Olderpeoplewithhearinglossmaysufferfasterratesofmentaldecline.PeoplewhohavehearingtroublesufferedmeaningfulimpairmentsinmemoryattentionandlearningaboutthreeyearsearlierthanpeoplewithnormalhearingastudypublishedonlineJanuary21inJAMAInternalMedicinereveals.

Thefindingsupportstheideathathearinglosscanhaveseriousconsequencesforthebrain，saysPatriciaTunofBrandeisUniversityinWaltham，Mass.whostudiesaging.“I'mhopingitwillbearealwake-upcallintermsofrealizingtheimportanceofhearing.”

ComparedwithothersenseshearingisoftenoverlookedTunsays.“Wearemadetointeractwithlanguageandtolistentoeachotheranditcanhavedamagingeffectsifwedon't.”

FrankLinofJohnsHopkinsSchoolofMedicineandcolleaguestestedthehearingof1984olderadults.Mostoftheparticipantswhoaveraged77yearsoldshowedsomehearingloss—1162volunteershadtroublehearingnoisesoflessthan25decibelscomparabletoawhisperorrustlingleaves.Thevolunteers;deficitsreflectthehearinglossinthegeneralpopulation:Overhalfofpeopleolderthan70havetroublehearing.

Overthenextsixyearstheseparticipantsunderwentmentalevaluationsthatmeasuredfactorssuchasshort-termmemoryattentionandtheabilitytoquicklymatchnumberstosymbols.Everybodygotworseatthetasksastimeworeonbutpeoplewithhearinglosshadanespeciallysharpdeclinetheteamfound.Onaverageasubstantialdropinperformancewouldcomeaboutthreeyearsearliertopeoplewithhearingloss.

Lincautionsthatthestudyhasfoundanassociationbetweenhearinglossandmentalabilities;theresearcherscan'tconcludethathearinglossdirectlycausesthedecline.Yetmoreandmorestudiesareturningupwaysthatdiminishedhearingcoulddamagethebrain.

Apersonwhocan'thearwellmightavoidsocialsituationsandisolation(孤立)isknowntobebadforthebrain.“Yougraduallybecomemoresociallywithdrawn”Linsays.“Socialisolationisamajormajorfactorfordementia(痴呆)andcognitivedecline.”

Otherstudiessuggestthatwhenpeoplestruggletointerpretanddecode(译解）wordstheirbrainsdivertenergyawayfromothertaskssuchasmemory.AudiologistandpsychologistKathyPich