''Sleep apnoea '' is defined as a temporary pause in breathing during sleep lasting at least-: (A) 40 seconds, (B) 30 seconds, (C) 20 seconds, (D) 10 seconds
Answer is D. Sleep OSAHS also may be diagnosed in the absence of symptoms if the AHI is above 15. Each episode of apnea or hypopnea represents a reduction in breathing for at least 10 sec Ref Harrison 19th edition pg 1723