How to stimulate your senses to improve cognitive function

In our our article How to nourish your brain, we took a deep dive into cognitive health. Cognitive health = your ability to think, learn and remember. Here, we explore why stimulating the senses (hearing, sight, smell, touch, taste) to create new memories and new learning is so beneficial. 

It could be why dancing (with others to music), which engages many senses in combination with movement, is especially powerful for brain health. Exercising the senses in stimulating and fun ways could help keep your brain in good shape for longer. 

Well-known essentials to keep our brains in good shape include:

• Adequate brain energy is essential for cognitive perfor­mance and brain function, especially during ageing, which depends on the brain continuing to successfully meet its energy needs.
  
  
• Good ingredients to support the brain – which includes a diet rich in antioxidants, such as colourful fruits and vegetables, essential fatty acids, such as those found in oily fish, and plenty of leafy green vegetables, ketogenic diet, olive oil, coconut oil or MCT (medium chain triglycerides) oil could potentially be useful, especially for people with poor blood sugar control.
  
  
• Natural light every day whatever the weather or the season.
  
  
• Exercise – dancing is one of the best types.
    
• New learning through activities that stimulate the senses for example, learning a foreign language, playing games, doing crossword puzzles, reading, listening to or playing a music, cooking, conversation, dog-walking.
  
  
• Avoiding the bad stuff – smoking, excess alcohol, added sugar, environmental toxins 
  
  
• Spending time with people you like/close relationships.
  
  
• Activities you enjoy that mitigate stress.

Most of us will know someone with memory problems and the devastating toll it takes on people’s lives. It’s tragically all too common for cognitive health to decline with advancing age but it need not be an inevitability. 

Contrary to conventional wisdom, we’re coming to understand that adult brain cells and the neurones that connect them, are capable of regeneration throughout life in a process called neuroplasticity.  

There is an old adage – ‘use it or lose it.’ In this sense, what really makes the difference to brain health is our lifestyle choices. Rather than simply avoiding the bad things, it’s helpful and more enjoyable to pay attention to the good, including exercising our senses as well as our muscles. 

Understanding neuroplasticity 

Essentially, the brain has the ability to adapt to its environment. When we learn something new, connections in the brain are created and existing ones are re-enforced. New pathways form and others become dormant depending on how often they’re used. That’s why it makes good sense to continue to learn new things and stimulate all our senses throughout life. 

Marian Diamond, the ‘mother of neuroplasticity’, was the first to prove that the brain shrinks with impoverishment and grows in an enriched environment at any age. 

The brain loves to run on autopilot like driving a car or riding a bicycle. Once we know how, we just do it – the brain likes to do the things it always does. As described David Brooks’ book “The Social Animal”, the brain awakens in the new and the best way to keep your brain sharp is to continue to learn new things e.g., learn a foreign language, play a musical instrument, dance, sing – the harder the better. 

An important feature of neuroplastic change is repetition. New pathways that form in the brain are structured according to use – those that you use most will become bigger and stronger – like super highways. Whenever we encounter the same situation, we’re drawn to the path we’ve always walked, but, with use, small pathways can become stronger and stronger. Once you know how to drive, you don’t ever have to think about it again.

The senses and brain health

Eyesight 

Vision declines with age, by age 80 few can drive at night, making the elderly especially vulnerable to the ill effects of inadequate light.

According to Turner and Mainster: “Light deficiency, whether due to improper timing [in other words, inappropriate light and darkness for the time of day] suboptimal spectrum or insufficient intensity, may contribute to medical conditions commonly assumed to be age-related inevitabilities.”

Stimulating our eyes with daily exposure to outdoor natural light, e.g., 30 minutes in the morning, is important to set our inner biological clocks (circadian rhythms) to the outside conditions. Inadequate environmental light, (or light reaching the retina in the eye and brain), can cause circadian disruption, which increases the risk of insomnia, and various other medical conditions, such as depression, and possibly even earlier mortality.

We need natural light to maintain visual health and good eyesight. Natural light is very different in quality to indoor lighting and is much brighter. Light entering the eye is the primary signal for circadian rhythms.

Deteriorating vision predicts declining cognitive health

In a 2018 study of 2,520 older people over a period of eight years, researchers looked at declining vision and its link with declining cognitive function and found that deteriorating vision predicts declining cognitive health more so than the other way around. They concluded that maintaining good vision may be important for mitigating age-related cognitive decline.

In a 2022 systematic review of vision impairment and cognitive decline in older adults, which included 110 articles, 91 (83%) reported that visual impairment was associated with cognitive impairment.

Some Australian researchers propose that approximately three-quarters of vision loss is avoidable. Maintaining good eye health with appropriate eye care interventions is both important and cost-effective. 

Amongst care home residents, it was reported that exposure to more than 1000 lux during the day could slow the rate of cognitive deterioration of people with dementia, as well as reduce feelings of depression. Elderly people in care are commonly getting much less than this. For example, it was shown in one study that the median light level that residents were exposed to was only 54 lux, with just 10 minutes a day spent in light over 1000 lux.  

Natural light, on the other hand, contains more than 10,000 lux (less on overcast days). A bright sunny day can reach over 100,000 lux.

Hearing 

“Deafness Separates You from People.”- Helen Keller

One in five adults in the UK are either deaf, have hearing loss or tinnitus, and 40% of people over 50 have hearing loss, rising to 70% in those over 70. The changes are gradual and creep in unnoticed. Commonly, the ability to hear high pitched noises, such as a phone ringing, is lost first. Age-related hearing loss is called “Presbycusis”.   

