Medical tests used to diagnose dementia

Naomi Carr
Author: Naomi Carr Medical Reviewer: Dr. Jenni Jacobsen, PhD Last updated:

Dementia can affect a person’s memory and cognition, mood and behavior, and mobility, and impair daily functioning. There are several types of dementia, such as Alzheimer’s disease, frontotemporal dementia, and vascular dementia, so when diagnosing dementia, medical professionals will conduct a thorough assessment to determine the cause of the presenting symptoms.

How do medical professionals diagnose dementia?

When making a diagnosis of dementia, professionals will utilize several different types of tests and examinations to gather all the necessary information about the individual’s mental, physical, and cognitive health [1].

Different types of dementia can affect people in different ways, so it is important when attempting to ascertain whether dementia is present to have a clear picture of all the symptoms that the individual is experiencing.

For example, someone may be experiencing changes in their mood and behavior but little change in their cognitive functioning, potentially resulting in an underlying cause of dementia going unnoticed or undiagnosed, if a full assessment is not completed [2].

As such, various tests are used as part of a thorough and comprehensive assessment and may be performed by several different types of medical specialists [3].

Medical history

Initially, a thorough medical history will be compiled, including information about any physical and mental health conditions that the individual has been diagnosed with in the past, and any current diagnoses and medications, particularly those that could create symptoms similar to dementia symptoms [1].

The individual will be asked about their current symptoms, including when these symptoms began, if and how they have changed, and how they are impacting daily functioning [4].

The professional may also ask questions relating to lifestyle, home environment, and wellbeing across all aspects of life, such as social, professional, and personal activities and functioning, to help in gathering information about the individual and if there are any specific factors that may be contributing to their presenting symptoms [3].

Similarly, they will ask questions about the individual’s family mental and physical health history, particularly whether a family member has been diagnosed with any type of dementia. It may be useful for the individual to attend this appointment with a family member, to help with providing information about their symptoms and medical history [1][5].

Cognitive tests

Cognitive tests are used to gather information about mental abilities and functioning, such as memory, planning, spatial awareness, concentration, language, and orientation to time and place. They usually involve a pen and paper and can be completed by the individual at their appointment, alongside a doctor or specialist [4][6].

The test is then scored and can typically indicate if there are impairments in any specific aspects of cognitive functioning, which can help in formulating a diagnosis of a particular type of dementia. These tests can be repeated over time, allowing for a comparison of scores which can indicate any changes in symptom severity [3].

Although cognitive tests can indicate that dementia might be present, they are not the only diagnostic tool used, as results can be influenced by education level; therefore, results are used as a part of the overall assessment [4].

There are several different cognitive tests, some of which can be completed in around 5 minutes, while others that are more comprehensive may take 30 minutes. These tests tend to utilize similar types of questions, which check aspects of functioning and mental state.

Examples of cognitive tests used in the diagnosis of dementia include [3][5][6]:

  • Montreal Cognitive Assessment (MoCA)
  • Mini Mental State Examination (MMSE)
  • Functional Activities Questionnaire (FAQ)
  • Neuropsychiatric Inventory Questionnaire (NPI-Q)
  • Alzheimer’s Disease Assessment Scale-Cognitive (ADAS-Cog)

These tests include questions such as [1][3]:

  • Orientation to time and place, such as asking for today’s date, which state or county they are currently in, or the name of the building they are in.
  • Following a set of instructions, such as drawing a clock face with a specific time.
  • Recollecting a set of words after a set amount of time.
  • Counting or calculation tasks, such as counting backward from 100 in increments of 7.
  • Completing problem-solving and visual-spatial awareness tasks, such as drawing connected lines in a specific pattern.

Physical examinations

Various physical examinations will be conducted when diagnosing dementia, to ascertain whether there are any underlying physical health conditions that may be contributing to the presenting symptoms [1].

It is likely that the doctor will ask questions relating to diet and alcohol use, as this can influence the development of certain dementia symptoms. Similarly, they will ask about any medications that are currently prescribed and if they are causing any side effects, as some medications could cause side effects that are similar to symptoms of dementia [5].

They will also check the individual’s vital signs, such as blood pressure, pulse, and temperature, as well as listening to the heart and lungs, to determine overall physical wellbeing. Additionally, they will ask questions about the individual’s mental health, such as symptoms relating to mood disorders, depression, or anxiety [4][5].

