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Appendix D: Glossary and Acronym List


Term Definition

conducting toward the center; for neurons, conducting nerve impulses toward the spinal cord and brain



total or partial loss of the ability to use or understand language; usually caused by stroke, brain disease, or injury


apraxia of speech

a speech disorder, also known as verbal apraxia or dyspraxia, in which a person has trouble speaking because of inability to execute a voluntary movement despite normal muscle function


assistive technologies

products, devices, or equipment that help maintain, increase, or improve the functional capabilities of people with disabilities


auditory nerve

eighth cranial nerve that connects the inner ear to the brainstem and is responsible for hearing and balance


auditory system

the outer, middle, and inner ear, along with the neurons and brain regions involved in hearing


autism spectrum disorders

a spectrum of developmental disorders that begin in early childhood and persists throughout adulthood; autism spectrum disorders affect three crucial areas of development: communication, social interaction, and creative or imaginative play



communities of bacteria, such as the potentially antibiotic-resistant bacterial communities that are present in the middle ears of most children with chronic ear infections



a specific physical trait or a measurable biologically produced change in the body connected with a disease or health condition



the “feel” of a chemical; the term describes chemically provoked irritation


chemical senses

taste and smell



the organ of hearing


cochlear implant

a medical device that bypasses damaged structures in the inner ear and directly stimulates the auditory nerve, allowing some people who are deaf or hard of hearing to learn to hear and interpret sounds and speech



the existence of one or more co-occurring disorders in addition to a primary disorder



conducting away from the center; for neurons, conducting outward from the spinal cord and brain


embryonic stem cells

cells that are derived from the inner cell mass of blastocyst stage embryos, are capable of dividing without differentiating for a prolonged period in culture, and are known to develop into cells and tissues of the three primary germ layers



the branch of medical science that investigates all the factors that determine the presence or absence of diseases and disorders in a population



the study of heritable changes caused by the activation and deactivation of genes without any change in the underlying DNA sequence of the organism


eustachian tube

a small passageway that connects the upper part of the throat to the middle ear; its job is to supply fresh air to the middle ear, drain fluid, and keep air pressure at a steady level between the nose and the ear


gene expression

the process by which the information encoded in a gene is used to direct the assembly of a protein molecule; different subsets of genes are expressed in different cell types or under different conditions



the study of particular genes, DNA, and heredity



the study of the genome (the entire genetic makeup) of an organism


hair cells

sensory cells of the inner ear, which are topped with hair-like structures (stereocilia) and which transform the mechanical energy of sound waves into nerve impulses


hearing aid

an electronic device that brings amplified sound to the ear; it usually consists of a microphone, amplifier, and receiver



relating to a disease or disorder that arises spontaneously or without a known cause


inner ear

part of the ear that contains both the organ of hearing (the cochlea) and the organ of balance (the labyrinth)



an organism that has been genetically engineered to lack one or more specific genes; scientists study knockout organisms to determine the impact of the missing gene, which helps determine its the function



valve structure between the trachea (windpipe) and the pharynx (the upper throat) that is the primary organ of voice production


model organism

animal species used in medical research to mimic aspects of a disease found in humans



a change in a DNA sequence that can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemical mutagens, or infection by viruses


neural prostheses

devices such as the cochlear implant that substitute for an injured or diseased part of the nervous system



the relatively unspecialized nerve cell endings that initiate the sensation of pain



the sense of smell; to perceive odor or scent through stimuli affecting the olfactory nerves


otitis media

inflammation of the middle ear caused by infection



a drug or compound such as a special class of antibiotics, aminoglycoside antibiotics, that can damage the hearing and balance organs located in the inner ear for some individuals



the development of a disease or condition, particularly the cellular and molecular origins and causes of disease development



an individual’s physical and behavioral characteristics



chemical substance secreted by an animal that elicits a specific behavioral or physiological response in another animal of the same species



one of two or more variants of a particular DNA sequence that can correlate with disease, drug response, and other phenotypes; the most common type of polymorphism involves variation at a single base pair (single nucleotide polymorphism) of DNA



the study of sound perception



inflammation of the mucous membranes of the nose, generally accompanied by discharge (runny nose) and usually caused by a virus infection (e.g., the common cold) or by an allergic reaction (e.g., hay fever)



inflammation or infection of one of the air-filled nasal sinuses


spasmodic dysphonia

momentary disruption of voice caused by involuntary movements of one or more muscles of the larynx


spiral ganglion

the group of nerve cells that serve the sense of hearing by sending a representation of sound from the cochlea to the brain; the cell bodies of the spiral ganglion neurons are found in the spiral structure of the cochlea



see “hair cells”


stria vascularis

specialized epithelium lining the cochlear duct that maintains the ion homeostasis of the fluid within the cochlea



a speech disorder in which sounds, syllables, or words are repeated or prolonged, disrupting the normal flow of speech



a junction between two nerve cells



sensation of a ringing, roaring, or buzzing sound in the ears or head when no actual sound stimulus is present in the environment



the spatial arrangement of where sounds of different frequency are processed in the brain. For example, the auditory nerves that carry signals from adjacent portions of the cochlea project their information to adjacent portions of the auditory cortex



the process by which stimuli in the environment are converted into electrical (neural) signals by sensory receptors



illusion of movement; a sensation as if the external world were revolving around an individual (objective vertigo) or as if the individual were revolving in space (subjective vertigo)


vestibular system system in the body that is responsible for maintaining balance, posture, and the body’s orientation in space; this system also regulates locomotion and other movements and keeps objects in visual focus as the body moves


Acronymn List

Acronymn Definition
ACC Autism Coordinating Committee
ARRA American Recovery and Reinvestment Act
ASD Autism Spectrum Disorder
DEA Division of Extramural Activities
DIR Division of Intramural Research
DNA Deoxyribonucleic Acid
DSP Division of Scientific Programs
EHDI Early Hearing Detection and Intervention
FY Fiscal Year
HHS Department of Health and Human Services
HPP High Program Priority
IACC Interagency Autism Coordinating Committee
ICOs Institutes, Centers, and Offices
M.D. Doctor of Medicine
NDCD National Deafness and Other Communication Disorders
NF2 Neurofibromatosis 2
NICHD Eunice Kennedy Shriver National Institute of Child Health and Human Development
NIDCD National Institute on Deafness and Other Communication Disorders
NIH National Institutes of Health
Ph.D. Doctor of Philosophy
Plan NIDCD Strategic Plan
SLI Specific Language Impairment
SPPB Science Policy and Planning Branch
T2R Type 2 Taste Receptors

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Last Updated Date: 
January 27, 2017