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Published on: August 25, 2014
French angles: a simple aid to neurodevelopmental examination
Insights
Passive range of motion, measured by "French angles," gradually increases in infants, indicating muscle relaxation. This simple goniometer measurement can help screen for neuromuscular disorders in babies.
Area of Science:
- Pediatric Neurology
- Developmental Pediatrics
- Biomedical Engineering
Background:
- Passive tone, a measure of muscle lengthening capacity, is crucial for assessing infant neurodevelopment.
- Existing methods for assessing passive tone can be subjective and lack quantitative precision.
- The "French angles" offer a potential objective measure of passive movement and muscle extensibility.
Purpose of the Study:
- To establish normative data for "French angles" in healthy infants aged 1-52 weeks.
- To evaluate the reliability and simplicity of using a goniometer for measuring "French angles" by non-expert examiners.
- To explore the utility of "French angles" as a screening tool for infant neuromuscular disorders.
Main Methods:
- Fifty healthy infants (1-52 weeks) had passive joint range of motion measured using a plastic goniometer to determine "French angles."
- Measurements were taken by non-expert examiners to assess practical application.
- Three infants with known neuromuscular disorders (cerebral palsy, Werdnig Hoffman syndrome) were included for comparison.
Main Results:
- "French angles" increased linearly and predictably from birth to one year, except for ankle dorsiflexion, indicating gradual relaxation of passive tone.
- Infants with cerebral palsy exhibited reduced adductor angles, consistent with adductor spasm.
- The infant with Werdnig Hoffman syndrome showed an increased adductor angle, suggesting increased extensibility.
Conclusions:
- "French angles" provide a quantitative, reliable, and simple method for assessing neurological maturation in infants.
- The measurement complements routine neurodevelopmental assessments and shows potential as a screening tool for neuromuscular conditions.
- Normative data suggest a gradual decrease in passive muscle tone during the first year of life.
Abstract:
"French angles" are the amplitude of passive movement at a single joint, which can be easily measured using a goniometer, and reflect the lengthening capacity of muscles--a component of passive tone. Fifty infants aged 1-52 weeks had their "French angles" measured by non-expert examiners using a plastic goniometer. All the angles measured, except ankle dorsiflexion, increased in a predictable, linear fashion from birth to one year of age. Thus in normal term infants passive tone gradually relaxes from birth to the age of one year. Three additional infants with known neuromuscular disorders were found to have angles outside the obtained normal range. The babies with cerebral palsy had reduced adductor angles reflecting adductor spasm, and the baby with Werdnig Hoffman syndrome had an increased adductor angle reflecting increased adductor extensibility. The results provide a quantitative measurement of neurological maturation during infancy, and should complement the routine neurodevelopmental assessment. The method proved quick, simple and reliable, and may become useful as a screening test for neuromuscular disorders.
