(UC Irvine) Dementia is a general term for memory loss and decline in mental ability that is severe enough to interfere with the activities of daily living. Dementia can result from a variety of causes, which fall into three categories: (1) potentially reversible, (2) non-progressive, and (3) progressive. An estimated 5-15% of all dementias are due to potentially reversible causes, while the remainder (85-85%) are irreversible and may be progressive or non-progressive. An early and accurate evaluation is critical to identify any potentially reversible causes of dementia, such as depression, vitamin B12 deficiency, hypothyroidism, side effects from medications, and infections.
Some dementias are non-progressive, characterized by a change in cognition that remains stable over time. The vast majority of dementias, however, are progressive, causing a steady irreversible decline until death. The most common progressive dementia among the elderly is Alzheimer’s disease, which accounts for approximately 60% of all cases. Nearly 36 million people in the world have Alzheimer’s disease, including 5.4 million in the USA. Nearly 600,000 Californians are affected, including an estimated 75,000 individuals in Orange County.
Dementias other than Alzheimer’s disease, dementia with Lewy bodies, frontotemporal dementia, vascular dementia, Parkinson’s disease dementia, Huntington’s disease dementia, Creutzfeldt-Jacob dementia and a number of other very rare conditions, account for 40% of cases.
Knowing one has dementia is not good enough, as treatments for the various types of dementia vary. Just like cancer medications don’t all work for all the various forms of cancers, medications and treatments for the different types of dementia can vary widely, highlighting the need for an accurate diagnosis. One in 9 individuals over 65 have dementia and currently over 70% of them do not ever receive a clear diagnosis and, consequently, do have the opportunity to benefit from the treatments and services that can improve quality of life.
Mild Cognitive Impairment
MCI: Transition from Normal Aging to Dementia
The transition from normal aging to Alzheimer’s disease is a subtle one with symptoms emerging gradually. Oftentimes, the development of Alzheimer’s disease is compared to the dimming of a light, as cognitive abilities are slowly lost over time.
Everyone can expect to experience cognitive changes as they age. Common changes associated with normal aging include slower recall of information such as names, increased effort to learn and store new information, heightened susceptibility to distraction, slower processing of new information, and greater difficulty multi-tasking.
Scientists and clinicians describe three stages in the development and progression of Alzheimer’s disease.
- Pre-clinical or pre-symptomatic phase, that is, the silent stage during which senile plaques are accumulating in the brain, but are insufficient to cause noticeable symptoms.
- Mild Cognitive Impairment (MCI) in which symptoms become noticeable to the affected individual and/or family and impairment is significant but does not interfere with everyday activities, as described further below.
- Dementia, in which significant loss of intellectual ability occurs, memory plus one or more other cognitive abilities are affected, and the impairment is so severe as to interfere with everyday functioning.
Progression from normal aging to Alzheimer’s disease or another dementia
Mild Cognitive Impairment (MCI)
An established risk factor for Alzheimer’s disease, Mild Cognitive Impairment (MCI) is a condition in which memory and/or other cognitive difficulties (e.g., language, visual-spatial skills) disrupt everyday life (e.g., missing appointments) and are noticeable to the person affected and/or others (e.g., family, friends, work colleagues), but are not severe enough to interfere with basic living skills. An individual with MCI will score significantly lower than others of the same age on neuropsychological measures of the particular cognitive domains (e.g., memory, language) affected. Some studies suggest that up to 10-20% of older adults age 65 and older have MCI. MCI may be caused by a variety of medical and mental health (e.g., depression) conditions as well as be a precursor to a progressive dementia like AD.