From the Guidelines
The Bayley Infant Neurodevelopmental Screener (BINS) is the most appropriate neurological exam for a 3-month-old baby, as it is a 10- to 15-min screen for neurological impairment or developmental delay with strong internal consistency and interrater reliability 1. When performing a neurological exam on a 3-month-old baby, it is essential to assess various aspects of development, including primitive reflexes, muscle tone, posture, cranial nerves, and developmental milestones.
- The exam should begin with observing the infant's general appearance, head shape, and spontaneous movements.
- Check head circumference and fontanelles, as these can provide valuable information about brain development.
- Assess primitive reflexes, including Moro, rooting, sucking, palmar and plantar grasp, and tonic neck reflexes, noting that some should be fading by this age.
- Evaluate muscle tone by observing posture at rest and resistance to passive movement; a 3-month-old should have decreasing flexor tone.
- Test cranial nerves by checking pupillary response to light, tracking objects visually, facial symmetry during crying, and response to sounds.
- Assess motor skills, including head control (should hold head steady when pulled to sitting), beginning to push up on forearms during tummy time, and bringing hands to midline. The BINS is a valuable tool in this assessment, as it provides a comprehensive screen for neurological impairment or developmental delay in infants from 3 to 24 months old, with test-retest reliability of 0.71-0.81 and strong internal consistency 1. Any asymmetry, persistent primitive reflexes that should be disappearing, absent age-appropriate reflexes, or failure to meet developmental milestones warrants further investigation, and the BINS can help identify these potential issues early on.
From the Research
Neurological Exams for 3-Month-Old Babies
- The Denver II screening test has been widely used and restandardized in many countries, with a major revision in 1992 2.
- However, its effectiveness in screening biologically vulnerable infants, such as those with low birth weight, has been questioned due to the limited validational support available for its use with children under 30 months of age 3.
- A study in 2019 provided guidance on conducting a thorough neurological examination of infants, including evaluating motor and sensory function, assessing cranial nerves, and testing primitive reflexes 4.
- The Hammersmith Infant Neurologic Examination (HINE) has been shown to have high predictive value in identifying cerebral palsy at 2 years of age, with movement quality and quantity being the most predictive items 5.
- For a 3-month-old baby, the HINE may be a suitable option, as it has been explored longitudinally in infants from 3 to 12 months post-term age 5.
- The Denver-II has been found to have fair accuracy in discriminating risk of Developmental Coordination Disorder (DCD) at school age in children born preterm, but its effectiveness in screening for other neurological conditions is still limited 6.