An easily derived Hammersmith Infant Neurological Examination asymmetry score, in combination with the total HINE score, differentiates typically developing infants from those with hemiplegic CP.
While cerebral palsy can now be diagnosed at 6 months of age – allowing for earlier interventions and better potential outcomes than ever before – evaluation can be difficult in very young children. Differences between typically developing infants and those with CP aren’t always clear; tools and specialized training that aid in diagnosis may be available in academic medical centers, but not in community clinics.
A recent study from the Nationwide Children’s Hospital Early Developmental Group may offer some solutions to both of those problems. The group’s physicians, researchers and therapists have shown that an asymmetry score from the Hammersmith Infant Neurological Examination (HINE), used in combination with that exam’s total score, can effectively differentiate young children with hemiplegic CP from typically developing children.
“The HINE is a very useful tool, and it is widely available, but the total score cannot always indicate relatively mild cases of CP,” says Nathalie Maitre, MD, PhD, director of Nationwide Children’s NICU Follow-up Programs and senior author of the study. “This asymmetry score takes no additional time to complete, but it makes our ability to differentiate much more precise.”
The study considered 74 infants with confirmed clinical diagnoses of CP, including 35 with hemiplegia. Thirteen of the children with hemiplegia had total HINE scores above 63 – that is, total scores that do not normally indicate cerebral palsy.
The study’s authors calculated a separate but related asymmetry score. If an item on the HINE test contained an asymmetry between the right and left sides, that item was given a score of 1. Every child with hemiplegia had an asymmetry score of at least 6 (and as high as 17), even if the total score was above the usual cerebral palsy cutoff.
No child with diplegia had an asymmetry score higher than 3, and children with quadriplegia had asymmetry scores ranging from 0 to 15.
The authors ultimately found that a total HINE score less than 63, with a HINE asymmetry score above 5, has a sensitivity of 91.8 percent and a specificity of 100 percent in differentiating hemiplegia from typical development. But even if the total score does not suggest a diagnosis of cerebral palsy, a child with an asymmetry score higher than 5 should be referred.
“These kinds of cutoffs are important for a couple of reasons,” says Dr. Maitre, who is also a principal investigator in the Center for Perinatal Research at Nationwide Children’s. “First, as a trained early intervention provider, you have a clear idea of when to call a specialist. If you have a 6-month old with an asymmetry score of 8, don’t wait. You also get some reassurance that a child with only two measures of asymmetry with a total HINE score above the cutoff is likely developing normally at that time.”
These cutoffs are especially important for using the HINE because of its accessibility. The exam is freely available to care providers, training is often free and the exam itself can take as little as five minutes. It is as easy to use by a trained, early intervention specialist in a rural area as it is in a tertiary metropolitan pediatric hospital. And it gives everyone who uses it a common language in speaking about cerebral palsy recognition.
“Other tools are great, and important for research, but they are not always affordable in clinical practice,” says Dr. Maitre. “The HINE is feasible in most settings. This study and others show how critical it can be in getting children with cerebral palsy the early attention they need.”
Hay K, Nelin M, Carey H, Chorna O, Moore-Clingenpeel Ma Mas M, Maitre N; NCH Early Developmental Group. Hammersmith Infant Neurological Examination asymmetry score detects hemiplegic cerebral palsy from typical development. Pediatric Neurology. 2018 Jul 25. [Epub ahead of print]