Researchers develop a digital cognitive test for diagnosing Alzheimer's disease

Researchers at Lund University in Sweden have developed a digital cognitive test for diagnosing Alzheimer's disease that is intended for use in primary care.

"This digital test, which patients perform on their own with minimal involvement from healthcare personnel, improves the primary care physician's ability to determine who should be further examined by blood tests for Alzheimer's pathology early in the investigation phase," says Professor Oskar Hansson, who led the study alongside Pontus Tideman.

The study in brief:

• Clinical memory research // quantitative study, applied research // cross-sectional study // 2 groups with 223 and 403 patients, respectively
• The researchers have designed a digital cognitive test, BioCog, intended for use in primary care as a first step in the investigation process for Alzheimer's disease.
• The test is self-administrated and tests the patient's cognitive abilities, primarily memory but also attention, and can show whether cognition is impaired. Patients whose tests show impaired cognition continue the assessment process with additional blood tests to determine whether Alzheimer's pathology is the cause of the impairment.

Alzheimer's disease is the most common cause of dementia. As new disease-modifying treatments for Alzheimer's disease are now becoming available, both early and accurate diagnosis in a resource-efficient assessment process are becoming increasingly important, as not everyone responds to the new drugs. Seeking medical care for cognitive impairment is not necessarily the result of Alzheimer's disease – it can for example be caused by depression, fatigue or other dementias.

Primary care does not have the resources, time or specialist knowledge to investigate possible Alzheimer's disease in the same way as specialised memory clinics. And this is where a digital cognitive test can make the biggest difference."

Oskar Hansson, professor of neurology, Lund University

Unlike pen-and-paper tests, which are generally used to assess cognitive impairment, digital tests provide a more detailed picture. More aspects and new variables that could not previously be measured as easily are included.

"The vast majority of people who experience memory loss will first seek treatment at their health centre. Our new digital test provides a first objective picture – at an earlier stage and with greater precision – of which patients have cognitive impairment indicative of Alzheimer's disease. This indicates who should proceed with the blood test that measures the level of phosphorylated tau and is able to detect Alzheimer's pathology in the brain with high accuracy," says Pontus Tideman, doctoral student in the research group, Clinical Memory Research at Lund University and psychologist at the Memory Clinic, Skåne University Hospital.

At the moment, these blood tests are only available in specialised clinics/memory clinics in hospitals. In the long term, they will also be available in primary care, but doing blood tests on all patients presenting with cognitive problems is not the intention.

The researchers believe that the digital tool could be of great benefit, as it is currently very challenging to diagnose Alzheimer's disease during a 15 to 20-minute patient encounter. This is where digital tools, which measure cognitive skills in an objective way, can make a big difference:

"The unique aspect of our BioCog test is that unlike other digital tests, it has been evaluated in a primary care population, i.e. patients seeking treatment at a health centre because they are experiencing cognitive problems, such as memory problems. Combining the results of the digital test and the blood test increases the accuracy of diagnosing Alzheimer's disease. The purpose of the test is to make things easier for primary care doctors," says Linda Karlsson, MSc in engineering physics and doctoral student in the research group, Clinical Memory Research at Lund University.

About the test

The digital test is done by the patient individually on a tablet computer. The test measures:

• memory (memorising ten words)
• cognitive processing speed and attention (how quickly or slowly they process information)
• orientation (what year, day etc.)
• delayed recall (recalling previously memorized information)
• recognition (among 30 words, recognise the ten words previously memorized)

The test measures aspects and variables that could not easily be measured in the past using pen-and-paper tests, such as how long it takes the patient to search among the words or how quickly they tap the screen. The combination of the sub-tests produces a result that is highly likely to indicate whether or not the patient has a cognitive impairment and can help the physician to decide which patients to take a blood test from, and ultimately which patients may benefit from the new drug treatments for Alzheimer's disease.