Glossary of Terms

Pervasive Developmental Disorder(PDD): Characterized by severe and pervasive impairment in several areas of development: reciprocal social interaction skills, communication skills, or the presence of stereotyped behavior, interests and activities. The qualitative impairments that define these conditions are distinctively deviant relative to the individuals' developmental level or mental age. These disorders consist of Autistic Disorder, Rett Syndrome, Childhood Disintegrative Disorder, Asperger Syndrome, and Pervasive Developmental Disorder Not Otherwise Specified.

Autistic Disorder: The essential features of Autistic Disorder are the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interests. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual. Three criteria are used to assess the autistic phenotype. These include the ADI (Autism Diagnostic Interview), the ADOS (Autism Diagnostic Observational Schedule-Generic), and the DSM IV Diagnostic Criteria for 299.00 Autistic Disorder (Diagnostic and Statistical Manual of Mental Disorder, Fourth edition, American Psychiatric Association, Washington, D.C., 1994). A representative Autistic Diagnostic Criteria Score Sheet used to collect data on the donor subjects is provided. Briefly, the criteria include the following:


  1. Qualitative impairment in social interactions.
  2. Qualitative impairment in communication.
  3. Restricted, repetitive, and stereotyped patterns of behavior, interests, and activities.
B) Delays or abnormal functioning in at least one of the following areas with onset prior to age 3 years:
  1. Social interaction,
  2. language as used in social communication, or
  3. symbolic or imaginative play.
C) The disturbance is not better accounted for by Rett Syndrome or Childhood Disintegrative Disorder

ADI: Autism Diagnostic Interview - Revised (Third Edition): The ADI is an investigator-based interview. The main purpose of this interview administered to the subject's principal caregiver is to obtain detailed descriptions of those behaviors that are necessary for the differential diagnosis of pervasive developmental disorders (PDD) and especially for the diagnosis of infantile autism. The interview focuses primarily on the key diagnostic characteristics specified in ICD-10 (International Classification of Disease, Tenth edition, Geneva, 1993), mainly those features concerned with developmental delays and deviance in reciprocal social interactions, language, communication and play, and on restricted, repetitive, and stereotyped behaviors and interests. Based on the interview the subject will be found to meet the cutoff for autism in the above three domains. Lord, C., Rutter, M., Le Couteur, A. Autism Diagnotic Interview-Revised: a revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. J. Autism Dev. Disord. 24: 659-85, 1994.

ADOS-G: Autism Diagnostic Observational Schedule - Generic: The ADOS-G is a semi-structured assessment of communication, social interaction, and pervasive developmental disorders (PDD). The ADOS-G consists of standard activities that allow the examiner to observe the occurrence or non-occurrence of behaviors that have been identified as important to the diagnosis of autism and other pervasive developmental disorders across developmental levels and chronological ages. The ADOS provides data from direct observation of the subject's behavior. Based on the individual's behavior, the subject will be found to meet either the cutoff for Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS) or the cutoff for Autism.

ModuleBehaviorAge level
1preverbal-single words 
3fluent speechchild/adolescent
4fluent speechadolescent/adult
Lord, C., Rutter, M., Goode, S., Heemsbergen, J., Jordan, H., Mawhood, L., Schopler, E. Autism diagnostic observation schedule: a standardized observation of communicative and social behavior. J. Autism Dev. Disord. 19: 185-212, 1989.

Asperger Syndrome: The essential features according to the DSM IV Diagnostic Criteria for 299.80 Asperger Syndrome (Diagnostic and Statistical Manual of Mental Disorder, Fourth edition, American Psychological Association, Washington, D.C., 1994) are:
A) Severe and sustained impairment in social interaction
B) The development of restricted repetitive patterns of behavior, interests and activities.
C) The disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning.
D) There is no clinically significant impairment in general delay in language.
E) There is no clinically significant delay in cognitive development or in the development of age appropriate self-help skills, adaptive behaviors.
F) Criteria are not met for another specific Pervasive Developmental Disorder or Schizophrenia.

Pervasive Developmental Disorder-Not Otherwise Specified: PDD-NOS: According to the DSM IV criteria for 299.80 Pervasive Developmental Disorder-Not Otherwise specified (including atypical autism), this category should be used when there is a severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present, but the critera are not met for a specific Pervasive Developmental Disorder, Schizophrenia, Schizotypal Personality Disorder or Avoidant Personality Disorder.

Atypical Features of Behavior: Mild degree of impairment is social interactions but does not meet criteria for a Pervasive Developmental Disorder.

Other Diagnostics

Apgar score: An assessment tool used at 1 and 5 minutes after delivery to assess an infant. The score consists of five (5) objective signs: heart rate, respiratory rate, muscle tone, response to catheter in nostril and color. For each of the five signs scores range from 0 to 2 with the highest total score being 10. The score is taken at one minute as an index of asphyxia and of the need for assisted ventilation; the five minute score is a more accurate index of likelihood of death.

Peabody Picture Vocabulary Test: A standardized test to assess receptive language skills. Scores are stated as a standardized score with an average score being 100. Peabody Picture Vocabulary Test, Third Edition. L. Dunn and L. Dunn, American Guidance Service, Minnesota, 1997.

Physical measurements/percentiles: Percentile values read from : Hamill et al: Physical growth: National Center for Health Statistics percentiles. Amer. J. Clin. Nutr. 32: 607-629, 1979, adapted by the National Center for Health Statistics (NCHS), Hyattsville, Maryland.

Raven Progressive Matrices: A standardized test to measure the ability to "draw out" or deduce relationships (which largely assesses non-verbal abilities). Scores are given as a percentage compared to a similar score among people of the same age. Colored Progressive Matrices, J. Raven, J.C. Raven and J.H. Court, Oxford Psychologists Press, 1998.

Wood's Lamp: Ultraviolet lamp used to identify neurocutaneous stigmata.