Epilepsia, 48(8):1506–1511, 2007 Blackwell Publishing, Inc. C  2007 International League Against Epilepsy Interobserver Reliability of Video Recording in the Diagnosis of Nocturnal Frontal Lobe Seizures Luca Vignatelli, Francesca Bisulli, Federica Provini, Ilaria Naldi, Francesca Pittau, Anna Zaniboni, Pasquale Montagna, and Paolo Tinuper Department of Neurological Sciences, University of Bologna, Bologna, Italy Summary: Background: Nocturnal frontal lobe seizures (NFLS) show one or all of the following semeiological patterns: (1) paroxysmal arousals (PA: brief and sudden recurrent mo- tor paroxysmal behavior); (2) hyperkinetic seizures (HS: motor attacks with complex dyskinetic features); (3) asymmetric bilat- eral tonic seizures (ATS: motor attacks with dystonic features); (4) epileptic nocturnal wanderings (ENW: stereotyped, pro- longed ambulatory behavior). Objective: To estimate the interobserver reliability (IR) of video-recording diagnosis in patients with suspected NFLS among sleep medicine experts, epileptologists, and trainees in sleep medicine. Methods: Sixty-six patients with suspected NFLS were included. All underwent nocturnal video-polysomnographic recording. Six doctors (three experts and three trainees) indepen- dently classified each case as “NFLS ascertained” (according to the above specified subtypes: PA, HS, ATS, ENW) or “NFLS excluded”. IR was calculated by means of Kappa statistics, and interpreted according to the standard classification (0.0–0.20 = slight agreement; 0.21–0.40 = fair; 0.41–0.60 = moderate; 0.61– 0.80 = substantial; 0.81–1.00 = almost perfect). Results: The observed raw agreement ranged from 63% to 79% between each pair of raters; the IR ranged from “moderate” (kappa = 0.50) to “substantial” (kappa = 0.72). A major source of variance was the disagreement in distinguishing between PA and nonepileptic arousals, without differences in the level of agreement between experts and trainees. Conclusions: Among sleep experts and trainees, IR of diag- nosis of NFLS, based on videotaped observation of sleep phe- nomena, is not satisfactory. Explicit video-polysomnographic criteria for the classification of paroxysmal sleep motor phe- nomena are needed. Key Words: Nocturnal frontal lobe seizures—Paroxysmal motor phenomena during sleep—Video- recording—Parasomnias—Diagnosis—Reliability of results. Nocturnal Frontal Lobe Epilepsy (NFLE) is character- ized by seizures with bizarre motor behavior or sustained dystonic postures occurring during sleep (Oldani et al., 1998; Tinuper et al., 1999; Provini et al., 2000; Tinuper et al., 2002, 2003). In a large series studied by video- polysomnographic recording, we described four main se- meiological patterns: minor motor events, the so called paroxysmal arousals (PA), characterized by brief sim- ple motor phenomena, similar to a sudden arousal, re- curring several times per night; major attacks, originally named nocturnal paroxysmal dystonia (NPD), that in- clude hyperkinetic seizures (HS), i.e., more complex mo- tor episodes with violent motor behavior, vocalization, screaming, fearful and repetitive movements of the trunk and limbs; and asymmetric bilateral tonic seizures (ATS), arising from involvement of the frontal mesial areas; pro- Accepted February 10, 2007. Address correspondence and reprint requests to Paolo Tinuper, Department of Neurological Sciences, University of Bologna, Via Ugo Foscolo 7, 40123 Bologna, Italy. E-mail: paolo.tinuper@unibo.it doi: 10.1111/j.1528-1167.2007.01121.x longed episodes, named epileptic nocturnal wandering (ENW), which can mimic sleepwalking episodes (Plazzi et al., 1995). These apparently different episodes often co- exist in the same patient (Montagna, 1992; Provini et al., 1999; Tinuper et al., 2005). But the motor patterns that represent the first ictal manifestations at the beginning of the attacks are highly stereotyped, as clearly shown using synchronized display methods (Tinuper et al., 2004). NFLS have often been misdiagnosed as parasomnias (Scheffer et al., 1994; Scheffer et al., 1995) and the differ- ential diagnosis is not always straightforward (Lugaresi et al., 1991; Scheffer et al., 1994; Plazzi et al., 1995; Scheffer et al., 1995; Oldani et al., 1998; Plazzi et al., 1998; Provini et al., 1999). There are four orders of prob- lems in differentiating epileptic seizures from nonepilep- tic sleep-related events. First, there could actually be a close similarity in patterns between NREM arousal para- somnias and REM behavior disorders and NFLS. Second, a reliable description of motor events during the night is often difficult to collect from a witness or sleep part- ner. Third, the available diagnostic tools, i.e., the standard 1506