A 10-year-old right-handed male without a significant past medical history was referred for evaluation of possible nocturnal seizures His seizures began at 7 years of age and have occurred almost exclusively during sleep, usually within 2 hours of falling asleep The stereotyped episode involves rocking and bicycling motions, gagging, rolling of the eyes, and profuse sweating lasting approximately 2 minutes These episodes have occurred on average three times per week, but recently have become more frequent He has had two similar episodes that have occurred while awake The patient's previous evaluation included two routine sleep-deprived EEGs and a 1 .5T noncontrast MRI of the brain, all of which were interpreted as normal Other laboratory tests included a complete blood count and comprehensive metabolic profile, which were also normal His physical and neurologic examination is unremarkable, but his family history is significant for a maternal aunt and brother with epileptic seizures since childhood that were primarily nocturnal
Ultimately, the patient was admitted for continuous video-EEG (electroencephalogram) monitoring to characterize the episodes of concern During this study, the patient had three typical clinical events identified by the family Clinically, the patient would arise, sit up in bed, rock, and look around the room, but not respond . He made some occasional nonsensical vocalizations . The events lasted from 47 to 83 seconds . During the events, the EEG demonstrated a change from a normal stage II sleep recording to a generalized frontal dominant rhythmic 3 Hz high-amplitude slow activity (See Figure 37. 1) . This activity lasted half a minute and gradually waned to a normal background rhythm without any focal slowing . Based on this video-EEG study, the diagnosis of nocturnal frontal lobe epilepsy was made, and the patient was started on carbamazepine . Genetic testing demonstrated a mutation in the CHRNA4 gene, consistent with the diagnosis of autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) . The patient responded well to carbamazepine, and would experience only rare seizures after missed doses of medication .
The unusual behaviors seen in patients with ADNFLE can make their diagnosis challenging Depending on the site of origin, patients may exhibit complex automatisms, such as bicycling or rocking, vocalizations, dystonic posturing, or clonic activity, but may retain awareness The differential diagnosis of paroxysmal nocturnal events involves distinguishing parasomnias from true epileptic seizures . Pediatric parasomnias (e g , night terrors, sleep walking, and confusional arousal) occur in up to 6% of the population, and may be difficult to differentiate from ADNFLE . Night terrors (aka, pavor nocturnus) often occur during slow-wave sleep in the first third of the night The patients will often make a loud cry and appear frightened They may have thrashing movements, as if defending themselves, but these are typically not stereotyped as in ADNFLE During the events, they are often unarousable, but after the events may recall a frightening dream
Confusional arousals often begin with simple movements or moaning that gradually progress to a more agitated and confused state that may last 5-15 minutes . The patients are often difficult to arouse and have little recollection of the event . Sleepwalking may occur in children, but is typically associated with a calm demeanor that differs from the parasomnias or seizures described earlier. REM sleep behavior disorder may also have similar presentations, but occurs later in the night and is uncommon in children Polysomnograms demonstrate a lack of atonia during REM sleep in these patients
Useful clues to help differentiate ADNFLE from parasomnias include the presence of stereotyped behaviors, events occurring during periods of wakefulness, a history of clear seizures, a family history of epilepsy, later age of onset (parasomnias usually begin between 4 and 6 years of age), and multiple events per night Seizures are less likely to occur during REM sleep, and more often arise during transition from sleep to waking The EEGs in ADNFLE often lack clear abnormalities, and may be normal despite multiple seizures per night
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