Central Nervous System Abnormalities Associated with Fetal
Alcohol Syndrome (FAS)
Central nervous system (CNS) abnormalities are classified as structural, neurologic, or functional.
- Documented evidence exists of small or diminished overall head circumference (also known as occipito-frontal circumference [OFC]) (i.e.,
<10th percentile), adjusted for age and sex (including head circumference at birth;
(1,2). For children who have overall growth deficiency (i.e., height and weight <10th percentile) to meet this criteria for
CNS abnormality, the child's head circumference should be disproportionately small to the child's overall size (i.e., OFC at
or below the third percentile).
- Clinically significant brain abnormalities are observable through imaging techniques (e.g. reduction in size or change
in shape of the corpus callosum, cerebellum, or basal ganglia), as assessed by an appropriately trained professional
(1,3--10). A child could have a structural abnormality
that would be consistent with a diagnosis of fetal alcohol syndrome
(FAS) but not demonstrate detectable functional deficits.
- Documented evidence exists of CNS neurologic damage. Neurologic problems can include seizures not attributable to
a postnatal insult or fever or other soft neurologic signs outside normal limits (e.g., coordination problems, visual
motor difficulties, nystagmus, or difficulty with motor control)
(11--14). As with head circumference, abnormal
neurologic findings among younger children can be most predictive of underlying CNS abnormality resulting from prenatal
alcohol exposure rather than later environmental factors. Use of norm-referenced measures of neurologic functioning
- Assessment findings indicate deficits, problems, or
abnormalities in functional CNS skills. Early brain damage is
usually generalized rather than specific, with increased
specificity of abnormalities revealed as development progresses.
Functional abilities affected by prenatal exposure to alcohol vary from person to person, depending on the amount, timing,
and pattern of alcohol exposure (e.g., chronic exposure versus binge episodes).
Despite this inherent variation in effects, areas of functional vulnerability have been observed consistently by clinicians and researchers with particular damage
to corresponding structures reported (e.g., corpus callosum, cerebellum, or basal ganglia).
For functional deficits, multiple locations in the brain (and corresponding functional capability) are generally accepted
to be affected by prenatal exposure to alcohol. Functional deficits consistent with CNS abnormality criteria can be identified
in two ways: 1) global cognitive deficit (e.g., decreased IQ) or substantial developmental delay in children too young for an
IQ assessment or 2) deficits in three or more specific functional domains. These two ways of assessing functional
CNS abnormality were adopted because of the composite nature of cognitive, intellectual, and developmental measures
(15,16). Decreased performance on a standardized measure of cognition, intelligence, and development assumes deficits in
multiple domains. In the absence of such a measure, multiple domains should be assessed individually to determine that
multiple functional domains have been affected. For each domain, other agents and environmental factors can produce deficits
or outcomes similar to prenatal alcohol exposure, making differential diagnosis essential.
The specific domains most often cited as areas of deficit or concern for persons with FAS are described below.
These descriptions are intended to be suggestive and are examples of likely and possible problems a clinician might encounter
and need to assess by using psychometric instruments. The examples are not intended to be exhaustive or to present a list
of behaviors to be used as a checklist without reliable and valid assessment.
- Cognitive deficits or significant developmental discrepancies.
Global deficits or delays can leave the child scoring
in the normal range of development but below what would be expected for the child's environment and background
22). In addition to formal testing (either through records or current testing), behaviors that might be observed
or reported in the clinical setting that suggest cognitive deficits or developmental delays that should be assessed
by standardized testing include but are not limited to specific learning disabilities (especially mathematic or
visual-spatial deficits), uneven profile of cognitive skills, low academic achievement, discrepancy between verbal and nonverbal
skills, and slowed movements or reaction to persons and stimuli (e.g., difficulty in processing information)
- Executive functioning deficits.
Executive functioning (EF) is defined as the ability to maintain an appropriate
problem solving set for attainment of a future goal. This ability includes the more specific skills of inhibition, planning,
and mental representation (28). Behaviors that can be observed or reported in the clinical setting that might indicate an
EF deficit that should be assessed by standardized testing include but are not limited to inadequate organization,
planning, or strategy use; concrete thinking; lack of inhibition; difficulty grasping cause and
effect; inability to delay gratification; difficulty following multistep directions; difficulty changing strategies or thinking of things in a different way
(i.e., perseveration); impaired judgment; and inability to apply knowledge to new situations
- Motor functioning delays or deficits.
