Majority of patients with NFLE have sporadic seizures with unknown origin; a minority of them have mutations of the nicotinic acetylcholine receptor subunits .
All the studies analyzing the distribution of NFLE seizures across the sleep/wake cycle emphasize their overwhelming occurrence during NREM sleep and only rare or even exceptional appearance during wake state.
Seizure Semiology as Symptoms of Arousal-Alarm-Frenetic Panic: A Parallelity in NFLE and AP.
 reinvestigated the semiology of video-EEG detected seizures in 63 NFLE patients and compared them with 57 arousal parasomnia events.
Comparison of NFLE and AP in the Derry study showed that in 79% of AP the events began with arousal behaviour and in 65% of the events followed by more dramatic manifestations, NFLE seizures were preceded also in 49% by arousal behaviour.
In the NFLE group environmental interactions were present only in 11% of seizures and coherent speech was rare, if present it was frenetic and not interactive type.
Parasomnias terminated in 74% with NREM sleep or with wakefulness (26%), while NFLE seizures awakened the patients in 88%.
The symptoms of NFLE seizures and parasomniac events are astonishingly overlapping and follow a parallel severity order.
The similarity of the symptoms continuum NFLE and arousal parasomnias (AP) increases the probability of a common brain mechanism of these disorders, as being an arousal disorder (recognized by Broughton coining the term "arousal parasomnia"), regardless of their epileptic or nonepileptic origin.
Another aspect of the Derry study is that in the light of the data provided by them the usual characterisation of NFLE seizures as simply "hypermotor" does not catch the essence that the increasing complexity of the seizures from fragments of banal arousal behaviour through nonagitated motor until serious alarm behaviour with emotional expressions may reflect different degree of arousal.