Functional Deficits Often Observed in Fetal Alcohol Syndrome

Individuals with fetal alcohol syndrome exhibit a multitude of cognitive, behavioural, and social deficits[1,2]. Many of these impairments can be intuitively related to the structural abnormalties, and are probably functional correlates to them to a certain extent.

Intelligence

While most individuals with fetal alcohol syndrome do not meet criteria for intellectual disability[1] (a <70 IQ cutoff), they still show significant intellectual impairment. One study cites their average IQ’s as 78 for verbal, 77 for performance, and 75 for full-scale IQ; these values are significantly lower when compared to those of healthy controls[3]. Since intelligence is such a multi-faceted concept that is difficult to operationalize, factors that may weigh into this reduction in IQ is listed below.

Executive Functioning

Given the widely recognized role of the frontal lobes in executive functioning and the cortical abnormalities found in fetal alcohol syndrome[4], it is not surprising that executive functioning deficits have been found in those with prenatal alcohol exposure. Children with fetal alcohol syndrome have been shown to demonstrate longer reaction times, as well as poorer performance in spatial working memory and problem solving tasks[5]. Such poor executive functioning could have a negative impact on one’s intelligence and performance on an IQ test.

Language Skills

Language skills are often compromised in those with fetal alcohol syndrome, which can intuitively be related to the abnormalities observed on the lateral aspect[4] and temporal lobe[7] of brains exposed to alcohol prenatally, since these areas are associated with language comprehension and production. In fact, both comprehension and production has been observed to be impaired in children with fetal alcohol syndrome[7,8], though they generally tended to do better on receptive language tasks[8]. It is worth noting that such language deficits may also be a factor impeding the performance of children with fetal alcohol syndrome.

Attention and Activity

Attention and Activity in FAS and ADHD
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Schematic summary of similarities and differences between fetal alcohol
syndrome and ADHD. Reprinted from “Fetal alcohol spectrum disorders: Neuropsychological
and behavioral features,” by Mattson, S.N. et al, Neuropsychology Review, 21(1) .

Children with fetal alcohol syndrome also often present with problems in attention and activity levels, which may also have an impact on the performance on tests of intelligence. In fact, there is a significant subset of children with fetal alcohol syndrome who are also diagnosed with Attention Deficit Hyperactivity Disorder (ADHD)[9]. At the same time, however, there is growing evidence suggesting that the nature of the problems in attention and activity levels between those observed in fetal alcohol syndrome and ADHD. Many aspects, including performance in set shifting tasks, social skills, and communication skills, are similar in fetal alcohol syndrome and ADHD children[1]. On the other hand, children with ADHD tend to, for example, have more problems with focused and sustained attention than those with fetal alcohol syndrome, while problem solving and language deficits may show the opposite pattern[1].

Motor Impairment

Aspects other than cognitive function can be affected in fetal alcohol syndrome, including motor skills. Children with fetal alcohol syndrome have been shown to present with developmental delays in motor movement, especially in their gross motor skills[10]. Adding on, such delays and impairment in motor skill and development showed a linear relationship to the amount of alcohol exposure[10]. This could in part have to do with basal ganglia and cerebellar dysmorphologies[11,12], as well as the altered cortical thicknesses around the frontal and parietal lobes[4,7].

Social Skills Deficits

Adding on to cognitive and motor abnormalities, social skills deficits are also observed in children with prenatal alcohol exposure. Affected children were found to be evaluated with poorer scores on the Social Skills Rating System[13] when compared to healthy controls. The same study also showed gender differences in the effects of alcohol exposure: girls were more heavily affected than boys in terms of showing social, internalizing, and behavioural problems[13].

