Correlations between motor performance and cognitive functions in children born < 1250 g at school age

Very low birth weight born children manifest a higher prevalence of motor and cognitive impairments than term children. Seventy-four prospectively enrolled children born < 1250 g underwent testing of motor (Zurich neuromotor assessment ZNA: timed motor performances and associated movements) and cognitive functions (Kaufman-ABC) at age six years. Children with cerebral palsy or mental retardation were excluded. Adaptive motor tasks (pegboard and dynamic balance) and visuomotor cognitive functions were specifically impaired, and a distinct correlation pattern between motor and cognitive abilities was detected. The adaptive fine motor task (pegboard) correlated with visuomotor functions of the Kaufman-ABC ("triangles", r = 0.35; "matrix analogies", r = 0.39), while pure motor tasks of the ZNA (repetitive, alternating, and sequential movements) did not in spite of impaired motor performance. Timed motor performance below the 10th percentile correlated strongly with cognitive delay (IQ < 85: adaptive fine motor: OR 6.0 [95% CI] 4.7-7.3; adaptive gross motor: OR 7.0 [CI 5.6-8.4]; static balance: OR 9.6 [CI 8.2-11.0]). In conclusion, motor deficits in children born < 1250 g without severe disabilities correlate with specific cognitive impairments, in particular of the visuomotor domain. The correlation pattern may indicate specific dysfunction in visuomotor transformation, the intermediate process between visual-perceptual input and motor output. Early assessment of both motor and cognitive functions using standardized assessment tools is important to determine the extent and combination of specific developmental disturbances and to tailor therapeutic intervention.