Sleep disturbance: a forgotten syndrome in patients with Chiari I malformation.

INTRODUCTION Chiari type I malformation (CM-I) is characterised by caudal ectopia of the cerebellar tonsils through the foramen magnum. This is associated with brain stem, high spinal cord, and cranial nerve compression phenomena. The most frequent symptoms are occipital headaches and dizziness. Less well-known symptoms are sleep disorders and nocturnal respiratory abnormalities. SOURCES MEDLINE and information from patients evaluated at the Neurosurgery and Clinical Neurophysiology Departments at Hospital Universitario Vall d'Hebron. DEVELOPMENT Review article based on data obtained from MEDLINE articles since 1966, using combinations of the following keywords: «Chiari malformation» or «Arnold-Chiari malformation» and «sleep apnea» or «sleep disorders». CONCLUSIONS CM-I patients show a higher prevalence of sleep disorders than that observed in the general population. Some studies report a 50% prevalence of sleep apnea-hypopnea syndrome (SAHS), probably associated with sudden death in some cases. These results support analysing sleep respiratory parameters in theses patients. Identifying SAHS symptoms may help optimise treatment, thereby improving quality of life and prognosis.