Cataplexy and cataplexy-like symptoms in narcoleptics, non-narcoleptic hypersomniacs, and normal controls Christian Sturzenegger, Johannes Mathis, Matthias Gugger*, Werner Pichler**, Claudio Bassetti Department of Neurology, Division of Pneumology*, Institute of Immunology**, University Hospital, 3010 Bern, Switzerland Background/Aim: Definite cataplexy is considered to be almost pathognomonic for narcolepsy, whereas cataplexy-like symptoms are occasionally reported also by normal subjects. Clinical criteria for recognition of definite ("true") cataplexy remain a matter of controversy. Patients and methods: We prospectively studied by questionnaire 54 consecutive narcoleptics (N, mean age±SD=43±18), 39 non-narcoleptic hypersomniacs (H, age=48±12) and 35 normal controls (C, age=43±21). The diagnoses of narcolepsy with and without cataplexy were made according to international criteria. Our questionnaire included the Epworth Sleepiness Score (ESS), the Ullanlinna Narcolepsy Score (UNS), and questions about frequency, triggering emotions or situations, localization, duration, and accompanying features of cataplexy. The frequency of symptoms is expressed as the percentage of patients reporting them to occur occasionally, often or always. Following current suggestions for the definition of definite cataplexy1 we divided our narcoleptic population into patients with (a) definite cataplexy (n=33), and (b) possible/atypical or no cataplexy (n=21). Possible/atypical cataplexy was diagnosed when loss of muscle tone 1) had no visible effect or involved only the leg muscles, 2) occurred less than monthly, 3) lasted often/always > 10 minutes, and 4) was often/always associated with loss of consciousness. The presence of the HLA haplotype was assessed in 26 narcoleptics. Results: ESS and UNS were significantly higher (p<0.001) in N (17±5 and 24±9 respectively) than in H (15±4; 13±6) and C (5±3; 6±4). UNS > 14 had a sensitivity and specificity for narcolepsy of 88% and 75% respectively. Sudden weakness or buckling of knees following emotions was significantly (p<0.001) more common in N (76%) than in H (34%) and particularly C (3%; when considering also episodes occurring less than monthly however 24%). Sagging of the jaw and nodding of the head was also more frequent (p<0.001) in N (60% and 56% respectively) than in H (11%; 6%) and C (both 0%). Falling to the ground was reported in N (19%) only. Compaired to H, N reported cataplexy more commonly following surprise (45% vs 14%, p=0.04), sudden joy/happiness (73% vs 38%, p=0.03), while being tickled (51% vs 15%, p=0.02), and in the presence of known persons (72% vs 31%, p=0.009). Conversely, N had less commonly cataplexy with stress (34% vs 67%, p=0.03), unpleasant feelings (30% vs 67%, p=0.01), and cataplexy with no visible effect (18% vs 46%, p=0.04). Narcoleptics with or without definite cataplexy had similar ESS (17±5 vs 16±6) but differed in USS (26±7 vs 21±10, p=0.03) as well as HLA DR2 positivity (93% vs 55%, p=0.02). Age of onset, triggering emotions, and accompanying symptoms of cataplexy (with the exception of loss of consciousness) did not differ between the two groups. Definite cataplexy was, however, experienced more commonly in the presence of known persons (80% vs 33%, p=0.02). Conclusions: 1) cataplexy-like symptoms may occur in patients with non-narcoleptic hypersomnia and, rarely, in normal controls, 2) UNS and analysis of clinical characteristics usually allow the differentiation between cataplexy-like symptoms and definite cataplexy, 3) currently suggested criteria for the diagnosis of definite cataplexy identify a genetic (HLA DR2 positive) homogeneous group of narcoleptics. Reference: 1Mignot E, Hayduk R, Black J, Grumet FC and Guilleminault C. Sleep 1997; 20(11):1012-1020. [14th Congress of the European Sleep Research Society, September 9-12, 1998, Madrid] 1998-99 by Christian Sturzenegger Update 03-01-99 contact webmaster@orangemind.ch