About subcortical dementia
What is subcortical dementia?
Binswanger disease is a progressive neurological disorder caused by arteriosclerosis and thromboembolism affecting the blood vessels that supply the white-matter and deep structures of the brain (basal ganglia and thalamus). Most patients experience progressive loss of memory and intellectual abilities (dementia), urinary urgency or incontinence, and an abnormally slow, shuffling, unsteady pattern of walking, usually over a 5-10 year period. Due to their vascular etiology, the symptoms and physical findings associated with Binswanger disease may suddenly worsen due to stroke, stabilize and then improve for a brief time, but the patient's overall condition continues to progress as the blood vessels become increasingly obstructed.
What are the symptoms for subcortical dementia?
Affected individuals often become depressed, uncaring (apathetic), inactive, and unable to act or make decisions (abulic). They become withdrawn, and exhibit poor judgement, reduced planning and organizational skills, and less spontaneous communication. In addition, affected individuals may have difficulty with speech (dysarthria), swallowing (dysphagia), and urinary bladder control (incontinence). Some patients exhibit abnormalities that are similar to those seen in Parkinson disease, such as slowness, poor balance and short, shuffling steps (Parkinsonism). Tremor is usually not a feature.
Many individuals with Binswanger disease have a history of strokes or transient ischemic attacks. Consequently, the symptoms and signs of this disease develop in a stuttering or stepwise fashion; in contrast to the insidious, gradually progressive course of neurodegenerative diseases.
What are the causes for subcortical dementia?
Binswanger disease is caused by arteriosclerosis, thromboembolism and other diseases that obstruct blood vessels that supply the deep structures of the brain. Hypertension, smoking, hypercholesterolemia, heart disease and diabetes mellitus are risk factors for Binswanger disease. Rare hereditary diseases such as CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) also cause Binswanger disease. Thus, Binswanger disease is actually a clinical syndrome of vascular dementia with multiple causes, not a specific disease. The reduced blood flow in brain tissue appears to produce secondary inflammation that may be a target for treatment.
What are the treatments for subcortical dementia?
The ischemic brain damage in Binswanger disease is not reversible, so treatment is focused on reducing risk factors for stroke, thereby retarding progression of the disease. Treatment usually involves the use of anti-hypertensive drugs to control blood pressure, antiplatelet drugs (e.g., aspirin) or warfarin to reduce thromboembolism, statins to reduce atherosclerosis, smoking cessation and diabetic control. Antidepressant drugs are helpful in the management of depression associated with Binswanger disease. Other treatment is symptomatic and supportive.
What are the risk factors for subcortical dementia?
MID generally occurs in people aged 55 to 75 years and is more common in men than in women.
Medical conditions that increase the risk of MID include:
- atrial fibrillation, which is an irregular, rapid heartbeat that creates stagnation that can lead to blood clots
- previous strokes
- heart failure
- cognitive decline prior to a stroke
- high blood pressure
- atherosclerosis, or hardening of the arteries
Lifestyle Risk Factors
The following are lifestyle risk factors for MID:
- a low level of education
- a poor diet
- little to no physical activity
Is there a cure/medications for subcortical dementia?
MID has no cure. Medications and cognitive training may help preserve mental function. The speed and advance of dementia varies. Some people die soon after an MID diagnosis, and others survive for years.