Bibliography
1. Mattson, S.N., Crocker, N., & Nguyen, T.T. Fetal alcohol spectrum disorders: Neuropsychological and behavioral features. Neuropsychology Review 2011; 21(1): 81-101.
2. Kully-Martens, K., Denys, K., Treit, S., Tamana, S., & Rasmussen, C. A review of social skills deficits in individuals with fetal alcohol spectrum disorders and prenatal alcohol exposure: Profiles, mechanisms, and interventions. Alcoholism: Clinical and Experimental Research 2011; 36(4): 568-576.
3. Dalen, K., Bruarøy, S., Wentzel-Larsen, T., & Lægreid, L.M. Cognitive functioning in children prenatally exposed to alcohol and psychotropic drugs. Neuropediatrics 2009; 40(4): 162-167.
4. Sowell, E.R., Mattson, S.N., Kan, E., Thompson, P.M., Riley, E.P., & Toga, A.W. Abnormal cortical thickness and brain-behavior correlation patterns in individuals with heavy prenatal alcohol exposure. Cerebral Cortex, 2009; 18(1): 136-144.
5. Green, C.R., Mihic, A.M., Nikkel, S.M., Stade, B.C., Rasmussen, C., Munoz, D.P., & Reynolds, J.N. Executive function deficits in children with fetal alcohol spectrum disorders (FASD) measured using the Cambridge Neuropsychological Tests Automated Battery (CANTAB). Journal of Child Psychology and Psychiatry 2009; 50(6): 688-697.
6. Sowell, E.R., Mattson, S.N., Kan, E., Thompson, P.M., Riley, E.P., & Toga, A.W. Abnormal cortical thickness and brain-behavior correlation patterns in individuals with heavy prenatal alcohol exposure. Cerebral Cortex, 2009; 18(1): 136-144.
7. Sowell, E.R., Thompson, P.M., Mattson, S.N., Tessner, K.D., Jernigan, T.L., Riley, E.P., & Toga, A.W. Voxel-based morphometric analyses of the brain in children and adolescents prenatally exposed to alcohol. Neuroreport 2001; 12(3): 515-523.
7. Wyper, K.R. & Rasmussen, C.R. Language impairments in children with fetal alcohol spectrum disorder. Journal of Population Therapeutics and Clinical Pharmacology 2011; 18(2): e364-e376.
8. McGee, C.L., Bjorkquist, O.A., Riley, E.P., & Mattson, S.N. Impaired language performance in young children with heavy prenatal alcohol exposure. Neurotoxicology and Tetratology 2009; 31(2), 71-75.
9. Fryer, S.L., McGee, C.L., Matt, G.E., Riley, E.P., & Mattson, S. Evaluation of psychopathological conditions in children with heavy alcohol exposure. Pediatrics 2007; 119(3), e733-e741.
10. Kalberg, W.O., Provost, B., Tollison, S.J., Tabachnick, B.G., Robinson, L.K., Hoyme, H.E., Trujillo, P.M., Buckley, D., Aragon, A.S., & May, P.A. Comparison of motor delays in young children with fetal alcohol syndrome to those with prenatal alcohol exposure and with no prenatal alcohol exposure. Alcoholism: Clinical and Experimental Research 2006; 30(12), 2037-2045.
11. Mattson, S.N., Riley, E.P., Sowell, E.R., Jernigan, T.L., Sobel, D.F., Lyons Jones, K. A decrease in the size of the basal ganglia in children with fetal alcohol syndrome. Alcoholism: Clinical and Experimental Research 1996; 20(6): 1088-1093.
12. O’Hare, E.D., Kan, E., Yoshii, J., Mattson, S.N., Riley, E.P., Thompson, P.M., Toga, A.W., & Sowell, E.R. Mapping cerebellar vermal morphology and cognitive correlates in prenatal alcohol exposure. Developmental Neuroscience 2005; 16(12): 1285-1290.
13. Rasmussen, C., Becker, M., McLennan, J., Urichuk, L., & Andrew, G. An evaluation of social skills in children with and without prenatal alcohol exposure. Child: Care, Health and Development 2011; 37(5): 711-718.

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