Abstract: Objective To investigate the characteristics of motor development in children with mental retardation. Methods Motor development was assessed with the Peabody Developmental Motor Scale 2 (PDMS-2) and mental development with adaptive developmental quotient (ADQ) of Gesell developmental schedules (GDS) in 430 infants (6~36 months old) with mental retardation. Results The gross (GDQ), fine (FDQ) and total motor developmental quotient were poor in all the children, and significantly different among children with slight, mild, and serious retardation (P<0.01). ADQ correlated with each sub-score of PDMS-2 (P<0.01). For PDMS-2, FDQ correlated with sub-scores of gross motor, and GDQ with sub-scores of fine motor (P<0.01) in all the mental retardate children. Conclusion The development of both gross and fine motor is poor in children with mental retardation. Mental development correlate with motor development, and gross with fine motor development.

Key words: mental retardation, Peabody Developmental Motor Scale, gross motor, fine motor