Anatomy and physiology of aging cochlea
Cochlea is a snail like-structure located at the inner ear . Canals which transmits pressure and The organ of corti the sensitive part which detects pressure impulses, that travels along the auditory nerve that absorbs electrical impulses from the cochlea. Semicircular canals that balance body organs and detects acceleration of three perpendicular planes. which helps you keep your balance.
Auditory hair cells are vital part of the ear’s to detect easily the sound it has microscopic hair-like projections which consist of channel or pores that open after the hair like projections are subjected to mechanical force. Channel opens and releases small molecules in a chemical reaction that directly tells the brain that the sound has been detected .
Three Fluid section of the cochlea are the following Perilymph fluid in canals, Endolymph cochlear duct fluid and Organ of Corti which detects pressure.
COMMON CAUSE OF HEARING IMPAIREMENTS:
Age is a general cause of acquire hearing impairments. According to Loh & Elango,( 2005), *Age correlated morphologic change in human cochlea which focus on deterioration of the Stria Vascularis ( SV) and the Spiral Ganglion (SG)*. In the study of Ramadan & Schuknecht ( 1989), *Stria Vascularis (SV) and the Spiral Ganglion (SG) showed a tendency for progressive degenerate to grow with age*. Statistically shown that the difference between aging and Stria Vascularis (SV) becomes atrophied only in the apical and basal cochlear turns stated by Ohlemiller & Gagnon (2004). In relation between Stria Vascularis or Spiral Ganglion which becomes atrophied and has audiometric findings noted. Most prominent anatomic characteristics of aged human cochlea is Stria Vascularis.(Suzuki et al., 2006)
In the study of Zagolski (2006), *The inevitable deterioration in hearing ability that occurs with age–presbycusis–is a multifactor process that can vary in severity from mild to substantial*. Unmanageable, Presbycusis is a moderate or greater degree that can affect the communication and quarantine, which can cause depression of the patient whose suffering Presbycusis, and dementia. These kind of psychological effect that can be reversible and restoration of a good health. A Comprehensive rehabilitation is understandable it can be available but underused because some part, of social attitudes that cannot value hearing, in addition to this it can cause spots in hearing aids. In remedy of presbycusis is an important factor of life in geriatric medicine and can includes education for a better communication, by using hearing aids, assistive listening devices, and cochlear implants to prevent severe hearing loss. According to Shehata-Dieler, Volter, Hildmann, Hildmann, & Helms (2007). The main focused of the physicians is to screen and referring their elderly patients for effective assessment and remediation. Hearing aids is sometimes not beneficial to the users, the best treatment of choice is cochlear implantation with excellent results even in octogenarians.(Gates & Mills, 2005)
According to Ulualp, Wright, Pawlowski, & Roland ( 2004 ), *they used human temporal bones to expound the result of aging on the auditory system. They had respondents of 68 individuals from ninety-six ears, from infancy to 84 years old serves as a “normal ears”. None of these cases had medical or pathological proof of exact ear disease. “Pathological ears” from 58 persons which consist of 89 ears which exhibit slowly progressive hearing loss, which had no specific recognized cause of the loss*. According to the learning of Ravnal, Kossowski, & Job (2006), *these two age phenomenon are found to manipulate the human ear. First is physiological, has been called ‘auditory senility’. This involve in dissimilar parts of the auditory mechanism and is liable for the rise in auditory threshold for the elevated frequencies, commonly seen in elderly people. Second phenomenon is pathological, termed as ‘auditory decay’. Pertaining to the system of the ear, resulting from dissimilar types of clinical performance, according to the structural layer involved*. The situation of this two aging phenomenon that affects the individual ear explain the cause why auditory acuity is related with old age. It is according to Belal (1975).
Hearing disability can be in all age groups. Hearing loss can be genetically acquired by the children because of infection due developmental stage of the fetus.
