Alzheimer's Disease Fact Sheet | National Institute on Aging

Alzheimer's disease is a brain disorder that slowly destroys memory and thinking skills, and, eventually, the ability to carry out the simplest tasks. Skiptomaincontent The.govmeansit’sofficial. Federalgovernmentwebsitesoftenendin.govor.mil.Beforesharingsensitiveinformation,makesureyou’reonafederalgovernmentsite. Thesiteissecure. The https:// ensuresthatyouareconnectingtotheofficialwebsiteandthatanyinformationyouprovideisencryptedandtransmittedsecurely. Breadcrumb Home HealthInformation Alzheimer'sDiseaseFactSheet Alzheimer'sDiseaseandRelatedDementiasBasicsofAlzheimer’sDiseaseandDementia Alzheimer'sDiseaseFactSheet Onthispage: Alzheimer’sdiseaseisabraindisorderthatslowlydestroysmemoryandthinkingskills,and,eventually,theabilitytocarryoutthesimplesttasks.InmostpeoplewithAlzheimer’s,symptomsfirstappearlaterinlife.Estimatesvary,butexpertssuggestthatmorethan6millionAmericans,mostofthemage65orolder,mayhavedementiacausedbyAlzheimer’s. Alzheimer’sdiseaseiscurrentlyrankedastheseventhleadingcauseofdeathintheUnitedStatesandisthemostcommoncauseofdementiaamongolderadults. Dementiaisthelossofcognitivefunctioning—thinking,remembering,andreasoning—andbehavioralabilitiestosuchanextentthatitinterfereswithaperson’sdailylifeandactivities.Dementiarangesinseverityfromthemildeststage,whenitisjustbeginningtoaffectaperson’sfunctioning,tothemostseverestage,whenthepersonmustdependcompletelyonothersforhelpwithbasicactivitiesofdailyliving. Sharethisinfographicandhelpspreadthewordaboutunderstandingdifferenttypesofdementia. Thecausesofdementiacanvary,dependingonthetypesofbrainchangesthatmaybetakingplace.OtherdementiasincludeLewybodydementia,frontotemporaldisorders,andvasculardementia.Itiscommonforpeopletohavemixeddementia—acombinationoftwoormoretypesofdementia.Forexample,somepeoplehavebothAlzheimer’sdiseaseandvasculardementia. Alzheimer’sdiseaseisnamedafterDr.AloisAlzheimer.In1906,Dr.Alzheimernoticedchangesinthebraintissueofawomanwhohaddiedofanunusualmentalillness.Hersymptomsincludedmemoryloss,languageproblems,andunpredictablebehavior.Aftershedied,heexaminedherbrainandfoundmanyabnormalclumps(nowcalledamyloidplaques)andtangledbundlesoffibers(nowcalledneurofibrillary,ortau,tangles). TheseplaquesandtanglesinthebrainarestillconsideredsomeofthemainfeaturesofAlzheimer’sdisease.Anotherfeatureisthelossofconnectionsbetweenneuronsinthebrain.Neuronstransmitmessagesbetweendifferentpartsofthebrain,andfromthebraintomusclesandorgansinthebody. HowdoesAlzheimer'sdiseaseaffectthebrain? ScientistscontinuetounravelthecomplexbrainchangesinvolvedinAlzheimer’sdisease.Changesinthebrainmaybeginadecadeormorebeforesymptomsappear.DuringthisveryearlystageofAlzheimer’s,toxicchangesaretakingplaceinthebrain,includingabnormalbuildupsofproteinsthatformamyloidplaquesandtautangles.Previouslyhealthyneuronsstopfunctioning,loseconnectionswithotherneurons,anddie.ManyothercomplexbrainchangesarethoughttoplayaroleinAlzheimer’saswell. Thedamageinitiallyappearstotakeplaceinthehippocampusandtheentorhinalcortex,whicharepartsofthebrainthatareessentialinformingmemories.Asmoreneuronsdie,additionalpartsofthebrainareaffectedandbegintoshrink.BythefinalstageofAlzheimer’s,damageiswidespreadandbraintissuehasshrunksignificantly. SignsandsymptomsofAlzheimer'sdisease