CMAJ • March 1, 2005; 172 (5_suppl).
doi:10.1503/cmaj.1040302.
© 2005 CMA Media Inc. or its
licensors
Fetal alcohol spectrum disorder: Canadian guidelines for diagnosis
Albert E.
Chudley, Julianne Conry, Jocelynn L. Cook,
Christine Loock, Ted Rosales and Nicole
LeBlanc
From the Children's Hospital,
Health Sciences Centre, Departments of Pediatrics and Child Health and
Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Man.
(Chudley); the Department of Educational and Counselling Psychology and Special
Education, University of British Columbia; Asante Centre for Fetal Alcohol
Syndrome, Maple Ridge, B.C. (Conry); the Department of Obstetrics and
Gynecology, University of Ottawa, Ottawa, Ont. (Cook); the Department of
Pediatrics, University of British Columbia, BC Children's Hospital, Vancouver,
B.C. (Loock); the Provincial Medical Genetics Program; the Department of
Pediatrics, Memorial University of Newfoundland, St. John's, Nfld. (Rosales);
and the Department of Pediatrics, Georges Dumont Hospital, Moncton, N.B.
(LeBlanc).
Correspondence to:
Dr. Jocelynn L. Cook, FASD Team, Public Health Agency of Canada, Division of
Childhood and Adolescence, Jeanne Mance Bldg. 9th flr, Tunney's Pasture, Address
Locator 1909C2, Ottawa ON K1A 0K9; jocelynn@primus.ca
 S1 -- Canadian Medical Association Journal_files/rarrow.gif) |
Abstract
|
THE
DIAGNOSIS OF FETAL ALCOHOL SPECTRUM DISORDER (FASD) is complex and
guidelines are warranted. A subcommittee of the Public Health Agency
of Canada's National Advisory Committee on Fetal Alcohol Spectrum
Disorder reviewed, analysed and integrated current approaches to
diagnosis to reach agreement on a standard in Canada. The purpose of
this paper is to review and clarify the use of current diagnostic
systems and make recommendations on their application for diagnosis
of FASD-related disabilities in people of all ages. The guidelines
are based on widespread consultation of expert practitioners and
partners in the field. The guidelines have been organized into 7
categories: screening and referral; the physical examination and
differential diagnosis; the neurobehavioural assessment; and
treatment and follow-up; maternal alcohol history in pregnancy;
diagnostic criteria for fetal alcohol syndrome (FAS), partial FAS and
alcohol-related neurodevelopmental disorder; and harmonization of
Institute of Medicine and 4-Digit Diagnostic Code approaches. The
diagnosis requires a comprehensive history and physical and
neurobehavioural assessments; a multidisciplinary approach is
necessary. These are the first Canadian guidelines for the diagnosis
of FAS and its related disabilities, developed by broad-based
consultation among experts in diagnosis.
In this document, we discuss the diagnostic approach to disabilities
associated with prenatal alcohol exposure. Fetal alcohol spectrum
disorder (FASD), along with its most visible presentation, fetal
alcohol syndrome (FAS), is a serious health and social concern
to Canadians. FASD is an umbrella term describing the range of
effects that can occur in an individual whose mother drank alcohol
during pregnancy. These effects may include physical, mental,
behavioural and learning disabilities with lifelong implications. The
term FASD is not intended for use as a clinical diagnosis.
