Thursday, October 21, 2021
October is Spina Bifida Awareness Month, and like all awareness months’ it is a good opportunity to learn something new. For me, it has been some time since I explored the research for Spina Bifida, so it was a good prompt to pause and take a look on PubMed to see what research I could find.
The incidence of babies born with Spina Bifida has decreased since the link to maternal folate intake was observed, however a small number of babies continue to be born each year with Spina Bifida. For many of us, older children and adults with Spina Bifida form part of our caseload, where we regularly see the diversity of presentations and abilities within this group.
For those who are less familiar with Spina Bifida, Spina Bifida is a type of neural tube defect that occurs when a baby’s neural tube fails to develop or close properly – the literal meaning for Spina Bifida is ‘split spine’. Typically occurring within the first 28 days of pregnancy (while the neural tube is forming), Spina Bifida often occurs before a woman knows she is pregnant. The cause of this neural tube defect is unknown; however it is believed to be a complex mix of both genetic and environmental factors acting together.
There are three types of Spina Bifida
Spina Bifida Occulta – this form usually does not cause any impairment and does not have any visible signs as the spinal cord and nerves are unaffected. It is typically discovered as an incidental finding on an X-Ray that is done for other reasons.
Meningocele – this causes part of the spinal cord to come through the spine like a sac that is pushed out. Nerve fluid is in the sac, and there is usually no nerve damage. Individuals with this condition may have minor disabilities.
Myelomeningocele (also called Spina Bifida Cystica) - this is the most severe form of Spina Bifida. This happens when parts of the spinal cord and nerves come through the open part of the spine. It causes nerve damage and other disabilities.
The Spina Bifida Association of America offers an impressive number of resources for families, clinicians and educators, and they appear to be linked to the publication of a number of care guidelines for people with Spina Bifida. One recently published guideline relates to skin integrity guidelines over childhood and into adulthood (Beierwaltes et al, 2020), while another that caught my interest was the Neuropsychological Care Guidelines (Queally et al, 2020).
Prior to looking at the neuropsychological care guidelines, it is worth noting that Spina Bifida Myelomeningocele (SBM) is also associated with a collection of changes in the brain. Looking at an article published by Juranek and Salman (2010), it is acknowledged that the failure in neural tube closure at the level of the spine also results in altered brain development, in both its structure and how it functions. Studies have documented a remarkable degree of variation among individuals with SBM in terms of the size, shape, and appearance of the cerebellum, corpus callosum, and cerebral cortex. Similarly, a wide range of cognitive strengths and relative weaknesses among individuals with SBM are also documented in the published literature.
Common structural characteristics associated with SBM include (Juranek and Salman 2010)
Changes in the development of the skull
Chiari II malformation – complex changes that involve the midbrain and hindbrain (i.e. pons, medulla, and the cerebellum) and cervical spinal cord, it is also associated with a significantly smaller posterior fossa with its contents crowded and distorted in appearance
Corpus callosum hypoplasia and dysgenesis
(For an overview of the anatomy of the brain, please see https://www.hopkinsmedicine.org/health/conditions-and-diseases/anatomy-of-the-brain)
Coming back to the neuropsychological care guidelines (Quelly et al 2020), it is noted that individuals with Spina Bifida show a pattern of strengths and weakness across different areas, with a particular pattern seen with individuals who are born with a myelomeningocele, as comparted to individuals born with other types of Spina Bifida, who tend to have a more typical cognitive development.
Individuals with Spina Bifida Myelomeningocele (SBM) tend to show strengths in learning skills that rely on rule-based processing (e.g., math fact retrieval, word reading) but have some difficulties when learning how to integrate this information (e.g., math problem-solving, reading comprehension). In language and reading areas, vocabulary, grammar, and word recognition are strengths, however, children with SBM experience challenges in listening and reading comprehension, with the cause of these challenges being linked to changes in the corpus callosum. In mathematics, children with SBM can learn math facts; however, complex procedures that require multiple steps and algorithms are an area of challenge. They often experience difficulties with estimating quantities and have impaired math problem-solving skills.