MemoryproblemsaretypicallyoneofthefirstsignsofcognitiveimpairmentrelatedtoAlzheimer’s.Somepeoplewithmemoryproblemshaveaconditioncalledmildcognitiveimpairment(MCI).WithMCI,peoplehavemorememoryproblemsthannormalfortheirage,buttheirsymptomsdonotinterferewiththeireverydaylives.MovementdifficultiesandproblemswiththesenseofsmellhavealsobeenlinkedtoMCI.OlderpeoplewithMCIareatgreaterriskfordevelopingAlzheimer’s,butnotallofthemdoso.Somemayevenreverttonormalcognition. ThefirstsymptomsofAlzheimer’svaryfrompersontoperson.Formany,declineinnonmemoryaspectsofcognition,suchasword-finding,vision/spatialissues,andimpairedreasoningorjudgmentmaysignaltheveryearlystagesofthedisease.Researchersarestudyingbiomarkers(biologicalsignsofdiseasefoundinbrainimages,cerebrospinalfluid,andblood)todetectearlychangesinthebrainsofpeoplewithMCIandincognitivelynormalpeoplewhomaybeatgreaterriskforAlzheimer’s.MoreresearchisneededbeforethesetechniquescanbeusedbroadlyandroutinelytodiagnoseAlzheimer’sinahealthcareprovider’soffice. StagesofAlzheimer'sdisease MildAlzheimer’sdisease AsAlzheimer’sworsens,peopleexperiencegreatermemorylossandothercognitivedifficulties.Problemscanincludewanderingandgettinglost,troublehandlingmoneyandpayingbills,repeatingquestions,takinglongertocompletenormaldailytasks,andpersonalityandbehaviorchanges.Peopleareoftendiagnosedinthisstage. ModerateAlzheimer’sdisease Inthisstage,damageoccursinareasofthebrainthatcontrollanguage,reasoning,consciousthought,andsensoryprocessing,suchastheabilitytocorrectlydetectsoundsandsmells.Memorylossandconfusiongrowworse,andpeoplebegintohaveproblemsrecognizingfamilyandfriends.Theymaybeunabletolearnnewthings,carryoutmultisteptaskssuchasgettingdressed,orcopewithnewsituations.Inaddition,peopleatthisstagemayhavehallucinations,delusions,andparanoiaandmaybehaveimpulsively. SevereAlzheimer’sdisease Ultimately,plaquesandtanglesspreadthroughoutthebrain,andbraintissueshrinkssignificantly.PeoplewithsevereAlzheimer’scannotcommunicateandarecompletelydependentonothersfortheircare.Neartheendoflife,thepersonmaybeinbedmostorallofthetimeasthebodyshutsdown. WhatcausesAlzheimer’sdisease? Inrecentyears,scientistshavemadetremendousprogressinbetterunderstandingAlzheimer’sandthemomentumcontinuestogrow.Still,scientistsdon’tyetfullyunderstandwhatcausesAlzheimer’sdiseaseinmostpeople.Inpeoplewithearly-onsetAlzheimer’s,ageneticmutationmaybethecause.Late-onsetAlzheimer’sarisesfromacomplexseriesofbrainchangesthatmayoccuroverdecades.Thecausesprobablyincludeacombinationofgenetic,environmental,andlifestylefactors.TheimportanceofanyoneofthesefactorsinincreasingordecreasingtheriskofdevelopingAlzheimer’smaydifferfrompersontoperson. ThebasicsofAlzheimer’sdisease Scientistsareconductingstudiestolearnmoreaboutplaques,tangles,andotherbiologicalfeaturesofAlzheimer’sdisease.Advancesinbrainimagingtechniquesallowresearcherstoseethedevelopmentandspreadofabnormalamyloidandtauproteinsinthelivingbrain,aswellaschangesinbrainstructureandfunction.ScientistsarealsoexploringtheveryearlieststepsinthediseaseprocessbystudyingchangesinthebrainandbodyfluidsthatcanbedetectedyearsbeforeAlzheimer’ssymptomsappear.FindingsfromthesestudieswillhelpinunderstandingthecausesofAlzheimer’sandmakediagnosiseasier. OneofthegreatmysteriesofAlzheimer’sdiseaseiswhyitlargelyaffectsolderadults.Researchonnormalbrainagingisexploringthisquestion.Forexample,scientistsarelearninghowage-relatedchangesinthebrainmayharmneuronsandaffectothertypesofbraincellstocontributetoAlzheimer’sdamage.Theseage-relatedchangesincludeatrophy(shrinking)ofcertainpartsofthebrain,inflammation,bloodvesseldamage,productionofunstablemoleculescalledfreeradicals,andmitochondrialdysfunction(abreakdownofenergyproductionwithinacell). Alzheimer'sdiseasegenetics