FASD is the result of maternal alcohol consumption during pregnancy
and has implications for the affected person, the mother, the
family and the community. Since FAS was first described in 1973,1
it has become apparent that it is complex; affected people exhibit
a wide range of expression, from severe growth restriction,
intellectual disability, birth defects and characteristic dysmorphic
facial features to normal growth, facial features and intellectual
abilities, but with lifelong deficits in several domains of
brain function. FASD requires a medical diagnosis in the context
of a multidisciplinary assessment. FASD itself is not a diagnostic
term. The purpose of this paper is to review and clarify the
use of the current diagnostic systems and make recommendations
on their application for diagnosis of FASD-related disabilities
in people of all ages. For a description of the characteristics
and the natural course of FASD, consult some of the broader
reviews.2,3,4,5,6,7
|
Epidemiology of FASD
|
The
prevalence of FAS in the United States has been reported as 1–3 per
1000 live births and the rate of FASD as 9.1 per 1000 live
births.8,9,10,11
However, diagnosis may often be delayed or missed entirely.2
There are no national statistics on the rates of FASD in Canada, although
studies have estimated its prevalence in small populations. In an
isolated Aboriginal community in British Columbia, FASD prevalence
was 190 per 1000 live births.12 In
northeastern Manitoba, an incidence of about 7.2 per 1000 live births
was found.13
In another Manitoba study in a First Nations community,14 the
prevalence of FAS and partial FAS was estimated to be 55–101 per
1000. In their survey, Asante and Nelms-Matzke15 estimated
the rate of FAS and related effects at 46 per 1000 native Canadian
children in the Yukon and 25 per 1000 in northern British Columbia.
Based on referrals to a diagnostic clinic in Saskatchewan, the rate
of FAS was estimated at 0.589 per 1000 live births in 1988–1992 and
0.515 per 1000 in 1973–1977.16 However,
none of these data should be generalized to other communities, other
populations or the Canadian population in general.
| FASlink Editor's Note: The above studies
were conducted as many as 25 years before the diagnostic criteria for Canada
were finally set and were all of remote, small First Nation's communities.
First Nations comprise 2.2% of the Canadian population. More recent statistical
analysis of the Statistics Canada - Canadian Community Health Survey, Binge
Drinking studies, combined with birth and population statistics, indicate
79% of Canadian children are exposed to alcohol during pregnancy, including
37% who are exposed to binge drinking (5+ drinks per occasion, multiple
times). Meconium assay testing of newborns for FAEE's formed by maternal
alcohol consumption indicate 15% to 18% have been exposed to alcohol in
the final 20 weeks of pregnancy, including 4% at elevated levels. In an
Ontario 28,000 student population, 21.4% are receiving Special Education
services, most for conditions of types known to be caused by prenatal exposure
to alcohol. |
|
Risk factors
|
A
common misconception is that FASD is associated with ethnocultural
background. However, the data suggest that risk factors for
prenatal alcohol exposure include higher maternal age and lower
education level, prenatal exposure to cocaine and smoking, custody
changes, lower socioeconomic status and paternal drinking and
drug use at the time of pregnancy;17 and
reduced access to prenatal and postnatal care and services,
inadequate nutrition and a poor developmental environment (e.g.,
stress, abuse, neglect).18
In a 5-year follow-up study of birth mothers of children with full
FAS, Astley and colleagues19
found that these women came from diverse racial, educational and
economic backgrounds. They were often challenged by untreated or
under-treated mental health concerns, they were socially isolated,
they were victims of abuse and they had histories of severe childhood
sexual abuse.
Because there are no large-scale studies of risk factors and
because risks are interrelated and could be different for different
populations, it is difficult to provide accurate figures for
relative risk. However, the most important risk factor for FASD
is related to high blood-alcohol concentration: the timing of
exposure during fetal development, the pattern of consumption,
i.e., binge drinking (4 or more drinks per occasion) and the
frequency of use. Although there seems to be no definite threshold
of exposure, there appears to be a dose-response relation.17,20,21
|
Importance of early
diagnosis |
An early
diagnosis is essential to allow access to interventions and resources
that may mitigate the development of subsequent "secondary
disabilities" (e.g., unemployment, mental health problems, trouble
with the law, inappropriate sexual behaviour, disrupted school
experience) among affected people.22
Furthermore, an early diagnosis will also allow appropriate
intervention, counselling and treatment for the mother and may
prevent the birth of affected children in the future.23 It
may also prompt caregivers to seek diagnosis and support for
previously undiagnosed siblings. A review of medical and behavioural
management of those with FASD can be found in other sources.3,24
Astley and Clarren25
suggest that accurate and timely diagnosis is essential to improve
outcome, as misclassification leads to inappropriate patient care,
increased risk of secondary disabilities, missed opportunities for
prevention and inaccurate estimates of incidence and prevalence.
