnitus, for example, is often found withdefective hearing. Hyperesthesia is frequently present in excitable andnervous persons. Migraine and all forms of pain often render thesufferer more sensitive to sudden noises, especially of high pitch, but. Fig. 50.—Diagram of a section showiDg the ori-gin of the eighth cranial nerve. V, Vestibuhir por-tion ; C, cochlear portion ; W, accessory of \\ ris-berg; A, accessory nucleus; T, acoustic tubercle;R, restiform body; NC, nucleus of Clarke (afterBrissaud). 132 DISEASES OF THE CRANIAL NERVES. actual hyperacousis is rare. In meningitis, acute mania, and under theinfluence of some stimulant drugs, such as alcohol, opium, anesthetics,Indian hemp, and caftein, the special sense of hearing is at times actuallyexalted. Stoddart insists that the hearing is often abnormally acutein maniacal patients. It is also conceivable that an irritant lesion of theauditory cortical centers might give rise to hyperacousis, and perhapsthis is also the explanation of some hallucinations of hearing and some-times of the rare auditory aurse of epilepsy. The increased acutenessof hearing for low tones in facial palsy has already been described. Irritation or disease of any part of
Size: 1495px × 1671px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectmentalillness, booksubjectnervoussys
