The Use of Functional Near-Infrared Spectroscopy to Differentiate Alcohol-Related Neurodevelopmental Impairment

Prenatal alcohol exposure and associations with physical size, dysmorphology and neurodevelopment: a systematic review and meta-analysis

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is a significant public health concern, yet there is no internationally agreed set of diagnostic criteria or summary of underlying evidence to inform diagnostic decision-making. This systematic review assesses associations of prenatal alcohol exposure (PAE) and outcomes of diagnostic assessments, providing an evidence base for the improvement of FASD diagnostic criteria.

METHODS

Six databases were searched (inception-February 2023). Case-controls or cohort studies examining associations between participants with/without PAE or a FASD diagnosis and the domains of physical size, dysmorphology, functional neurodevelopment and/or brain structure/neurology were included. Excluded studies were non-empirical, sample size < 10, PAE determined via biological markers only, or no suitable comparison group. Summary data were extracted and associations between outcomes and standardised levels of PAE or FASD diagnosis determined using random-effects meta-analyses. Certainty of the evidence was assessed using GRADE.

RESULTS

Of the 306 included studies, 106 reported physical size, 43 dysmorphology, 195 functional neurodevelopment and 110 structural/neurological outcomes, with 292 different outcomes examined. There was a dose-response relationship between PAE and head circumference, as well as measures of physical size, particularly at birth. There was also an association between higher PAE levels and characteristic sentinel facial dysmorphology, as well as many of the current functional neurodevelopmental outcomes considered during diagnosis. However, data were often lacking across the full range of exposures. There was a lack of evidence from studies examining PAE to support inclusion of non-sentinel dysmorphic features, social cognition, speech-sound impairments, neurological conditions, seizures, sensory processing or structural brain abnormalities (via clinical MRI) in diagnostic criteria. GRADE ratings ranged from very low to moderate certainty of evidence.

CONCLUSIONS

This comprehensive review provides guidance on which components are most useful to consider in the diagnostic criteria for FASD. It also highlights numerous gaps in the available evidence. Future well-designed pregnancy cohort studies should specifically focus on dose-response relationships between PAE and dysmorphology, neurodevelopment and brain structure/neurological outcomes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO: CRD42021230522.

Identifying Prenatal Alcohol Exposure and Children Affected by It: A Review of Biomarkers and Screening Tools

PURPOSE

Early identification of prenatal alcohol exposure (PAE) and of those in need of services resulting from this exposure is an important public health concern. This study reviewed the existing literature on potential biomarkers and screening tools of PAE and its impact.

SEARCH METHODS

Electronic databases were searched for articles published between January 1, 1996, and November 30, 2021, using the following search terms: ("fetal alcohol" or "prenatal alcohol" or "FASD" or "alcohol-related neurodevelopmental disorder" or "ARND" or "ND-PAE") and ("screening" or "identification" or "biomarker"). Duplicate articles were electronically eliminated. Titles and abstracts were reviewed for appropriateness, and selected articles were retrieved for further analysis. Additional articles were added that were referenced in the reviewed articles or identified from expert knowledge. Information about the characteristics of the sample, the biomarker or screening tool, and the predictive validity outcome data were abstracted. A narrative analysis of the studies was then performed on the data.

SEARCH RESULTS

A total of 3,813 articles were initially identified, and 1,215 were removed as duplicates. Of the remaining articles, 182 were identified as being within the scope of the review based on title and abstract inspection, and 181 articles were successfully retrieved. Of these, additional articles were removed because they were preclinical (3), were descriptive only (13), included only self-report of PAE (42), included only mean group comparison (17), were additional duplicates (2), focused on cost analysis (9), missed predictive validity data (24), or for other reasons (23). The remaining articles (n = 48) were abstracted. An additional 13 manuscripts were identified from these articles, and two more from expert knowledge. A total of 63 articles contributed to the review.

DISCUSSION AND CONCLUSIONS

Biomarkers and screening tools of PAE and its impact fall short of ideal predictive validity characteristics. Higher specificity than sensitivity was found for many of the biomarkers and screening tools used to identify PAE and its impact, suggesting that current methods continue to under-identify the full range of individuals impacted by PAE. Exceptions to this were found in recent investigations using microRNAs related to growth and vascular development, proteomic changes associated with PAE, and combinations of markers estimating levels of various cytokines. Replications of these findings are needed across other samples to confirm the limited data available. Future research on biomarkers and screening tools should attend to feasibility and scalability of implementation. This article also recommends a systematic process of evaluation to improve early identification of individuals impacted by PAE so that harm reduction and habilitative care efforts can be implemented.

Screening approaches for identifying fetal alcohol spectrum disorder in children, adolescents, and adults: A systematic review

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is a prevalent neurodevelopmental disorder that is caused by prenatal alcohol exposure (PAE) and associated with a range of cognitive, affective, and health concerns. Although the identification of FASD can facilitate the provision of interventions and support, and plays a protective role against adverse outcomes, there are high rates of missed detection. The identification of FASD via screening may improve its recognition across settings. The current systematic review examined the available evidence on FASD screening tools and approaches across age groups and settings.

