Dementia and Alzheimer’s Disease

Dementia is a universal term used for an assortment of symptoms relating to a loss or reduction of memory and brain function that inhibits daily life (Chapman et al., 2006). Dementia may be caused by several disorders that affect the brain, including Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, Creutzfeldt-Jakob disease, or may result from a vascular stroke.

It is estimated that over half of cases with dementia are related to Alzheimer’s disease (2). A clinical diagnosis for dementia ensues when two or more of the subsequent cognitive functions are significantly impaired without loss of consciousness: (1) memory, (2) language skills, (3) ability to focus attention, (4) reasoning and judgment, and (5) visual perception.

Some causes of dementia may be treated (e.g., vitamin deficiencies, drug interactions) with the condition altered. Correct diagnosis is required to enable appropriate treatments that can mitigate the problems and evade misdiagnosis. For example, while dementia is often believed to be connected to Alzheimer’s disease, this may not be correct. Without a professional clinical diagnosis, the situation can be confusing, particularly as an individual starts to realise some of the symptoms.

Currently, despite ongoing research, Alzheimer’s disease is unfortunately degenerative and incurable. The pathology of this disease progressively worsens over time, whereas dementia may be more static. Working with individuals who have Alzheimer’s disease or dementia is difficult due to their functional understanding and how much impairment exists at the time of initial intervention and over time.

Dementia and Alzheimer’s Disease

The progression of Alzheimer’s disease with ageing is not typical or normal, although the greatest recognised risk factor for the disease is increased age (most common with 65+ years of age), followed by genetic factors. Nevertheless, 5% of people with Alzheimer’s disease have early-onset Alzheimer’s, which is also known as younger-onset disease; this can occur in individuals in their 40s or 50s. The CDC estimates that as many as 5 million Americans have some level of Alzheimer’s disease. It is further estimated that about 5% of the population between 65 and 74 years old has some level of Alzheimer’s disease and that nearly half of those aged 85 and older may have the disease (Corrada et al., 2010). In the UK, Alzheimer’s disease affecting around six in every 10 people with dementia. It is estimated that around 5% of people with Alzheimer’s are under 65, about 42,000 people.

The prevalence of dementia within the overall population varies with age. There is a 13.5% prevalence in the U.S. population for individuals 80 to 84 years old, 30.8% for those aged 85 to 89 years, 39.5% for those aged 90 to 94 years, and 52.8% for those older than 94 years (Corrada et al., 2010). The per cent of new cases of dementia reported per year ranges from 6% for the population from 80 to 84 years up to 20.7% among those over 94 years old. Research in 2019 reported that there were over 850,000 people with dementia in the UK (Alzheimer's Society, 2019). This is approximately 1 in every 14 of the population aged 65 years and over. In 2040, it is projected that there will be over 1.5 million people with dementia in the UK, at the current rate of prevalence.

Pathology of Alzheimer’s Disease

Individuals with cognitive impairments can have significantly diminished intellectual functioning that restricts their usual activities and social relationships. This regrettably may lead to a loss of their capability to solve both simple and complex problems with the National Institutes of Health defining this as possible evidence of dementia (49).

The development of dementia can lead to an inability to maintain emotional control with individuals feasibly experiencing several behavioural problems (e.g., agitation, delusions, or hallucinations) which can develop into personality changes over time. Although dementia is related to ageing, there is no age delineation concerning when it happens within the life span (Corrada et al., 2010).

Alzheimer’s is an irreversible, progressive brain disease that gradually destroys memory and cognitive skills, ultimately limiting the ability to perform elementary tasks (National Institute on Aging, 2016). This disease is tiered into a tri-level diagnosis (i.e., mild, moderate, or severe) that is founded on the severity of memory and cognitive difficulties alongside the loss of self-care skills that occur over the lifetime. It is reported that both younger and older people are at risk for the development of Alzheimer’s disease; however, the disorder typically begins after 60 years of age, and the risk increases as individuals age.

Presently, there is no definitively known cause for Alzheimer’s disease, with a combination of risk factors and causes for its development being documented. These factors can include a genetic susceptibility for the disease (modification of the APOE gene) alongside limitations in components of an “active lifestyle” (i.e., being physically active, engagement in psychologically stimulating activities, and having regular social interactions) (Cheng, 2016). Moreover, there is emerging evidence that links the onset of Alzheimer’s disease and the age of the individual, a family history of Alzheimer’s disease, high blood pressure, high total cholesterol, and a history of diabetes (Corrada et al., 2010).