Many children with SBM also meet criteria for Attention Deficit/Hyperactivity Disorder, however their presentation differs to children with developmental forms of ADHD related to self-regulation. The attention profile of children with SBM is characterized by under-arousal and are related to disruptions in midbrain and posterior cortex, with evidence of this present from infancy.
There remains a large amount of variability in the neuropsychological outcomes of people with SBM, these can be attributed to variability in the changes in the brain, as well as variables that impact on all individuals, such as socio-economic status and education. Health related challenges, such as more severe hydrocephalus or repeated shunt malfunctions can also influence outcomes, and individuals with higher lesion levels have more severe neuroanatomic brain malformations and higher rates of intellectual disability.
The neuropsychology guidelines offer evidence based or best practice recommendations for children by age group, highlighting different areas of cognitive development that needs to be considered. The ultimate goal for these guidelines is to maximise a person’s performance in education and in turn their ability to participate in both employment and independently in the wider community.
Another article that caught my attention was the The Management of Myelomeningocele Study by Farmer et al (2018). This article followed on from previously published research on this randomised control trial. The Management of Myelomeningocele Study (MOMS) was a multi-centre study comparing outcomes of an antenatal repair to the traditional postnatal repair, with 183 people recruited for the study, randomised into two groups. Eligible patients were women carrying a foetus diagnosed with Spina Bifida Myelomeningocele between 19-25 weeks gestation. Initial outcomes of the study demonstrated that prenatal repair of the myelomeningocele reduced the need for cerebrospinal fluid shunting and improved neurologic function. A urologic subgroup study identified that prenatal surgery did not reduce the need for clean intermittent catherization, however it did reduce the incidence of secondary complications of the bladder. The prenatal surgery group featured less females and the level of the lesion tended to be higher, however when followed up at 30 months of age, children in this group were more likely to have a level of function better than expected according to the anatomical level of the lesion. The prenatal group were also more likely to walk (44.8% vs 23.9%) and have better gross motor skills.
The research team explored the prenatal surgery group further, to help identify which children are likely to benefit most from the prenatal surgery, given prenatal surgery does not come without its risks. Looking at the 39 children who later gained independent walking, these children all demonstrated spontaneous hip movement (with 38 also demonstrating knee movement) in their antenatal ultrasound. However only approximately half of those shown to have hip or knee movement on ultrasound could later walk. For the nine children who did not demonstrate any hip movement on ultrasound, none of these children could walk independently at 30 months. Other factors that correlated with the ability to walk included the level of the lesion and the absence of a sac over the lesion, however the need for a shunt was not associated with motor function. The 30 month review also assessed for cognitive development, however no differences in cognitive development were seen between the groups.
For those who are keen to learn more about Spina Bifida, the American Spina Bifida awareness website is well worth a visit, other resources include orthopaedic management, aging with Spina Bifida and general wellbeing, not to mention easy to read resources for parents.
https://www.spinabifidaassociation.org/ - American Spina Bifida Association
Beierwaltes, P., Munoz, S. & Wilhelmy, J. (2020) Integument: Guidelines for the care of people with spina bifida. Journal of Pediatric Rehabilitation Medicine: An Interdisciplinary Approach. 13: 543-548 DOI 10.3233/PRM-200723
Farmer, D.L., Thom, E.A., Brock, J.W., Burrows, P.K., Johnson, M.P., et al (2018) The Management of Myelomeningocele Study: full cohort 30-month pediatric outcomes. Americal Journal of Obstetrics & Gynecology. https://doi.org/10.1016/j.ajog.2017.12.001
Juranek, J. & Salman, M.S. (2010) Anomalous development of brain structure and function in spina bifida myelomeningocele. Dev Disabil Res Rev. 16(10) 23-30. doi:10.1002/ddrr.88.
Quelly, Q.T., Barnes, M/A., Castillo, H., Castillo, J., Fletcher, J.M. (2020) Neuropsychological care guidelines for people with spina bifida. Journal of Pediaric Rehabilitation Medicine: An Interdisclipinary Approach. 13: 663-673 DOI 10.3233/PRM-200761