This study investigated the concurrent and construct validity of the Posture and Fine Motor Assessment of Infants (PFMAI) (Case-Smith, 1991). The subjects were 90 infants, 65 of whom were healthy and full-term and 25 of whom were premature and had medical risk factors.
Concurrent validity was investigated through administration of the Peabody Developmental Motor Scales (Folio & Fewell, 1983) and the PFMAI (n = 25). Strong positive correlations resulted between the Peabody Gross Motor scale and PFMAI Posture scale and between the Peabody Fine Motor scale and PFMAI Fine Motor scale. Concurrent validity was also measured through correlation scores on the Bayley Scales of Infant Development (Bayley, 1969) with scores on the PFMAI. The correlations between the Bayley Motor scale and the PFMAI Posture scale and between the Bayley Mental scale and the PFMAI Fine Motor scale were high.
Construct validity was estimated through an evaluation of how accurately the PFMAI discriminated between the premature subjects and the full-term subjects . A discriminant analysis indicated that the PFMAI accurately classified 78% of the subjects as being either premature or full-term (i.e., 80% of the full-term subjects and 72% of the premature subjects). When the premature subjects were categorized as low-risk or high-risk according to their medical histories, the PFMAI accurately classified 66.7% of the total subject population as full-term, low-risk premature, or high-risk premature. These results indicate that the PFMAI has the adequate reliability and validity necessary for use as a clinical and a research instrument. Uses of this instrument include obtaining baseline data for planning therapy and evaluating the short-term effectiveness of intervention focused on enhancing posture and movement. The PFMAI can assist occupational therapists in analyzing posture and movement when using a neurodevelopmental approach and provides a prototype for objective measurement of the qualitative aspects of movement.