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Autism Research Glossary
- ADI-R, ADOS-G, Anecdotal
- Bias, Blind, Blood Brain Barrier, Broad Autism Phenotype
- CARS, Case, Case study, CHAT, Clinical trial, Cohort, Comorbid, Confounding variable or confound, Control group, Correlation, Cross-section, Crossover study or trial
- Deidentified data, Dependent variable, Descriptive study, Double-blind
- EEG, Endophenotype, Epidemiology, Etiology, Evidence-based, Experiment, Experimental or treatment group, Exploratory study
- Face validity
- Generalizable, Genome, Genotype
- Idiopathic, Incidence, Independent variable, Informed consent, Inherited trait
- Joint attention
- Knockout mouse
- Longitudinal study
- M-CHAT, Manipulation, Mean, MRI, Multiplex, Mutation
- N, n, NDAR, Neurotransmitter, Null hypothesis
- Observational study, Off-label, Open or Open label trial
- P value (P-value), Peer review process, Phenotype, Pilot study, Placebo, Placebo effect, Placebo-controlled, Prevalence
- Random sample, Randomized, Reliable, Representative sample
- S.P.E.C.T, Significance level or alpha, Simplex, Standard deviation, Susceptibility gene
- Type I error, Type II error, Typical peers
- Unstructured interview
- Variable, Vineland Adaptive Behavior Scales
- X chromosome
- Y chromosome
Autism Diagnostic Interview – Revised (Third Edition); a semi-structured interview for a clinician to use with a child’s parent. It focuses on the three key areas defining autism: (1) reciprocal social interaction; (2) communication and language; and (3) repetitive, stereotyped behaviors.
Autism Diagnostic Observation Schedule – Generic; a semi-structured assessment of communication, social interaction, and play for individuals suspected of having autism or another pervasive developmental disorder (PDD). It involves direct observation of a person’s behavior by an examiner who is taking careful note of traits and behaviors central to the diagnosis of autism.
Subjective and usually unpublished observations. Generally considered to be less reliable than objective, scientific studies.
A factor that can influence the results of a research study if not controlled.
When a participant is "blinded" in a research study, s/he does not know whether s/he is receiving the treatment or placebo (i.e., group assignment). See double-blind.
- Blood Brain Barrier
A semi-permeable membrane separating the brain and cerebrospinal fluid from the blood. It allows small and lipid soluble molecules to pass freely but is impermeable to large or ionized molecules and cells.
- Broad Autism Phenotype
Abbreviated BAP, this refers to the finding that relatives of people with autism often have mild autism-like characteristics including difficulty reading social cues, social anxiety, or obsessive-compulsive traits. The fact that autism-like features appear in members of the same family supports the notion that there is a genetic basis for autism.
Childhood Autism Rating Scale; a test which aids in evaluating a child’s body movements, adaptation to change, listening response, verbal communication, and relationship to people. The child’s behavior is rated on a scale based on deviation from the typical behavior of children of the same age.
Refers to one group under observation in a study or one instance of something occurring.
- Case study
A descriptive study that focuses on a single participant or a small group of participants. Case studies can generate a large amount of information about small groups of individuals; however, their conclusions should be understood and applied with caution because of the small sample size. With such small samples, the findings may not be applicable or generalizable to the rest of the population of interest.
Checklist for Autism in Toddlers; a brief screening tool that is intended to detect possible autism in toddlers. It provides a very basic, top-level determination of whether autism may be likely in a toddler. Often used by pediatricians at the 18-month check-up, it would indicate whether the child should go on for more intensive diagnostic evaluation
- Clinical trial
A research study involving human volunteers. The study is designed to answer specific questions concerning the effectiveness of a drug, treatment, or diagnostic method, or to improve patients’ quality of life.
A group of individuals identified by a common characteristic, which is studied over a period of time as part of a scientific investigation.
Two or more diseases or disorders, which although separate and unique, are occurring at the same time in the same person. For example, ADHD and autism are often comorbid conditions.
- Confounding variable or confound
– A variable that is not a focus of the study that is correlated with the independent variable such that as the independent variable changes, the confounding variable changes too. In an experiment, scientists attempt to eliminate all differences between the groups so that the only difference between them is the independent variable. When the independent variable (e.g. treatment or control group) is the only difference, any differences in the dependent variable (e.g., treatment response) are attributed to manipulation of the independent variable. However, if a confounding variable exists, it might be the cause of the differences not the independent variable. Confounds significantly affect the interpretation of a study’s results.
- Control group
Participants who do not receive the experimental treatment
– A mutual relationship or connection between two or more factors or variables. If two variables are correlated, the relationship alone is not sufficient to prove the variables are causally related (i.e., one causes the other).
A group of people who differ in age and/or other factors who provide information for the research study at the same point in time.
- Crossover study or trial
A type of clinical trial in which the study participants receive each treatment in a random sequence.
- Deidentified data
Data from which names and other identifying information have been stripped away
- Dependent variable
The outcome variable of interest
- Descriptive study
A study that describes a population or phenomenon
– In a double-blind study, the participant does not know whether s/he is receiving the treatment or placebo and neither do the researchers. See blind.
