The first symptoms are often mistakenly attributed to ageing or stress. These early symptoms can affect the most complex daily living activities. The most noticeable symptom is short term memory loss, as well as functions of attentiveness, planning, flexibility, and abstract thinking, or impairments in semantic memory (memory of meanings, and concept relationships). Apathy can be observed at this stage, depression, irritability and reduced awareness of subtle memory difficulties are also common. This is found to be a transitional stage between normal ageing and dementia. MCI can have a variety of symptoms, and when memory loss is the predominant symptom, it is seen as a prodromal stage of Alzheimer's disease.
There is an increasing impairment of learning and memory eventually leads to a definitive diagnosis. Some cases show, difficulties with language, executive functions, perception, or execution of movements are more prominent than memory problems. Older memories of the person's life (episodic memory), facts learned (semantic memory), and implicit memory (the memory of the body on how to do things, such as using a fork to eat) are affected to a lesser degree than new facts or memories. The person with Alzheimer's is capable of communicating basic ideas adequately, and may still perform fine motor tasks such as writing, drawing or dressing, certain movement coordination and planning difficulties may be present, but they are commonly unnoticed. As the disease progresses, the person may need assistance or supervision with the most cognitively demanding activities.
Progressive deterioration makes them unable to perform most common activities of daily living.
Speech difficulties become evident, reading and writing skills are also progressively lost. Complex motor sequences become less coordinated as time passes.
During this phase, memory problems worsen, and the person may fail to recognize close relatives, long term memory, which was previously intact, becomes impaired. Common manifestations are wandering, irritability and labile effect, leading to crying, outbursts of unpremeditated aggression, or resistance to caregiving. Some of these people become delusional to and lose insight of their disease process and limitations. Urinary incontinence can develop, which create stress for relatives and care givers, which can be reduced by moving the person from home care to other long term care facilities.
During the final stages, the patient is completely dependent upon caregivers. Language is reduced to simple phrases or even single words, and in the end speech loss. Aggressiveness can still be present, as well as extreme apathy and exhaustion. People with Alzheimer's lose muscle mass and mobility deteriorate to the point where they are bedridden and unable to feed themselves. The cause of death is usually caused by, an infection of pressure ulcers or pneumonia, not the disease itself.