Symptoms of Alzheimer’s Disease Dementia
The symptoms of Alzheimer’s disease dementia can vary from one person to the next and will get worse with time. Memory loss symptoms may be accompanied by other changes in thinking and judgement.
The initial memory symptoms can include:
- Repeating oneself often without realizing it
- Forgetting details or conversations
- Misplacing things with increasing frequency.
- Remembering how to get to places to familiar places
The activities that are affected earliest tend to be the ones that are the most complex or that may have the most significant consequences if errors are made. Everyday activities that are affected may include driving, managing finances, keeping track of medications, cooking and remembering appointments. Impairments in these things do not suddenly develop overnight, but more frequent small slips or errors noticed by family are usually the indication that someone may need assistance.
These changes may not be apparent to the person experiencing them. Part of the difficulty of short-term memory loss is that, though the person experiencing it may have a general sense that their memory is worsening, they may not be aware of the full extent to which it is affecting them. A person who does not notice their progressively worsening memory problems is not simply “in denial.” From their perspective, they truly do not notice or cannot remember the lapses in their memory that are occurring. For this reason, another symptom of Alzheimer’s disease dementia can be increasing irritability or frustration, especially when a person feels their abilities to manage things for themselves are being questioned.
What Happens Over Time?
Because Alzheimer’s disease dementia is progressive, memory ability will continue to worsen with time and will be accompanied by more severe changes in other thinking abilities over time.
The earliest symptoms tend to be the most prominent, even as other symptoms also develop. So, if a person’s initial symptom was memory loss, that will usually continue to be the most obvious problem, though they may also start having difficulty with attention, problem solving, judgment, or finding words. This occurs because abnormal proteins causing the symptoms, continue to accumulate in memory regions of the brain, and also gradually spread to other parts of the brain that are important for these other functions.
As a result of gradually worsening symptoms, a person will need more assistance in their daily affairs. The symptoms can vary from one person to the next and the pace of decline is also variable with some individuals experiencing slower decline than others.
With time, a person will often have more trouble recognizing people, remembering where they live, and remembering events from their distant past. Communication also usually worsens such that a person may say things irrelevant to the conversation at hand or simply have trouble communicating their thoughts at all. Gradually, more basic daily functions will be affected such that a person may need supervision at all times and eventually help with things like bathing, dressing, toileting and other aspects of basic personal care.
What Causes Alzheimer's disease dementia?
The symptoms of Alzheimer’s disease dementia occur when brain cells malfunction in memory-related parts of the brain due to the accumulation of abnormal proteins. Alzheimer’s disease dementia is most commonly caused by Alzheimer’s disease neuropathology. A diagnosis of Alzheimer’s disease neuropathology is made when two abnormal proteins called amyloid and tau accumulate in the brain. These proteins accumulate in and around brain cells, which gradually damages and impairs their function.
The neuropathologic diagnosis of AD can only be definitively determined at autopsy through examination of brain tissue with a microscope. However, scientists are working to identify biomarkers that can be used to make the diagnosis during life. Specialized brain scans using positron emission tomography (PET) and examination of cerebral spinal fluid (CSF), obtained through lumbar puncture, are two biomarkers currently being investigated to assist with determining the neuropathologic diagnosis. Scientists are working to identify additional reliable biomarkers, including detecting markers of the disease using blood samples.
The biggest risk factor for Alzheimer’s disease dementia is age, though there are other factors that can contribute as well. The vast majority (>95%) of cases of Alzheimer’s disease are sporadic, meaning there is no single genetic mutation that causes the disease. There are many genes that, although they cannot cause the disease by themselves, can increase the risk that a person may develop the disease as they get older. These genes may run in families and be the reason that many people in a family develop Alzheimer disease as they get older.
A very small proportion of people (<5%) with Alzheimer’s disease will develop it because of a single mutation that causes the disease by itself. This is called familial Alzheimer disease and it almost always affects people at a very young age (40s or even 30s). In a family that carries one of these mutations, approximately half of the members of the family will develop the disease, usually all at about the same age.