This seven-stage framework is based on a system developed by Barry Reisberg, M.D., clinical director of the New York University School of Medicine's Silberstein Aging and Dementia Research Centre.
Stage 1: No Impairment
The person does not experience any memory problems. An interview with a medical professional does not show any evidence of symptoms of dementia.
Stage 2: Very Mild Cognitive Decline
Here, the problem is that it is fought to distinguish between normal age-related changes or earliest signs of Alzheimer's disease.
The person may feel as if he or she is having memory lapses — forgetting familiar words or the location of everyday objects. But no real symptoms of dementia can be detected during a medical examination or by friends, family or co-workers.
Stage 3: Mild Cognitive Decline
Early-stage Alzheimer's can be diagnosed in some, but not all, individuals with these symptoms.
Friends, family or co-workers begin to notice that the patient in question is having trouble. During a detailed medical review, doctors may be able to find problems with remembering things or a lack of concentration.
Common stage 3 difficulties include:
Stage 4: Moderate Cognitive Decline
Mild or early-stage Alzheimer's disease. It is at this point that most patients get diagnosed when they are examined by competent professionals. In this time period, a careful medical interview should be able to detect clear-cut symptoms in several areas:
Stage 5: Moderately Severe Cognitive Decline
Moderate or Mid-stage Alzheimer's disease. Medical and Occupational Therapies can have a lasting effect when initiated here. Gaps in memory and thinking are noticeable, and individuals begin to need help with day-to-day activities.
At this stage, those with Alzheimer's may:
Stage 6: Severe Cognitive Decline
Memory continues to worsen, personality changes may take place and individuals need extensive help with daily activities.
At this stage, individuals may:
Of note here are the major personality and behavioural changes. Suspiciousness, Delusions (such as believing that their caregiver is an impostor)or compulsive and repetitive behaviour like hand-wringing or tissue shredding.
Stage 7: Very Severe Cognitive Decline
Severe or late-stage Alzheimer's disease. In the final stage of this disease, individuals lose the ability to analyse, understand and react to their environment. Carrying on a conversation becomes almost impossible. Voluntary movements become un-coordinated. Though in speech they may still say words or phrases.
At this point, patients need help with much of their daily personal care, including eating or using the toilet. They may also lose the ability to smile, to sit without support and to hold their heads up. Reflexes become abnormal. Muscles grow rigid and even swallowing is impaired.