Artificial intelligence

Voice and speech analyses can detect dementia

Using artificial intelligence, DTU start-up company DemensAI can detect early signs of dementia.

DemensAI receives Sten Scheibye Innovation Award at DTU Startup Day.
DemensAI receives Sten Scheibye Innovation Award at DTU Startup Day. Photo: Marie Bentzon.


A Large Language Model (LLM) is a type of artificial intelligence trained using large amounts of data in the form of articles, books, websites, etc. From the data, the model acquires an understanding of human-like language, enabling it to calculate the probability of an answer or result.

ChatGPT, Siri, and Google Translate are examples of services that use an LLM.

Changes in the voice

DemensAI uses a language model similar to ChatGPT to accurately diagnose dementia at an early stage. An audio recording of a consultation between a doctor and a patient with suspected dementia is run through the language model on the computer. The model then analyses both the acoustic and the linguistic features of the recording. The acoustic analysis includes tracking the volume of the patient’s voice and pauses taken while speaking, and the linguistic analysis includes transcribing the audio file, much in the same way that automatic subtitles are generated on YouTube, and then analysing the patient’s vocabulary and grammar.

“We can learn so much about a person’s voice that a human would never be able to detect. This includes detecting dementia through microscopic changes or patterns in the voice or the words that are used. For example, a typical pattern in people with dementia is forgetting people’s names. The problem is that if you have early-stage dementia, there’s a risk that your doctor will wrongfully conclude that you don’t have it because the symptoms are so difficult to spot. Our language model will help to detect dementia in more people,” says Anton Birn.

Tests have shown that DemensAI’s language model can diagnose dementia in 87 per cent of cases.


A condition that affects the brain and is most common in elderly people. More than 200 different diseases can cause dementia.

The Danish Dementia Research Centre estimates that:

  • About 96,000 people in Denmark have dementia.
  • The number is expected to rise to more than 134,000 by 2035.

Early diagnosis can be crucial

Dementia is one of the main causes of death in Denmark. As life expectancy increases, so does the number of people with dementia, and with the healthcare system under pressure, the waiting time for a dementia assessment can be over a year. The long wait can be a big problem for people with dementia, who are missing out on valuable preparation time.

“A dementia diagnosis gives the patient an important understanding of why they suddenly struggle with things at work or at home with the family. It also opens the door to opportunities such as seeking support from the municipality so they can maybe work for longer and their family understands why they’ve changed. In some forms of dementia, the symptoms can also be delayed through medical treatment, a healthy diet, staying physically active, socializing, and stimulating the brain,” says Lene Iben Hvidkjær, professional Dementia Advisor for the Danish Alzheimer’s Association (Alzheimerforeningen).

Further model training

Patients with suspected dementia will initially be examined by their own doctor, who can then provide a referral to a memory clinic. And this is where the wait can be long.

“The problem is that pinpointing the specific dementia diagnosis with the current screening tools can be very difficult in patients with early-stage dementia. The screening tools are expensive and only available at memory clinics, which have very long waiting lists. The screening tests currently available to general practitioners can only be used to assess the degree of cognitive impairment and not the underlying cause. This means that many of the patients referred later turn out to have depression instead of dementia, for example, which requires a completely different referral,” says Anton Birn.

The team behind DemensAI is working to establish a collaboration with several memory clinics. Through this collaboration, their model will get a larger data set with audio recordings from consultations, which will enable the team to further train the model and make it even more accurate. The plan is to use 2024 to verify the model’s performance before testing and implementing it at clinics in 2025.


DemensAI is a start-up founded in October 2023. The team consists of Anton Birn, Laurine Dargaud, Abhista Partal, and Petros Maravelakis. Tests have shown that DemensAI’s language model can diagnose dementia in 87 per cent of cases.

The company originates from DTU X-Tech - an entrepreneurship learning programme for students.

Follow the work of DemensAI.


Artificial intelligence is developing at an incredibly fast pace. The potential is enormous and it's hard to see where it will end.

Artificial intelligence is based on maths and logic. We know the work processes, but we don't always know how the AI arrives at a particular solution. Therefore, as researchers and society, we must make demands on the use of the technology, both in legislation and morally.

At DTU, we have a special focus on the ethical aspect of future AI solutions.

Read more in our topic about artificial intelligence.