Glossary of Acoustic Neuroma Related Terms



Audiogram A chart of hearing acuity recorded during hearing test.
Audiologist A medical professional who assesses and manages hearing and balance related disorders.
Audiovestibular Specialist A medical professional specializing in the diagnosis and treatment of hearing, balance and communication problems, including tinnitus.
Auditory Brainstem Implant (ABI) A type of hearing device that bypasses the cochlea in the middle ear and the auditory nerve and is implanted in the brainstem. The ABI does not require the presence of the cochlear nerve or blood supply.
Benign Not malignant, non-cancerous. Does not invade surrounding tissue or spread to other parts of the body.
Bilateral Pertaining to both sides of the body.
Bone Anchored Hearing Aid (Baha) A hearing device for persons who are single-side deaf which works through bone conduction with a sound processor attached to a small titanium implant. The sound processor is placed on the deaf side, behind the ear and sound is transferred through the bone of the skull, stimulating the cochlea in the hearing ear. The brain is then able to distinguish between the sounds that it receives from the deaf side via the Baha system, from the sound that it receives directly from the hearing ear. This ultimately results in the sensation of hearing from the deaf side. The name Baha is a registered trademark of Cochlear Americas.
Brainstem Connects the upper brain to the spinal cord - less than three inches (7.6 cm) long. The pons is one part of the brainstem which may be compressed by acoustic neuromas.
British Acoustic Neuroma Association The British Acoustic Neuroma Association (BANA) is an international, registered charity organisation in the United Kingdom, that is dedicated to promoting the exchange of mutual support and information among individuals affected by acoustic neuromas, with similar purposes to ANA.
Centimeter (cm) 0.394 inch (2.54 cm equals one inch) - Ten millimeters equal one centimeter.
Cerebellopontine Angle Space bounded by the petrous bone, brainstem, and cerebellum, and through which cranial nerves six (VI), seven (VII), eight (VIII), nine (IX), ten (X) and eleven (XI) pass.
Cerebellum Located behind the brainstem, extending from the brainstem out toward each mastoid bone. It carries 11% of the brain's weight and controls muscular coordination.
Cerebrospinal Fluid (CSF) A watery fluid, continuously being produced and absorbed, which flows in the ventricles (cavities) within the brain and around the surface of the brain and spinal cord.
Cochlear Implants Cochlear implants are indicated when the patient has significant hearing loss in both ears. In addition, the ear to be implanted must still have the cochlear nerve and blood supply intact. Unfortunately, this is often not the case in patients with acoustic neuromas because of the size of the tumour or treatment with radiation and/or surgery. However, some patients after tumour removal have some remaining hearing, and then they lose hearing in the other ear.
It is a small complex electronic device that is implanted within the inner ear to increase hearing capabilities. Whereas hearing aids amplify sound, cochlear implants compensate for damaged or non-working parts of the inner ear. A cochlear implant electronically finds useful sounds and then sends them to the brain.
Cochlear Nerve A branch of the auditory nerve that arises in the spiral ganglion of the cochlea and conducts sensory stimuli from the organ of hearing to the brain.
Computerized Tomography (CT Scan) A special x-ray test which creates a cross-sectional picture of any part of the body. This x-ray can distinguish among tissue, fluid, fat and bone, and after intravenous injection of a dye, will show an acoustic neuroma unless the tumour is very small.
Cranial Nerves The cranial nerves control the sensory and muscle functions around the eyes, face and throat. There are two sets each of twelve cranial nerves. Each set involves one side of the body.
CROS Hearing Aid Contralateral Routing of Sound - A CROS aid is used with single-sided deafness. It receives sound on the deaf side, amplifies it, and carries it to the good ear.
Cyberknife (CK) A robotic radiosurgery system that delivers multiple beams of radiation, used to treat benign tumours, cancers and other medical conditions located anywhere in the body. It consists of a linear accelerator and a robotic arm, delivered in multiple sessions.
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Ear, Nose and Throat Physician (ENT) A physician specializing in the diagnosis and treatment of diseases of the head and neck, especially those involving the ears, nose and throat (ENT). Also called an Otolaryngologist.
Electronystagmogram (ENG) A recording of the eye movements, usually done to confirm the presence of involuntary eye movements but can also be done in cases of vertigo to determine if there is damage to the vestibular portion of the acoustic nerve or in cases of possible acoustic neuroma.
Fractionated Stereotactic Radiation Fractionated stereotactic radiation refers to any focused radiation treatment that requires more than one treatment delivery session. Several different dosing schedules are available.
Gadolinium A contrast material given at the time of MRI which concentrates in the tumour and makes it more visible.
Gamma Knife (GK) The Gamma Knife is a radiosurgical machine that contains 195-201 separate radioactive cobalt sources. The radiation beams from each source (gamma rays) are focused together at the tumour.
