By: Catherine Joachin
What is Alzheimer’s Disease?
Alzheimer’s disease is a severe neurodegenerative disease marked by a gradual decline in cognitive functions, notably memory, thinking and reasoning (Cleveland Clinic, n.d.). It is the primary cause of dementia and generally affects people aged 65 and older (Cleveland Clinic, n.d.).
Causes and risk factors
Although the etiology of Alzheimer’s disease remains unclear, researchers have suggested that an unusual buildup of amyloid and tau proteins in the brain plays a role in the development of the disease (Cleveland Clinic, n.d.). This abnormality is believed to cause significant brain damage to regions that govern memory and beyond through progressive cell death (Mayo Clinic, 2024).
Alzheimer’s disease most likely originates from a combination of genetic, environmental and lifestyle factors that are still poorly understood (Mayo Clinic, 2024). Age is the main contributor to this disease, although early-onset Alzheimer’s disease can affect people as young as 40 (Mayo Clinic, 2024; National Health Service, 2024.). A family history of Alzheimer’s disease, Down’s syndrome, severe head trauma, depression and cardiovascular disease such as obesity, diabetes, high blood pressure or cholesterol can also increase one’s likelihood of developing this condition (NHS, 2024).
Signs and symptoms
Alzheimer’s disease slowly progresses over the course of several years, with symptoms changing throughout this period.
Memory loss is the most common symptom observed in the early stages of the disease (NHS, 2024). Signs of memory lapses include forgetting important dates or events, asking questions repetitively, having trouble keeping track of time or whereabouts and misplacing objects (NHS, 2024; Johns Hopkins, 2024.). Personality changes and mood changes (e.g., increased agitation) are also early signs of Alzheimer’s disease (NHS, 2024; Johns Hopkins, 2024).
With time, memory problems worsen and patients begin to experience personality changes, language difficulties, sleep disturbances, delusions and a decline in judgment-making, planning and task performance (Mayo Clinic, 2024; NHS, 2024). These symptoms translate into confusion, disorientation, difficulty concentrating, frequent mood swings, depression, frustration, anxiety and agitation (NHS, 2024). Consequently, Alzheimer’s disease can impair a person’s ability to execute even routine tasks such as figuring out what to wear (Mayo Clinic, 2024).
The later stages of Alzheimer’s disease are marked by more severe physical symptoms such as gradual speech loss, problems eating and swallowing (dysphagia), poor bladder control, bowel incontinence and weight loss (NHS, 2024). Infections, strokes and delirium can exacerbate these symptoms (NHS, 2024).
In spite of major brain changes, patients with this condition do preserve certain skills, such as dancing, drawing or singing, which are controlled by brain regions that only become affected in the later stages of the disease (Mayo Clinic, 2024).
Treatment and management
There is no cure for Alzheimer’s disease, but treatment options can temporarily relieve symptoms. Medicine can target different symptoms, such as memory loss or behavioural and psychological symptoms of dementia (BPSD) (NHS, 2024). For instance, acetylcholinesterase (AChE) inhibitors are used to prevent rapid decline in memory and thinking in patients in the mild to moderate stages, while memantine can be prescribed to help those with moderate to severe Alzheimer’s disease function independently for longer (National Institute on Aging, 2023).
BPSD symptoms of dementia can be managed with risperidone, antipsychotic drugs, antidepressants and non-pharmacological treatment options such as cognitive stimulation therapy (CST) and cognitive rehabilitation (NIA, 2023).
Epilepsy related complications
Seizures are a less common symptom of Alzheimer’s disease associated with poorer cognitive performance (Vöglein et al., 2020). Research highlighting similarities between the brains of individuals with Alzheimer’s disease and those with temporal lobe epilepsy supports evidence that people with Alzheimer’s disease can experience spontaneous recurrent seizures (Scharfman, 2012). Experiments performed on mouse models also showed that the SCN1A gene mutation, which is responsible for generalized epilepsy with febrile seizures plus (GEFS+) and severe myoclonic epilepsy of infancy (SMEI), may be involved in the development of seizures in patients with Alzheimer’s disease (Scharfman, 2012).
A recent study has put forward evidence suggesting that neuroinflammation plays a role in the progression of Alzheimer’s disease and epilepsy (Liew et al., 2023). Liew and colleagues (2023) write that pathological similarities between both conditions (i.e., hippocampal atrophy, neuroinflammation and neuronal loss) suggest that epilepsy and neurodegeneration possibly share common underlying mechanisms.
Conclusion
Alzheimer’s disease is a form of dementia characterized by progressive memory loss and cognitive impairment. While it remains incurable, several treatment options exist to help manage symptomatic changes. Lastly, the prevalence of Alzheimer’s disease-related seizures supports research suggesting a comorbidity in the pathogenesis of epilepsy and dementia.
References:
Cleveland Clinic (n.d.). Alzheimer’s Disease. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/9164-alzheimers-disease#signs-and-symptoms
Johns Hopkins Medicine (2024). Early-Onset Alzheimer’s Disease. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/alzheimers-disease/earlyonset-alzheimer-disease
Liew, Y., Retinasamy, T., Arulsamy, A., Ali, I., Jones, N. C., O’Brien, T. J., & Shaikh, M. F. (2023). Neuroinflammation: A Common Pathway in Alzheimer’s Disease and Epilepsy. Journal of Alzheimer’s Disease, 94(s1), S253–S265. https://doi.org/10.3233/JAD-230059
Mayo Clinic (2024). Alzheimer’s disease – Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/alzheimers-disease/symptoms-causes/syc-20350447
National Health Service (2024). Treatment. National Health Service. nhs.uk. https://www.nhs.uk/conditions/alzheimers-disease/treatment/
National Institute on Aging (2023). How Is Alzheimer’s Disease Treated?. National Institute on Aging. https://www.nia.nih.gov/health/alzheimers-treatment/how-alzheimers-disease-treated#mild
Scharfman, H. E. (2012). “Untangling” Alzheimer’s Disease and Epilepsy: “Untangling” Alzheimer’s Disease and Epilepsy. Epilepsy Currents, 12(5), 178–183. https://doi.org/10.5698/1535-7511-12.5.178
Vöglein, J., Ricard, I., Noachtar, S., Kukull, W. A., Dieterich, M., Levin, J., & Danek, A. (2020/10//). Seizures in Alzheimer’s disease are highly recurrent and associated with a poor disease course. Journal of Neurology, 267(10), 2941-2948. https://doi.org/10.1007/s00415-020-09937-7