Together, these inaccuracies could hinder efforts to allocate
sufficient social and health care services to the vulnerable
populations and preclude accurate assessment of primary prevention
efforts.
Because of limited capacity and expertise and the need to involve
several professionals in a comprehensive multidisciplinary diagnostic
evaluation, only a fraction of those affected currently receive
a diagnosis. Results26
from the Canadian national survey regarding knowledge and attitudes
of health professionals suggest that standardized guidelines for
diagnosis and further professional education and training are needed
for practitioners to participate in diagnosis. In response to these
concerns, Health Canada's National Advisory Committee on FASD, along
with experts and practitioners in FAS diagnosis and treatment,
present the following guidelines for diagnosis.
|
Process of guideline
development |
These
guidelines are the result of more than 10 face-to-face consultations
with Canadian and American experts in the diagnosis of FAS and its
related disabilities (Appendix
1). Many of the participants are currently providing diagnostic
services across Canada. Review and feedback were provided by a
diverse group of individuals; professional organizations and
societies; and provincial, territorial and federal levels of
government. Guidelines are presented in 6 areas related to the
diagnostic process: 1. screening and referral; 2. the physical
examination and differential diagnosis; 3. neurobehavioural
assessment; 4. treatment and follow-up; 5. maternal alcohol history
in pregnancy; and 6. diagnostic criteria for FAS, partial FAS and
alcohol-related neurodevelopmental disorder. We also include
recommendations for harmonization of the 2 main approaches to
diagnosis.
There are multiple approaches to diagnosis, and the working group
sought to integrate these to achieve consistent diagnoses across
Canada. Current knowledge of the complexity of the disabilities
associated with prenatal alcohol exposure dictates that a
comprehensive, multidisciplinary assessment is necessary to make an
accurate diagnosis and provide recommendations for management. We
are recommending such a multidisciplinary approach. This
approach will also allow for collection of Canadian data for
estimating incidence and prevalence of FASD. This information is
essential to identify the need for and the development of
appropriate prevention and intervention programs and services.
|
Background and
terminology for the diagnosis of FAS |
The first
recognition of a variety of birth defects and developmental
disabilities in offspring born to alcoholic parents is attributed
to Lemoine and colleagues.27 A
specific pattern of birth defects following maternal alcohol exposure
was described in the United States.1,28 The
specific pattern, referred to as FAS, consists of facial
abnormalities (smooth philtrum [the space between the upper lip and
the nose], thin vermilion border [the exposed mucosal, or red part,
of the upper lip], short palpebral fissures), impaired prenatal or
postnatal growth (or both) and central nervous system or
neurobehavioural disorders. Alcohol probably acts through multiple
mechanisms and a range of disabilities has been observed in the
absence of dysmorphic features reflecting varying degrees of damage
during fetal development; undoubtedly, timing and degree of exposure
are important variables that contribute to the variation. Thus, the
term "suspected fetal alcohol effects" (FAE) was created.29
These "effects" were further delineated by the United States'
Institute of Medicine (IOM), which published recommendations in 1996
for diagnosis of FAS in consultation with a panel of experts.4 The
diagnostic categories presented were: FAS with and without a
confirmed history of alcohol exposure, partial FAS, alcohol-related
birth defects (ARBD), and alcohol-related neurodevelopmental disorder
(ARND) (Table
1).