Both gross and fine motor skills can be impaired for persons with FAS
(34,35). Visual-motor/visual-spatial coordination is a particularly vulnerable area of functioning
(22,36--38). Behaviors that can be observed or reported in the clinical setting that indicate motor problems that should be
assessed by standardized testing include but are not limited to delayed motor milestones, difficulty with writing or drawing, clumsiness,
balance problems, tremors, and poor dexterity. For infants, a poor suck is often observed
- Attention and hyperactivity problems.
Attention problems are often noted for children with FAS, with
children frequently receiving a diagnosis of attention-deficit
hyperactivity disorder (ADHD) (41). Although such a diagnosis
can be applied, attention problems for children with FAS do not appear to be consistent with the classic pattern of
ADHD. Persons with FAS tend to have difficulty with the encoding of information and flexibility (shifting) aspects of
attention, whereas children with ADHD typically display problems with focus and sustaining attention
(42,43). Persons with FAS also can appear to display hyperactivity because their impulsivity might lead to increased activity levels. Behaviors
that might be observed or reported in the clinical setting that suggest attention problems related to FAS that should be
assessed by standardized testing include but are not limited to
being described by adults as "busy," inattentive, easily
distracted, difficulty calming down, being overly active, difficulty completing tasks, and/or trouble with transitions. Parents
might report inconsistency in attention from day to day (e.g., "on" days and "off" days)
- Social skills problems. The executive, attention, and
developmental problems described previously often lead
to clinically significant difficulty for persons with FAS when interacting with peers and others. Because of the
mental representation problems, persons with FAS often have social perception or social communication problems that make
it difficult for them to grasp the more subtle aspects of human interactions
(51,52). Consistent difficulty understanding
the consequence of behavior or inappropriate behavior frequently is described for persons with FAS
(53,54). Behaviors that can be observed or reported in the clinical setting that indicate these types of social difficulties that should be assessed
by standardized testing include but are not limited to lack of fear of strangers, naiveté and gullibility, being taken
advantage of easily, inappropriate choice of friends, preferring younger friends, immaturity, superficial interactions, adaptive
skills significantly below cognitive potential, inappropriate sexual behaviors, difficulty understanding the perspective of
others, poor social cognition, and clinically significant inappropriate initiations or interactions
(55--57). Standardized assessment of social
problems can be difficult; social functioning is a multifaceted domain that can require multiple areas
- Other potential domains that can be affected.
In addition to these five most-often-cited problem areas, deficits
and problems to be assessed by standardized testing can present in several other areas, including sensory problems (e.g.,
tactile defensiveness and oral sensitivity), pragmatic language problems (e.g., difficulty reading facial expression, and
poor ability to understand the perspectives of others), memory deficits (e.g., forgetting well-learned material, and
needing many trials to remember), and difficulty responding appropriately to common parenting practices (e.g.,
not understanding cause-and-effect discipline). Although abnormalities in these areas have been reported for persons
with FAS, deficits in these areas are reported at a lower frequency than are those in the other five specific domains
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National Task Force on Fetal Alcohol Syndrome and Fetal Alcohol Effect
Membership List, as of July 2004
Kristen L. Barry, PhD, Department of Veterans Affairs, Ann Arbor, Michigan; James E. Berner, MD, Alaska Native Tribal Health Consortium,
Anchorage, Alaska; Raul Caetano, MD, PhD, University of Texas School of Public Health, Dallas, Texas; Faye B. Calhoun, DPA, National Institute on Alcohol
Abuse and Alcoholism, Bethesda Maryland; Michael E. Charness, MD, Harvard Medical School, Cambridge, Massachusetts; Deborah E. Cohen, PhD,
New Jersey Office for Prevention of Mental Retardation and Developmental Disabilities, Trenton, New Jersey; Claire D. Coles, PhD, Marcus Institute,
Atlanta, Georgia; Chris Cunniff, MD, University of Arizona,Tucson, Arizona; Karla Damus, PhD, March of Dimes, White Plains, New York; Nancy L. Day,
PhD, University of Pittsburgh, Pittsburgh, Pennsylvania; Jocie C. Devries, FAS Family Resource Institute, Lynnwood, Washington; Mark B. Mengel, MD,
St. Louis University School of Medicine, St. Louis, Missouri; Lisa Miller, MD, Colorado Responds to Children with Special Needs, Denver,
Colorado; Kathleen T, Mitchell, MHS, LCADC, National Organization on Fetal Alcohol Syndrome, Washington, DC; Raquelle Myers, JD, National Indian
Justice Center, Santa Rosa, California; Edward Riley, PhD, San Diego State University, San Diego, California; Luther K. Robinson, MD, State University of
New York Buffalo School of Medicine, Buffalo, New York; Charles M. Schad, EdD, University of South Dakota, Spearfish, South Dakota; Robert J.
