Situation: A nurse works in the pediatric rehabilitation clinic and the emergency room of a regional hospital. During developmental screening, which finding in an 8-month-old should the nurse recognize as an early sign of cerebral palsy?

Hand preference before about 12 months suggests weakness of the other side and is an early sign of cerebral palsy, along with persistent primitive reflexes, abnormal tone, scissoring, and delayed motor milestones. At 8 months the Moro reflex has normally disappeared, stranger anxiety is expected, and sitting without support is a normal milestone.

Core answer

The correct finding is preference for using one hand. In an 8-month-old infant, consistent use of one hand while the other remains relatively inactive is not a normal developmental variation—it reflects asymmetric motor function. Before about 12 months of age, infants typically use both hands fairly equally, so early unilateral hand preference raises concern for weakness or abnormal tone on the opposite side, which is a recognized early sign of cerebral palsy.

Why the other options are expected findings at 8 months

Crying when a stranger comes near describes stranger anxiety, a normal social-emotional milestone that commonly emerges between 6 and 9 months. It reflects healthy attachment and cognitive recognition of familiar versus unfamiliar people, not neurologic impairment.

Sitting alone without support is a normal gross motor milestone. Most infants achieve independent sitting between 6 and 8 months, so an 8-month-old who sits unsupported is developing appropriately.

Absent Moro reflex when startled is expected at this age. The Moro reflex normally integrates and disappears by 4 to 6 months. Its absence at 8 months is not a warning sign; rather, persistence of the Moro reflex beyond the expected integration period would be the concerning finding, because retained primitive reflexes are associated with cerebral palsy.

Pathophysiology and clinical reasoning

Cerebral palsy results from a non-progressive injury or malformation in the developing brain that disrupts motor control. When the lesion affects one hemisphere—such as in spastic hemiplegic cerebral palsy—the contralateral side of the body shows increased tone, weakness, or reduced spontaneous movement. An infant with right-sided weakness will naturally favor the left hand for reaching and grasping because the left hand moves more easily and effectively. Early hand preference before 12 months is therefore a lateralizing sign that points to asymmetric neurologic function, not simply a behavioral quirk.

The case report by Kastner and colleagues describes a 9-month-old boy whose presenting features included unequal hand movements and right-hand preference on examination; brain MRI revealed cortical dysplasia, and the diagnosis was cerebral palsy ^[2]. This illustrates that early hand preference can be one of the earliest observable clues to cerebral palsy, even when classic risk factors such as prematurity or intrapartum complications are absent ^[2]. The authors also note that while spasticity is the most common neurologic sign, other presentations include early hand preference, hypotonia, and oral motor dysfunction ^[2].

A systematic review of warning signs for neurodevelopmental disorders identified motor-domain red flags including delayed sitting and other early motor asymmetries . Although the abstract is truncated, the grouping of motor signs as early indicators aligns with the principle that asymmetric motor development—manifesting as early hand preference—warrants prompt developmental evaluation .

Differential considerations in developmental screening

Finding at 8 months	Normal or expected	Concerning for cerebral palsy
Stranger anxiety	Expected; emerges 6–9 months	Not a motor sign
Sits without support	Expected; milestone at 6–8 months	Delayed sitting beyond 9 months is a red flag
Absent Moro reflex	Expected; integrated by 4–6 months	Persistence beyond 6 months is concerning
Consistent one-hand preference	Not expected before 12 months	Early sign of asymmetric motor function [2]

Key point! The timing of a finding matters as much as the finding itself. Hand preference, retained primitive reflexes, and delayed motor milestones are only red flags when they occur outside the expected developmental window.

Watch out! Do not confuse absent Moro reflex with persistent Moro reflex. At 8 months, absence is normal; persistence would be the abnormal finding associated with cerebral palsy.

Nursing implications for screening

During developmental screening, the nurse should observe how the infant reaches for and manipulates toys. An 8-month-old who consistently reaches with only one hand, keeps the other hand fisted, or shows visible asymmetry in spontaneous movement should be referred for further neurologic evaluation. The finding of early hand preference does not confirm cerebral palsy by itself, but it is a red flag that warrants closer developmental surveillance and possible imaging or specialist referral ^[2].