MostpeoplewithAlzheimer’shavethelate-onsetformofthediseaseinwhichsymptomsbecomeapparentintheirmid-60sorlater.Researchershavenotfoundaspecificgenethatdirectlycauseslate-onsetAlzheimer’s,buthavingaformoftheapolipoproteinE(APOE)geneincreasesaperson’srisk.Thisgenehasseveralforms,andoneofthose,APOEε4,increasesaperson’sriskofdevelopingAlzheimer’sandisalsoassociatedwithanearlierageofdiseaseonset.However,carryingtheAPOEε4formofthegenedoesnotmeanthatapersonwilldefinitelydevelopthedisease,andsomepeoplewithnoAPOEε4mayalsodevelopAlzheimer’s. Scientistsalsohaveidentifiedseveralregionsofinterestinthegenome(anorganism’scompletesetofDNA)thatmayincreaseordecreaseaperson’sriskforlate-onsetAlzheimer’stovaryingdegrees. Early-onsetAlzheimer’soccursbetweenaperson’s30sandmid-60sandrepresentslessthan10%ofallpeoplewithAlzheimer’s.Somecasesarecausedbyaninheritedchangeinoneofthreegenes.Forothers,researchshowsthatothergeneticcomponentsareinvolved. MostpeoplewithDownsyndromedevelopAlzheimer’s.ThismaybebecausepeoplewithDownsyndromehaveanextracopyofchromosome21,whichcontainsthegenethatgeneratesharmfulamyloid. FormoreaboutAlzheimer’sgeneticsresearch,seeNIA’sAlzheimer’sDiseaseGeneticsFactSheet. Health,environmental,andlifestylefactors ResearchsuggeststhatahostoffactorsbeyondgeneticsmayplayaroleinthedevelopmentandcourseofAlzheimer’s.Thereisagreatdealofinterest,forexample,intherelationshipbetweencognitivedeclineandvascularconditions,suchasheartdisease,stroke,andhighbloodpressure,aswellasmetabolicdiseases,suchas diabetesandobesity.OngoingresearchwillhelpusunderstandwhetherandhowreducingriskfactorsfortheseconditionsmayalsoreducetheriskofAlzheimer’s. Anutritiousdiet,physicalactivity,socialengagement,andmentallystimulatingpursuitshaveallbeenassociatedwithhelpingpeoplestayhealthyastheyage.ThesefactorsmightalsohelpreducetheriskofcognitivedeclineandAlzheimer’s.Researchersaretestingsomeofthesepossibilitiesinclinicaltrials. HowisAlzheimer’sdiseasediagnosed? DoctorsuseseveralmethodsandtoolstohelpdeterminewhetherapersonwhoishavingmemoryproblemshasAlzheimer’sdisease. TodiagnoseAlzheimer’s,doctorsmay: Askthepersonandafamilymemberorfriendquestionsaboutoverallhealth,useofprescriptionandover-the-countermedicines,diet,pastmedicalproblems,abilitytocarryoutdailyactivities,andchangesinbehaviorandpersonality. Conducttestsofmemory,problemsolving,attention,counting,andlanguage. Carryoutstandardmedicaltests,suchasbloodandurinetests,toidentifyotherpossiblecausesoftheproblem. Performbrainscans,suchascomputedtomography(CT),magneticresonanceimaging(MRI),orpositronemissiontomography(PET),tosupportanAlzheimer’sdiagnosisortoruleoutotherpossiblecausesforsymptoms. Thesetestsmayberepeatedtogivedoctorsinformationabouthowtheperson’smemoryandothercognitivefunctionsarechangingovertime. PeoplewithmemoryandthinkingconcernsshouldtalktotheirdoctortofindoutwhethertheirsymptomsareduetoAlzheimer’soranothercause,suchasstroke,tumor,Parkinson’sdisease,sleepdisturbances,sideeffectsofmedication,aninfection,oranothertypeofdementia.Someoftheseconditionsmaybetreatableandpossiblyreversible. IfthediagnosisisAlzheimer’s,beginningtreatmentasearlyaspossibleinthediseaseprocesscouldhelppreservedailyfunctioningforawhile.Anearlydiagnosisalsohelpsfamiliesplanforthefuture.Theycantakecareoffinancialandlegalmatters,addresspotentialsafetyissues,learnaboutlivingarrangements,anddevelopsupportnetworks. Inaddition,anearlydiagnosisprovidespeoplewithmoreopportunitiestoparticipateinclinicaltrialsorotherresearchstudiestestingpossiblenewtreatmentsforAlzheimer’s. ParticipatinginAlzheimer'sdiseaseclinicaltrials