Bilingualism and Alzheimer’s Disease

Speak­ing two or more lan­guages may help de­lay Alzheimer’s dis­ease symp­toms by as much as five years, re­search has found.

A new study ex­am­ined med­i­cal records of 211 pa­tients di­ag­nosed with prob­a­ble Alzheimer’s, a dev­as­tat­ing mem­o­ry-erasing dis­or­der es­ti­mat­ed to af­fect one in eight peo­ple 65 years of age or old­er in the Un­ited States alone.

The re­search­ers found that symp­toms started as much as five years lat­er for peo­ple who had spo­ken two or more lan­guages con­sist­ently over many years. The study led by sci­en­tists at Bay­crest, an ac­a­dem­ic cen­ter af­fil­i­at­ed with the Uni­vers­ity of To­ron­to, is pub­lished in the Nov. 9 is­sue of the jour­nal Neu­rol­o­gy.

“We are not claim­ing that bi­lin­gual­ism in any way pre­vents Alzheimer’s or oth­er de­men­tias, but it may con­trib­ute to cog­ni­tive re­serve in the brain which ap­pears to de­lay the on­set of Alzheimer’s symp­toms for quite some time,” said Fer­gus Craik of Bay­crest, lead in­ves­ti­ga­tor of the study and co-editor of The Ox­ford Hand­book of Mem­o­ry.

The brains of peo­ple who speak two lan­guages still show de­te­riora­t­ion from Alzheimer’s pa­thol­o­gy, the re­search­ers not­ed. But their ex­tra lan­guage abil­i­ties seem to equip them with com­pen­sa­to­ry skills to hold back the tell-tale symp­toms, such as mem­o­ry loss, con­fu­sion, and dif­fi­cul­ties with problem-solving and plan­ning.

The pa­tients in the study had been di­ag­nosed be­tween 2007 to 2009 at Bay­crest’s Sam and Ida Ross Mem­o­ry Clin­ic.

The re­search­ers found that bi­lin­gual pa­tients had been di­ag­nosed with Alzheimer’s 4.3 years lat­er and had re­ported the on­set of symp­toms five years lat­er than one-lang­uage pa­tients. The groups were equiv­a­lent on meas­ures of cog­ni­tive and oc­cupa­t­ional lev­el, there was no ap­par­ent ef­fect of im­migra­t­ion sta­tus, and there were no gen­der dif­fer­ences, the in­ves­ti­ga­tors not­ed.

The pa­per repli­cates find­ings from a 2007 study led by El­len Bia­ly­stok of York Uni­vers­ity in Can­a­da, a col­la­bo­ra­tor in the new study al­so, and pub­lished in the jour­nal Neu­ropsy­cholo­gia. That anal­y­sis ex­am­ined the records of 184 pa­tients di­ag­nosed with prob­a­ble Alzheimer’s and oth­er forms of de­men­tia – and found that bi­lin­gual pa­tients de­layed the on­set of their symp­toms by four years com­pared to mon­o­lin­gual pa­tients.

The cur­rent study adds to mount­ing ev­i­dence that lifestyle fac­tors – such as reg­u­lar ex­er­cise, a healthy di­et, and speak­ing more than one lan­guage – can play a cen­tral role in how the brain copes with age-related cog­ni­tive de­cline and dis­eases such as Alzheimer’s, in­ves­ti­ga­tors said.

“Although a great deal of re­search is be­ing fo­cused on the de­vel­op­ment of new and more ef­fective med­ica­t­ions… there are cur­rently no drug treat­ments that show any ef­fects on de­laying Alzheimer’s symp­toms,” said Mor­ris Freed­man, who dir­ects the mem­o­ry clin­ic at Bay­crest.

World Science