On the value and the limits of cognitive screening, as seen in President Trump’s examination

by

Exam­ple clocks, cour­tesy of William Souil­lard-Man­dar et al (2015)

In the News:

Why you may be mis­un­der­stand­ing the men­tal test that Trump passed with fly­ing col­ors (The Wash­ing­ton Post):

“On its sur­face, the Mon­tre­al Cog­ni­tive Assess­ment (MoCA) test seems pret­ty easy. Can you draw a three-dimen­sion­al cube? Can you iden­ti­fy these var­i­ous ani­mals? Can you draw a clock? Can you repeat back the phrase, “The cat always hid under the couch when dogs were in the room”?…The point is not that the test is easy. The point is that an inabil­i­ty to com­plete aspects of the test reveals dif­fer­ent types of men­tal decline. The clock test is about exec­u­tive brain func­tion: mem­o­ry, plan­ning ahead. The dif­fer­ent parts of the MoCA are labeled accord­ing to what they test, with the clock test falling under “visuospatial/executive.” Ques­tions about the cur­rent year and date are under “ori­en­ta­tion.” The request to iden­ti­fy a draw­ing of a camel is under “nam­ing.” In the test’s scor­ing instruc­tions, it explains what is cov­ered: “atten­tion and con­cen­tra­tion, exec­u­tive func­tions, mem­o­ry, lan­guage, visuo­con­struc­tion­al skills, con­cep­tu­al think­ing, cal­cu­la­tions and orientation.”

It is, as Trump’s doc­tor not­ed, a tool for iden­ti­fy­ing ear­ly signs of men­tal dete­ri­o­ra­tion, like the men­tal ver­sion of a blood sam­ple on which your doc­tor runs a bat­tery of tests. It’s not the SAT; it’s a screen­ing device…

Yes, Trump passed with fly­ing col­ors, as any adult with nor­mal cog­ni­tive func­tion prob­a­bly would. And that’s the point…You’re sup­posed to get 30 out of 30 — and when you don’t, that’s when the doc­tors learn something.”

In clinical practice: Comparing 2 common cognitive screening tools

TESTING FOR DEMENTIA: THE MONTREAL COGNITIVE ASSESSMENT (MOCA) (Dai­ly­Car­ing):

“How are the MoCA and MMSE different?

The MoCA looks sim­i­lar to the MMSE, but the MoCA tests a vari­ety of dif­fer­ent cog­ni­tive func­tions and the MMSE focus­es most­ly on mem­o­ry and recall.

The MoCA is gen­er­al­ly bet­ter at detect­ing mild impair­ment and ear­ly Alzheimer’s dis­ease because it’s a more sen­si­tive test and is more dif­fi­cult. So, if a doc­tor sees a patient who is ques­tion­ing their men­tal func­tion­ing, they might give the MoCA. But if a patient comes in and is clear­ly cog­ni­tive­ly impaired, a very sen­si­tive test wouldn’t be as nec­es­sary since the issues are more obvious.

The MoCA has also been shown to be a bet­ter screen­ing tool for con­di­tions like:

  • Parkinson’s dis­ease
  • Vas­cu­lar dementia
  • Trau­mat­ic brain injury (often from falls)
  • Huntington’s dis­ease
  • Brain tumors
  • Mul­ti­ple sclerosis

How are the MoCA and MMSE similar?

Even though these are good screen­ing tools for cog­ni­tive impair­ments, nei­ther test was designed to diag­nose cog­ni­tive conditions.

They also can’t be used to dis­tin­guish between con­di­tions. For exam­ple, you couldn’t use either test to diag­nose some­one with Alzheimer’s ver­sus fron­totem­po­ral demen­tia. After the ini­tial screen­ing, more test­ing would be needed.”

In the scientific literature:

Tra­jec­to­ry and vari­abil­i­ty char­ac­ter­i­za­tion of the Mon­tre­al cog­ni­tive assess­ment in old­er adults. (Aging Clin­i­cal and Exper­i­men­tal Research). From the abstract:

  • BACKGROUND: The Mon­tre­al cog­ni­tive assess­ment (MoCA) has become one of the most wide­ly used cog­ni­tive screen­ing instru­ments since its ini­tial pub­li­ca­tion. To date, only a hand­ful of stud­ies have explored lon­gi­tu­di­nal char­ac­ter­is­tics of the MoCA.
  • AIM: The aim of this study is to char­ac­ter­ize the tra­jec­to­ry of MoCA per­for­mance across a broad age con­tin­u­um of old­er adults.
  • METHODS: Data from 467 cog­ni­tive­ly nor­mal par­tic­i­pants were used in this analy­sis. The sam­ple was grouped into four stra­ta based on the par­tic­i­pants’ age at base­line (60–69, 70–79, 80–89, and 90–99). Mixed mod­el repeat­ed mea­sures (MMRM) analy­sis and mixed-effects spline mod­els were used to char­ac­ter­ize the tra­jec­to­ry of MoCA scores in each age stra­tum and in the entire sam­ple. Intra­sub­ject stan­dard devi­a­tion (ISD) was used to char­ac­ter­ize the nat­ur­al vari­abil­i­ty of indi­vid­ual MoCA per­for­mance over time.
  • RESULTS: The ISD (Note: Intra­sub­ject Stan­dard Devi­a­tion) val­ues for each of the age stra­ta indi­cat­ed that year-to-year indi­vid­ual vari­a­tion on the MoCA ranged from zero to three points. MMRM analy­sis showed that the 60–69 stra­tum remained rel­a­tive­ly sta­ble over time while the 70–79 and 80–89 stra­ta both showed notable decline rel­a­tive to base­line per­for­mance. The mixed-effects spline mod­el showed that MoCA per­for­mance declines lin­ear­ly across the old­er adult age span.
  • DISCUSSION: Among cog­ni­tive­ly nor­mal old­er adults MoCA per­for­mance remains rel­a­tive­ly sta­ble over time, how­ev­er across the old­er adult age-span MoCA per­for­mance declines in a lin­ear fash­ion. These results will help clin­i­cians bet­ter under­stand the nor­mal course of MoCA change in old­er adults while researchers may use these results to inform sam­ple size esti­mates for inter­ven­tion studies.

Cognitive monitoring and testing in the near future: