Polysomnographic respiratory findings in patients with Arnold-Chiari type I malformation and basilar invagination, with or without syringomyelia: preliminary report of a series of cases

Patients with craniocervical disorders (CCD) show a wide variety of symptoms and signs suggesting cerebellar and/or high cervical lesion. The anatomic localization of respiratory centers and their possible injury may explain the presence of respiratory disturbances in these diseases. The aim of this preliminary study was to evaluate the polysomnographic findings in a group of patients with CCD, most of them with Arnold-Chiari malformation type I, since sleep apnea has been referred to in isolated cases in the literature. Eleven patients (seven females and four males) with CCD diagnosed by magnetic resonance imaging referred from the neurosurgery unit were submitted to clinical history, physical examination with sleep questionnaires, and scored on the Epworth Sleepiness Scale. Full night polysomnography was performed in an Oxford SAC system where EEG, electro-oculography, electrocardiography, chin and leg electromyography, chest and abdominal efforts, airflow, and oximetry were recorded continuously. Nine patients presented with Arnold-Chiari type I malformation, of whom six showed associated syringomyelia. The other two had basilar invagination. Ninety percent of these patients complained of sleep problems (snoring, choking, and witnessed apneas) and 72% presented hypersomnolence (ESS >9). The polysomnographic findings showed sleep fragmentation in 81% of the patients and a reduction of rapid eye movement sleep in 63%. The apnea/hypopnea index was above 5 in 72%, with a predominance of central apnea. Patients with craniocervical disorders present a higher probability of displaying sleep respiratory disturbances. Their sleep complaints should be assessed and patients should be submitted to an overnight sleep recording in order to identify sleep apnea.