Sokol, MD, Wayne State University, Detroit, Michigan; Daniel C. Vinson, MD, University of Missouri, Columbia, Missouri; Jean A. Wright, MD,
Backus Children's Hospital, Savannah, Georgia; José Cordero, MD, Louise Floyd, DSN, National Center on Birth Defects and Developmental Disabilities, CDC.
Scientific Advisory Panel
Membership List, as of July 2004
Herb Bischoff, PhD, Project Alaska, Anchorage, Alaska; Julia M. Bledsoe, MD, University of Washington, Seattle, Washington; Larry Burd, PhD,
North Dakota Fetal Alcohol Syndrome Center, Grand Forks, North Dakota; Tom Donaldson, National Organization on Fetal Alcohol Syndrome,
Washington, DC; Daniel Dubovsky, MSW, Fetal Alcohol Syndrome Center for Excellence, Rockville, Maryland; Sheila Gahagan, MD, University of Michigan,
Ann Arbor, Michigan; Marian Kummer, MD, National Committee of Children with Disabilities, Billings, Montana; Carole M. Lannon, MD,
Initiative for Children's Healthcare Quality, Boston, Massachusetts; Theresa Maresca, MD, University of Washington, Seattle, Washington;
Sarah McGovern, National Initiative for Children's Healthcare Quality, Boston, Massachusetts; Uday C. Mehta, MD, University of Medicine and Dentistry
of New Jersey-Robert Woods Johnson Medical School, Mountainside, New Jersey; Colleen A. Morris, MD, University of Nevada School of Medicine,
Las Vegas, Nevada; Rick L. Olson, MD, Greenwood Genetic Center, Greenwood, South Carolina; Natalie E. Roche, MD, New Jersey Medical
School, Newark, New Jersey; Thomas F. Tonninges, MD, American Academy of Pediatrics, Elk Grove Village, Illinois; Martha Alexander, MPH, Hani K.
Atrash, MD, Jacquelyn Bertrand, PhD, Carol Cabal, PhD, José Cordero, MD, Yvette Dominique, Larry Edmonds, MSPH, Paul Fernoff, MD, R Louise
Floyd, DSN, Connie Granoff, Melissa Hogan, Karen Hymbaugh, MPH, Cynthia Moore, MD, PhD, Elizabeth Parra, MPH, Jorge Rosenthal, PhD,
Tanya Sharpe, PhD, Jasjeet Sidhu, MD, Mary K. Weber, MPH, Marshalyn Yeargin-Allsopp, MD, National Center on Birth Defects and
Developmental Disabilities, CDC.
Scientific Working Group
Susan J. Astley, PhD, Heather Carmichael Olson, PhD, University of Washington, Seattle, Washington; Jocelynn L. Cook, PhD, Health Canada,
Ottawa, Ontario, Canada; Chris Cunniff, MD, University of Arizona, Tucson, Arizona; Lewis B. Holmes, MD, Massachusetts General Hospital for
Children, Boston, Massachusetts; Kenneth Lyons Jones, MD, University of California School of Medicine, San Diego, California; Kathleen T. Mitchell,
MHS, LCADC, National Organization on Fetal Alcohol Syndrome, Washington, DC; Mary O'Connor, PhD, University of California at Los Angeles,
Los Angeles, California; Edward Riley, PhD, San Diego State University, San Diego, California; Luther K. Robinson, MD, State University of New
York Buffalo School of Medicine, Buffalo, New York; Kenneth R. Warren, PhD, National Institute on Alcohol Abuse and Alcoholism, Bethesda,
Maryland; Martha Alexander, MPH, Jacquelyn Bertrand, PhD, José Cordero, MD, R. Louise Floyd, DSN, Connie Granoff, Elizabeth Parra, MPH, Jasjeet
Sidhu, MD, Mary K. Weber, MPH, National Center on Birth Defects and Developmental Disabilities, CDC.
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