Rare Types of Dementia

Binswanger’s Disease (White matter disease)

Binswanger's disease (BD), also called subcortical vascular dementia, or white matter disease is a rare type of dementia caused by widespread areas of damage to the deep layers of white matter in the brain. The damage is the result of the hardening and narrowing (atherosclerosis) of arteries that supply the subcortical areas of the brain. As the arteries become more and more narrowed, the blood supplied by those arteries decreases and brain tissue dies. A characteristic pattern of BD-damaged brain tissue can be seen with brain imaging techniques such as CT scans or magnetic resonance imaging (MRI).

The symptoms associated with BD are related to the disruption of subcortical neural circuits that control executive cognitive functioning: short-term memory, organization, mood, attention, the ability to act or make decisions, and appropriate behaviour. The most characteristic feature of BD is psychomotor slowness - an increase in the length of time it takes for a thought to be translated into action, for example, for the fingers to turn the thought of a letter into the shape of a letter on a piece of paper. Other symptoms include forgetfulness (but not as severe as the forgetfulness of Alzheimer's disease), changes in speech, an unsteady gait, clumsiness or frequent falls, changes in personality or mood (most likely in the form of apathy, irritability, and depression), and urinary symptoms that aren't caused by urological disease.

Diagnosis: Brain imaging, which reveals the characteristic brain lesions of BD, is essential for a positive diagnosis.

Treatment: There is no specific course of treatment for BD. Treatment is basically symptomatic. Antidepressant medications such as Serotonin-Specific Reuptake Inhibitors (SSRI) such as Sertraline, or Citalopram are indicated for people with depression or anxiety. Atypical antipsychotic drugs, such as Risperidone and Olanzapine, may be helpful for individuals with agitation and disruptive behaviour. Recent drug trials with the drug Memantine have shown improved cognition and stabilization of global functioning and behaviour. The successful management of high blood pressure and diabetes can slow the progression of atherosclerosis, and subsequently slow the progress of BD. Since there is no cure, the best approach is preventive, early in the adult years, by controlling risk factors such as hypertension, diabetes, and smoking.

Prognosis: BD is a progressive disease; there is no cure. Symptoms may be sudden or gradual and the progression is in a stepwise manner. BD can often coexist with Alzheimer's disease. Behaviours that slow the progression or control risk factors of atherosclerosis -  high blood pressure, diabetes,  -- such as eating a healthy diet and keeping healthy wake/sleep schedules, exercising, and avoiding smoking, and limiting alcohol -- can also slow the progression of BD.

Research: The National Institute of Neurological Disorders and Stroke (NINDS) conducts research related to BD in its laboratories at the National Institutes of Health (NIH), and also supports additional research through grants to major medical institutions across the country. Much of this research focuses on finding better ways to prevent, treat, and ultimately cure neurological disorders, such as BD.

For more information visit the National Institute of Neurological Disorders and Stroke:

https://www.ninds.nih.gov/Disorders/All-Disorders/Binswangers-Disease-Information-Page

Dementia associated with corticobasal degeneration

Corticobasal degeneration (CBD), sometimes referred to as corticobasal ganglionic degeneration, is considered to be a part of the spectrum of Frontotemporal dementia (FTD). It is characterized by nerve cell death and atrophy or shrinkage of multiple areas of the brain, including the cerebral cortex and basal ganglia. CBD typically occurs in individuals between the ages of 45-70. Rarely, there is a family history of dementia, psychiatric problems or a movement disorder.

Signs & Symptoms: Individuals with CBD usually present with either a movement disorder or cognitive deficits. As the disease progresses, they can go on to develop both types of symptoms.

The movement symptoms can be very similar to Parkinson’s disease, with slowness, and rigidity, but tremor is less common. These symptoms do not respond to Parkinson’s disease medications. Many individuals with CBD experience a subtle change in sensation or an inability to make the affected limb follow commands. They may have difficulties completing some specific tasks such as brushing teeth, opening a door or using tools such as a can opener. When it affects the legs, a person can have difficulty dancing or may show an increased tendency to trip and fall. Other symptoms include involuntary stiffening, twisting or contraction (dystonia), or uncontrolled movement of the affected limb (myoclonus).

