Presbycusis: Gradual bilateral hearing loss associated with aging that is due to progressive degeneration of cochlear structures and central auditory pathways. Hearing loss usually begins with the high frequencies then progresses to sounds of middle and low frequencies.Audiometry, Pure-Tone: Measurement of hearing based on the use of pure tones of various frequencies and intensities as auditory stimuli.Mastoid: The posterior part of the temporal bone. It is a projection of the petrous bone.Auditory Threshold: The audibility limit of discriminating sound intensity and pitch.Evoked Potentials, Auditory, Brain Stem: Electrical waves in the CEREBRAL CORTEX generated by BRAIN STEM structures in response to auditory click stimuli. These are found to be abnormal in many patients with CEREBELLOPONTINE ANGLE lesions, MULTIPLE SCLEROSIS, or other DEMYELINATING DISEASES.Stria Vascularis: A layer of stratified EPITHELIUM forming the endolymphatic border of the cochlear duct at the lateral wall of the cochlea. Stria vascularis contains primarily three cell types (marginal, intermediate, and basal), and capillaries. The marginal cells directly facing the ENDOLYMPH are important in producing ion gradients and endochoclear potential.Hearing Tests: Part of an ear examination that measures the ability of sound to reach the brain.Spiral Ganglion: The sensory ganglion of the COCHLEAR NERVE. The cells of the spiral ganglion send fibers peripherally to the cochlear hair cells and centrally to the COCHLEAR NUCLEI of the BRAIN STEM.Temporal Bone: Either of a pair of compound bones forming the lateral (left and right) surfaces and base of the skull which contains the organs of hearing. It is a large bone formed by the fusion of parts: the squamous (the flattened anterior-superior part), the tympanic (the curved anterior-inferior part), the mastoid (the irregular posterior portion), and the petrous (the part at the base of the skull).Cochlea: The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Hearing Loss: A general term for the complete or partial loss of the ability to hear from one or both ears.Hearing Loss, Sensorineural: Hearing loss resulting from damage to the COCHLEA and the sensorineural elements which lie internally beyond the oval and round windows. These elements include the AUDITORY NERVE and its connections in the BRAINSTEM.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Hearing Aids: Wearable sound-amplifying devices that are intended to compensate for impaired hearing. These generic devices include air-conduction hearing aids and bone-conduction hearing aids. (UMDNS, 1999)Auditory Diseases, Central: Disorders of hearing or auditory perception due to pathological processes of the AUDITORY PATHWAYS in the CENTRAL NERVOUS SYSTEM. These include CENTRAL HEARING LOSS and AUDITORY PERCEPTUAL DISORDERS.Auditory Pathways: NEURAL PATHWAYS and connections within the CENTRAL NERVOUS SYSTEM, beginning at the hair cells of the ORGAN OF CORTI, continuing along the eighth cranial nerve, and terminating at the AUDITORY CORTEX.Alzheimer Disease: A degenerative disease of the BRAIN characterized by the insidious onset of DEMENTIA. Impairment of MEMORY, judgment, attention span, and problem solving skills are followed by severe APRAXIAS and a global loss of cognitive abilities. The condition primarily occurs after age 60, and is marked pathologically by severe cortical atrophy and the triad of SENILE PLAQUES; NEUROFIBRILLARY TANGLES; and NEUROPIL THREADS. (From Adams et al., Principles of Neurology, 6th ed, pp1049-57)Hearing Loss, Bilateral: Partial hearing loss in both ears.Hearing: The ability or act of sensing and transducing ACOUSTIC STIMULATION to the CENTRAL NERVOUS SYSTEM. It is also called audition.Cognition Disorders: Disturbances in mental processes related to learning, thinking, reasoning, and judgment.Mild Cognitive Impairment: A prodromal phase of cognitive decline that may precede the emergence of ALZHEIMER DISEASE and other dementias. It may include impairment of cognition, such as impairments in language, visuospatial awareness, ATTENTION and MEMORY.Neuropsychological Tests: Tests designed to assess neurological function associated with certain behaviors. They are used in diagnosing brain dysfunction or damage and central nervous system disorders or injury.Cognition: Intellectual or mental process whereby an organism obtains knowledge.Medical History Taking: Acquiring information from a patient on past medical conditions and treatments.Hearing Loss, Noise-Induced: Hearing loss due to exposure to explosive loud noise or chronic exposure to sound level greater than 85 dB. The hearing loss is often in the frequency range 4000-6000 hertz.Anemia, Iron-Deficiency: Anemia characterized by decreased or absent iron stores, low serum iron concentration, low transferrin saturation, and low hemoglobin concentration or hematocrit value. The erythrocytes are hypochromic and microcytic and the iron binding capacity is increased.Iron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.Anemia, Hypochromic: Anemia characterized by a decrease in the ratio of the weight of hemoglobin to the volume of the erythrocyte, i.e., the mean corpuscular hemoglobin concentration is less than normal. The individual cells contain less hemoglobin than they could have under optimal conditions. Hypochromic anemia may be caused by iron deficiency from a low iron intake, diminished iron absorption, or excessive iron loss. It can also be caused by infections or other diseases, therapeutic drugs, lead poisoning, and other conditions. (Stedman, 25th ed; from Miale, Laboratory Medicine: Hematology, 6th ed, p393)Ferritins: Iron-containing proteins that are widely distributed in animals, plants, and microorganisms. Their major function is to store IRON in a nontoxic bioavailable form. Each ferritin molecule consists of ferric iron in a hollow protein shell (APOFERRITINS) made of 24 subunits of various sequences depending on the species and tissue types.Library Services: Services offered to the library user. They include reference and circulation.Libraries, MedicalHospitals, Voluntary: Private, not-for-profit hospitals that are autonomous, self-established, and self-supported.Patient Care Team: Care of patients by a multidisciplinary team usually organized under the leadership of a physician; each member of the team has specific responsibilities and the whole team contributes to the care of the patient.Hospitals, Proprietary: Hospitals owned and operated by a corporation or an individual that operate on a for-profit basis, also referred to as investor-owned hospitals.Accreditation: Certification as complying with a standard set by non-governmental organizations, applied for by institutions, programs, and facilities on a voluntary basis.Certification: Compliance with a set of standards defined by non-governmental organizations. Certification is applied for by individuals on a voluntary basis and represents a professional status when achieved, e.g., certification for a medical specialty.Noise: Any sound which is unwanted or interferes with HEARING other sounds.Noise, Occupational: Noise present in occupational, industrial, and factory situations.Personality Disorders: A major deviation from normal patterns of behavior.Workers' Compensation: Insurance coverage providing compensation and medical benefits to individuals because of work-connected injuries or disease.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.JapanSocial Work: The use of community resources, individual case work, or group work to promote the adaptive capacities of individuals in relation to their social and economic environments. It includes social service agencies.Hearing Disorders: Conditions that impair the transmission of auditory impulses and information from the level of the ear to the temporal cortices, including the sensorineural pathways.Diagnostic Errors: Incorrect diagnoses after clinical examination or technical diagnostic procedures.Deafness: A general term for the complete loss of the ability to hear from both ears.Spleen: An encapsulated lymphatic organ through which venous blood filters.Cellulitis: An acute, diffuse, and suppurative inflammation of loose connective tissue, particularly the deep subcutaneous tissues, and sometimes muscle, which is most commonly seen as a result of infection of a wound, ulcer, or other skin lesions.Fever: An abnormal elevation of body temperature, usually as a result of a pathologic process.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.