Spasticity, Dystonia Commonly Under-Identified in Children With High Cerebral Palsy Risk

Bhooma Aravamuthan, MD, DPhil

Findings from a single-center study showed a low rate of child neurologists specifying the specific type of hypertonia—either spasticity or dystonia—in children who may be at high-risk for cerebral palsy following neonatal brain surgery. The study authors concluded that educational efforts should be directed at helping identify specific tone types with regard to cerebral palsy diagnostic evaluation and early treatment selection.

This retrospective analysis included 168 children who underwent whole-body therapeutic hypothermia for hypoxic-ischemic encephalopathy, with the goal to determine how comfortable experts were in documenting the specific type of tone observed in their patients as opposed to hypertonia” alone. All individuals had clinical notes on motor assessments reviewed through age 5 years.

Senior author Bhooma Aravamuthan, MD, DPhil, assistant professor of pediatric neurology, Department of Neurology at Washington University in St. Louis, and colleagues used logistic regression to determine which subject variables affected the odds of practitioners specifying the tone type versus hypertonia alone. Of the 168 children, 83 demonstrated no motor abnormalities and 22 had only hypotonia without hypertonia.

Of the remaining 63 children, only 19 (30%) had their hypertonia type specified as either only spasticity (4 of 19), only dystonia (4 of 19), or both types of tone (11 of 19). In contrast, the other 44 children (70%) were identified as having hypertonia without the type of tone abnormality specified.

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Aravamuthan et al wrote that these findings suggest an important actionably step in that "we must make clear that a diagnosis of hypertonia is insufficient and should include a description of the type of tone abnormality. Identifying the type of hypertonia early is important for cerebral palsy diagnostic workup, differentiating cerebral palsy from potential cerebral palsy mimics, meeting family expectations, and for early institution of the appropriate tone-specific treatments that could have a direct and potentially time-sensitive impact on patient function."

In total, 38 children were documented as having both hypertonia and hyperreflexia, but only 15 of those children (39%) were identified explicitly has having spasticity. This indicated that most children who demonstrated key examination features of upper motor neuron injury, and therefore likely had spasticity on examination, did not have spasticity explicitly identified.

The average age for the identification of spasticity or dystonia among the 19 identified patients was 1.8 years on average (95% CI, 1.3-2.4 years); however, unspecified hypertonia was identified earlier, on average by age of 10.2 months (95% CI, 4.2-15.6 months [0.35-1.3 years]). By the time they were 6 months old, 46 of the 63 children who were documented as having persistent hypertonia had their hypertonia identified.

Using the logistic regression model, investigators found that markers of more severe neonatal hypoxic-ischemic encephalopathy helped predict whether a practitioner would identify spasticity or dystonia by the time a child turned 5 years old (P <.005). As opposed to those identified as having hypertonia without further tone type specification, children who were ultimately identified as having spasticity or dystonia had significantly more several neonatal encephalopathy scores (P = .009) and were more likely to have seizures during the neonatal period (P = .008).

There were some notable limitations to the study, including the fact that this was conducted at a single-center and that results may not be generalizable to all centers. Aravamuthan et al. noted that it was possible that experts were able to identify that a child’s hypertonia type was spasticity or dystonia but simply chose not do document that in the medical record. Additionally, other motor abnormalities, such as ataxia, athetosis, and chorea, which may be present in children with cerebral palsy, were not assessed.

Aravamuthan has been at the forefront with trying to improve the diagnosis for children with cerebral palsy, as well as the role that child neurologists and neurodevelopmentalists play in that increasingly complicated process. Watch below as she discussed the state of cerebral palsy care and how multiple specialists fit into the care for these patients with NeurologyLive® in early 2021.

REFERENCE

Miao H, Mathur AM, Aravamuthan BR. Spasticity and dystonia are underidentified in young children at high risk for cerebral palsy. J Child Neurol. Published online December 6, 2021. doi:10.1177/08830738211059683