Glossary of Research Terms


The following scientific definitions will help you in reading the tinnitus research-focused articles (Pages 10-30) in this issue of Tinnitus Today. Each word in the glossary, appears italicized the first time it appears on the page. If you come across a word that’s not listed that you still don’t understand, visit ATA.org/glossary for a more complete list of research terms and definitions.


Acoustic startle reflex: an audiological test where a loud, abrupt sound will result in a quick, usually observable movement by the patient.


Amplitude modulation: to change the strength or volume of an acoustic or electromagnetic signal, usually measured in decibels.


Amygdala: a limbic system structure involved in many of our emotions and motivations, particularly those that are related to survival.


Audiogram: a graphic representation of the relation of vibration frequency that shows the softest sounds a person can hear at different pitches or frequencies.


Auditory: of or relating to hearing, the organs of hearing or the sense of hearing.


Auditory cortex (AC): sensory area of the brain’s temporal lobe.


Binaural: of, relating to, or used with both ears. Perception of sound with both ears; transmission of sound from two sources.


Central lesion: any visible local abnormality of the tissues of the skin, such as a wound, sore, rash, or boil. In neurology the central indicates that it is on the brain or spinal cord (i.e. the central nervous system).


Clonazepam: benzodiazepine drug having anticonvulsant and muscle relaxant properties, works by decreasing abnormal electrical activity in the brain.


Cochlear implant: medical device that bypasses damaged structures in the inner ear and directly stimulates the auditory nerve, allowing some deaf individuals to learn to hear and interpret sounds and speech.


Cochlear nucleus: a collection of neurons in the brainstem divided, into the dorsal and ventral cochlear nucleus, that receive input from the cochlear nerve that carries sound information from the cochlea.


Cognitive behavioral therapy (CBT): attempts to solve emotional, behavioral or thought disorders through a psychotherapeutic approach and often used in combination with sound therapy for tinnitus.


Decibel (dB): Unit that measures the intensity or loudness of sound.


Electroencephalography (EEG): a test that measures and records electrical brain activity.


Funtional magnetic resonance imaging (fMRI): Unlike a standard MRI, which can only record the physical appearance of the brain, an fMRI records brain activity. An fMRI scan can show the region of the brain where there is a change in neural activity associated with an external event (e.g., sound) or internal process (e.g., tinnitus).


Frontal cortex: lobe of the brain that contains most of the dopamine-sensitive neurons in the cerebral cortex. The dopamine system is associated with reward, attention, short-term memory tasks, planning, and motivation.


GABAA receptor: An ionotropic receptor of gamma- aminobutyric acid (a neurotransmitter in the brain).


GABAergic: transmitting or secreting γ-aminobutyric acid, an inhibitory neurotransmitter in the brain that contributes to motor control, vision and other cortical functions; helps induce relaxation, sleep and balances the brain by inhibiting over-excitation.


Gap detection threshold: the ability for a patient to determine when there is a break (gap) in between two stimulus sounds. The threshold is the shortest amount of time between two sounds where a patient can distinguish the silence between the sounds.


Ginkgo biloba: a supplement derived from the Maidenhair tree that improves blood flow to the brain, cognition, and acts as an antioxidant.


Habituation: process by which repeated and harmless (auditory) stimulation leads to less and less perception of and reaction to tinnitus.


Heterodyning: to combine (a radio-frequency wave) with a locally generated wave of different frequency in order to produce a new frequency wave.


Kilohertz (kHz): one thousand hertz or one thousand cycles per second (sound processing). A unit of frequency equal to 1,000 hertz.


Magnetoencephalography (MEG): technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain.


Masking: sound source that interferes with the perception of another sound.


Microvascular decompression: a surgical procedure that relieves abnormal compression of a cranial nerve.


Nanoparticles: in nanotechnology, a particle that is between one and 100 nanometers that behaves as a whole unit in terms of its transport. This is an area of intense scientific interest due to a wide variety of potential applications in biomedical, optical and electronic fields.


Neural networks: biological neurons that are connected or functionally related in a nervous system that often perform a specific physiological function.


Neural correlate: any bodily component, such as an electro-neuro-biological state or the state assumed by some biophysical subsystem of the brain, whose presence necessarily and regularly correlates with such a specific content of experience.


Neuroimmunoendocrine: the ‘brain-skin’ connection. Refers to brain function and chemical expression.


Neuron: excitable cells in the nervous system that process and transmit information by electrochemical signaling.


Neuronal degeneration: progressive loss of structure or function of neurons including the death of neurons in the brain.


Neuroplasticity: changes in neural pathways and synapses which are due to changes in behavior, environment and neural processes, as well as changes resulting from bodily injury.


Neurostimulation: modulation of the nervous system to electrically activate neurons in the body.


Summer 2012 | Tinnitus Today 11


Neurotransmitters: chemicals in the brain which allow the transmission of signals from one neuron to the next across synapses.


Pathophysiology: the study of the changes of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from an abnormal syndrome.


Plasticity: the ability of the synapse (connection) between two neurons to change in strength.


Pure-tone thresholds: the measurement of an individual’s hearing sensitivity for calibrated pure tones.


Repetitive transcranial magnetic stimulation (rTMS): noninvasive method of treatment that sends focused magnetic pulses to stimulate targeted neurons in the brain.


Somatosensory: neural activity caused by activation of sensory receptors on the body (e.g., through touch, vibrations, movements of muscles). For some people, somasensory activity can cause the perception of tinnitus to change.


Statistically significant: when changes caused by a treatment are greater than the change that could be expected based on chance.


Synapse: a structure in the nervous system that permits a neuron to pass an electrical or chemical signal to another cell.


Temporal cortex: each of the paired lobes of the brain lying beneath the temples, including areas concerned with the understanding of speech.


Temporal processing: the rate at which auditory information is processed.


Temporoparietal cortex: a region of the brain known to be involved in speech perception.


Thalamus: a symmetrical structure within the brains, situated between the cerebral cortex and midbrain that relays sensory and motor signals to the cerebral cortex, along with the regulation of consciousness, sleep, and alertness.


Tonotopic map: the orderly projection of inputs originating from the cochlea to sensory areas in the brain, such that neighboring neurons in the target regions respond to progressively higher frequencies.


Vagus nerve: conveys sensory information about the state of the body’s organs to the central nervous system.


Vagus nerve stimulation (VNS): an implanted stimulator sends electric impulses to the left vagus nerve in the neck via a lead wire implanted under the skin and is currently being tested as a new treatment for tinnitus.


Visual analog scale (VAS): a measurement instrument used for subjective characteristics or attitudes that cannot be directly measured.


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