Pathophysiology of Dementia and Alzheimer’s Disease

The development and specific causes of Alzheimer’s disease are not fully understood but are understood to be associated with neural degradation due to the build-up of proteins by amyloid plaques (between neurons) and neurofibrillary tangles (within neurons). Amyloid plaque develops when the normal process of breaking down and eliminating amyloid protein fragments is defective. Alzheimer’s disease is also linked to neurofibrillary tangles in which tau protein (an essential factor in the integrity of the neural microtubules) degenerates into tangles of filaments. While the accumulation of amyloid plaque and neurofibrillary tangles is part of the normal ageing process, with Alzheimer’s disease the rate of accumulation is greater. This leads to continuing and accelerated regression in cognitive function compared to normal ageing. Oxidative stress, or damage to cellular structures by toxic oxygen molecules (called free radicals), is also considered a pathology trait of Alzheimer’s disease.

Individuals who develop Alzheimer’s disease and dementia are inclined to have a poor lifestyle and general fitness levels (Alzheimer’s Society, 2016). Although, there is no reported causal relationship between Alzheimer’s disease and training status. Research suggests that cardiovascular disease and other related risk factors increase the risk of dementia and Alzheimer’s disease. Psychological and behavioural interventions are frequently used prior to medications (due to efficacy issues) (Alzheimer’s Society, 2016). Physical activity and exercise are among the treatments that have been reported to improve dementia or slow its progression, Generally, exercise can improve brain function and structure through improvements in an individual’s vascular health.

Effects of Exercise in Individuals with Dementia and Alzheimer’s Disease

The capability of individuals with dementia to participate safely and effectively in physical activities and exercise is affected by where they are on the spectrum of the disorder. In the initial phases of dementia and Alzheimer’s disease, more established exercises may be considered, while in advanced stages, exercise may be performed only in a wheelchair or in bed. While exercise has been suggested to enhance cognitive function throughout our life span, the specific mechanisms through which this transpires are still being studied. Generally, exercise can have conflicting effects on dementia and Alzheimer’s disease, feasibly due to the rate of progression or stage of the disease.

With higher-functioning individuals, improvement may occur in memory, cognitive function, and functional status rating. However, with lower-functioning individuals, limited changes may be identified (Morley et al., 2015). Furthermore, physical exercise may indirectly affect cognition by improving stress levels and sleep quality, as well as decreasing chronic disease components that can affect cognitive function (Bherer et al., 2013). Similarly, specific to the type of exercise performed can lead to improvements in cardiovascular fitness, muscular strength, balance, and other determinants of functional independence. Evidence suggests that incorporating specific manipulations of the program variables of intensity, duration, volume, exercise choice, and others should be performed to clarify which exercise programs better enhance cognitive function, physical health, and function.

Exercise Training Considerations for Individuals with Dementia or Alzheimer’s Disease

Exercise has been reported to improve cognitive and age-related losses in many individuals with dementia; however, there is a significant individual variation that should be considered (Barnes, 2015). Exercise recommendations for individuals with dementia or Alzheimer’s Disease are associated with the functional state of the client whether in a home-based program, a specialised nursing care facility, or a hospital program.

With initial phases of the pathologies, more established guidelines and programs with well-established resistance and aerobic exercise components may be applied (Eshkoor et al., 2015). However, as the condition progresses, many individuals with dementia or Alzheimer’s Disease will need substantial adjustments to this type of programming. For example, group activities may be appropriate with most individuals requiring specific implementation with detailed communication required from their physical therapist, doctor, or other health care professional due to the continuing decline in cognitive function and related physical capacities.

Behavioural issues arising from anger and agitation may also require innovative approaches for sustaining engagement. The exercise professional should be prepared for an outpouring of anger or aggression with the understanding that these are due to the disease process and not a personal attack. This may mean having suitable support in the exercise environment to calm the situation. Importantly, the loss of memory can make each day a new one that requires repetition of directions, reassurance, and appraisal of status.