Electroencephalogram; a study of electrical current within the brain. Electrodes are attached to the scalp and wires attach these electrodes to a machine that records the electrical impulses.
An endophenotype identifies a trait that is found more often in individuals with a disorder than in the general population. Such a trait is commonly also found in relatives not affected by the disorder, making them potential genetic carriers. Examples of endophenotypes in autism include social deficits and repetitive behaviors.
The study of the distribution of diseases in populations and of factors that influence the occurrence of disease. Epidemiologists consider how many people have a condition, where they are located, and what genetic, geographic, and environmental factors they share.
The cause or origin of a disease or disabling condition.
Claim founded upon rigorous, valid research rather than upon hearsay, personal stories, etc. The gold standard for an "evidence-based" therapeutic intervention is the randomized, double-blind, placebo-controlled trial. In such a trial, selection of participants is "random" (such that there is not a distorted concentration of any one type of person included); the trial is double-blind (so neither participants nor researchers know which group of participants is receiving the "real" intervention and cannot bias the outcome); and placebo-controlled (which is required for a study to be double-blind because if you don’t give a "fake" treatment, the group not being treated will know it, as will the researchers.). A variation of this is when two treatments are compared, as opposed to a placebo ("fake") and a real treatment.
A research study in which the independent variables are manipulated and subjects are randomly assigned to different conditions.
- Experimental or treatment group
Participants who receive the experimental treatment or intervention.
- Exploratory study
A type of study design used to explore or gain insights into a population or phenomenon.
The extent to which a researcher is able to conclude with a certain degree of confidence that the findings of a study can be applied to other persons or situations.
The genetic material of an organism.
The class to which an organism belongs as determined by the description of the actual physical material made up of DNA that was passed to the organism by its parents at the organism’s conception. See Phenotype.
Describing a disease of unknown or uncertain cause
– The rate of occurrence of new cases of a particular disease in a population being studied. Compare to Prevalence.
- Independent variable
Factors that are explored in their influence on the dependent variable
- Informed consent
Consent to participation in a research study by a participant after achieving an understanding of what is involved. The informed consent process involves three key features: (1) disclosing to potential research subjects information needed to make an informed decision, including details about the study procedures and treatment, the associated risks and benefits, and the risks and benefits of any alternatives or of not undergoing the study procedures; (2) facilitating the understanding of what has been disclosed; and (3) promoting the voluntariness of the decision about whether or not to participate in the research. Informed consent must be legally effective and obtained prior to participation in any research activities. The prospective subjects should be in a position to freely decide whether to initially enroll in the research, or later, to withdraw or continue participating in the research. The informed consent process should ensure that all critical information about a study is completely disclosed, and that prospective subjects or their legally authorized representatives adequately understand the research so that they can make informed choices.
- Inherited trait
A genetic trait passed on from parent to child.
- Joint attention
The process by which an infant learns to recognize the direction of an adult’s gaze, orient their own gaze to follow it, and then look in the same direction.
- Knockout mouse
A knockout mouse is a laboratory mouse in which researchers have inactivated or "knocked out" an existing gene by replacing it or disrupting it with an artificial piece of DNA. The loss of gene activity often causes changes in a mouse’s phenotype, which includes appearance, behavior and other observable physical and biochemical characteristics.
Modified Checklist for Autism in Toddlers; a brief screening tool that parents fill in to detect possible autism in toddlers. It has been developed for screening children ages 16 months through 30 months old.
In an experiment, "manipulation" occurs when a researcher does something to one variable to see if it affects another variable.
The average value. This is typically seen as the average score of a group of participants on a particular test or average age of a group of participants.
Magnetic Resonance Imaging; a non-invasive procedure that uses powerful magnets and radio waves to construct pictures of the body.
A term used to refer to families that include more than one person with a certain disease or disorder. When autism researchers say they are studying multiplex families, they mean they are studying families that have more than one child with autism. See Simplex.
Any alteration in a gene from its natural state; may be disease causing or a benign, normal variant. Mutations can be caused by many factors, including the aging process, environmental toxins, and UV radiation from the sun.
Designates the entire sample size.
Designates the number of participants within a subgroup.
National Database for Autism Research – A computer system run by the National Institutes of Health containing information from many NIH-funded autism studies, allowing researchers investigating autism to share information with each other.
A chemical that is released from a nerve cell; these chemicals transmit impulses from a nerve cell to another nerve, muscle, organ, or other tissue. Irregular neurotransmitter activity is often involved in mental illness. Neurotransmitters include dopamine, serotonin, and norepinephrine.
- Null hypothesis
A null hypothesis is a statistical hypothesis that is tested for possible rejection under the assumption that it is true. The null hypothesis assumes that any difference or significance you see in a set of data is due to chance rather than a real effect. The hypothesis contrary to the null hypothesis, usually that the observations are the result of a real effect, is known as the alternative hypothesis.
- Observational study
A study in which the investigators do not seek to intervene, and simply observe the course of events.
Use of a drug for which the US Food and Drug Administration has not issued formal approval.
