[ Browse by Service Category : Topics Related to Acoustic Neuroma (1) ]
Tinnitus
A condition in which there the perception of sound in one or both ears or in the head when no external sound is present. It is often referred to as "ringing in the ears", although some people hear hissing, roaring, whistling, chirping, or clicking. Tinnitus can be intermittent or constant, with single or multiple tones, and its perceived volume can range from subtle to shattering. Causes may include noise-induced hearing loss, wax build-up in the ear canal, ear or sinus infections, jaw misalignment, cardiovascular disease, head or neck trauma, certain types of tumours, a side effect of some medications or as a symptom of disorders such as hypothyroidism, hyperthyroidism, lyme disease and fibromyalgia.
Hearing Loss
A disruption in the normal hearing process that may occur in the outer, middle, or inner ear, which prevents sound waves from being converted to electrical signals and nerve impulses from being transmitted to the brain to be interpreted. Included are conductive hearing loss that results from abnormalities of the external ear and/or the ossicles of the middle ear; sensorineural hearing loss that results from malfunction of inner ear structures (i.e., cochlea); and central auditory dysfunction that results from damage or dysfunction at the level of the eighth cranial nerve, auditory brain stem, or cerebral cortex. Hearing loss may be present at birth (congenital) or become evident later in life (acquired); and may or may not preclude the normal development of language. The severity of hearing loss is measured in decibles (dB). The threshold or 0 dB mark for each frequency refers to the level at which typical young adults perceive a tone burst 50% of the time. Hearing is considered normal if an individual's thresholds are within 15 dB of normal thresholds. Severity of hearing loss is graded as mild (26-40 dB), moderate (41-55 dB), moderately severe (56-70 dB), severe (71-90 dB) and profound (90 dB).
The above terms and definitions are part of the Taxonomy of Human Services, used here by permission of INFO LINE of Los Angeles.