SummaryTwenty-six patients underwent a polysomnygraphic study allowing sleep staging and respiratory events scoring with the use of the oronasal flow, abdominal, thoracic and total displacement (Respitracet), and ear oxymetry. Moreover the patients were also equipped with a tracheal microphone giving a power rectified enveloppe (sonospirogram).Eleven patients showed abnormal respiratory events that were scored by visual lecture using all respiratory Parameters (excluding the sonospirogram) and were classified as obstructive central and mixed apneas-hypopneas. Periodic breathing was also appreciated. Detection of the same events was tried with the sonospirogram alone.The sonospirogram could accurately detect snoring and periodic breathing and finally central obstructive mixed apnea (the apneic index being well correlated: P<0.0()1 as well as the mean apnea duration: p<0.005).In contrast hypopneic events related to snoring could not be accurately appreciated.We conclude that a sonospirogram may be useful for the detection of abnormal respiratory events when used alone (screening) as when added to other respiratory signals.