It includes congenital syndrome such as Down Syndrome or Trisomy 21, Parent with familial deafness can be genetically acquired, infections during pregnancy of the mother for example the mother had German measles ( rubella) or cytomegalovirus during high risk of pregnancy. With superficial hearing loss can have dilemma in speech development and learning. In adults, most common cause of hearing loss are caused by progressive bilateral hearing loss or senile deafness and noise that can be made by men. “old hearing” which affects men rather than woman, it also linked to noise exposure, most of this are men who are working in industrialized company or military men whose in the field. Mechanism of hearing is complicated. Sound waves which enters the ear canal and moves freely in the eardrum we called it tympanic membrane; eardrum is located to the hearing organ or cochlea with small bones called ossicles which anchored to the eardrum. Cochlea also called oval window, movement of the eardrum that sets up movements in the bones which in return the oval window, these tiny hair cells that lines the part of the cochlea are stimulated by these waves, which transmits nerve impulses that travels along the brain which can detect if the sound is received. Conductive Hearing loss is cerumen or so called earwax, impaction, it is caused by cleaning the ears with cotton swabs because putting a swab in the ear it pushes the earwax from the back of canal that can cause of impaction. Children are notorious introducing foreign object to there ear it should removed to avoid damage of the inner ear. Another cause of hearing loss is disruption or dislocation of the bone in the inner ear it is caused by perforation of the eardrum and dislocation of the bones, it requires immediate operation, common cold and other upper respiratory tract infections can cause of hearing impairment, which includes infections in the inner ear. Eustachian tube that drains the inner ear going back to the throat. Cholesteatoma is a build up of the skin cell that surrounds the ear bones that prevents moving, that can cause complication of chronic middle ear infections. Ostosclerosis is a slowly progressive hearing loss that is common in woman than in man, caused by changes in bone and surgery. Inflexible of the eardrum is one that cause of conductive hearing caused by marked left by in the eardrum caused by matured ear infections a series of holes in eardrums and injury of a certain organ especially the ear.
Belal, A., Jr. (1975). Presbycusis: physiological or pathological. J Laryngol Otol, 89(10), 1011-1025.
Gates, G. A., & Mills, J. H. (2005). Presbycusis. Lancet, 366(9491), 1111-1120.
Loh, K. Y., & Elango, S. (2005). Hearing impairment in the elderly. Med J Malaysia, 60(4), 526-529; quiz 530.
Ohlemiller, K. K., & Gagnon, P. M. (2004). Apical-to-basal gradients in age-related cochlear degeneration and their relationship to “primary” loss of cochlear neurons. J Comp Neurol, 479(1), 103-116.
Ramadan, H. H., & Schuknecht, H. F. (1989). Is there a conductive type of presbycusis? Otolaryngol Head Neck Surg, 100(1), 30-34.
Raynal, M., Kossowski, M., & Job, A. (2006). Hearing in military pilots: one-time audiometry in pilots of fighters, transports, and helicopters. Aviat Space Environ Med, 77(1), 57-61.
Shehata-Dieler, W., Volter, C., Hildmann, A., Hildmann, H., & Helms, J. (2007). [Clinical and audiological findings in children with auditory neuropathy]. Laryngorhinootologie, 86(1), 15-21.
Suzuki, T., Nomoto, Y., Nakagawa, T., Kuwahata, N., Ogawa, H., Suzuki, Y., et al. (2006). Age-dependent degeneration of the stria vascularis in human cochleae. Laryngoscope, 116(10), 1846-1850.
Ulualp, S. O., Wright, C. G., Pawlowski, K., & Roland, P. S. (2004). Cochlear degeneration in leigh disease: histopathologic features. Laryngoscope, 114(12), 2239-2242.
Zagolski, O. (2006). Management of tinnitus in patients with presbycusis. Int Tinnitus J, 12(2), 175-178.
ANATOMY AND PHYSIOLOGY OF THE AGING COCHLEA