Rhythmic movement disorder, such as repetitive motion of the head, trunk, or extremities, usually occurs as a parasomnia during the transition from wakefulness to sleep or from sustained sleep (8). Head banging can last from 15 to 30 minutes as the infant drifts off to sleep and, unlike similar daytime activity, is usually not related to emotional disturbance, frustration, or anger. No abnormal electroencephalographic (EEG) findings are noted. These benign movements usually disappear within 1 year of onset, typically by the second or third year of life, without treatment (7,8).

Rapid and forceful myoclonic movements may involve one extremity or many parts of the body. Occurring during sleep in early infancy, these bilateral, asynchronous, and asymmetric movements usually migrate from one muscle group to another. Unlike seizures, their rhythmic jerking is not prolonged, although clusters of these movements may occur episodically in all stages of sleep. Attacks are usually only a few minutes long but may last for hours. This myoclonus is not stimulus sensitive, and EEG shows no epileptiform activity. The movements stop as the infant is awakened and should never be seen in a fully awake and alert state. No treatment is required, but clonazepam or other benzodiazepines have been suggested in children who demonstrate a large amount of benign myoclonic activity. The movements typically disappear over several months (9).

Neonates and young infants demonstrate this rapid generalized tremulousness, which in neonates may be severe
enough to be mistaken for clonic seizures. The infants are alert, and the movements may be decreased by passive flexion or repositioning of the extremities. Although jitteriness may occur spontaneously, it is typically provoked or increased by stimulation. Because neonatal jitteriness may be caused by certain pathologic states, jittery newborns are more likely than normal infants to experience seizures, and their EEG tracings may show abnormalities. Central nervous system dysfunction is the suspected etiology, but hypoxic-ischemic insults, metabolic encephalopathies such as hypoglycemia and hypocalcemia, drug intoxication or withdrawal, and intracranial hemorrhage are implicated. The more benign forms of jitteriness usually decrease without specific therapy. Prognosis depends on the etiology and in neonates with severe, prolonged jitteriness may be guarded. Nevertheless, in 38 full-term infants who were jittery after 6 weeks of age, the movements resolved at a mean age of 7.2 months; 92% had normal findings on neurodevelopmental examinations at age 3 years (10). Sedative agents may be used, but their adverse effects usually increase the irritability (10,11).

Head banging, head rolling, and body rocking often occur in awake infants (7). In older infants, head banging may be part of a temper tantrum. Head rolling and body rocking seemingly are pleasurable forms of self-stimulation and may be related to masturbation. If the infants are touched or their attention is diverted, the repetitive movements cease. They are more common in irritable, excessively active, mentally retarded infants (7). Nevertheless, most of this activity decreases during the second year. Particularly bothersome movements may be diminished by behavior-modification techniques, but drug treatment usually is unnecessary.

Infantile masturbation may mimic abdominal pain or seizures in infant girls, who may sit with their legs held tightly together or straddle the bars of the crib or playpen and rock back and forth. Distracting stimuli usually stop these movements, which disappear in several months. Masturbation in older children is less likely to be confused with seizure activity. In some mentally retarded children, however, self-stimulation can also be associated with a fugue state. Because these children are difficult to arouse during the activity, seizures are commonly suspected (12).

Myoclonic movements occur in awake children and may resemble infantile spasms but are not associated with EEG
abnormalities. Infants are usually healthy, with no evidence of neurologic deterioration. The myoclonic episodes abate without treatment after a few months (13).

Spasmodic torticollis is a disorder characterized by sudden, repetitive episodes of head tilting or turning to one side with rotation of the face to the opposite side. The episodes may last from minutes to days, during which children are irritable and uncomfortable but alert and responsive. Although behavior may be episodic while the attack continues, EEG findings remain normal. Nystagmus is not associated with this disorder. The etiology is unknown, although dystonia and labyrinthine imbalance have been proposed. A family history of torticollis or migraine may be present. Tonic or rotary movements also may be seen with gastroesophageal reflux (Sandifer syndrome), but they will be longer and less paroxysmal than torticollis without reflux (14, 15, 16, 17).

The differential diagnosis includes congenital, inflammatory, and neoplastic conditions of the posterior fossa, cervical cord, spine, and neck in which the episodes of torticollis are sustained, lacking the usual on-and-off variability. An evaluation is necessary, but spasmodic torticollis usually subsides without treatment during the first few years of life.

