Disorders of Sleep and Breathing during Sleep in Neuromuscular Disease

Abstract

The role of upper airway muscle contractile dysfunction in the pathophysiology of sleep apnea is not clear. The conventional understanding of this disorder is that anatomical narrowing of the upper airway combined with inadequate activation of upper airway dilator muscles leads to airway closure and obstructive apneas. 1 The possibility of upper airway muscle contractile failure playing a role in this process is based on a number of findings: (a) increased motor activity to these muscles in humans and dogs with compared to without sleep apnea, 2,3 (b) studies of upper airway muscle contractile and structural properties indicating low fatigue resistance due to a high proportion of fast fibers and myosins, 4-8 (c) changes in pharyngeal muscle properties in conditions associated with sleep apnea (e.g., hypothyroidism, Down syndrome, old age), 6,8,9 and (d) abnormalities in pharyngeal muscle structural properties in humans and bulldogs with sleep apnea. [10][11][12] In support of the notion of pharyngeal muscle dysfunction leading to sleep apnea and alterations in sleep architecture are a number of studies examining sleep and breathing during sleep in (generally a small number of) subjects with disorders of skeletal muscles or the neuromuscular junction-myotonic dystrophy, Duchenne muscular dystrophy, and myasthenia gravis. 13-18 These studies have described a high prevalence of sleep apnea (e.g., 11 of 20 subjects with myasthenia gravis studied at time when they were clinically stable had a respiratory disturbance index of greater than 5), 18 worsening of nighttime hypoxemia over time (e.g., 9 of 10 patients with muscular dystrophy who were hypoxemic at their initial evaluation had worsened hypoxemia at a follow-up study), 16 and altered sleep architecture

Sleep and Neuromuscular Disease

“…Knowledge of respiratory anatomy and physiology allows an understanding of how pharyngeal muscle weakness predisposes to airway collapse and obstructive hypopnea or apnea, whereas weakness of the diaphragm produces nonobstructive hypoventilation maximal during sleep. [1][2][3]9,10 Reductions in muscle tone and chemosensitivity, especially during REM sleep, mean that any superimposed weakness of upper airway muscles, or medications that further reduce tone, reduce airway patency. Depending on severity, this could result in an increase in upper airway resistance, hypopnea, or even apnea.…”

Utilidad de un cuestionario clínico para el diagnóstico de trastornos respiratorios del sueño en niños con enfermedades neuromusculares

“…Sin embargo, se ha demostrado que los TRS están presenten en etapas muy iniciales de las ENM y pueden ser subvalorados 3 . Utilizando polisomnografía (PSG) como el estándar de oro para el diagnóstico de TRS, se han identifi cado en niños con ENM apneas centrales, obstructivas, hipopneas y desaturaciones en la oxigenación arterial 4 , siendo los eventos respiratorios anteriormente señalados más frecuentes en el sueño REM. Con la progresión de la ENM de base, los TRS empeoran gradualmente, hasta poder ser reconocidos en el sueño no-REM y posteriormente hacerse evidente en vigilia.…”

“…Se realizó un análisis de validez diagnóstica de los resultados del cuestionario comparados con los de la PSG. Resultados: La mediana de edad fue de 10,7 años (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). De acuerdo a la PSG, se clasifi có a 8 pacientes como normales, 3 roncadores primarios, 5 con síndrome de apneas centrales y 5 con síndrome de apneas obstructivas (SAOS).…”

Schlafbezogene Atmungsstörungen bei neuromuskulären Erkrankungen

“…Sie treten bevorzugt im REM(rapid eye movement)-Schlaf auf, einer Schlafphase mit herabgesetzter Muskelaktivität vor allem im Bereich der oberen Atemwege und des Thorax [2]. Typische Manifestationen reichen von episodischen Sauerstoffentsättigungen, umschriebenen Hypopnoen und Apnoen bis zur anhaltenden alveolären Hypoventilation [3]. Prognostisch sind SBAS mit einer reduzierten Lebenserwartung verbunden [4].…”