In
the late 1990s, another diagnostic strategy was developed by Astley
and Clarren.25,30They
created a 4-Digit Diagnostic Code using data from the Washington
State Fetal Alcohol Syndrome Diagnostic and Prevention Network of
clinics. The system uses quantitative, objective measurement scales
and specific case definitions. The 4 digits in the code reflect the
magnitude of expression or severity of the 4 key diagnostic features
of FAS in the following order: growth deficiency; the FAS facial
phenotype; central nervous system damage or dysfunction; gestational
exposure to alcohol. The magnitude of expression of each feature
is ranked independently on a 4-point Likert scale with 1 reflecting
complete absence of the feature and 4 reflecting its extreme
expression. The 4-Digit Diagnostic Code is now being used for
diagnosis, screening and surveillance in clinics throughout the
United States and Canada. Terminology from Astley's 2004 revision of
the 4-Digit Diagnostic Code are used in this article.*
Although the approaches are different, the underlying, fundamental
criteria of the IOM and the 4-Digit Diagnostic Code are similar.
Some clinics are choosing to integrate the diagnostic tools and
precision reflected in the 4-Digit Diagnostic Code with the
diagnostic categories and language recommended by the IOM committee.
Although both IOM criteria and the 4-Digit Diagnostic Code have been
published, many clinicians still use the less desirable and
potentially misleading gestalt approach (Table 2).
|
The diagnostic process
|
The
diagnostic process consists of screening and referral, the physical
examination and differential diagnosis, the neurobehavioural
assessment and treatment and follow-up. Because of the complexity
and the range of expression of dysfunction related to prenatal
alcohol exposure, a multidisciplinary team is essential for an
accurate and comprehensive diagnosis and treatment recommendations.
The assessment process begins with recognition of the need for
diagnosis and ends with implementation of appropriate
recommendations. The multidisciplinary diagnostic team can be
geographic, regional or virtual; it can also accept referrals from
distant communities and carry out an evaluation using
telemedicine.
The core team may vary according to the specific context, but
ideally it should consist of the following professionals with
appropriate qualifications, training and experience in their
particular discipline:
- Coordinator for case management (e.g., nurse, social worker).
- Physician specifically trained in FASD diagnosis.
- Psychologist.
- Occupational therapist.
- Speech-language pathologist.
Additional members may include addiction counsellors, childcare
workers, cultural interpreters, mental health workers, parents
or caregivers, probation officers, psychiatrists, teachers,
vocational counselors, nurses, geneticists or dysmorphologists,
neuropsychologists, family therapists.
Comments
Clearly, funding for development, training and maintenance of
multidisciplinary diagnostic teams is necessary so that major
centres will have the expertise and capacity to serve their
communities. To optimize the outcome of the diagnosis, the community
and the family must be prepared, ready to participate in, and
be in agreement with the diagnostic assessment. The diagnostic
process should be sensitive to the family's and the caregiver's
needs. In each community, referrals must be evaluated and their
level of priority established. The family and guardian must be
in agreement on the purpose of diagnosis. They must be made aware of
the potential psychosocial consequences of a diagnosis of FASD (e.g.,
increasing a sense of guilt and anger, especially with the birth
mother, or potential stigmatization of the child). The family or
guardian will likely need help to move confidently through the
diagnostic process. This help might include some preparatory
education concerning FASD and linking them with community supports
and resources.
Information from multiple sources (e.g., school records, hospital
records, social services, previous assessments) should be obtained;
this might involve meetings with relevant professionals who
know the patient (e.g., teachers, physicians, social workers,
psychologists). Other relevant documentation would include birth
and pregnancy records, medical and hospital records, adoption
records, academic records, achievement tests, developmental
assessments, psychological and psychometric assessments, legal
reports and documentation of the family history.
The comprehensive assessment by the diagnostic team provides
important information about the individual's unique needs and
allows interventions to be tailored to his or her strengths and
challenges. The post-diagnostic report should state the basis for the
diagnosis by including the history of alcohol use, the physical
criteria and the psychological data that support it.
Multidisciplinary teams work with community partners and resources
to develop and implement management plans to maximize the potential
of the affected individual. Following assessment, a report containing
recommendations should be made available to caregivers, educators,
and biological families, as well as other appropriate individuals
who work with the child (i.e., daycare workers, early intervention
workers, social workers, etc). The team findings should be discussed
with the guardian. Older children who have the cognitive ability
should have the opportunity to learn about their diagnosis from
the team. The team might also take on the responsibility for
facilitating and providing follow-up with the family and community
resources regarding outcomes of the recommendations. Ultimately,
the diagnostic process will result in concrete management
recommendations to improve the lives of the affected individuals,
their families and the communities.
