Differentials

Seizures (nocturnal)

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Nocturnal frontal lobe seizures may be accompanied by incontinence, tongue-biting, tonic-clonic movements, and drooling. All these features are atypical in the parasomnias.

Seizures may occur when the patient is awake or asleep; parasomnias are almost always related to sleep.​[44]

INVESTIGATIONS

Polysomnography (PSG) with expanded electroencephalographic (EEG) measurements: EEG demonstrates abnormal electrical activity consistent with the diagnosis of epilepsy.

Narcolepsy

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

May present with similar features to recurrent isolated sleep paralysis.

Typically has other symptoms, including cataplexy (sudden focal or generalised loss of muscle tone in the body, brought about by strong emotional experiences), hypnagogic or hypnopompic hallucinations at sleep onset or awakening, and irresistible sleep attacks.[59]

INVESTIGATIONS

Multiple sleep latency tests in narcolepsy demonstrate a mean sleep latency of <8 minutes and ≥2 sleep-onset rapid eye movement (REM) periods (SOREMPS).[36] One of the qualifying SOREMPs may occur in the preceding overnight sleep study.[11]

Periodic limb movement disorder (PLMD)

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Parents may report that the child makes rhythmic limb movements during sleep (although not an accurate predictor of periodic limb movement disorder diagnostic index, or PLMS-I).

INVESTIGATIONS

Polysomnography (PSG) with leg electromyography (assessment enhanced using split-screen, video-polysomnographic analysis): demonstrates typical features.[54][57][58]​​​​

Obstructive sleep apnoea

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Snoring, gasping, choking while asleep, or breathing through an open mouth.

Night sweats.

Sleeping with neck hyperextension.

Hypertension.

INVESTIGATIONS

Polysomnography (PSG) demonstrates obstruction (apnoea-hypopnoea index >1 per hour of sleep).

Enlarged adenoids or tonsils may be found via nasal endoscopy or lateral neck films.

Overnight oximetry may show arterial oxygen desaturation.

Restless legs syndrome

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Dysaesthesias.

Symptoms occur in the evening.

May have relief with stretching.

INVESTIGATIONS

Diagnosis is primarily clinical.

Iron deficiency should be excluded.

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