Tailoring the screening for cognitive impairment to the individual patient with Computerised Adaptive Testing (CAT)

The screening for and monitoring of cognitive decline in the elderly forms an
important part of the diagnostic care provided in outpatient clinics and other
clinical facilities. Because of time constraints, clinicians tend to opt for
brief cognitive instruments such as the Mini Mental State Examination (MMSE).
The MMSE is basically a set of standard cognitive tasks administered to every
patient.

However, it is well-known that brief cognitive instruments such as the MMSE
have reduced sensitivity in the prodromal or early stages of dementia. Previous
research shows that longer cognitive instruments and neuropsychological tests
have better diagnostic accuracy and precision in the early stages of dementia.

This research aims to combine the efficiency of short cognitive screenings with
the validity of extensive cognitive and neuropsychological instruments. Instead
of administering the same set of question to every individual patient, items
with difficulty levels appropriate to the patient's impairment level will be
selected, while too easy and too difficult items will be skipped.

This tailored individualised testing can be achieved with a technique called
Computerised Adaptive Testing (CAT). Using CAT we aim to administer the tasks
with optimal diagnostic accuracy in the time span that is needed to complete a
short cognitive screening.

To examine whether it is possible to combine the sensitivity of
neuropsychological tasks with the efficiency of brief cognitive instruments.

A prospective CAT validation study. We examine if a more extensive cognitive
instrument (the CAMCOG, total administration time of about 25 minutes) can be
administered in a time span similar to the time to administer a brief cognitive
test instrument (the MMSE, total administration time of about 10 minutes) using
CAT. We examine whether the CAT administration of the CAMCOG can reproduce the
results of the entire CAMCOG item set. Subsequently, we examine whether the
expansion of the CAMCOG with additional neuropsychological tasks to construct
an itembank that is subsequently administered with CAT enhances the diagnostic
accuracy and precision of the cognitive examination. We consider the clinical
diagnosis of dementia as the reference standard. In both studies we compare the
results of the cognitive examination with a heteroanamnestic questionnaire
which assesses daily cognitive functioning (the IQ-Code) and control for the
presence of depression.

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