Head nodding, head tilt, and nystagmus comprise spasmus nutans. Head nodding or intermittent nystagmus (or both) is usually noted at 4 to 12 months of age; nystagmus may be more prominent in one eye. The symptoms can vary depending on position, direction of gaze, and time of day. The children are clinically alert, and although symptoms may fluctuate throughout the day, episodic alterations in level of consciousness do not occur. Spasmus nutans usually remits spontaneously within 1 or 2 years after onset but may last as long as 8 years. Minor EEG abnormalities may be noted, but classic epileptiform paroxysms are not associated. Because mass lesions of the optic chiasm or third ventricle have been noted in a small number of these infants, computed tomography or magnetic resonance imaging studies generally should be performed (18). It is difficult to distinguish eye movements persisting into later childhood or adulthood from congenital nystagmus (18, 19, 20).

Opsoclonus is a rare abnormality characterized by rapid, conjugate, multidirectional, oscillating eye movements that are usually continuous but may vary in intensity. Because of this variation and occasionally associated myoclonic movements, generalized or partial seizures may be suspected. The children remain responsive and alert. Opsoclonus usually implies a neurologic disorder such as ataxia myoclonus or myoclonus. Children who develop these signs early in life may have a paraneoplastic syndrome caused by an underlying neuroblastoma (21, 22, 23). This triad of opsoclonus, myoclonus, and encephalopathy is termed Kinsbourne encephalopathy (dancing eyes, dancing feet) and responds to removal of the neural crest tumor or treatment with corticosteroids or corticotropin (24).

Rumination attacks involve hyperextension of the neck, repetitive swallowing, and protrusion of the tongue and are secondary to an abnormality of esophageal peristalsis. Episodes typically follow or accompany feeding. The child is alert but sometimes seems under stress and uncomfortable. Variable feeding techniques are helpful in this disorder, which resolves as the child matures (25).

A rare familial disorder with major and minor forms, startle disease (or hyperexplexia) involves a seemingly hyperactive startle reflex, sometimes so exaggerated that it causes falling. In the major form, the infant becomes stiff when handled, and episodes of severe hypertonia cause apnea and bradycardia. Forced flexion of the neck or hips may interrupt these episodes. Also noted, along with transient hypertonia, are falling attacks without loss of consciousness, ataxia, generalized hyperreflexia, episodic shaking of the limbs resembling clonus, and excessive startle. The minor form, in which startle responses are less consistent and not associated with other findings, may represent an augmented normal startle reflex (26). The interictal electroencephalogram shows normal results, but a spike may be associated with a startle attack. Whether this discharge represents an evoked response to the stimulus or an artifact is a subject of debate. The disorder must be distinguished from so-called startle epilepsy, in which a startle is followed by a partial or generalized seizure, which suggests a defect in inhibitory regulation of brainstem centers (27,28). The prognosis in hyperexplexia is variable (26). Seizures do not develop after this benign disorder; however, clonazepam and valproic acid have been used to treat its associated startle, stiffness, jerking, and falling (29,30).

Shuddering attacks far exceed the normal shivering seen in most older infants and children. A very rapid tremor involves the head, arms, trunk, and even the legs; the upper extremities are adducted and flexed at the elbows or, less often, adducted and extended. The episodes may begin as early as 4 months of age, decreasing gradually in frequency and intensity before age 10 years. Treatment with antiepileptic drugs does not modify the attacks. Except for the artifact, results of electroencephalography are normal. Essential tremor may be more common in the families of children with shuddering spells than in unaffected families (31,32).

Alternating hemiplegia of childhood may be confused with epilepsy because of the paroxysmal episodes of weakness, hypertonicity, or dystonia. Presenting as tonic or dystonic events, these intermittent attacks may alternate from side to side and at times progress to quadriplegia. They usually occur at least monthly and may be part of a larger neurologic syndrome in children with delayed or retarded development who also have seizures, ataxia, and choreoathetosis. Attacks begin before 18 months of age and can be precipitated by emotional factors or fatigue. The hemiplegic episodes may last minutes or hours, and the etiology and mechanism are unknown. Although anticonvulsants and typical migraine treatments are unsuccessful, flunarizine, a calcium-channel blocker (5 mg/kg per day), has been reported to reduce recurrences (33,34).