Canada is a large country with vast distances between communities,
some of which are remote and isolated. Specialists providing
consultation to remote areas require specialized training in
FASD assessment and need to link with centres that have
multidisciplinary teams to assist in the diagnostic process. A number
of tools may be useful for distant diagnosis. More frequent use of
telemedicine, for example, will allow assessment of children in
distant communities.31Other
examples include the use of digital photographs32,33 and
3-D laser surface scanning34,35sent
electronically to teams in larger centres.
We recognize that there is currently a limited capacity even in
some large communities in Canada to provide a multidisciplinary
team-based approach to FAS diagnosis. Professionals should make
the best use of available resources and expertise to provide an
accurate assessment and treatment plan for affected individuals and
their families, recognizing the key role of psychology.
1. Screening and
referral
Recommendations
- 1.1 All pregnant and post-partum women should be screened
for alcohol use with validated screening tools (i.e.,
T-ACE, TWEAK) by relevant health care providers. Women at
risk for heavy alcohol use should receive early brief
intervention (i.e., counselling).
- 1.2 Abstinence should be recommended to all women during
pregnancy, as the mother's continued drinking during
pregnancy will put the fetus at risk for effects related
to prenatal alcohol exposure.
- 1.3 Referral of individuals for a possible FASD-related
diagnosis should be made in the following
situations:
- Presence of 3 characteristic facial features (short
palpebral fissures, smooth or flattened philtrum, thin
vermilion border).
- Evidence of significant prenatal exposure to alcohol at
levels known to be associated with physical or
developmental effects, or both.
- Presence of 1 or more facial features with growth
deficits plus known or probable significant
prenatal alcohol exposure.
- Presence of 1 or more facial features with 1 or
more central nervous system deficits plus known or
probable significant prenatal alcohol
exposure.
- Presence of 1 or more facial features with pre- or
postnatal growth deficits, or both (at the
10th percentile or below [1.5 standard deviations
below the mean]) and 1 or more central nervous
system deficits plus known or probable
significant prenatal alcohol exposure.
- 1.4 Individuals with learning or behavioural difficulties,
or both, without physical or dysmorphic features and
without known or likely prenatal alcohol exposure should
be assessed by appropriate professionals or specialty
clinics (i.e., developmental pediatrics, clinical
genetics, psychiatry, psychology) to identify and treat
their problems.
Comments
- Screening should not be equated with diagnosis. We know
that in some places with no diagnostic services, screening
tools have been inappropriately used in lieu of a proper
diagnosis. One purpose of screening is to identify and refer
pregnant women who may be at risk for an alcohol use disorder and
who may place their child at risk for FASD. Several alcohol
screening tools have been found to be effective in identifying
problem drinking in a primary care setting (e.g., TWEAK, T-ACE,
CAGE, AUDIT, S-MAST, B-MAST).2,36,37,38
- There is moderate evidence37,38
to support the use of T-ACE and TWEAK to identify women
who would benefit from intervention for alcohol use
during pregnancy. If the woman cannot abstain, she
should receive support and be referred to appropriate
counselling and treatment. Stopping drinking at any
point during the pregnancy will improve the outcome for
the baby. Research is being carried out to develop
gender and culturally appropriate instruments for the
screening of all women during their child-bearing years.38
- The purpose of screening individuals at risk for the
effects of prenatal alcohol exposure is to determine
whether a pattern of learning and behavioural problems
may be related to prenatal alcohol exposure. The
screening could be conducted through the education
system, the mental health system, the judicial system or
social services. The purpose of screening should be to
facilitate referral to a diagnostic clinic and highlight
the need for referral and support for the birth
mother.
