ARTICLE IN PRESS Sleep Medicine ■■ (2015) ■■–■■
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Letter to the Editor Reply to Piano et al. To the Editor: Piano et al. recently found a higher periodic leg movements (PLM) index during wake and sleep in 30 patients with advanced Huntington’s disease (HD) than in the control group (17.6 ± 19.4 PLMs vs. 0.5 ± 1.0) [1]. Now, they ask whether these periodic movements could primarily cause the arousal-related abnormal movements that we recently reported in 29 patients with HD [2]. In our video-clips, a few arousals started with bilateral limb flexion movements. They were, however, not simple (they constituted complex, target-oriented movements, suggestive of repositioning behaviors), not stereotypic (severe opisthotonos-like as well as bruxism were observed), and, most important, these movements were not periodic (according to the PLM definition, which includes series of at least four 0.5–10 second long limb movements, separated by 5–90 seconds [3]). Consequently, these movements cannot constitute PLMs followed by a complete awakening and behaviors. In our first series of 25 patients with HD, the PLM index was slightly higher in patients than in controls (9 ± 11 vs. 2 ± 5), but still within normal values (below 15) and not causing frequent arousals [4]. If we pool together the 43 patients with HD monitored by our consortium, this difference with controls disappears (Table 1). Thus, PLMs seem to be motor manifestations of
Table 1 Demographical, clinical, and sleep motor characteristics in two European cohorts of patients with Huntington disease (HD).
n Age, y Sex, male % Treatmentsb that may trigger PLMs, % with UHDRS, motor part Sleep measures Total sleep time, min REM sleep, % REM sleep without atonia, % Arousal index PLM index during sleep
HD consortium [2,4]a
Italian HD cohort [1]
HD
Controls
HD patients
Controls
43 49.11 ± 12.3 51 30
43 48.8 ± 13.3 51 5
30 57.30 ± 12.24 47 >60
30 56.50 ± 11.85 47 0
26.79 ± 19.99
NA
55.55 ± 23.43
NA
413.1 ± 120.9
392.9 ± 66
303.5 ± 105.8*
406.3 ± 51.5
9.8 ± 7.2* Not shown
19.2 ± 5.1 Not shown
15.5 ± 7.1 4.3 ± 6.5
18.6 ± 7.8 1.2 ± 2.1
19.9 ± 11.8 6.6 ± 8.3
21.2 ± 16.4 4.8 ± 17.9
37 ± 23* 17.6 ± 19.4*
14 ± 5 0.5 ± 1.0
Abbreviations: UHDRS, Unified Huntington Disease Rating Scale; PLM, periodic leg movements; SD, standard deviation. * p < 0.05 for a difference with local controls. a Including patients with HD from France (n = 29), Denmark (n = 7), Germany (n = 4), and Great Britain (n = 3) and local matched controls. b Neuroleptics, lithium, and antidepressants. Data are expressed as mean ± SD.
HD in older, more severe patients (with more frequent treatmentinduced PLMs) rather than in patients with very mild to moderate HD (see Table 1 for comparison of both cohorts). Our data cannot support the concept of a periodic motor (or even cortical) activity as a background for this abnormal motor activity upon arousals. Rather, one may imagine that any cause of arousals (possibly PLMs in aged patients, but also apnea, or simply ambient noises, but nothing necessarily periodic) could trigger them because they resemble a transient exacerbation of choreic movements upon arousal.
Conflict of interest The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2015.08.009.
References [1] Piano C, Losurdo A, Virdis D, et al. Polysomnographic findings and clinical correlates in Huntington disease. A cross sectional cohort study. Sleep 2015 (in press). [2] Neutel D, Tchikviladze M, Charles P, et al. Nocturnal agitation in Huntington disease is caused by arousal-related abnormal movements rather than by rapid eye movement sleep behavior disorder. Sleep Med 2015;16(6): 754–9. [3] Berry R, Brooks R, Gamaldo C, et al. for the American Academy of Sleep Medicine. The AASM manual for the scoring of sleep and associated events: rules, terminology and technical specifications. Westchester, IL: American Academy of Sleep Medicine; 2012. [4] Arnulf I, Nielsen J, Lohmann E, et al. Rapid eye movement sleep disturbances in Huntington disease. Arch Neurol 2008;65:482–8.
Dulce Neutel APHP, Sleep Disorder Unit, Pitié-Salpêtrière University Hospital, Paris, France Smaranda Leu-Semenescu APHP, Sleep Disorder Unit, Pitié-Salpêtrière University Hospital, Paris, France Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière – Université Pierre et Marie Curie-Paris 6, Inserm UMR_S 975, CNRS UMR 7225, France Emmanuel Roze Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière – Université Pierre et Marie Curie-Paris 6, Inserm UMR_S 975, CNRS UMR 7225, France Isabelle Arnulf * APHP, Sleep Disorder Unit, Pitié-Salpêtrière University Hospital, Paris, France
http://dx.doi.org/10.1016/j.sleep.2015.08.009 1389-9457/© 2015 Elsevier B.V. All rights reserved.
Please cite this article in press as: Dulce Neutel, Smaranda Leu-Semenescu, Emmanuel Roze, Isabelle Arnulf, Reply to Piano et al., Sleep Medicine (2015), doi: 10.1016/ j.sleep.2015.08.009
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D. Neutel et al./Sleep Medicine ■■ (2015) ■■–■■
Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière – Université Pierre et Marie Curie-Paris 6, Inserm UMR_S 975, CNRS UMR 7225, France * Address: Service des Pathologies du Sommeil, Hôpital Pitié-Salpêtrière, 47-83 Boulevard de l’Hôpital,
75651 Paris Cedex 13, France. Tel.: +33 1 42 16 77 01; fax: +331 4216 7700. E-mail address:
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Please cite this article in press as: Dulce Neutel, Smaranda Leu-Semenescu, Emmanuel Roze, Isabelle Arnulf, Reply to Piano et al., Sleep Medicine (2015), doi: 10.1016/ j.sleep.2015.08.009