ic ▁Em issions ▁( O AE ), ▁Aud itory ▁Bra inst em ▁Response ▁( AB R ), ▁and ▁ac oust ic ▁ref lex es . ▁The ▁classic ▁AN ▁parad ig m ▁would ▁include ▁present ▁O A Es ▁indicating ▁normal ▁outer ▁hair ▁cell ▁function , ▁absent ▁or ▁ab normal ▁A BR ▁with ▁presence ▁of ▁the ▁co ch lear ▁micro ph onic , ▁and ▁absent ▁ac oust ic ▁ref lex es . ▁Other ▁tests ▁would ▁include ▁pure - t one ▁and ▁speech ▁audi ometry . ▁AN ▁patients ▁can ▁have ▁a ▁range ▁of ▁hearing ▁th resh olds ▁with ▁difficulty ▁in ▁speech ▁per ception . ▁Pat ients ▁with ▁aud itory ▁ne urop ath y ▁spectrum ▁dis orders ▁have ▁to ▁date ▁never ▁been ▁shown ▁to ▁have ▁normal ▁middle ▁ear ▁mus cle ▁ref lex es ▁at ▁ 9 5 ▁d B ▁H L ▁or ▁less ▁despite ▁having ▁normal ▁o to ac oust ic ▁em issions . ▁▁▁ ▁Aud itory ▁ne urop ath y ▁can ▁occur ▁sp ont ane ously , ▁or ▁in ▁combination ▁with ▁dise ases ▁like ▁Char cot - Marie - To oth ▁disease ▁and ▁Fried reich ' s ▁at ax ia . AN ▁can ▁have ▁either ▁con gen ital ▁or ▁acquired ▁causes . ▁AN ▁can ▁be ▁due ▁to ▁gen etic ▁factors ▁in ▁synd rom ic , ▁non - s y nd rom ic , ▁and ▁mit och ond rial ▁related ▁patterns . ▁Appro xim ately ▁ 4 0 % ▁of ▁AN ▁cases ▁are ▁estimated ▁to ▁have ▁a ▁gen etic ▁cause ▁( Man cha iah , ▁Z ha