- The FAS Diagnostic and Prevention Network has had
encouraging results in applying the FAS facial
photographic screening tool in foster children and
school-age children populations.39
However, in the wide array of FASDs, facial
dysmorphology is often absent and, in the final analysis,
has little importance compared with the impact of prenatal
alcohol exposure on brain function. However, it is
important to note that the facial phenotype is a midline
defect that is the most sensitive and specific marker for
alcohol-related brain damage.
- All those suspected of having brain dysfunction should be
referred to an appropriate professional or clinic for
assessment (i.e., developmental pediatrics, clinical
genetics, psychiatry, psychology). Because of the
specificity of FASD clinics in addressing issues related
to prenatal alcohol exposure, those with no prenatal alcohol
exposure should be referred to an appropriate professional or
clinic for assessment, treatment and follow-up.
2. The physical examination and
differential diagnosis
The purpose of dysmorphology assessment is to identify those with
features related to prenatal alcohol exposure and also to identify
children with dysmorphic features due to other causes. Occasionally,
children with prenatal alcohol effects may have another genetic
syndrome as a comorbidity. When in doubt and if feasible, a genetic
dysmorphology assesment is advisable.
A general physical and neurologic examination, including appropriate
measurements of growth and head size, assessment of characteristic
findings and documentation of anomalies (e.g., cleft palate,
congenital heart defects, epicanthic folds, high arched palate,
poorly aligned or abnormal teeth, hypertelorism, micrognathia,
abnormal hair patterning, abnormal palmar creases, skin lesions)
is required to exclude the presence of other genetic disorders
or multifactorial disorders that could lead to features mimicking
FAS or partial FAS (Table 3).
Some children will have significant neurologic deficits, such as
deafness, blindness or seizures, and these should be assessed and
documented as essential components of the child's profile. These
features do not discriminate alcohol-exposed from unexposed children.
The face of FAS is the result of a specific effect of ethanol
teratogenesis altering growth of the midface and brain. Those exposed
to other embryotoxic agents may display a similar, but not identical,
phenotypic facial development, impaired growth, a higher frequency of
anomalies and developmental and behavioural abnormalities (for a
review, see Chudley and Longstaffe24).
However, because FAS facial criteria have been restricted to short
palpebral fissures, smooth philtrum and thin upper lip, there is far
less overlap with the facial phenotypes associated with other
syndromes. Knowledge of exposure history will decrease the
possibility of misdiagnosing FASD.
Children may be found to need other medical assessments to address
co-occurring issues. For example, sleep disturbance is common
with prenatal alcohol exposure and medical problems related to
obstructive sleep apnea may have been overlooked previously. Atypical
seizures may also be present and endocrinopathies may exist as a
comorbid reason for growth deficiency. These individuals should be
assessed by appropriate health professionals.
2a. Growth
Recommendations
- 2.1 Growth should be monitored to detect deficiency.
Presence of pre- or post-natal growth deficiency, defined
as height or weight at or below the 10th percentile (1.5
standard deviations below the mean) or a
disproportionately low weight-to-height ratio (at or below the 10th
percentile) using appropriate norms. To determine that a child is
growth deficient requires taking into consideration confounding
variables such as parental size, genetic potential and associated
conditions (e.g., gestational diabetes, nutritional status,
illness).
Comments
- Children affected by prenatal alcohol exposure may have
prenatal or postnatal growth deficits. They can be small
for gestational age in utero and remain below average
throughout their lives with respect to head
circumference, weight and height. Many children can have
normal growth parameters, but be at risk in later
development for clinically significant learning, behavioural and
cognitive deficits. If there is no alcohol exposure in the third
trimester, the growth parameters can be normal. Gestational
diabetes can lead to increased fetal size, which can mask the
effects of growth retardation from prenatal alcohol exposure.
Furthermore, if the infant is born into a family or a community
where "normal" size is above the average for the general
population, growth impairment may be masked if the child is
compared with standard growth parameters rather than community
norms.14
Growth deficiencies may not persist with age, and infant growth
records may not be available for adults coming in for assessment
for the first time. There is a need to establish growth norms
for the Canadian population and subpopulations that differ
from the general population.
