Status quo is not enough: Common tests for Mild Cognitive Impairment lack both sensitivity and specificity

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misdiagnosisCur­rent screen­ing meth­ods miss wor­ri­some num­ber of per­sons with mild cog­ni­tive impair­ment (Sci­enceDai­ly):

“Mild cog­ni­tive impair­ment (MCI) is a slight but notice­able and mea­sur­able decline in cog­ni­tive abil­i­ties, such as remem­ber­ing names or a list of items. While changes may not be severe enough to dis­rupt dai­ly life, a clin­i­cal diag­no­sis of MCI indi­cates an increased risk of even­tu­al­ly devel­op­ing Alzheimer’s dis­ease or anoth­er type of dementia.

In a paper pub­lished in the cur­rent Jour­nal of Alzheimer’s Dis­ease, researchers at Uni­ver­si­ty of Cal­i­for­nia San Diego School of Med­i­cine and Vet­er­ans Affairs San Diego Health­care Sys­tem say exist­ing screen­ing tools for MCI result in a false-neg­a­tive error rate of more than 7 per­cent. These per­sons are mis­clas­si­fied as not hav­ing MCI based on stan­dard screen­ing instru­ments, but actu­al­ly do have MCI when more exten­sive test­ing is conducted.

“There are con­se­quences to misdiagnosis…At the indi­vid­ual lev­el, peo­ple incor­rect­ly iden­ti­fied as cog­ni­tive­ly nor­mal might not receive appro­pri­ate med­ical advice or treatment…(beyond that) If research par­tic­i­pants are mis­clas­si­fied when they enroll in a study, this can weak­en the study’s results, which makes it even more dif­fi­cult to find and devel­op effec­tive treat­ments or therapies.”

“We have pre­vi­ous­ly found that as many as one-third of MCI cas­es diag­nosed with the stan­dard method are false-pos­i­tive errors,” said Edmonds. “This, cou­pled with our recent find­ing of a 7 per­cent false-neg­a­tive error rate, is con­cern­ing and tells us that the diag­nos­tic cri­te­ria could be improved.”

Study: “Missed” Mild Cog­ni­tive Impair­ment: High False-Neg­a­tive Error Rate Based on Con­ven­tion­al Diag­nos­tic Cri­te­ria (Jour­nal of Alzheimer’s Disease)

  • Abstract: Mild cog­ni­tive impair­ment (MCI) is typ­i­cal­ly diag­nosed using sub­jec­tive com­plaints, screen­ing mea­sures, clin­i­cal judg­ment, and a sin­gle mem­o­ry score. Our pri­or work has shown that this method is high­ly sus­cep­ti­ble to false-pos­i­tive diag­nos­tic errors. We exam­ined whether the cri­te­ria also lead to “false-neg­a­tive” errors by diag­nos­ti­cal­ly reclas­si­fy­ing 520 par­tic­i­pants using nov­el actu­ar­i­al neu­ropsy­cho­log­i­cal cri­te­ria. Results revealed a false-neg­a­tive error rate of 7.1%. Par­tic­i­pants’ neu­ropsy­cho­log­i­cal per­for­mance, cere­brospinal flu­id bio­mark­ers, and rate of decline pro­vid­ed evi­dence that an MCI diag­no­sis is war­rant­ed. The impact of “missed” cas­es of MCI has direct rel­e­vance to clin­i­cal prac­tice, research stud­ies, and clin­i­cal tri­als of pro­dro­mal Alzheimer’s disease.

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