Participants
All procedures performed were in accordance with the ethical standards of the University Institutional Review Board (IRB) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Written copies of the consent/assent forms were given to all participants. Procedures were thoroughly described and read to participants with an opportunity to ask questions. All physical measurements were made in the presence of the child’s parent(s). All participants gave their informed consent/assent prior to study inclusion.
Children were recruited from community and parent organizations, national websites, community-posted flyers, direct mailings, and local child psychiatry/pediatric clinics. Recruitment flyers invited families of typically developing children or children who may have been exposed to alcohol prenatally to participate. This recruitment strategy yielded 196 inquiries with 82 children meeting screening and eligibility criteria.
Inclusion criteria for all participants were: Full-Scale IQ > 70 on the Wechsler Abbreviated Scale of Intelligence, Second Edition (WASI-II, Wechsler, 2011); gestation > 34 weeks; and English as the primary language in the home. Participants were excluded if they had been diagnosed with autism spectrum disorder, a specific genetic disorder, or neurological disorder.
Two groups of children, aged 8–13 years, were included in the sample: (1) children with PAE (n = 46) and (2) TD controls without PAE (TD; n = 36).
Regarding sample characteristics, 58.5% of the children were male, their mean age was 10.30 (SD = 1.61) years, 39% identified as White, non-Hispanic, 8.5% as Black/African American, 20.7% as Hispanic, 22% as Mixed Race, and 9.8% as Other. Average mother’s education (a proxy for socioeconomic status) was 16.70 (SD = 3.46 years).
Procedures
Overview
Briefly, all participants were screened for study eligibility including questions about prenatal alcohol exposure. Families meeting research inclusion criteria were asked to participate in the study. A demographic questionnaire and medical/developmental history were completed for every child. Eligible children were first administered the physical examination by the trained examiners and then completed a neuropsychological test battery conducted by different examiners naïve to prenatal alcohol history. Neurocognitive/behavioral impairment was used to finalize FASD classifications and was scored using criteria described in detail below. The mother was interviewed regarding her prenatal alcohol use privately in a one-to-one setting. In the absence of the biological mother, information was obtained via birth, medical, or adoption records, or from reports from reliable informants (see section on “Prenatal Alcohol Exposure” below).
Physical Examination
Every child was assessed for the presence of the diagnostic features of FASD using the modified IOM criteria according to the updated guidelines proposed in the Clinical Guidelines for Diagnosing Fetal Alcohol Spectrum Disorders (Hoyme et al., 2016). This system is the most commonly used methodology in ascertainment prevalence studies in the USA and in other countries (May et al., 2018). Moreover, it was designed for clinicians and is more inclusive in identifying individuals with salient physical feature of an FASD. The system examines the expression of four key diagnostic features of FAS: (1) growth retardation; (2) the FAS facial phenotype, including a flat upper vermillion border, flat philtrum, and short palpebral fissures; (3) neurocognitive/behavioral impairment; and (4) gestational alcohol exposure. Growth retardation was defined as height and/or weight at or below the 10th percentile on national growth charts at any point in time from birth. With regard to facial features, two of the three seminal facial features of FAS were required to be present (Hoyme et al., 2016). The upper vermillion border and philtrum were scored using a racially normed Lip-Philtrum Guide with scores of 4 or 5 meeting criteria consistent with PAE (Astley, 2013). Palpebral fissure length was scored using the Canadian palpebral fissure guidelines (Clarren et al., 2010) and the guidelines for Black/African American and Hispanic children from Iosub et al. (1985). The parent(s) provided information on preferred racial identity which determined which guide to use in the assessment of the face.
Prenatal Alcohol Exposure
Alcohol exposure was assessed using the Health Interview for Women (HIW) or the Health Interview for Adoptive and Foster Parents (HIAFP, Quattlebaum & O’Connor, 2013). The HIW assesses frequency and quantity of typical and binge drinking and use of other teratogens prior to and following recognition of pregnancy. For adopted/fostered participants, information on prenatal exposure to alcohol and other teratogens was obtained via birth, medical, or adoption records or reports by reliable informants. Because many individuals with FASD are adopted or fostered, it is often necessary to use such records, and this is a method accepted in the scientific community for establishing PAE (Centers for Disease Control and Prevention, 2004). Criteria for alcohol exposure reported by the biological mother included > 6 drinks/week for ≥ 2 weeks and/or ≥ 3 drinks on ≥ 2 occasions including the time periods prior to and following pregnancy recognition (Hoyme et al., 2016). These criteria are based on findings that 1 drink/day (or > 6 drinks/week) is an adequate measure of exposure for an FASD, and on epidemiologic studies demonstrating adverse fetal effects of episodic drinking of ≥ 3 drinks per occasion (Hoyme et al., 2016). No child in the alcohol exposed group was accepted without a clear history of PAE. Alcohol inclusion criterion for the TD group was PAE < 2 standard drinks throughout gestation.
Training Procedures and Measures
Training
Diagnostic training of two child psychologists began with exposure to reading materials on PAE, a thorough description of the criteria for diagnosis of FAS that included pictures of children’s faces, followed by a description of the measurements they were being trained to take on each child, and practice performing these measurements. Both examiners were observed administering the physical examination of several children with immediate feedback provided by the study senior alcohol researcher who had extensive training and expertise in the assessment of FASD. The examiners were trained to reliability and fidelity was checked throughout the study by the senior alcohol researcher. Both examiners were blind to the child’s history of exposure to alcohol prenatally.
