First symptoms

The first symptoms are often mistakenly attributed to aging or stress.[25] Detailed neuropsychological testing can reveal mild cognitive difficulties up to eight years before a person fulfills the clinical criteria for diagnosis of Alzheimer's disease.[26] These early symptoms can affect the most complex activities of daily living.[27] The most noticeable deficit is short term memory loss, which shows up as difficulty in remembering recently learned facts and inability to acquire new information.[26]

Subtle problems with the executive functions of attentiveness, planning, flexibility, and abstract thinking, or impairments in semantic memory (memory of meanings, and concept relationships) can also be symptomatic of the early stages of Alzheimer's disease.[26] Apathy and depression can be seen at this stage, with apathy remaining as the most persistent symptom throughout the course of the disease.[28][29] Mild cognitive impairment (MCI) is often found to be a transitional stage between normal aging and dementia. MCI can present with a variety of symptoms, and when memory loss is the predominant symptom, it is termed amnestic MCI and is frequently seen as a prodromal stage of Alzheimer's disease.[30] Amnestic MCI has a greater than 90% likelihood of being associated with Alzheimer's.[31]