Everybody—thosewithAlzheimer’sdiseaseorMCIaswellashealthyvolunteerswithorwithoutafamilyhistoryofAlzheimer’s—maybeabletotakepartinclinicaltrialsandstudies.ParticipantsinAlzheimer’sclinicalresearchhelpscientistslearnhowthebrainchangesinhealthyagingandinAlzheimer’s.Currently,atleast270,000volunteersareneededtoparticipateinmorethan250activeclinicaltrialsandstudiesthataretestingwaystounderstand,diagnose,treat,andpreventAlzheimer’sdisease. VolunteeringforaclinicaltrialisonewaytohelpinthefightagainstAlzheimer’s.Studiesneedparticipantsofdifferentages,sexes,races,andethnicitiestoensurethatresultsaremeaningfulformanypeople.Tolearnmoreaboutclinicaltrials,watchthisvideofromNIH'sNationalLibraryofMedicine. NIAleadsthefederalgovernment’sresearcheffortsonAlzheimer’s.NIA-supportedAlzheimer’sDiseaseResearchCentersthroughouttheU.S.conductawiderangeofresearch,includingstudiesofthecauses,diagnosis,andmanagementofthedisease.NIAalsosponsorstheAlzheimer’sClinicalTrialsConsortium,whichisdesignedtoaccelerateandexpandstudiesandtherapiesinAlzheimer’sandrelateddementias. TolearnmoreaboutAlzheimer’sclinicaltrialsandstudies: Talktoyourhealthcareprovideraboutlocalstudiesthatmayberightforyou. ContactAlzheimer’sDiseaseResearchCentersormemoryorneurologyclinicsinyourcommunity. SearchtheAlzheimers.govClinicalTrialsFinderforatrialnearyouorsignupforemailalertsaboutnewtrials. Signupforaregistryormatchingservicetobeinvitedtoparticipateinstudies. Learnmoreaboutparticipatinginclinicaltrials. WatchvideosofparticipantsinAlzheimer’sdiseaseclinicaltrialstalkingabouttheirexperiences. HowisAlzheimer’sdiseasetreated? Alzheimer’siscomplex,anditisthereforeunlikelythatanyonedrugorotherinterventionwillsuccessfullytreatitinallpeoplelivingwiththedisease. Scientistsareexploringmanyavenuestodelayorpreventthediseaseaswellastotreatitssymptoms.Inongoingclinicaltrials,scientistsaredevelopingandtestingseveralpossibleinterventions.Understudyaredrugtherapiesaimedatavarietyofdiseaseinterventions,aswellasnondrugapproachessuchasphysicalactivity,diet,cognitivetraining,andcombinationsofthese.Justaswehavemanytreatmentsforheartdiseaseandcancer,wewilllikelyneedmanyoptionsfortreatingAlzheimer’s.Precisionmedicine—gettingtherighttreatmenttotherightpersonattherighttime—willlikelyplayamajorrole. CurrentapproachestotreatingAlzheimer’sfocusonhelpingpeoplemaintainmentalfunction,treatingtheunderlyingdiseaseprocess,andmanagingbehavioralsymptoms. MedicationstomaintainmentalfunctioninAlzheimer'sdisease SeveralmedicationsareapprovedbytheU.S.FoodandDrugAdministration(FDA)totreatsymptomsofAlzheimer’s.Donepezil,rivastigmine,andgalantamineareusedtotreatthesymptomsofmildtomoderateAlzheimer’s.Donepezil,memantine,therivastigminepatch,andacombinationmedicationofmemantineanddonepezilareusedtotreatmoderatetosevereAlzheimer’ssymptoms.Allofthesedrugsworkbyregulatingneurotransmitters,thechemicalsthattransmitmessagesbetweenneurons.Theymayhelpreducesymptomsandhelpwithcertainbehavioralproblems.However,thesedrugsdon’tchangetheunderlyingdiseaseprocess.Theyareeffectiveforsomebutnotallpeopleandmayhelponlyforalimitedtime. MedicationstotreattheunderlyingAlzheimer'sdiseaseprocess