2b. Facial
features
Recommendations
- 2.2 The 3 characteristic facial features that discriminate
individuals with and without FAS are:
- Short palpebral fissures, at or below the 3rd percentile
(2 standard deviations below the mean).
- Smooth or flattened philtrum, 4 or 5 on the
5-point Likert scale of the lip-philtrum guide.25,39
- Thin vermilion border of the upper lip, 4 or 5 on the
5-point Likert scale of the lip-philtrum guide.
- 2.3 Associated physical features (abnormalities such as
midface hypoplasia, micrognathia, abnormal position or
formation of the ears, high arched palate,
hypertelorism, epicanthic folds, limb and palmar crease
abnormalities and short-upturned nose) should be
recorded but do not contribute to establishing the
diagnosis.
- 2.4 Facial features should be measured in all age groups.
If a patient's facial features change with age, the
diagnosis of the facial features should be based on the
point in time when the features were most severely
expressed. When diagnosing adults, it can be helpful to
view childhood photographs.
Comments
- A characteristic craniofacial profile associated with FAS
was first described by Jones and Smith40
in 1975 and later refined by Astley, Clarren and
others.25,32,39
Individuals with FAS have short palpebral fissures, a
thin upper lip and an indistinct philtrum (Fig. 1).
Palpebral fissure length, philtrum and upper lip differ with race
and age. Growth and facial anthropometric data are needed for the
specific population, as sensitivity and specificity of the
assessment will be lowered without the use of appropriate norms.
Some discriminating characteristic features in FAS (i.e., upper lip
or philtrum) may become less recognizable with age, making accurate
diagnosis more difficult in older groups, but facial features
should always be measured. More longitudinal research is needed to
correlate changes in these characteristic physical findings in
adolescents and adults diagnosed with FAS or partial FAS.
Palpebral fissure length (Fig. 2) is
difficult to measure accurately without training. Thomas
and co-workers41
have published norms for palpebral fissure length at 29
weeks gestation to 14 years. There are a number of
opinions about which norms are appropriate,41,42,43,44
but it is generally agreed that all are flawed in some
respect.
Two graphs of palpebral fissure length
are presented in Appendix 2. Some discrepancies exist.
Both studies used North American white subjects;
standards for other populations in Canada are not
currently available. Appendix
2-1 may be more reliable when measuring palpebral
fissure length using a plastic ruler (in the experience
of one of the authors); Appendix
2-2 may be more reliable if slide calipers are used
(in the experience of one of the authors). Percentile
ranks for both graphs seem to be in agreement until age
7 years, after which Appendix 2-2 shows longer palpebral
fissures in older children and adolescents than Appendix 2-1. We
believe this may be due to differences in measurement technique.
Because calipers are not a common tool in most medical clinics, we
recommend the use of a clear flexible plastic ruler.
There is a need to establish updated norms
for all ages and subpopulations. Astley and Clarren25,39
have developed norms for the assessment of the lip and
philtrum using their pictorial guide. Lip-philtrum
guides were developed for use in Caucasian and
African-American populations, but no standards are currently
available for other populations.
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Fig. 1: Lip-philtrum guide. A
5-point pictorial scale for measuring philtrum smoothness and upper
lip thinness. Features are measured independently; for example, an
individual can have a rank 5 philtrum and a rank 1 upper lip. Photo:
Susan Astley, FAS
DPN
| |
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version (87K):
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Fig. 2: Palpebral fissure length.
To measure palpebral fissure length, identify the inner corner or
encanthion (en) and outer corner or excanthion (ex) for each eye.
Have the patient look up so that ex can be seen clearly. With a
clear flexible ruler held in the horizontal plane, measure the
length of each ex-en interval immediately below the eye, being
careful not to touch the eye or eyelashes. Plot the result on an
appropriate nomogram chart to determine the percentile or standard
deviation for each eye. Photo: Albert
Chudley
| |
3. Neurobehavioural
assessment
Recommendations
- 3.1 The following domains should be assessed:
- Hard and soft neurologic signs (including sensory-motor signs).
