Historically, dementia has been thought of as a disease of old age. Just a century ago, people did not live long enough to acquire dementia and thus it was not very prevalent. Today, by the time people reach the age of 85, one third will be living with dementia. Dementia is a cognitive impairment that is usually progressive and involves functional impairments as well. The neurodegenerative dementias are progressive and irreversible.
There are 4 types of neurodegenerative dementias: Alzheimer’s dementia (AD), vascular dementia (VaD), Lewy body dementia (LBD) and frontotemporal lobar dementia (FTD). AD is the most prevalent form of dementia and accounts for roughly 60% of all diagnosed cases. AD and FTD exhibit slow progression while LBD exhibits rapid progression.
The chance of developing dementia increases with age. Only 5% of individuals between the ages of 71-79 develop dementia. This number increases to 37% for those over the age of 90.
Pathogenesis & Clinical Features
Though dementia can be caused by cerebrovascular damage, infections (virus, bacteria, etc.), injuries or chemical imbalances of the body, neurodegenerative dementias occur as a result of dying brain cells, which cause permanent and progressive changes to mental and physical functions. Heredity has been shown to play a role in certain forms of dementia.
Typically, AD and FTD progress slowly while LBD progresses very rapidly. However, the clinical profiles of dementias vary greatly. As an example, AD-affected individuals may have sporadic or familial AD. Some have slow progressing AD while others have rapid progressing AD.
External factors have been shown to influence dementia. The functional status of persons with dementia is heterogeneous not only because of the nature of the disease but also due to external and environmental factors.
People with dementia often have problems with memory and completing simple daily activities like making dinner, bathing or remembering a doctor’s appointment. Mood swings and personality changes often accompany these symptoms.
Alzheimer’s Dementia (AD) – Often the age of onset is before the age of 65. Most cases are sporadic, but about 5-10% are familial. Usual symptoms include language impairment (progressing to mutism), depression, insomnia, incontinence, delusions, and agitation.
Lewy Body Dementia (LBD) – Affected individuals usually alternate between periods of normal cognition and periods of abnormal cognition. LBD is usually very rapidly progressing. Symptoms include motor speech disorder, hypophonia, daytime drowsiness, and periods of delirium.
Vascular Dementia (VaD) – Affected individuals will typically suffer abrupt deteriorations. Symptoms include motor speech disorder, depression and mood changes
Frontotemporal Lobar Dementia (FTD) – Often the age of onset is before 65 and the progression of the disease is typically slow. Symptoms vary greatly though patients generally exhibit both communication and behavior changes.
Current Therapies/Future Aims
Dementia is a progressive disease and there is no known cure. However, there are things people can do to reduce the risk for dementia or slow the progression of the disease. Regular exercise, healthy diet, mental activities and engaging in social activities have all shown to have positive effects.
Though there is no cure for dementia, several medications are available to help treat the symptoms. Some medications are aimed at improving brain functions and slow the progression of symptoms. Other medications are aimed at controlling mood (depression, anxiety) or sleep problems.