Hand Assessment for Infants: normative reference values.

Aim: To create normative reference values for unilateral and bilateral use of the hands, using the Hand Assessment for Infants (HAI), a newly developed criterion-referenced assessment measuring hand use in infants aged 3 months to 12 months at risk of cerebral palsy (CP).

Method: In total, 489 HAI assessments of typically developing infants (243 females, 246 males), aged 3 months to 10 months (mean 6mo 14d [SD 2mo 5d]), were collected in Italy and Sweden. Normative growth curves based on mean and SDs were created, as well as skill acquisition curves for each test item. Correlation to age and differences between groups based on sex and nationality, as well as differences between the right and the left hand, were investigated.

Results: The growth curves showed a steady increase in mean value and a decrease in SD over age. There were no differences between groups based on sex or nationality. There was a negligible mean difference (0.1 raw score) between the right and left hands.

Interpretation: HAI normative reference values are now available, which can assist in identifying deviating hand use for each month of age, as well as a side difference between hands in infants at risk of CP.

What This Paper Adds: A Hand Assessment for Infants (HAI) result greater than 2SD below the mean indicates atypical hand use. Skill acquisition curves describe the age at which typically developing infants master the HAI items. Most typically developing infants do not demonstrate asymmetry in hand use.