Relationship between central hypotonia and motor development in infants attending a high-risk neonatal neurology clinic

Purpose: To study the relationship between central hypotonia and motor development, and to determine the relative contribution of nuchal, truncal, and appendicular hypotonia domains to motor development. Methods: Appendicular, nuchal, and truncal tones of high-risk infants were assessed, as was their psychomotor developmental index (PDI). Infants with peripheral hypotonia were excluded. Results: We included 164 infants (mean age 9.6 ±4 months), 36 with normal tone in all 3 domains and 128 with central hypotonia. Twenty-six of the latter had hypotonia in 1 domain and 102 had multiple combinations of 3 domains. Hypotonia domains were distributed as follows: truncal (n = 115), appendicular (n = 93), and nuchal (n = 70). Each domain was significantly associated with PDI scores (P < .001) but not with a later diagnosis of cerebral palsy. On linear regression, nuchal hypotonia had the strongest contribution to PDI scores (β =-0.6 [nuchal], -0.45 [appendicular], and -0.4 [truncal], P < .001). Conclusions: Central hypotonia, especially nuchal tone, is associated with lowered motor development scores.