Child Measurements
Child height and weight were measured in cm and kg, respectively, to assess for growth retardation. Children were asked to remove their shoes and heavy clothing. To measure height, children were asked to stand with feet flat together, with legs straight, arms at their sides, and shoulders level against a wall in front of a height chart calibrated in centimeters. They were instructed that their head, shoulders, and heels had to be touching the wall. A flat headpiece forming a right angle with the wall was lowered until it firmly touched the crown of the child’s head making sure the examiner’s eyes were at the same level as the headpiece. Height was measured to the nearest cm. Weight was measured using a digital scale on a flat surface. Children were instructed to stand still with both feet in the center of the scale. Weight was measured in kg to the nearest decimal fraction (for example, 25.1 kg) and then .5 kg was subtracted to account for clothing.
The occipital frontal circumference (OFC), considered a screening measure of central nervous system (CNS) integrity, was assessed using the standardized method of measurement with a flexible tape measure calibrated in cm. OFC was measured over the most prominent part of the back of the head (occiput) and just above the eyebrows (supraorbital ridges) in order to measure the largest circumference of the head. Measurements were repeated until 2 measurements yielded identical results.
Assessment of facial features included the use of the Astley (2013) Lip-Philtrum Guides for White or Black/African American children. The Lip-Philtrum Guide is a 5-point photographic guide that is used to objectively measure the flatness of the upper vermillion border and philtrum smoothness. A rank of 1 reflects a well-formed upper lip and a deeply grooved philtrum. As one moves up the guide from a rank of 1 to a rank of 5, the upper vermillion border is portrayed as becoming flatter and the philtrum as becoming smoother. The rank of 5 reflects an upper vermillion border that is completely flat or philtrum that is completely smooth. A score of 4 or 5 on each feature meets criterion for face. Measurements were taken with the child and examiner seated facing one another at eye level with the guide held to the side of the child’s face. Children were asked to relax their facial expression, without smiling, and with their lips gently closed (a smile can cause the upper lip and philtrum to appear flatter and smoother than they actually are). Lip and philtrum were each measured separately.
To measure the length of the palpebral fissures, the examiner sat at eye level in front of the child and placed one hand lightly on the top of the child’s head to prevent the child from lifting the head. The children were asked to open their eyes widely and to direct their gaze up to the ceiling without lifting their heads. The lengths of the right and left palpebral fissures were measured with a plastic ruler (1 cm by 14 cm in size) calibrated in mm held as closely as possible to the bottom of the opening of the eye without touching the eye or eye lashes. Measurements were taken between the endocanthion and the exocanthion landmarks (Astley, 2013). The measurement of the smallest of the two palpebral fissures was used in analysis.
Diagnostic Criteria for Physical Characteristics
Physical features of height, weight, and OFC were converted to percentiles according to sex and age-based CDC Growth Charts: United States (Kuczmarski, 2002) for individuals 2 to 20 years using the Simulconsult calculator (Simulconsult.com). Upper vermillion border and philtrum ratings were scored using the Astley Lip-Philtrum Guide (Astley, 2013). The smallest of the right or left palpebral fissure was scored based on sex and age percentile norms for White/non-Hispanic children reported by Clarren et al. (2010) and norms for Black/African American and Hispanic children reported by Iosub et al. (1985). All measurements then were scored as “yes” or “no” based on whether or not participants met the physical diagnostic criteria proposed by Hoyme et al. (2016): height (≤ 10th percentile), weight (≤ 10th percentile), OFC (≤ 10th percentile), upper vermillion border (≥ rank 4), philtrum (≥ rank 4), and palpebral fissure (≤ 10th percentile).
Reliability of Measurements of Facial Features
Deidentified digital photographs of participants’ faces were scored for reliability in meeting facial criteria by the study senior investigator who had extensive training and experience using the diagnostic system. Taken together, kappas for the whole sample were 0.95 for upper vermillion border, 0.93 for philtrum, and 0.90 for palpebral fissure length.
Confirmatory Diagnoses of an FASD
Deidentified scoring sheets containing all physical and neurocognitive/behavioral findings for each participant were assigned a confirmatory diagnostic classification for each child along the FASD spectrum. Neurocognitive/behavioral impairment was defined less conservatively than the criterion proposed by Hoyme et al. (2016) and was considered significant if the participant demonstrated functioning more than 1 standard deviation below or above the mean depending on whether or not a lower or higher score indicated higher levels of deficit functioning on standardized measures of neurocognitive and socioemotional development. Given the relatively higher IQs of our subjects (IQs of > 70), we determined that it was unlikely that 1 ½ standard deviations from the mean, as proposed by Hoyme et al. (2016), would adequately capture subtler deficits that might characterize this group of individuals. Moreover, these criteria are in accordance with the report by Doyle and Mattson (2015) suggesting that for most standardized neurocognitive measures, 1 standard deviation from the mean typically indicates problems in behavior or neurocognitive development.
Statistical Analysis
Group differences in demographic and morphological characteristics were evaluated using ANOVA for continuous variables and two-tailed Fisher’s exact tests for categorical variables using SPSS v27 (IBM Corp., Armonk, NY).