Hearing loss commonly precedes dementia

639 adults were tracked for 12 years and those with mild hearing loss had double the risk of dementia, moderate hearing loss tripled the risk, and those with severe impairment were three times more likely to develop dementia. 

In an ongoing online study called Protect involving 25,000 people over 50 years old, early findings have concluded that people who wear a hearing aid for age-related hearing problems maintain better brain function over time than those who don’t, in terms of improved working memory and attention. 

Protect researcher Dr Anne Corbett says: “Previous research has shown that hearing loss is linked to a loss of brain function, memory and an increased risk of dementia. Our work is one of the largest studies to look at the impact of wearing a hearing aid, and suggests that wearing a hearing aid could actually protect the brain. We now need more research and a clinical trial to test this and perhaps feed into policy to help keep people healthy in later life.” 

It’s not uncommon for people to wait for up to a decade until things are bad enough to seek help, by which time hearing damage through social isolation and lack of sensory stimulation have progressed insidiously. 

Stimulating the ears by engaging with music (learning to playing an instrument, singing, listening to music) is beneficial for the brain. Non-musical people (aged 60-84) who listened to background music (Mozart) had better memories compared to those who sat in silence. Certain types of music have known benefits for retaining information when studying.

Smell 

By age 70 we identify only 50% of the smells. It’s also understood that viral upper respiratory tract infections are a major cause of the loss of the sense of smell.

Loss of smell could also be an early warning sign of declining cognitive function, and a loss in ability to smell is a feature of degenerative disorders, such as dementia and Parkinson’s disease. One small study showed that having a problem identifying and remembering smells could be a predictor of those who went on to have signs of diagnosed memory problems. It was only a snapshot but suggests watching out for a declining sense of smell could be useful for detecting problems early on.  

The idea that it’s possible to improve the sense of smell with practice might seem unusual but, like other types of practice, this does seem to be the case. 

In a test to see if the sense of smell could be improved, participants where given vials containing essential oils – rose, eucalyptus, lemon, and clove. They were instructed to sniff each of the odours for 20 to 30 seconds twice a day for 12 weeks and to keep a journal to monitor their progress. The participants who practiced improved their sense of smell.

You could try this for yourself using a home essentials oils diffusor, or add a few drops of essentials oils to the bath.

Dancing

This activity might be an especially good choice for brain health because it appears to enhance neuroplasticity better than other types of exercise. It’s an amazing fact that our brain cells, when viewed with sophisticated scanners, are actually moving (almost dancing) as they make new connections.  

In a review, eight studies showed that dance led to improvements in memory, attention, balance, social interactions, as well as improved blood markers. But even more impressively, dancing increased brain size in key areas involved with learning and memory e.g., the hippocampus. Dancing was shown to be particularly good at strengthening connections between the left and right sides of the brain. The eight studies included 562 women and 299 men aged between 18 and 94 years, one looked at dance in people with mild cognitive impairment and schizophrenia, whilst the others were in healthy older people. 

Dance has such beneficial effects on the brain that it’s being used to treat people with Parkinson’s disease. In fact, a small cohort study of 469 subjects older than 75 years comparing 11 different types of physical activity, including cycling, golf, swimming, and tennis, found only dance lowered the risk of getting dementia.  

These results echo those of a  2008 Journal of Aging and Physical Activity study  of older people who danced the tango and showed that, in the long-term, tango dancing was associated with better balance and walking in older adults. Since falls are the top cause of injury and death among elderly people, dancing can be potent tool – not to mention fun! 

Proprioception – our 6th sense

Proprioception is about sensing our bodies in space, including the effort, force and heaviness needed.  Simply stated, it’s quite similar to balance. Ageing causes a loss of proprioception, and with that, an increased risk of falls. The detectors for proprioception are located in and around muscles, tendons and joints and they’re stimulated by movement. In a small study of 40 healthy adults aged 19–65 years randomly assigned to balance or relaxation training twice a week for 12 weeks, the balance group significantly improved their balance and tests of memory and spatial cognition.

Balancing practises, and practises involving skillful movement of the body in space, are nothing new. Practises like Qigong, tai chi and yoga are thousands of years old. Tai chi, for example, has been shown in studies to improve brain health, both for cognitively healthy people and those with cognitive impairment. A 2022 review of 40 selected studies on tai chi and Qigong reported benefits for Parkinson’s disease, stroke, mild cognitive impairment, dementia, and traumatic brain injury.

Other activities with brain benefits: 

Activities, such as doing crossword puzzles and engaging with music, may delay the occurrence of dementia. Other examples include reading, writing, crossword puzzles, board or card games, group discussions, playing music, or learning a language. Learning to juggle was shown to induce brain changes in as little as seven days.

A growing amount of work underlines the importance of the senses not only to predict cognitive health, but almost more importantly, how taking steps to prevent sensory decline could also preserve cognitive health. 

Summary

It’s entirely possible to preserve our long-term cognitive health for longer by adopting healthy lifestyle habits. 

Exercising all our senses is an important aspect of learning new things and committing them to memory, which helps us stay sharp. It’s an emerging field that experts are looking at to help people stay well for longer. It makes good sense with perhaps some fun to be had along the way. 

Eating well, exercising regularly, reducing stress and engaging in cognitively stimulating activities have benefits for brain health.

Dance has particular benefits. It integrates important brain areas to improve neuroplasticity, which includes increases in the volume of important structures in the brain, such as the hippocampus, as well as improving memory, attention and body balance.

Reviewed by:

Anna Keeble MA BA Head of Content and Wellbeing Expert

Dr Claire Marie Thomas MRCGP DFSRH DTMH DipNLP MBChB BMedSci Medical Expert

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