- Brain structure (occipitofrontal circumference, magnetic resonance
imaging, etc.).
- Cognition (IQ).
- Communication: receptive and expressive.
- Academic achievement.
- Memory.
- Executive functioning and abstract reasoning.
- Attention deficit/hyperactivity.
- Adaptive behaviour, social skills, social communication.
- 3.2 The assessment should include and compare basic and complex
tasks in each domain, as appropriate.
- 3.3 The domains should be assessed as though they were
independent entities, but where there is overlap
experienced clinical judgment is required to decide how
many domains are affected.
- 3.4 A domain is considered "impaired" when on a
standardized measure:
- Scores are 2 standard deviations or more below the mean,
or
- There is a discrepancy of at least 1 standard deviation
between subdomains. For example:
- i. Verbal v. non-verbal ability on standard IQ tests,
- ii. Expressive v. receptive language,
- iii. Verbal v. visual memory, or
- There is a discrepancy of at least 1.5–2 standard
deviations among subtests on a measure, taking
into account the reliability of the specific
measure and normal variability in the population.
- 3.5 In areas where standardized measurements are not
available, a clinical judgment of "significant dysfunction"
is made, taking into consideration that important
variables, including the child's age, mental health
factors, socioeconomic factors and disrupted family or
home environment (e.g., multiple foster placements,
history of abuse and neglect), may affect development but
do not indicate brain damage.
- 3.6 Evidence of impairment in 3 domains is necessary for a
diagnosis, but a comprehensive assessment requires that
each domain be assessed to identify strengths and
weaknesses.
- 3.7 The diagnosis should be deferred for some at-risk
children (e.g., preschool-age) who have been exposed to
alcohol but may not yet demonstrate measurable deficits
in the brain domains or may be too young to be tested in
all the domains. However, developmental assessment
should identify areas for early intervention.
Examples of tests that are most widely used to assess the domains
and their criteria are provided in Appendix
3.
Comments
- Research reports have documented a range of cognitive and
behavioural outcomes associated with prenatal alcohol
exposure. Contemporary studies have reported some of
these outcomes in the absence of FAS physical features.
Currently, no modal profile of abilities has been found
to be unique to alcohol exposure, is observed in all
those with prenatal alcohol exposure, or can be distinguished
from that observed with some other neurobehavioural
disorders. Furthermore, not every deficit that we may
identify in a child with prenatal exposure to alcohol
may be solely the result of alcohol exposure. An expert
analysis of neurodevelopmental deficits caused by a
range of teratogens and congenital disorders failed to
result in a consensus on core deficits associated only with
FASD.4
- Research and experience has shown that features of FASD
are complex and multifaceted, originating with organic
brain damage caused by alcohol, but interacting with
genetic and other influences. Over the lifespan of the
affected person, these features may be exacerbated or
mitigated by environmental experiences.
- To make the diagnosis of FAS, features such as
microcephaly, structural abnormalities (as may be detected
on brain scans) and hard neurologic signs are taken as
strong evidence of organic brain damage. We believe that
low-average to borderline intelligence and soft
neurologic signs alone are insufficient evidence of
brain damage because they are frequently found in the
general population. Features such as learning difficulties,
attention deficit/hyperactivity disorder and deficits in
adaptive skills, memory, higher-level language and
abstract thinking are frequently seen in children with
prenatal alcohol exposure, but also among those with
other etiologies. These deficits can be multifactorial
in etiology and can also be attributed to genetics or
postnatal experiences.
- The 4-Digit Diagnostic Code evaluation of the FASD brain
is based on levels of certainty, in the judgement of the
clinician, that the individual's cognitive and
behavioural problems reflect brain damage. A higher rating
may reflect a more severe expression of functional
disability, asynchronous patterns across domains or
certainty based on deficits in multiple domains. The
determination is based on objective evidence of
"substantial deficiencies or discrepancies across
multiple areas of brain performance."25,39
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