Alzheimer’s disease

Understanding Alzheimer’s Disease: A Neurodegenerative Disorder

Alzheimer’s disease is a neurodegenerative disorder that affects 60-70% of dementia cases, making it one of the most prevalent forms of cognitive decline. Imagine your brain as a complex network of roads and highways; Alzheimer’s disease can be likened to a slow-moving traffic jam that gradually blocks these pathways, leading to memory loss and other cognitive impairments.

The Progression of Alzheimer’s Disease

Alzheimer’s starts slowly but worsens over time. Think of it as a thief creeping into your home, taking away memories one by one. Symptoms include memory loss, language problems, disorientation, mood swings, and behavioral issues. These symptoms can be mistaken for normal aging, making early diagnosis challenging.

Diagnosis and Treatment

The progression of the disease is characterized by amyloid plaques and neurofibrillary tangles that interfere with normal cell function, leading to irreversible degeneration of neurons. Diagnosis is based on history, cognitive testing, medical imaging, and blood tests, but a definitive diagnosis can only be made after death.

Currently, there are no treatments to stop or reverse the progression of Alzheimer’s disease, although some may temporarily improve symptoms. A healthy diet, physical activity, and social engagement may help reduce the risk of cognitive decline. These lifestyle changes act like a shield, protecting your brain from the ravages of time.

Impact on Society

Alzheimer’s affects approximately 50 million people worldwide, with women more likely than men to develop it. The financial burden on society is significant, with an estimated US$1 trillion annual cost. Research is being conducted to better understand the disease, with funding from organizations such as the National Institutes of Health.

The disease targets the hippocampus associated with memory, leading to progressive cognitive and functional impairment. Early symptoms include short-term memory loss, difficulty remembering recently learned facts, and impairments in executive functions, attentiveness, planning, flexibility, and abstract thinking. Apathy and depression are also common early symptoms, often accompanied by mild cognitive impairment (MCI).

Pathophysiology of Alzheimer’s Disease

The cause of most Alzheimer’s cases is unknown, except for 1-2% where deterministic genetic differences have been identified. The most predominant hypothesis is the amyloid beta hypothesis, which proposes that extracellular amyloid beta deposits are the fundamental cause of the disease.

A specific isoform of apolipoprotein, APOE4, is a major genetic risk factor for Alzheimer’s disease, and late-onset Alzheimer’s is about 70% heritable. Between 40% and 80% of people with Alzheimer’s disease possess at least one APOEε4 allele, which increases the risk of the disease.

Management and Care

The course of Alzheimer’s is generally described in three stages: early or mild, middle or moderate, and late or severe. The disease targets the hippocampus associated with memory, leading to progressive cognitive and functional impairment.

In the early stage, difficulties with language, perception, or movement coordination may be more prominent than memory problems. Language problems are characterized by a shrinking vocabulary and decreased word fluency, while fine motor tasks may require assistance due to apraxia.

Pharmaceutical Treatments

In the middle stage, independence is hindered, and speech difficulties become evident due to an inability to recall vocabulary. Reading and writing skills are lost, complex motor sequences become less coordinated, and behavioral changes become more prevalent. Common manifestations include wandering, irritability, emotional lability, sundowning, illusionary misidentifications, anosognosia, urinary incontinence, and reduced language abilities.

During the late stage, people become completely dependent on caregivers, lose speech, experience extreme apathy and exhaustion, and are bedridden due to muscle mass and mobility deterioration. Alzheimer’s disease is believed to occur when abnormal amounts of amyloid beta and tau proteins accumulate in the brain, affecting neuronal functioning and connectivity.

Research and Future Directions

The cause of most Alzheimer’s cases is unknown, except for 1-2% where deterministic genetic differences have been identified. The most predominant hypothesis is the amyloid beta hypothesis, which proposes that extracellular amyloid beta deposits are the fundamental cause of the disease.

Research on preventing AD has shown inconsistent results, with no clear measures proven to be effective. Cardiovascular risk factors and certain medications, such as statins and antidepressants, may decrease the risk of dementia, while lifestyle activities like physical exercise, higher education, and quitting smoking may also have a protective effect.

Receiving adequate sleep (7-8 hours) may help prevent Alzheimer’s disease. Stress can contribute to the development of AD, and stress-reducing strategies like meditation may be beneficial. Management of AD includes:

• Pharmaceutical treatments: Acetylcholinesterase inhibitors (tacrine, rivastigmine, galantamine, donepezil): intended for mild to severe AD
• Memantine: intended for moderate or severe Alzheimer’s disease. These medications aim to increase acetylcholine levels and reduce its breakdown.

Other treatments include:

• EGb 761 (Ginkgo biloba extract): approved in Europe for treating AD; limited evidence due to insufficient clinical trials
• Combination therapy: some studies suggest that combining memantine with donepezil may be effective.

Atypical antipsychotics may reduce aggression and psychosis in people with Alzheimer’s Disease (AD), but have serious adverse effects such as stroke, movement difficulties, and cognitive decline. They should be used for short-term periods only after first-line therapies have failed.

Caregiving

Management of AD includes psychosocial interventions that can help reduce specific problem behaviors, such as incontinence or behavioral issues related to music therapy. Emotion-oriented approaches like reminiscence therapy show inconsistent results, while simulated presence therapy may reduce challenging behaviors.

Conclusion

The journey through Alzheimer’s disease is a complex and often heartbreaking one for both the patient and their caregivers. As we continue to research and understand this condition better, it becomes clearer that prevention and early intervention are key. By staying informed and proactive, we can potentially slow down its progression and improve the quality of life for those affected.