Aducanumabisthefirstdisease-modifyingtherapyapprovedbytheFDAtotreatAlzheimer’sdisease.ThemedicationhelpstoreduceamyloiddepositsinthebrainandmayhelpslowtheprogressionofAlzheimer’s,althoughithasnotyetbeenshowntoaffectclinicaloutcomessuchasprogressionofcognitivedeclineordementia.Adoctororspecialistwilllikelyperformtests,suchasaPETscanoranalysisofcerebrospinalfluid,tolookforevidenceofamyloidplaquesandhelpdecideifthetreatmentisrightforthepatient. AducanumabwasapprovedthroughtheFDA’sAcceleratedApprovalProgram.Thisprocessrequiresanadditionalstudyafterapprovaltoconfirmtheanticipatedclinicalbenefit.Ifthefollow-uptrialfailstoverifyclinicalbenefit,theFDAmaywithdrawapprovalofthedrug.Resultsofthephase4clinicaltrialforaducanumabareexpectedtobeavailablebyearly2030. Severalotherdisease-modifyingmedicationsarebeingtestedinpeoplewithmildcognitiveimpairmentorearlyAlzheimer’saspotentialtreatments. ManagingAlzheimer'sdiseasebehavior CommonbehavioralsymptomsofAlzheimer’sincludesleeplessness,wandering,agitation,anxiety,andaggression.Scientistsarelearningwhythesesymptomsoccurandarestudyingnewtreatments—drugandnondrug—tomanagethem.ResearchhasshownthattreatingbehavioralsymptomscanmakepeoplewithAlzheimer’smorecomfortableandmakesthingseasierforcaregivers. SupportforfamiliesandAlzheimer'sdiseasecaregivers CaringforapersonwithAlzheimer’scanhavesignificantphysical,emotional,andfinancialcosts.Thedemandsofday-to-daycare,changesinfamilyroles,anddecisionsaboutplacementinacarefacilitycanbedifficult.NIAsupportseffortstoevaluateprograms,strategies,approaches,andotherresearchtoimprovethequalityofcareandlifeforthoselivingwithdementiaandtheircaregivers. Becomingwell-informedaboutthediseaseisoneimportantlong-termstrategy.ProgramsthatteachfamiliesaboutthevariousstagesofAlzheimer’sandaboutwaystodealwithdifficultbehaviorsandothercaregivingchallengescanhelp. Goodcopingskills,astrongsupportnetwork,andrespitecareareotherthingsthatmayhelpcaregivershandlethestressofcaringforalovedonewithAlzheimer’s.Forexample,stayingphysicallyactiveprovidesphysicalandemotionalbenefits. Somecaregivershavefoundthatjoiningasupportgroupisacriticallifeline.Thesesupportgroupsenablecaregiverstofindrespite,expressconcerns,shareexperiences,gettips,andreceiveemotionalcomfort.Manyorganizationssponsorin-personandonlinesupportgroups,includinggroupsforpeoplewithearly-stageAlzheimer’sandtheirfamilies. Formoreinformation,seeAlzheimer’sCaregiving. ReadaboutthistopicinSpanish.Leasobreestetemaenespañol. Signupforemailupdates ReceiveweeklytipsandresourcesonAlzheimer'sdiseaseandrelateddementiasfromNIA'sAlzheimers.gov EmailAddress FormoreinformationaboutAlzheimer’sdisease NIAAlzheimer’sandrelatedDementiasEducationandReferral(ADEAR)Center 800-438-4380 [email protected] www.nia.nih.gov/alzheimers TheNIAADEARCenteroffersinformationandfreeprintpublicationsaboutAlzheimer’sandrelateddementiasforfamilies,caregivers,andhealthprofessionals.ADEARCenterstaffanswertelephone,email,andwrittenrequestsandmakereferralstolocalandnationalresources. Alzheimers.gov www.alzheimers.gov ExploretheAlzheimers.govportalforinformationandresourcesonAlzheimer’sandrelateddementiasfromacrossthefederalgovernment. Alzheimer'sAssociation 800-272-3900  866-403-3073(TTY) [email protected] www.alz.org EldercareLocator 800-677-1116 [email protected] https://eldercare.acl.gov MedlinePlus NIHNationalLibraryofMedicine       www.medlineplus.gov ThiscontentisprovidedbytheNIHNationalInstituteonAging(NIA).NIAscientistsandotherexpertsreviewthiscontenttoensureitisaccurateanduptodate. Contentreviewed:July08,2021 Articles ParticipatinginActivitiesYouEnjoyAsYouAge QuittingSmokingforOlderAdults AdvanceCarePlanning GettingYourAffairsinOrder LatestNews Overactivewakefulnessneuronsdisruptsleepinagingmice 06/30/2022 RelatedArticles WhatHappenstotheBraininAlzheimer'sDisease? HowIsAlzheimer'sDiseaseTreated? DoMemoryProblemsAlwaysMeanAlzheimer'sDisease?