Approach Considerations
No consistent irregularities in laboratory evaluation have been identified, and no additional workup is required in a classic sleep terror presentation. No specific imaging is indicated with normal development and no focal neurologic abnormalities. If trauma during an episode has been sustained, appropriate imaging should be sought to evaluate the injury.
A sleep diary may help families identify particular triggers for sleep terror events. Comorbidities should be investigated independently of their association with sleep terrors.
Further evaluation and intervention may be required for individuals with significant daytime somnolence, for those who exhibit violent behavior during the episodes that threatens harm to self or others, or in situations where the sleep terrors generate severe distress to family members. Polysomnography is useful if a respiratory disturbance is suspected. However, note that a normal sleep study does not rule out a diagnosis of sleep terror. [2]
If the individual clearly wakes up at the end of the episode abruptly and at no point in time sits up, stands, or walks, the individual may have nocturnal frontal lobe epilepsy. Also, if the individual is seen to undergo head turning to one direction and dystonic posturing during the event, it suggests epilepsy. [18]
When nocturnal seizures are a possibility, routine electroencephalography (EEG) or sleep-deprived EEG may be helpful. [24, 13] EEG findings are often similar with sleep terrors and nocturnal seizures, especially nocturnal frontal lobe epilepsy (NFLE), making diagnosis difficult. Additionally, a normal awake EEG or interictal sleep EEG may not rule out a seizure disorder. [14] Findings on EEG that suggest parasomnias rather than NFLE include the presence of vertex waves, sleep spindles, non-rhythmic theta activity, or evidence of EEG state dissociation with a posterior dominant alpha rhythm. Additionally, NFLE most often presents in stages 1 and 2 of sleep as opposed to parasomnias, which most often present in stages 3 and 4. [25]
Tables
| Features | DSM-5 | ICSD-3 |
|---|---|---|
| Frequency | Recurrent episodes | Recurrent episodes |
| Awakening | Abrupt arousal from sleep | Incomplete awakening from sleep |
| Responsiveness | Relative unresponsiveness | Inappropriate or absent responsiveness |
| Recall | Little or no recall of dream imagery | Little or no associated cognition or dream imagery |
| Amnesia | Amnesia of the episode | Partial or complete amnesia of the episode |
| Functional Impact | Significant distress or impairment in social, occupational, or other areas of functioning | |
| Differential | Symptoms cannot be explained by another mental disorder, medical condition, or the effects of drugs of abuse or medication | Symptoms cannot be explained by another mental disorder, medical condition, or the effects of drugs of abuse or medication |
| Initial Expression of Fear | Panicked scream | Alarming vocalization, such as a frightened scream |
| Autonomic Symptoms | Autonomic arousal | Mydriasis, tachycardia, tachypnea, diaphoresis during an episode |
| Feature | Sleep Terror | Nightmare |
|---|---|---|
| Categorization | Disorder of arousal | REM parasomnia |
| Timing | Usually occurs during the first half of the night and typically out of stage N3 slow-wave sleep | Begins out of REM sleep and typically occurs in the last third of the night |
| Family history | Frequently positive | May be positive |
| Behavior semiology | Sudden arousal with intense screaming, inconsolable crying, agitation, heightened autonomic discharge | Paroxysmal awakenings with anxiety dream recall |
| Event duration | Few seconds to minutes | Few seconds to minutes |
| Age at onset | Typically < 10 years old | Typically < 10 years old |
| Triggers | Sleep deprivation, febrile illness, anxiety, stress, sleep apnea, motor disorders of sleep | Sleep deprivation, febrile illness |
| Frequency | Few times per month/week; very rarely >1 episode in a single night | Few times per month/week; very rarely >1 episode in a single night |
| Post-spell | Limited to no recall of the events with confusion | Recall is typical at times with vivid detail |
| PSG changes | Abrupt arousal from slow-wave sleep (stage N3) with expression of confusion/ambulation/intense fright in all three arousal types, followed by return to sleep; increased cyclic alternating pattern | Dense eye(phasic) movements during REM sleep |