METHODS

A systematic search was carried out for both peer-reviewed studies and gray literature sources published between January 1990 and May 2020 and was preregistered with PROSPERO (#CRD42019122077). Studies included in the review focused on human applications of FASD screening in children, adolescents, and adults. The quality of the studies was assessed using the QUADAS-2 and GRADE frameworks.

RESULTS

The search yielded 20 screening tools and approaches across 45 studies, broadly characterized in 2 groups. The first group included approaches currently in use that aim to identify individuals at risk of FASD using a range of markers (n = 19) or associated sentinel dysmorphic facial features (n = 6). Another group of studies, characterized as emerging, focused on identifying promising biomarkers of PAE/FASD (n = 20). Overall, we identified limited research supporting the psychometric properties of most screening approaches. The quality review provided evidence of bias due to the common use of case-control designs and lack of adequate reference standards.

CONCLUSIONS

Although several FASD screening tools and approaches are available for use across a range of age groups and settings, the overall evidence base supporting their psychometric properties is weak, with most studies demonstrating significant risk of bias. Service providers should exercise caution in selecting and implementing FASD screening tools given these limitations. It is critically important to accurately identify individuals with FASD across ages and settings to support healthy outcomes. Thus, there is a pressing need for additional research in this area, particularly validation studies in large and representative samples using robust methodological approaches.

Fifty Years of Research on Prenatal Substances: Lessons Learned for the Opioid Epidemic

Current efforts to design research on developmental effects of prenatal opioid exposure can benefit from knowledge gained from 50 years of studies of fetal alcohol and prenatal drug exposures such as cocaine. Scientific advances in neurobiology, developmental psychopathology, infant assessments, genetics, and imaging support the principles of developmental neurotoxicology that guide research in prenatal exposures. Important to research design is accurate assessment of amount, frequency, and timing of exposure which benefits from accurate self-report and biomarkers of exposure. Identifying and control of pre- and postnatal factors that impact development are difficult and dependent on appropriate research design and selection of comparison groups and measurement of confounding, mediating, and moderating variables. Polysubstance exposure has increased due to the number of prescribed and nonprescribed substances used by pregnant women and varying combinations of drugs may have differential effects on the outcome. Multiple experimental and clinical assessments of infant behavior have been developed but predicting outcome before 18-24 months of age remains difficult. With some exceptions, prenatal substance exposure effect sizes have been small, and cognitive and behavioral effects tend to be specific rather than global. Studies require large sample sizes, adequate retention, and support for social services in at-risk samples. The ethical and legal contexts and stigma associated with drug/alcohol use disorder should be considered in order to prevent harm to families in research programs. Recognition of the pervasive use of addictive substances in this nation should lead to broad scientific efforts to understand how substances affect child outcomes and to initiate prevention and intervention where needed.

Characterizing Alcohol-Related Neurodevelopmental Disorder: Prenatal Alcohol Exposure and the Spectrum of Outcomes

BACKGROUND

The effects of prenatal alcohol exposure (PAE) are conceptualized as fetal alcohol spectrum disorder, with fetal alcohol syndrome (FAS) as the most severe. Many find it more difficult to characterize behavioral and cognitive effects of exposure on the central nervous system when physical signs are not present. In the current study, an operational definition of alcohol-related neurodevelopmental disorder (ARND) was examined to determine its usefulness in discrimination of children classified as ARND based on behavior (ARND/B) and cognition (ARND/C) from children in 4 contrast groups: (i) children exposed to study-defined "risky drinking"; (ii) children with any reported PAE; (iii) children classified as "Higher Risk" for developmental problems; and (iv) children classified as "Lower Risk."

METHODS

A total of 1,842 children seen as part of a surveillance study (J Am Med Assoc, 319, 2018, 474) were evaluated for alcohol exposure and physical characteristics of FAS, and completed neurodevelopmental testing. Ninety-one were identified as either ARND/B or ARND/C and contrasted with other groups to further identify distinguishing patterns. Multinomial logistic regression (MLR) was used to examine the accuracy of classification and to identify factors contributing to such classification.

RESULTS

Children described as ARND/C were distinct from other groups based on cognition and behavior as well as demographic factors (e.g., age, race, SES), child characteristics (e.g., gestational age; sex), and other drug exposures, while those described as ARND/B differed only on behavior and other drug exposures. MLR models successfully discriminated ARND groups from children in other groups with accuracy ranging from 79% (Higher Risk) to 86.7% (Low Risk).

CONCLUSIONS

ARND has been a subject of debate. This analysis suggests the effects of alcohol on behavior and cognition even in the absence of the characteristic facial features and growth deficiency that can be identified. The results also indicate that it may be possible to distinguish such children from those in other high-risk groups.

Neurodevelopmental Outcomes Associated with Prefrontal Cortical Deoxygenation in Children with Fetal Alcohol Spectrum Disorders

Relationships between neurodevelopmental functioning and hemodynamic changes in the prefrontal cortex (PFC) were contrasted between children with prenatal alcohol exposure (PAE) and children who differed relative to their history of PAE and the presence of other neurodevelopmental impairment. For all groups, deoxygenated hemoglobin (HBR) levels in the medial PFC area were negatively related to externalizing problems and levels in the medial and right lateral PFC were positively related to errors on a cognitive inhibition task. Hemodynamic changes in the medial and right lateral PFC of children with PAE demonstrated stronger relationships to aspects of executive functioning relative to contrast groups.