Foetal Alcohol Spectrum Disorder (FASD) diagnostic guidelines: a neuropsychological diagnostic criteria review proposal

Lack of evidence is not the same as evidence of absence of risk and, in this case, no evidence of harm does not mean evidence of no harm. Subsequently, research shows that no amount of alcohol consumption during pregnancy can be considered as safe [1].

One of the deleterious health consequences of prenatal alcohol exposure is foetal alcohol spectrum disorder (FASD), with the most severe form defined as foetal alcohol syndrome (FAS). The clinical features of FAS can be broadly divided into: (1) Morphological malformations, especially craniofacial defects, (2) Growth retardation, and (3) Central nervous system (CNS) impairment, expressed mainly as learning disabilities and behavioural problems [2,3]. However, most patients with FASD exhibit only a subset of the characteristics of FAS, mainly cognitive and behavioural deficits [4].

The neurodevelopmental deficits associated with FASD are complex and multifaceted. It is thought that the differences in dosing and timing of exposure, as well as interacting genetic and environmental influences on brain development, are responsible of the variability in presentation [5-9]. It is well studied that the most common neurodevelopmental disabilities and affected domains include attention, executive function, spatial working, memory and adaptive behaviour [10-12].

The presence of a vast amount of research accumulated over the years has led to the development of several FASD diagnostic guidelines and, consequently, to a lack of consensus on diagnostic categories and conditions. It has not been until the latest update of the Diagnostic and Statistical Manual of Mental Disorders 5^th edition (DSM-5), that clinicians have been provided with a diagnostic category intended to embrace the range of neurobehavioral effects related to PAE. The new DSM-5 includes a new diagnostic category, “Neurobehavioral Disorder Associated with Prenatal Alcohol Exposure” (ND-PAE) in Section III, as a “condition in need of further study” and also as a specified for the broader diagnostic term of an “Other Specified Neurodevelopmental Disorder” (315.8). Before this addition, the only reference available for this purpose has been the International Classification of Diseases on its 10^th edition (ICD-10). This classification system includes two terms related to FASD, “foetal alcohol syndrome, dimorphic” (Q86.0) and “new-born (suspected to be) affected by maternal use of alcohol” (P04.3) [13].

The research suggests high comorbidity between FASD and mood and anxiety disorder and negative emotionality or the intensity of negative moods. These are some of the earliest observable signs of PEA in infants [14,15].

Up to now, there is no single neuropsychological measure, nor pattern of neuropsychological profiles, that are specific to all individuals with FASD [16,17]. Despite there is a consensus about which domains are needed to evaluate in order to get FASD diagnosis and the criterion for significant impairment (at least three CNS domains with scores on standard measures 2 or more standard deviations below the mean), there is not a consensus about which tests are the better ones to assess this domains.

The last FASD Canadian Guidelines for Diagnosis, published on December 2015, try to clarify and validate standardized anthropometric measures and neurodevelopmental assessment domains. Moreover, the guide has provided suggestions about when tests might be treated with high and low confidence and special considerations in the neurodevelopmental assessment of infants and young children.

In spite of all this effort, we can conclude that more research is needed to homogenize the neurodevelopmental evaluation in order to better compare the results in clinical studies [18].