A biomarker – short for biological marker – is a characteristic of the body that can be measured. Biomarkers tell us how the body’s doing. Body temperature, blood pressure, cholesterol values, and X-rays are common biomarkers. Digital biomarkers are biomarkers that are collected and measured through your smartphone.
Mindstrong tracks five digital biomarkers associated with brain health: Executive function, cognitive control, working memory, processing speed, and emotional valence. These biomarkers are generated from patterns in smartphone use such as swipes, taps, and other touchscreen activities, and are scientifically validated to provide measurements of cognition and mood.
From blood test lab values to glucose measurements in diabetes, to X-rays or CAT scans, doctors use biomarkers to detect changes in our health. They can determine if a patient has a particular health condition, evaluate whether they’re responding to treatment, or predict if they are at risk of relapse.
Executive function is what you use to plan, organize, and manage your life. It allows you to filter out distractions, keep track of deadlines, break down big projects into smaller steps, and set and achieve goals. You use executive function in making sure your driver’s license gets renewed, and that the insurance card and car registration are in the glove compartment.
You need executive function to get things done. Things like finding and keeping a job, juggling family members’ schedules, making sure your bills get paid on time, and preparing your tax returns all take high levels of executive function.
Say you’re planning a family vacation: You need to look at everyone’s schedules, request time off from work, make reservations, think about what you’ll need for the trip, find a pet sitter, and pack the bags. Taking care of all those details requires planning and organization.
When your executive function isn’t working as it should, you may:
- Have a hard time getting started on big projects
- Forget appointments or show up late; you find you lose track of time
- Find it hard to keep a tidy workspace or home; the papers just pile up
- Become frustrated when things don’t go as planned
- Struggle to follow conversations because you are distracted
As with all the biomarkers, sleep, diet, exercise, substance use, and certain medical conditions can impact executive function. Anxiety and stress can also interfere; think about a time you were deeply preoccupied, and found it hard to concentrate or problem solve. People with ADHD, depression, or learning disabilities often struggle with these skills.
Cognitive control is the ability to stay on task, delay gratification, and make choices in line with your goals, rather than impulses or habits. You use cognitive control to stick to a health plan or kick a bad habit.
You use cognitive control to resist indulging in behaviors you know may not be the healthiest for you. It’s what gives you the discipline to complete a task when there are distractions and temptations to do something more interesting or enjoyable. Cognitive control is also needed in group situations: It keeps you from blurting out an inappropriate comment or giving the first answer that occurs to you.
When your cognitive control is weaker, you might:
- Not be able to resist staying up late when you know you need to be at work early the next morning
- Feel more distracted than usual, for instance, checking incoming texts when you're talking with someone
- Feel like your mind is wandering during a conversation, or when you're watching a movie
- Find it hard to make healthy lifestyle choices
Cognitive control, like the other digital biomarkers, can be affected by things like stress, diet, sleep, exercise, and certain medical conditions. People with ADHD, depression, anxiety and addiction often show less cognitive control.
Working memory is what your brain uses to temporarily store and use information to make decisions or think through a problem. Think of it like a sticky note where you store bits of information you plan to use soon. You use working memory to add numbers in your head. You also use it in conversation: You need to remember the last thing a person said in order to respond.
Working memory is important for reading comprehension, reasoning, or remembering multi-step directions. Everyone struggles with the limits of working memory sometimes. Think about a time you went to another room to get something and forgot what you went there for.
When you have issues with working memory, you might:
- Lose your keys
- Have to reread a paragraph several times before you feel like you understand or can explain the information
- Struggle in conversations: You might find yourself forgetting what the other person said, or forgetting what you wanted to say
- Get lost even after someone gives you directions
- Have trouble remembering a phone number
- Go to the grocery store with a mental shopping list and forget items
Working memory, like all the digital biomarkers, can be affected by things like sleep, exercise, substance use, and certain medical conditions. Anxiety and stress can deplete your working memory. Rumination – when you get negative thoughts repeatedly stuck in your head and can’t set them aside, even though they’re unproductive – can also affect your working memory.
Processing speed is how fast your brain takes to begin or complete a task. Think of it as your reaction time to new information. Imagine you are driving and the car in front of you slams on the brakes. Your processing speed dictates how quickly you notice and react. Your processing speed varies from day to day.
Processing speed governs how quickly we take in information and figure out what to do. We use it to make decisions, pick up on social cues, follow directions, and drive a car.
When your processing speed slows down:
- You feel sluggish, and it takes you longer to do a task or an assignment than usual.
- You are slow to react as you're driving, such as responding to a traffic light, or a car turning in front of you.
- It takes you longer to read a book or news article.
- You have a hard time following instructions or planning a specific activity in an allotted time.
Like the other biomarkers, exercise, sleep, stress, substance use, and medical conditions can impact your processing speed. Depression, diabetes, ADHD, autism spectrum disorders, and schizophrenia can cause slow processing speed. Processing speed also varies over the course of our lives: It increases from childhood to adolescence, remains relatively stable into adulthood and then declines slowly from middle age.
Emotional Valence is how you respond emotionally to situations, events or people. Think of it as your mood, energy, and outlook on life. A person with high emotional valence takes on new challenges, is eager to engage with the world, and takes active care of themselves. Someone with low emotional valence is more likely to interact with the world in a guarded way, which makes it difficult to get help, work with people, or just feel good about experiences throughout the day.
You can feel positive or negative about yourself, your situation or how things are going. Changes in your emotional valence can influence how you interpret information.
For example, you send a text to a friend and don't hear back. You might interpret that as your friend ignoring you and take it personally (low valence) or simply that they're busy and unable to respond (high valence).
When your emotional valence is low, you may:
- Feel sad, hopeless, helpless, or worthless
- Experience lower energy
- Have feelings of guilt
- Be in a pessimistic mood
- Stop enjoying things that used to make you happy, like being with friends or taking care of your health
- Withdraw socially
Your mental health is influenced by all sorts of factors, including the amount of sleep you get, stress levels, diet, medication, brain chemistry, and physical activity. Low emotional valence can in turn affect your other biomarkers, like executive function and working memory. Think about how hard it is to concentrate or remember things when you’re feeling depressed.
Several scientific studies have shown that all sorts of things can have impact on cognition and mood, depending on the individual. Stress, diet, sleep, anxiety, and alcohol will affect all of the biomarkers. Depression, in addition to affecting your emotional valence, can also impact your cognitive function.
Researchers have found a significant association between mood and physical activity. Exercise can have benefits for cognition and brain function.
Sleep has been found to play a critical role in brain health.
Stopping smoking is associated with reduced depression and anxiety and better mood.
Multiple studies have found connections between a healthy diet (low in saturated fat, refined carbohydrates, and processed foods) and improved mood and brain function.
Mindfulness has been shown to have multiple positive psychological effects, including improved working memory, focus, and feelings of well-being.
Stress can affect cognition in many ways, both positive and negative.
Many health conditions can affect brain health and cognitive function. Heart disease and high blood pressure, diabetes, kidney disease, and underactive thyroid are some conditions linked with memory, attention, and other aspects of cognition. Physical health problems can also have significant effects on your emotional outlook. Depression and anxiety are common among people with chronic illness like diabetes, cancer, and heart disease. Furthermore, medications or treatments of these conditions, such as chemotherapy, have also been associated with cognitive impact.
Neurological and mental disorders, including Parkinson’s disease, bipolar disorder and schizophrenia, are also associated with cognitive and mood issues like depression.