Cognitive Decline: Older and, yes, wiser. Science says so

Getting old? Yo u may also be getting smarter in some ways. Newish research says ageing brains may be sharper in certain aspects. The old trope about old people – about a broad decline in mental abilities with advancing age – is being challenged. A youngster may have better memory, rattle off multiple 10-digit phone numbers, but oldies are usually better at difficult jobs, for example, navigating tricky situations or roads.This, and much more, in a research paper published byGeorgetown University Medical Centre in Washington in August 2021 adds substance to that old saw: older but wiser.
Published during the Covid pandemic, the paper studied over 700 people in the 58-90 age group and found that two key brain functions, processing new information and focusing on what is important in a given situation, can improve in older individuals. “Although various aspects of cognition decline, such as working memory (for example, holding a telephone number actively in mind), others seem to improve, including our vocabulary and our general knowledge,” the study’s senior author Michael T Ullman, director of Georgetown’s Brain and Language Lab, told TOI over email.
He said the neurological function of ‘executive inhibition’, or the ability to “inhibit distracting information” to focus on what is important, also improves with age. His team believes the study could influence how ageing is viewed and improve management of patients with ageing disorders, such as Alzheimer’s disease.
Ageing, or ways to check it with diet and lifestyle changes, has emerged as an interesting topic for medical research in recent years. Information is being sought on ‘blue zones’, where people live longer than average, and various diets and exercises to control harmful inflammation processes within the body. The medical community has now identified factors that could alter or delay neuro or brain degeneration. In August 2020, the Lancet Commission on dementia prevention added three new risk factors – excessive alcohol consumption, traumatic brain injury and air pollution – to the existing nine that include less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes and low social contact.
Closer home, a team from NIMHANS (National Institute of Mental Health and Neurosciences), Bengaluru, led by neurologist Dr Suvarna Alladi found bilingualism could delay neuro degeneration. The team found those who were bilingual developed dementia 4.5 years later than the monolingual ones (while many Indians speak more than one language, the technical definition of bilingualism underlines effective communication skills in two languages. Less than 2% of Indians qualify as bilingual as a result).
Another paper by the Georgetown University team of Dr Ullman found that early education appeared to protect older adults, especially women, against memory loss. Dr Sangeeta Ravat, dean of Mumbai’s premier G S Seth medical school and KEM Hospital and a neurologist by training, said the ageing brain is very disciplined. “As long as there is discipline or a well-laid-out routine, older individuals perform well. But even a slight change in routine or changing homes or neighbourhoods could adversely affect the ageing brain,’’ she said.
The doctor who has studied the maximum number of brains in the country as the head of the country’s oldest brain bank, Dr Anita Mahadevan from NIMHANS, said there is a dire need for local research. “All published literature is from the West. Given that ageing is a lifestyle disorder dictated by diet, nutrition, exercise and, of course, education, the patterns here are likely to be very different from what the West sees.’’
One of her research papers on the midbrain of Indians versus the British affected by Parkinson’s disease underlines this point effectively. The study found no difference in the number of neurons between Indians and the British even though the prevalence of Parkinson’s is low in India. “Clearly, other factors, including diet and lifestyle, play a role,’’ said Dr Mahadevan, adding that Western data cannot be extrapolated to the Indian subcontinent. “We need to study what is happening in Indian brains with ageing and dementia, among other neurodegenerative diseases.”
Georgetown varsity team’s findings
The team studied three widely used processes of brain networks – alerting, orienting and executive inhibition. Alerting is de?ned as achieving and maintaining a state of high sensitivity to incoming stimuli, orienting is the selection of information from sensory input; and executive attention involves mechanisms for monitoring and resolving con?icts among thoughts, feelings and responses.
For example, when driving a car, alerting is your increased preparedness when you approach an intersection. Orienting occurs when you shift your attention to an unexpected movement, such as a pedestrian. And executive function allows you to inhibit distractions such as birds or billboards so you can stay focused on driving. The study found that only alerting abilities decline with age. In contrast, both orienting and executive inhibition actually improved.
How to stay sharp with age
The Lancet Commission on dementia prevention says there are 12 modi?able risk factors : excessive alcohol consumption, head injury, air pollution, less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, and infrequent social contact. Modifying these risk factors might prevent or delay up to 40% of dementia Aim to maintain systolic BP of 130mm Hg or less from the age of 40 years (antihypertensive treatment for hypertension is the only known effective preventive medication for dementia).
Use hearing aids for hearing loss and reduce hearing loss by protection of ears from excessive noise exposure. Reduce exposure to air pollution and second-hand tobacco smoke.
Prevent head injury.
Limit alcohol use, as alcohol misuse and drinking more than 21 units weekly increase the risk of dementia. Avoid smoking uptake and support smoking cessation to stop smoking, as this reduces the risk of dementia even in later life. Provide all children with primary and secondary education. Reduce obesity and the linked condition of diabetes.