[Respiratory disorders during sleep in degenerative diseases of the brain stem]

Sleep-disordered breathing may be present in patients with degenerative diseases affecting the brainstem. Indeed, this last structure contains the executive system of rapid eye movement (REM) sleep (tegmentum of the pons), of respiratory drive (medulla oblongata and pons) and motor neurons of upper airways dilators (fifth, seventh, ninth, tenth and twelfth cranial roots). Patients with Parkinson's disease suffer frequently from insomnia, partly caused by nocturnal motor disability, and from REM sleep behavior disorder. In 20 percent of the patients, excessive daytime sleepiness is caused by a sleep apnea syndrome, with a partly levodopa-dependent upper airway dysfunction. In 40 percent of the patients, sleepiness mimics a secondary narcolepsy and may be associated with hypnagogic hallucinations. During supranuclear palsy, REM sleep is progressively curtailed with rare sleep-disordered breathing. Patients with multiple systemic atrophy may present a nocturnal stridor caused by laryngeal palsy and benefit from tracheotomy or continuous nasal positive airway pressure. Seldom sleep and respiratory studies in genetic ataxic diseases suggest a normal respiratory drive, occasional diaphragmatic dysfunction and night hypopneas. During amyotrophic lateral sclerosis, the progressive loss of phrenic nerve leads to a diaphragmatic dysfunction, dyspnea and a lesser survival. Adequate ventilation is jeopardized during REM sleep with a consequent loss of this state.