Infant seizures are a sudden, abnormal surge of electrical activity in the developing brain, causing temporary changes in movement, behavior, or consciousness. Unlike the dramatic full-body convulsions often seen in older children and adults, seizures in babies are frequently subtle and challenging to recognize due to the immaturity of their nervous system. Recognizing these presentations is important because the neonatal period (the first 28 days of life) is the time of highest risk for seizures, often signaling a serious underlying health concern. The symptoms depend heavily on the seizure type and the region of the brain involved.
Distinct Manifestations of Infant Seizures
Motor seizures involve repetitive, involuntary movements that cannot be stopped by gently restraining the baby’s limb. Tonic seizures are characterized by sustained stiffening or rigidity of the muscles, affecting the entire body or just a limb. This stiffening can cause the baby to arch their back, hold their arms and legs in fixed, awkward positions, or turn their head and eyes rigidly to one side.
Clonic seizures are rhythmic jerking movements, usually slower than a tremor. These movements are often focal or unilateral, occurring in a specific part of the body (e.g., one side of the face, a single arm, or a leg). The jerking may start in one area and then migrate to other parts of the body, a phenomenon known as a Jacksonian march, reflecting the spread of abnormal electrical activity across the motor cortex.
Myoclonic seizures are rapid, single, shock-like jerks lasting only a fraction of a second. These sudden movements can affect a finger, a limb, or the whole body, sometimes causing the baby’s head to nod or their arms to fling out. While these jerks can be isolated events, they often occur in clusters over a short period, especially around the time the baby is waking up or falling asleep. The classic generalized tonic-clonic seizures, which involve a loss of consciousness followed by both stiffening and sustained jerking, are rare in the youngest infants.
Non-Motor and Subtle Seizure Indications
Subtle seizures are the most common presentation in newborns and are frequently overlooked because they mimic normal infant behaviors. These seizures involve minimal or no gross motor activity, dominated instead by signs related to the eyes, face, and autonomic functions. One of the most common signs is sustained ocular deviation, where the eyes roll up or fixate to one side for several seconds, or rapid, uncontrolled eye movements like nystagmus or eyelid fluttering.
Oral-buccal movements are frequent indicators of subtle seizures, presenting as repetitive sucking, smacking, or chewing motions without feeding. The baby may also exhibit tongue protrusions or a fixed, vacant stare. These minor movements can be the sole manifestation of an ongoing seizure.
Autonomic and automatic movements can also signal a seizure event. This includes unusual pedaling or bicycling motions of the legs or thrashing movements that appear purposeless. A long pause in breathing (apnea) can be a symptom of a subtle seizure, although isolated apnea is more frequently due to non-neurological issues.
Normal Infant Movements Mistaken for Seizures
Many benign, non-epileptic phenomena are often mistaken for seizures in infants. Jitteriness is a common example, presenting as a tremor-like movement of the limbs or face. Jitteriness is characterized by a symmetrical, rapid, “to and fro” motion and is most often seen when the baby is startled, crying, or has low blood sugar. The key differentiator is that jitteriness will immediately stop if the affected limb is gently held or repositioned.
Benign neonatal sleep myoclonus is a non-epileptic condition often confused with myoclonic seizures. This involves repetitive, shock-like jerks of the body, arms, or legs, which only occur when the baby is asleep. The movement will consistently cease the moment the infant is roused or fully awakened, which is a simple way to distinguish it from a true seizure.
The Moro reflex (startle reflex) is a normal, involuntary reaction to a sudden noise or movement, causing the baby to throw out and then bring in their arms. This reflex is present at birth and begins to disappear around three to four months of age. While infantile spasms can look similar, they typically begin later (between four and nine months of age) and occur spontaneously rather than in response to a stimulus. Capturing any concerning event on video helps professionals differentiate between a benign phenomenon and a seizure.
What to Do During a Suspected Seizure
The first priority during a suspected seizure is to ensure the baby’s safety and prevent injury. Gently place the baby on a safe, soft surface away from any hard or sharp objects. Do not attempt to restrain the baby or stop the movements, as this will not halt the seizure and may cause injury.
Caregivers should immediately note the time the event begins and ends, which is crucial information for medical diagnosis. As soon as it is safe, turn the baby onto their side to help prevent choking and keep their airway clear. Never place anything into the baby’s mouth, as this poses a risk of injury or airway blockage.
Call emergency medical services immediately if this is the baby’s first seizure, if the seizure lasts longer than five minutes, or if the baby is having trouble breathing or appears to be turning blue. Even if the seizure is brief and resolves quickly, medical evaluation is necessary to determine the cause, and prompt medical follow-up is recommended.