Sleep disordered breathing in neurologic diseases

A complex homoeostatic control system of sensors (afferent input), a central controlling mechanism and an effector system maintain arte-rial blood gases (PaO2, PaCO2) and pH within nar-row limits (fig. 1). The respiratory control system output is system-dependent and is regulated by two anatomically distinct but functionally inte-grated elements, referred to as automatic (meta-bolic, involuntary) and behavioural (voluntary and involuntary) respiratory control systems [1–3] (fig. 2). The automatic control system depends upon respiratory neurons in the medulla, as already recognised by Legallois in the 19th century and by Lumsden at the beginning of the 20th century. The normal inspiratory-expiratory cycle is gener-ated by the interaction between a primary respira-tory pacemaker (pre-Bötzinger complex) in the ventrolateral medulla [4] and other medullary res-piratory centres in the nucleus tractus solitarius Wakefulness, NREM sleep, and REM sleep are ac-companied by specific changes in breathing control, which arise from the interaction of automatic (meta-bolic, involuntary) and behavioural (voluntary and in-voluntary control systems. Considering the complexity in the neuroanatomy and neurophysiology of breathing control, it is not suprising that neurologic disorders are frequently accompanied by sleep disordered breathing. An introduction on pathophysiology, clinical features, diagnosis, and treatment of sleep disordered breathing in such diseases as stroke, epilepsy, dementia, spinal cord disease, polyneuropathies, and myopathies is presented. Key words: sleep; breathing; apnea; neurologic disorders; stroke; epilepsy; myopath