What is Cognitive Decline?
Cognitive decline is the gradual deterioration of mental faculties due to a neurological and/or psychological disturbance such as Alzheimer’s disease, dementia, depression, or substance abuse. (Miquel et al; 2017) Cognitive issues can stem from different factors including environmental circumstances, genetic traits, and/or hormonal changes.
People can experience varying symptoms including memory lapses, poor judgment, lack of focus, volatile behaviour, and general confusion (Park et al; 2018) The consequences of cognitive decline carry significant health and safety risks for employers where job performance skills requiring mental acuity, analysis, communication and firm decision-making are an essential function.
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Employers are responsible for identifying signs of cognitive decline based on telltale factors that indicate chemical dependency issues or if an applicant and/or employee is a potential candidate for a neurological disorder. Early intervention can avoid future economic setbacks where individuals with progressive cognitive decline pose liability risks with marked oversights in following health and safety protocol. (Anastasiou et al; 2018)
Cognitive decline can affect both a young and old demographic, and it is essential that a physician, neurologist, psychiatrist, or other qualified specialist diagnoses the issue at hand and renders proper medical care.
The cognitive function appears to peak around age 20 and diminishes steadily over the remaining years of life. With life expectancies increasing dramatically in the last century, cognitive decline and dementia have become major contributors to disability and mortality.
Ageing is associated with gradual changes in the brain that slow and reduce its function. As a result of these changes, it is common for elderly people, even those without neurological disease, to find it takes longer to perform mental tasks and to experience diminished memory, attention, and abilities to learn, reason, and solve problems.
Although some cognitive decline occurs during normal ageing, its rate of progression is affected by lifestyle, environmental, and genetic factors, some of which may be modifiable. Aging is a complex process, and age-related conditions like cognitive decline are multifactorial. Some factors that likely contribute to age-related cognitive decline are:
- stem cell senescence,
- brain oxidative stress and mitochondrial dysfunction,
- neuroinflammation (inflammation in the brain),
- circadian rhythm and metabolic disturbances,
- disordered homocysteine metabolism,
- changing hormone levels, and
- epigenetic factors—changes in the way genes are expressed.
The Aging Brain
With age, the number of brain neurons decreases and the cells and tissues that support them deteriorate slowly after age 20 and more rapidly after age 60. By age 90, brain mass is decreased by 11% compared with individuals in their 50s. (Wyss-Coray; 2016) The majority of neuronal loss is in the cerebral cortex, where most information processing occurs, and the hippocampus, a brain structure involved in memory and learning.
These age-related brain changes manifest in the diminished mental abilities typically associated with older age, namely reduced short-term and episodic memory, difficulty recalling words, slower reaction times, and possibly depressed mood.
Age-related cognitive decline is the term used to describe the natural diminishment inability to learn, remember, and process information. Mild cognitive impairment is the condition characterized by cognitive changes that are more than expected for age but are not debilitating. It is estimated that 10–20% of adults aged 65 years and older have mild cognitive impairment.
When cognitive decline becomes severe enough to interfere with social and occupational function and the ability to live independently, the condition is called dementia. Dementia affects approximately 5–10% of adults aged 65 and older.
Alzheimer disease is the number one cause of dementia in the elderly, followed by cerebrovascular dysfunction. Importantly, most people with age-related losses in cognitive function never develop these more advanced conditions.
Distinguishing between normal age-related cognitive change and mild cognitive impairment is challenging, but a comprehensive assessment that includes a history of cognitive changes, physical exam, neurological exam, and cognitive function testing is the basis of accurate diagnosis.
What is Mid Cognitive Impairment?
Mild cognitive impairment is a condition in which a person experiences a slight – but noticeable – decline in mental abilities (memory and thinking skills) compared with others of the same age. The minor decline in abilities is noticeable by the person experiencing them or by others who interact with the person, but the changes are not severe enough to interfere with normal daily life and activities.
What’s the difference between mild cognitive impairment and decline due to normal ageing?
Some gradual mental (cognitive) decline is seen with normal ageing. For example, the ability to learn new information may be reduced, mental processing slows, speed of performance slows, and the ability to become distracted increases. However, these declines due to normal ageing do not affect overall functioning or ability to perform activities of daily living. Normal ageing does not affect recognition, intelligence, or long-term memory.
In normal ageing, a person may occasionally forget names and words and misplace things. With mild cognitive impairment, the person frequently forgets conversations and information that one would ordinarily remember such as appointments and other planned events.
How common is mild cognitive impairment?
The American Academy of Neurology estimates that mild cognitive impairment is present in about 8% of people age 65 to 69, in 15%of 75 to 79 year-olds, in 25% of those age 80 to 84, and about 37% of people 85 years of age and older. (Richardson; 2019)
References:
American Academy of Neurology. Practice Guideline Update Summary: Mild Cognitive Impairment
Richardson K, Fox C, Maidment I, et al. Anticholinergic drugs and risk of dementia: case-control study BMJ 2018;361:k1315.
Miquel S, Champ C, Day J, et al. Poor cognitive ageing: Vulnerabilities, mechanisms and the impact of nutritional interventions. Ageing Res Rev. 2018;42:40-55.
Park DC, Festini SB. Theories of Memory and Aging: A Look at the Past and a Glimpse of the Future. The journals of gerontology Series B, Psychological sciences and social sciences. 2017;72(1):82-90.
Anastasiou CA, Yannakoulia M, Kontogianni MD, et al. Mediterranean Lifestyle in Relation to Cognitive Health: Results from the HELIPAD Study. Nutrients. 2018;10(10).
Wyss-Coray T. Ageing, neurodegeneration and brain rejuvenation. Nature. 2016;539(7628):180-186
Munodiwa Zvemhara is a consultant at Industrial Psychology Consultants (Pvt) Ltd a management and human resources consulting firm.
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