Apnea usually occurs during sleep and may be associated with centrally mediated hypoventilation, airway obstruction, aspiration, or congenital hypoventilation. Formerly called (near) sudden infant death syndrome, these symptoms now are referred to as apparent life-threatening events. In central apnea, chest and abdominal movements decrease simultaneously with a drop in air flow. In obstructive apnea, movements of the chest or abdomen (or both) continue, but there is diminished air flow. Central apnea presumably results from a disturbance of the respiratory centers, whereas obstructive apnea is a peripheral event; some infants have a mixed form of the disorder. A few jerks may occur with the apneic episodes but do not represent epileptic myoclonus. The apnea that follows a seizure is a form of central apnea with postictal hypoventilation. Primary apnea, however, is only rarely followed by seizures (36,37).

The etiology and characteristics vary among infants. Apnea of prematurity responds to treatment with xanthine derivatives. In older infants with primary central apnea, elevated cerebrospinal fluid levels of β-endorphin have been reported, and treatment with the opioid antagonist naltrexone has been successful (38). The role of home cardiopulmonary monitors is controversial. Parents should be encouraged to follow the recommendations of the American Academy of Pediatrics that healthy term infants be put to sleep on their back or side to decrease the risk of apnea and possible sudden infant death syndrome (39).

Although apnea occurs less often when the child is fully awake, it may be associated with gastroesophageal reflux (40,41). Aspiration may follow. Reflux is frequently accompanied by staring or flailing or posturing of the trunk or extremities, perhaps in response to the pain of acidic contents washing back into the esophagus. Gastroesophageal reflux is more common when infants are laid supine after feeding. Diagnosis is established by radiologic demonstration of reflux or by abnormal esophageal pH levels. Reflux is treated by upright positioning of the baby during and after feeding (42), thickened feedings, the use of agents to alter sphincter tone, and fundal plication.

Although common between the ages of 6 months and 6 years, cyanotic infant syncope (breath-holding spells) is frequently confused with tonic seizures (43). Typically precipitated by fear, frustration, or minor injury, the spells involve vigorous crying, following which the child stops breathing, often in expiration. Cyanosis occurs within several seconds, followed by loss of consciousness, limpness, and falling. Prolonged hypoxia may cause tonic stiffening or brief clonic jerking of the body. After 1 or 2 minutes of unresponsiveness, consciousness returns quickly, although the infant may be briefly tired or irritable. The crucial diagnostic point is the history of an external event, however minor, precipitating the episode. The electroencephalogram does not show interictal epileptiform discharges but may reveal slowing or suppression during the anoxic event (see Chapter 13, Figs. 13.52 and 13.53). The pathophysiologic mechanism is not well understood, but correction of any underlying anemia may reduce the attacks (44). Children with pallid breath-holding spells have autonomic dysregulation caused by parasympathetic disturbance distinct from that found in cyanotic breath-holding (45). Although the episodes appear unpleasant for the child, they do not result in neurologic damage. Antiepileptic medication may be appropriate for the rare patients with frequent postsyncopal generalized tonic-clonic seizures triggered by the anoxia.

Precipitated by injury or fright, sometimes trivial, pallid infant syncope occurs in response to transient cardiac asystole in infants with a hypersensitive cardioinhibitory reflex. Minimal crying, perhaps only a gasp, and no obvious apnea precede loss of consciousness. The child collapses limply and subsequently may have posturing or clonic movements before regaining consciousness after a few minutes (43, 46, 47, 48). The asystolic episodes can be produced by ocular compression, but this procedure is risky and of uncertain clinical utility (see Chapter 13, Figs. 13.52 and 13.53). As with cyanotic breath-holding spells, the key to diagnosis is the association with precipitating events.

The long-term prognosis is benign. Most children require no treatment, although atropine has been recommended for frequent pallid attacks or those followed by generalized tonic-clonic seizures (49). A trial of the anticholinergic drug atropine sulfate 0.01 mg/kg every 24 hours in divided doses (maximum 0.4 mg per day) may increase heart rate by blocking vagal input. Atropine should not be prescribed during very hot weather because hyperpyrexia may occur.