- Open or Open label trial
A clinical trial in which the investigators and participants are aware of which intervention is being used for which participant (i.e., the opposite of a blinded trial).
- P value (P-value)
The statistical probability of the occurence of a given finding by chance alone in comparison with the known distribution of possible findings, considering the kinds of data, the technique of analysis, and the number of observations. The P value may be noted as a decimal: P <.01 means that the likelihood that the phenomena tested occurred by chance alone is less than 1%. The lower the P value, the less likley the finding would occur by chance alone.
- Peer review process
Academic and scientific journals generally require that articles be submitted to a committee of one’s peers to review for scientific merit and accuracy before appearing in a journal.
Class to which an organism belongs as determined by the description of its physical and behavioral characteristics; in autism, this refers to the fact that the disorder is diagnosed based upon observable behavior rather than upon some biological marker or gene. See Genotype.
- Pilot study
A small preliminary study conducted to test the research plan and methodology.
A pretend treatment that participants believe is the real treatment.
- Placebo effect
Psychological benefit a participant experiences through the belief that s/he is receiving treatment.
Refers to a research study in which one group is receiving a new intervention and the other is receiving a placebo, such as a sugar pill. Ideally, people in the groups do not know if they are receiving the new intervention or not so that their hopes, fears, and expectations cannot bias the outcome. Results of such a study are more highly valued than results of a study where there was no placebo-controlled group.
The percentage of a population that is affected with a particular disease at a given time. Compare to Incidence.
A type research design in which subjects are not randomly assigned to treatment conditions, but manipulation of the independent variable does occur.
- Random sample
A sample selected in a way that ensures that every subject has an equal chance of being included. If a study or research project is not using a random sample, bias is introduced, which casts doubt on results.
Refers to an experimental design in which a researcher does not control who gets put in the group receiving a new treatment and who is placed in the group receiving a placebo or standard treatment (also called a "control group"). Participants are assigned to whichever group by chance in order to eliminate bias.
A test, instrument, or treatment is considered to be reliable if it produces similar results when tested at different times.
- Representative sample
A sample that includes the same proportion of every type of participant as a larger whole. An example would be if you are polling voters in a certain county and 35% of the county’s population is African-American, you will want 35% of those you poll to be African-American. If only 10% of those you poll are African-American, you will be under-representing that population. The results of your poll are therefore likely to be skewed and inaccurate. The same applies to scientific research.
Single Photon Emission Computed Tomography; imaging system that generates three-dimensional images of a person’s particular organ or body system. SPECT detects the course of a radioactive substance that is injected, ingested, or inhaled. In neurology, a SPECT scan is often used to visualize the brain’s cerebral blood flow and thereby, indicate metabolic activity patterns in the brain.
- Significance level or alpha
The probability that an observed relationship could be caused by chance. A significance level of .05 indicates that the observed relationship would be found by chance only 5 times out of 100 or 5% of the time.
A family with only one child with a certain disease or disorder. When autism researchers say they are looking only at simplex families, for example, they mean they want to study only families that have one child with autism rather than more than one. See Multiplex.
- Standard deviation
A measure of variability of data. The standard deviation is the average of the deviations from the mean.
- Susceptibility gene
A gene that predisposes a person to having a certain condition.
- Type I error
(alpha error) – Occurs when it is concluded that an observed difference between groups was not due to chance when in fact it was (i.e., a true null hypothesis is rejected).
- Type II error
(beta error) – Occurs when it is concluded that an observed difference between groups was due to chance when it fact it was due to the effects of the independent variable (i.e., a false null hypothesis is accepted).
- Typical peers
Refers to typically developing peers or peers without ASD.
- Unstructured interview
An interview in which the researcher asks open-ended questions. The researcher aims to give respondents the latitude to talk freely on a topic and to influence the direction of the interview. There is no predetermined plan about the specific information to be gathered from these types of interviews.
A characteristic, attribute, or outcome.
- Vineland Adaptive Behavior Scales
Measure designed to assess the personal and social self-sufficiency of individuals from birth to early adulthood.
Acronym for Wechsler Adult Intelligence Scale, a comprehensive test of cognitive ability for adults.
- X chromosome
The sex-determining chromosome in mammals and other animal species is known as X chromosome. The XX chromosome is a pair of 23 homologous pairs of chromosomes in a female.
- Y chromosome
The sex-determining chromosome in mammals and other animal species is known as X chromosome. The XY chromosome contains SRY gene that triggers the development of the embryo as a male.
Click here to recommend a research term.
University of Maryland Medical Center-Nursing Research Council. Glossary of research terms http://www.umm.edu/
Organization for Autism Research. Glossary of research terms http://www.
Research Autism. Glossary of terms on autism http://www.
Department of Psychology, Fresno State. Confounding variables http://psych.
US Department of Health and Human Services. http://answers.hhs.
“Genome.” Merriam-Webster.com. 2012. http://www.merriam-
“Informed consent.” Merriam-Webster.com. 2012. http://www.merriam-
Research Connections. Child care and early education glossary http://www.
Buzzle. Science – Glossary of science terms and scientific definitions http://www.buzzle.com/