SLPs Blogging About Research: August Edition -FASD

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This month I am joining the ranks of bloggers who are blogging about research related to the field of speech pathology.  Click here for more details.

Today I will be reviewing a recently published article in The Journal of Neuroscience  on the topic of brain development in children with Fetal Alcohol Spectrum Disorders (FASD), one of my areas of specialty in speech pathology.

Title: Longitudinal MRI Reveals Altered Trajectory of Brain Development during Childhood and Adolescence in Fetal Alcohol Spectrum Disorder

Purpose: Canadian researchers performed advanced MRI brain scans of 17 children with FASD between 5 and 15 years of age and compared them to the scans of 27 children without FASD. Each participant underwent 2-3 scans and each scan took place 2-4 years apart. The multiple scan component over a period of time is what made this research study so unique because no other FASD related study had done it before.

Aim of the study: To better understand how brain abnormalities evolve during key developmental periods of behavioral and cognitive progression via longitudinal examination of within-subject changes in white brain matter (Diffusion Tensor Imaging – DTI) ) in FASD during childhood and adolescence.

Subjects: Experimental subjects had a variety of FASD diagnoses which included fetal alcohol syndrome (FAS), partial FAS (pFAS), static encephalopathy alcohol exposed (SE:AE), neurobehavioral disorder alcohol exposed (NBD:AE), as well as alcohol related neurobehavioral disorder (ARND). Given the small study size the researchers combined all sub diagnoses into one FASD group for statistical analysis.

In addition to the imaging studies, FASD subjects underwent about ∼1.5 h of cognitive testing at each scan, administered by a trained research assistant. The test battery included:

  • Woodcock Johnson Quantitative Concepts 18A&B (mathematics)
  • Woodcock Reading Mastery Test-Revised (WRMT-R) Word ID
  • Comprehensive Expressive and Receptive Vocabulary Test (CREVT)
  • Working Memory Test Battery for Children (WMTB-C)
  • Behavior Rating Inventory of Executive Function (BRIEF) parent form
  • NEPSYI/II (auditory attention and response set; memory for names, narrative memory; arrows).

9/17 participants in the FASD group were also administered the Wide Range Intelligence Test (WRIT) at scan 2.

Control subjects were screened for psychiatric and neurological impairments. Their caregivers were also contacted retrospectively and asked to estimate in utero alcohol exposure for their child. Of the 21 control subject caregivers who were reached, 14/21 reported no exposure, 2/21 unknown, and 5/21 reported minimal alcohol exposure (range: 1–3 drinks; average of two drinks total during pregnancy). Control subjects did not undergo a full battery of cognitive testing, but were administered WRMT-R Word ID at each scan.

Summary of results: The FASD group performed significantly below the controls on most of the academic, cognitive, and executive function measures  despite average IQ scores in 53% of the FASD sample. According to one of the coauthors, Sarah Treit,  “longitudinal increases in raw cognitive scores (albeit without changes in age-corrected standard scores) suggest that the FASD group made cognitive gains at a typical rate with age, while still performing below average”. For those of us who work with this population these findings are very typical.

Imaging studies revealed that over time subjects in the control group presented with marked increases in brain volume and white matter – growth which was lacking in subjects with FASD. Furthermore, children with FASD who demonstrated the greatest changes in white matter development (on scans) also made the greatest reading gains. Children with the most severe FASD showed the greatest diffusion changes in white matter brain wiring and less overall brain volume.

Implications: “This study suggests alcohol-induced injury with FASD isn’t static – those with FASD have altered brain development, they aren’t developing at the same rate as those without the disorder.” So not only does the brain altering damage exists in children with FASD at birth, but it also continues to negatively affect brain development through childhood and at least through adolescence.

Given these findings, it is very important for SLPs to perform detailed and comprehensive language assessments and engage in targeted treatment planning for these children in order to provide them with specialized individualized services which are based on their rate of development.

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