The cognitive symptoms associated with CBD include language problems such as a word-finding problem or naming problem. Reading, writing, and simple mathematical calculations may be impaired. Personality changes, inappropriate behaviour, or repetitive or compulsive activities are as seen in FTD are also common. Short-term memory problems are less common.

Diagnosis: Patients with CBD who present with cognitive symptoms are often initially diagnosed with FTD or Alzheimer’s disease. It is when movement symptoms develop that the possibility of CBD is considered. Occasionally, a diagnosis of CBD is not apparent until at autopsy, when a microscopic examination of the brain shows ballooned neurons and protein inclusions from the accumulation of tau protein.

Progression: CBD usually progresses slowly over 6-8 years. Movement symptoms tend to progress slowly from one side of the body to the other or from leg to arm on the same side of the body.

Treatment: There is no specific course of treatment for CBD at this time. Treatment is basically symptomatic. Patients with rigidity and walking difficulty may respond to medications used for treating Parkinson’s disease. Dystonia and myoclonus may respond to muscle relaxants or anti-seizure medications. Memory and behaviour problems may or may not respond to Aricept, a medication for Alzheimer’s disease. Associated depression and or anxiety may respond to antidepressants such as Sertraline, Citalopram etc. Physical therapy and stretching exercises may be recommended to relieve rigidity, prevent contractions and deformities, and maintain muscle strength. Assistive devices such as walkers, cane, and speech, physical, and occupational therapy are other helpful strategies to manage movement disorders and language difficulties.

Source: UCSF Memory and Aging Center

For more information, visit the National Institute of Neurological Disorders and Stroke:

https://www.ninds.nih.gov/Disorders/All-Disorders/Corticobasal-Degeneration-Information-Page

Dementia associated with HIV

HIV (Human Immunodeficiency Virus) is an infection that weakens the immune system, decreasing the ability of the body to fight infections and diseases. HIV infection can affect the brain in up to half of people with HIV. The effects on the brain result in mild cognitive complaints and dementia. Cognitive impairment is common in HIV but dementia is much rarer. Before the use of antiretroviral drugs, around 20-30 per cent of people with advanced HIV infection developed dementia. This has now decreased to around 2 per cent.

Neurocognitive impairment in people with HIV may be caused by the virus directly damaging the brain or could be the result of a weakened immune system enabling infections and cancers to attack the brain.

Symptoms may include problems with short-term memory, language and thinking, difficulties with concentration and decision making, unsteadiness, mood changes and hallucinations. People may also have problems with their sense of smell. Some people may experience only mild cognitive impairment such as a decline in the ability to think quickly or clearly.

HIV is easily overlooked as a possible cause of dementia and, even when someone is known to have HIV infection, cognitive impairment can sometimes be difficult to diagnose because the symptoms are similar to those of other conditions such as depression.

Treatment with a combination of at least three antiretroviral drugs often prevents cognitive impairments worsening and, for many people, can reverse the cognitive damage caused by HIV. Rehabilitation programmes may also help people with HIV-related cognitive impairment to re-learn skills.

Source: www.alzheimers.org.uk

Dementia associated with Multiple Sclerosis

Some people with multiple sclerosis (MS) experience some change in their mental abilities depending on the part of the brain affected by the disease. Individuals may be affected in different ways and to different degrees, over a period of time. The mental abilities most likely to be affected are memory, concentration and problem-solving. There may also be emotional problems, such as mood swings.

The decline in mental abilities associated with MS is not usually severe enough to be categorized as dementia. It is more typical to describe the symptoms as cognitive difficulties. For more information please contact the MS Society.

Source: www.alzheimers.org.uk