Hydrocephalus A condition in which the primary characteristic is excessive accumulation of cerebrospinal fluid (CSF) in the brain. This excessive fluid can cause expansion of the cerebral ventricles, enlargement of the skull and especially the forehead, and atrophy of the brain.
Internal Auditory Canal A short auditory canal in the petrous portion of the temporal bone, part of the base of the skull that extends from the ear toward the center of the head, through which pass the vestibulocochlear and facial nerves.
Intracranial Pressure Pressure within the skull that can be caused by acoustic neuroma growth.
LINAC Linear accelerator is a radiosurgical machine that produces radiation electronically. These radiation beams are called X-rays. LINACs are also commonly used for conventional radiation treatment of tumours elsewhere in the body.
Magnetic Resonance Imaging (MRI) A body imaging system employing a magnet which surrounds the patient. A magnetic field causes small harmless movement of the atoms in the area of the body being studied. A low energy radio wave is then passed through the same area and the small change this imparts to the atoms in the magnetic field causes signals to be emitted which are picked up and analyzed by modern computer technology. An image of the tissue is produced in clear detail. Copies of MRI's are available to patients.
Middle Fossa A surgical approach to an acoustic neuroma primarily used for the purpose of hearing preservation.
Millimeter (mm) A metric unit of measure, 10 mm = 1 cm.
Neurofibromatosis Type II (NF2) A genetic, familial condition. The hallmark of this disorder is bilateral acoustic neuromas (an acoustic neuroma on both sides).
Neurological Having to do with the nerves or the nervous system.
Neurosurgeon A physician with a surgical specialty concerned with the treatment of diseases and disorders of the brain, spinal cord and peripheral and sympathetic nervous system.
Neurotologist A physician specializing in the neurological aspects of the auditory and vestibular apparatus.
Otolaryngologist A physician that specializes in the diagnosis and treatment (including surgery) of head and neck disorders, especially those involving the ear, nose and throat (ENT).
Otologist An ENT physician that specializes in the diagnosis and treatment of ear disorders only.
Parathyroid Adenoma A benign tumour found in proximity to the thyroid gland controlling calcium metabolism.
Peacock Radiation The Peacock device is an attachment to the LINAC radiosurgery system that allows complex radiation beam shapes to be generated.
Pons Located at the base of the brain in front of the cerebellum. This section of the cranium is a mass of nerve tissue which coordinates the activities of the various lobes of the brain.
Porus The opening of the internal auditory canal, through which pass the vestibulocochlear and facial nerves.
Posterior Fossa The cavity in the back part of the skull which contains the cerebellum, brainstem and cranial nerves 5-12
Proton Radiation Proton radiation differs from the photon radiation produced by both the Gamma Knife and LINAC systems. Proton beams have a unique physical property that allows them to be sharply focused within a tumour. They are theoretically advantageous for radiosurgery treatment.
Radiotherapy (RT) Typically radiation treatment delivered over an extended period of time with multiple doses.
Retrosigmoid / Suboccipital A surgical approach to an acoustic neuroma creating an opening in the cranium behind the mastoid part of the ear.
Sensorineural Hearing Loss (SHL) Deafness caused by failure of the acoustic nerve.
Shunt A tube implanted in the cranium to balance the flow of cerebrospinal fluid and used in the treatment of hydrocephalus.
Stereotactic Radiosurgery A technique based on the principle that a single or fractionated dose of radiation delivered precisely to a small area will arrest or kill the tumour, while minimizing injury to surrounding nerves and brain tissue and/or function. Typically this is performed in a single session.
Sub-totally Somewhat less than complete; nearly total.
Sudden Sensorineural Hearing Loss (SSHL) A rapid loss of hearing that can happen all at once or over a period of time up to 3 days. It should be considered a medical emergency and anyone experiencing SSHL should visit a doctor immediately.
Suppressor Gene A protective gene that normally limits the growth of tumours. When a tumour suppressor gene is mutated (altered), it may fail to keep a tumour from growing.
Translabyrinthine A surgical approach to an acoustic neuroma through the mastoid bone and inner ear (labyrinthine).
Trigeminal Nerve The trigeminal nerve functions both as the chief nerve of sensation for the face and the motor nerve controlling the muscles of mastication (chewing). Also known as the fifth cranial nerve.
Unilateral Involving only one side.
Unilateral Sporadic Tumours Non-hereditary tumours occurring on only one side.
Vertigo Dizziness, a symptom sometimes caused by an acoustic neuroma.
Vestibular Associated with the balance system.
Vestibular schwannoma Another term used for acoustic neuroma. A slow-growing tumour that starts in the Schwann cells (fatty cells) on the outside of the 8th cranial nerve and is caused by an overproduction of Schwann cells.