Commonly, a blood test will be carried out to rule out any other causes of the individual’s symptoms. This will usually check levels of vitamins and electrolytes, test for infection and inflammation, check liver, kidney, and thyroid functioning, and test blood sugar levels to look for diabetes [1][6].

It may also be necessary to conduct a urine test if there is a suspected urinary tract infection, as this can impact mood and functioning, thus contributing to dementia symptoms [4].

Physical and mental health conditions, alcohol use, and medication side effects can all contribute to the development of symptoms that are similar to those of dementia, so it is useful to gather this information to rule out any underlying causes of the individual’s symptoms. Furthermore, many of these conditions can be treated, which can reduce or reverse symptoms [5].

Neurological examinations

Neurological testing may include the testing of reflexes, balance, movement and mobility, and sensory functions. This can help to determine the presence of specific types of dementia or other types of brain damage [1][5].

In some cases, it may be necessary to carry out a brain scan, if a clear diagnosis has not been found with the use of other tests. Brain scans can help to determine a specific type of dementia and find specific causes of cognitive or mobility issues, helping to rule out conditions that may be contributing to the individual’s symptoms.

Commonly used brain scans include [6]:

  • Magnetic Resonance Imaging (MRI)
  • Computed Tomography (CT)

These scans produce images of the brain that can help in discovering tumors, stroke, vascular damage, shrinkage or changes in certain areas of the brain, fluid or plaque buildup, and signs of brain damage from a traumatic head injury [1][4].

Other types of scans that are sometimes used include [6]:

  • Positron Emission Tomography (PET)
  • Single-Photon Emission Computerized Tomography (SPECT)

These scans are used to look at activity or blood flow in the brain [4].

Neurological examinations can provide more detailed information about brain damage, neurological functioning, and other contributing causes of dementia symptoms. However, it may not always be necessary to conduct these examinations if a clear diagnosis of a specific type of dementia can be made from other types of testing [3].

When to seek a dementia diagnosis

Some changes in memory and physical functioning may occur as people get older and are a natural part of aging. However, symptoms of dementia are often more concerning or potentially dangerous and can have a severe impact on an individual’s ability to function [2].

As such, it can be a good idea to seek a professional assessment and diagnosis if persistent or worrying symptoms occur, in order to receive appropriate treatment and support.

Symptoms that may be early warning signs of dementia can include [2][7]:

  • Significant and persistent memory loss
  • Trouble finding the right words and phrases
  • Difficulty concentrating or completing tasks
  • Regularly becoming confused about the date or time
  • Getting lost in familiar places
  • Regularly losing items and finding them in strange places, such as keys in the fridge
  • Confusion around numbers and symbols, such as difficulty paying the bills or counting change
  • Extreme changes in mood, behavior, or personality
  • Loss of interest in social activities and hobbies
  • Impaired decision-making, such as unsafe judgments or actions

Although dementia cannot be cured, receiving a diagnosis and treatment as early as possible can help to slow deterioration, manage symptoms, and reduce impairments in functioning [1][7].

  1. Stanford Medicine. (n.d). Dementia Diagnosis. Stanford Health Care. Retrieved from
  2. National Health Service. (Reviewed 2020). Symptoms of Dementia. NHS. Retrieved from
  3. Alzheimer’s Society. (Reviewed 2022). How Will A Specialist Test For Dementia? Alzheimer’s Society. Retrieved from
  4. National Health Service. (Reviewed 2020). Tests For Diagnosing Dementia. NHS. Retrieved from
  5. Alzheimer’s Association. (n.d). Medical Tests for Diagnosing Alzheimer’s. Alzheimer’s Association. Retrieved from
  6. Dementia Australia. (2022). Tests Used in Diagnosing Dementia. Dementia Australia. Retrieved from
  7. Alzheimer Society. (n.d). The 10 Warning Signs of Dementia. Alzheimer Society. Retrieved from
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Naomi Carr
Author Naomi Carr Writer

Naomi Carr serves as our talented writer, dedicated to raising awareness about mental health and providing support to those in need.

Published: Jun 21st 2023, Last edited: Sep 22nd 2023

Dr. Jenni Jacobsen, PhD
Medical Reviewer Dr. Jenni Jacobsen, PhD LSW, MSW

Dr. Jenni Jacobsen is our expert medical reviewer, holding roles as a licensed social worker, behavioral health consultant, and PhD in clinical psychology.

Content reviewed by a medical professional. Last reviewed: Jun 21st 2023