Recognising Alzheimer’s disease – how AD affects patients

The causes of dementia are many, and they vary depending on the age of the patient. The most common by far is Alzheimer’s disease (AD). Alzheimer’s is an insidious condition in which symptoms creep up on patients, often unnoticed by family members at first, but with serious effects becoming evident as the disease progresses. Expert neurologist Professor Peter Garrard is here to talk about the signs that can identify Alzheimer’s disease.

What is Alzheimer’s disease?

Alzheimer’s can have devastating effects on a person’s thinking skills, but can also affect the lives of their loved ones. It can cause problems with higher functions such as memory, language, and social behaviour. The preservation of limb function means that patients can become prone to wandering disoriented and getting lost in the later stages of the disease. It may take over a decade for AD to exert its full effects, by which time severe problems are evident in multiple cognitive domains.

Diagnosing Alzheimer’s disease

Although direct examination of the structure of brain tissue is technically the only way to make a definitive diagnosis, in practice the symptoms are usually sufficient to make an accurate diagnosis of Alzheimer’s disease, which is often supported by diagnostic investigations.

Signs and symptoms of AD

Signs of Alzheimer’s to look out for include:

• Memory impairment – there are four different ‘types’ of memory: episodic, semantic, procedural, and working. Episodic memory is usually the most affected by Alzheimer’s. Episodic memory enables us to learn new information and recall recent events. Alzheimer’s patients progressively lose the ability to learn, retain and process new information, while preserving earlier learned memories relatively well. Episodic memory loss is not the same as “short-term memory loss”, which refers to working memory, i.e. concentration and the ability to retain information for a few seconds (e.g. remembering the digits of a phone number for long enough to write them down).
• Language – patients with Alzheimer’s may have difficulty finding the right word in conversation. Although this problem gets more pronounced as the disease advances, it is very often seen and experienced in the early stages as well and is a useful clinical marker of disease. Language difficulty may be the only symptom of AD and remain so for a number of years.
• Apraxia – advanced motor skills may become impaired and may (rarely) be an isolated problem.
• Agnosia – difficulty or inability to recognise objects, places, or faces.
• Frontal executive function – the ability to organise, plan, and sequence becomes impaired.
• Personality – in AD, personality and social behaviour usually remain fairly normal until late in the disease, while in other forms of dementia these aspects may deteriorate earlier.
• Anosognosia – the patient will often display a lack of insight into their condition and many are reluctant to go to their doctor until pressured by a family member.
• Visuospatial difficulties – difficulty with orientation and navigation can be caused by parietal lobe involvement. It is often subtle in the early stages but there is a parietal presentation of the disease (posterior cortical atrophy – or PCA) in which these difficulties are prominent but memory relatively well preserved.

There are also several non-cognitive features that can develop later in the progression of Alzheimer’s disease. These include:

• Myoclonus
• Seizures
• Reversal of the sleep-wake cycle
• Incontinence
• Swallowing may become impaired – this can lead to aspiration pneumonia, which can prove fatal.

If you notice any of these symptoms in a friend or relative, encourage them to see their doctor or a specialist. If they have Alzheimer’s, there is a wealth of care and support available, and the sooner Alzheimer’s is diagnosed, the more can be done to slow its progress and ensure the best possible care for the patient.