<prompt> Commonest complication of CSOM isSubperiosteal abscessMastoiditisBrain abscessMeningitis  <response>: 50 of brain abscesses in adults and 25 in children are otogenic in origin. In adults, an abscess usually follows CSOM with cholesteatoma. Ref: Textbook of diseases of ENT, PL Dhingra, 7th edition, pg no. 90 