Causes of Dementia: Understanding Why Memory Loss Happens 

Forgetting where you put your keys is a normal part of getting older. Forgetting what keys are for is something different.  

Understanding that distinction – and knowing when to seek help – is one of the most important things families can do. 

Dementia is not a single disease. It’s a term used to describe a group of symptoms affecting memory, thinking, communication, and the ability to manage daily life. According to Dementia Australia, around 421,000 Australians are currently living with dementia – a number expected to grow as the population ages. 

The good news is that understanding the causes of dementia can help with early intervention, better planning, and in some cases, prevention. At Dovida, our in-home dementia care is built around this understanding – supporting people living with dementia and the families who care for them. 

How Dementia Develops 

Dementia occurs when brain cells are damaged or die faster than normal, disrupting the connections between them. Over time, this affects the brain’s ability to process information, regulate emotions, and carry out everyday tasks. 

Different types of dementia involve different kinds of brain cell damage – which is why symptoms, progression, and care needs can vary so much from person to person. 

Common Types of Dementia and Their Causes 

Alzheimer’s Disease 

Alzheimer’s disease is the most common type, accounting for around 60-70% of dementia cases. It’s caused by the build-up of abnormal proteins in the brain – amyloid plaques and tau tangles – which interfere with how brain cells communicate and eventually cause them to die. Memory loss, confusion, and difficulty with language are among the most common early symptoms. 

Vascular Dementia 

Vascular dementia develops when blood flow to the brain is reduced or interrupted – often following a stroke or a series of smaller vascular events. It commonly affects judgement, planning, and the ability to organise thoughts. Managing blood pressure, diabetes, and cholesterol can significantly reduce the risk. 

Lewy Body Dementia 

Lewy body dementia is caused by abnormal deposits of a protein called alpha-synuclein forming inside brain cells. Symptoms often include visual hallucinations, changes in alertness, movement difficulties similar to Parkinson’s disease, and disrupted sleep. It frequently coexists with Alzheimer’s. 

Frontotemporal Dementia 

Frontotemporal dementia (FTD) involves the progressive loss of nerve cells in the frontal and temporal lobes of the brain – the areas responsible for personality, behaviour, and language. It tends to affect people under 65 more often than other types, and personality changes or social withdrawal are often among the first signs. 

Mixed Dementia 

Mixed dementia involves a combination of two or more types – most commonly Alzheimer’s and vascular dementia. It is more common than previously recognised, particularly in older adults, and symptoms can overlap. 

Reversible Causes 

Not all dementia-like symptoms are caused by permanent brain changes. Vitamin B12 deficiency, thyroid problems, certain medications, urinary tract infections, and sleep apnoea can all cause cognitive symptoms that may improve with treatment. This is why early medical assessment is so important – particularly when symptoms appear suddenly or progress quickly. 

Risk Factors for Dementia 

Some risk factors cannot be changed. Age is the biggest – the likelihood of developing dementia increases significantly after 65. Family history and certain genetic factors, such as the APOE gene, also play a role. 

But many risk factors are modifiable. Research suggests that up to 45% of dementia cases may be linked to preventable or manageable factors (Lancet Commission, 2020), including: 

• High blood pressure 

• Diabetes and obesity 

• Physical inactivity 

• Smoking and excessive alcohol consumption 

• Hearing loss 

• Social isolation and low cognitive engagement 

• Poor sleep 

Ways to Support Brain Health 

While there are no guarantees, there are meaningful steps that may help reduce risk and support cognitive health over time: 

• Eat well – a Mediterranean-style diet rich in vegetables, wholegrains, fish, and healthy fats is associated with better brain health 

• Stay active – regular aerobic and strength exercise supports blood flow to the brain 

• Keep the mind engaged – reading, puzzles, learning new skills, and social connection all contribute to cognitive resilience 

• Manage cardiovascular health – blood pressure, cholesterol, and blood sugar are all worth monitoring regularly 

• Address hearing and vision changes – untreated sensory loss has been linked to increased dementia risk 

• Prioritise sleep – quality sleep of seven to nine hours supports the brain’s ability to clear waste products 

• Seek medical advice early if memory changes feel out of the ordinary 

When to Seek Help 

Memory loss that disrupts daily routines, difficulty finding familiar words, personality changes, confusion about time or place, or withdrawal from activities a person once enjoyed – these are signs worth taking seriously. A GP can assess what’s happening, rule out reversible causes, and refer for further assessment if needed. 

Early diagnosis opens up more options – for treatment, planning, and putting the right support in place. 

Supporting Loved Ones at Home 

A dementia diagnosis doesn’t mean leaving home. Research consistently shows that people living with dementia benefit significantly from remaining in familiar surroundings for as long as possible. 

Dovida’s Circle of Care brings together the older person, their family, and trained healthcare professionals into a connected support network. Our dementia-trained caregivers are carefully matched with clients based on personality and shared interests, so that familiar, consistent faces become a comfort rather than a disruption. 

Support can include home help, personal care, companion care, live-in care and 24-hour home care – adjusted as needs evolve over time. Our home care services are built to be flexible around the individual, not the other way around. 

If you’re caring for someone living with dementia and looking for support, Dovida’s team is here to help. 

📞 1300 008 018 ✉️ care@dovida.com.au 🌐 dovida.com.au