Introduction

Binswanger disease is a progressive disease that affects subcortical structures, with the parent condition being the cerebral small vessel disease. These diseases fall under the category of vascular cognitive impairment, which is a form of the most common forms of dementia. Binswanger disease is when there is injury to the small vessels of the brain and is recognised through extensive white matter hyperintensities and subcortical ischemia. Simply, it is a type of vascular dementia that is caused by damage to small blood vessels in the brain.¹ It can arise in the late 30s to 40s and progress with age.² This is a condition that severely impacts the patient, as well as their friends, family and caregivers, due to the behavioural, cognitive and motor symptoms that arise.

Effect of Binswanger disease on the brain

When the small blood vessels are damaged, they become stiff, thick and twisted which leads to reduced blood flow between them and within the brain. These gradually cause more damage to the parts of the brain that are vital for memory, attention and language. These areas of the brain are known as the subcortical regions, which also encompass areas responsible for motor control.³

Diagnosis of Binswanger disease

Binswanger disease was very hard to diagnose and rarely diagnosed when it was first discovered. This was before the use of computer tomography and magnetic resonance imaging, which make it much more recognisable nowadays. A typical diagnosis includes performing a clinical evaluation, ancillary tests and using neuroimaging techniques. During a clinical or physical evaluation, there are typically upper motor signs, parkinsonism and asymmetric hyperreflexia. In most cases, hypertension is a key sign of the disease, and an absence of it should cause a questioning of the diagnosis. Ancillary tests may also be performed to assess cognitive dysfunctions such as a slowed processing speed or memory, as well as behavioural disorders such as depression.¹

Symptoms of Binswanger disease

Individuals with Binswanger disease typically have different severities of cognitive impairment but having episodes of transient ischemic attacks or “mini strokes” can be a sign. Symptoms are gradually progressive but can sometimes also have fluctuating appearances.¹ Early symptoms may include:³

• Mood swings
• Slower thought processes
• Forgetfulness or mild memory difficulties
• Language difficulty
• Difficulties with making decisions, organising and concentrating

While later and more progressive symptoms may include:³

• Hallucinations
• Difficulties walking and eating
• Behaviour changes
• Balance difficulties
• Major memory losses
• Severe confusion

Imaging techniques

Neuroimaging techniques are the most accurate and clear form of diagnosing Binswanger disease and will therefore always contribute to the diagnosis process. As use of imaging becomes more popular, there is a higher number of diagnoses, especially in the older generations, because some patients are asymptomatic and only show white matter changes on CT or brain MRI scans.¹

Computer tomography (CT)

A CT scan is an imaging technique that combines X-rays with computer technology to generate images of the internal body. It can show bones, muscles, fat, organs and blood vessels. During a CT scan, the X-ray beam moves around the body in a circle motion, to gain multiple different views of the same area with much a larger amount of detail. This information is then sent to a computer which can interpret the X-ray data and display it as a two-dimensional image on a screen for the radiologist to interpret and find any abnormalities.⁴ CT scans can recognise lesions. The disease is represented through changes that occur to the subcortical white matter, which has a bilateral presentation. These lesions are most common in the periventricular regions. These changes may also be present without any neurological signs and are associated with age.⁵ CT scans reveal hypodensities in deep white matter that are more prominent in the centrum semiovale and frontal lobes.⁶

Magnetic resonance imaging (MRI)

An MRI is a non-invasive imaging technique that produces three-dimensional and detailed images. A magnetic field is produced using a powerful magnet that leads to protons within the body aligning with this magnetic field. When a radiofrequency current is then run through a patient, the protons spin out of equilibrium and against the pull of the magnetic field. When the radiofrequency is stopped, MRI sensors detect the energy released when these protons realign with the field. This energy and the time taken for realignment depend on the environment and nature of the molecules. Specialists can analyse these results and magnetic properties to distinguish between the types of tissues.⁷ The protocol when performing an MRI should include FLAIR, T2, echo gradients or susceptibility weighted imaging to detect blood vessels. In an MRI image, white matter hyperintensities are always seen with no specific size threshold for a diagnosis. They are typically clear on the image and divided into types of periventricular or deep by their location. Both types are common, but periventricular white matter lesions have a stronger relationship with aging.¹ MRI is better than CT for characterising white matter disorders, because MRI has greater sensitivity. An image that shows a presence of Binswanger disease will have large and confluent areas of demyelination on T2WI and FLAIR sequences; lesions on T1WI sequences are hypointense. Typically, lesions appear as bilateral, symmetric and grouped around the frontal horns. As mentioned previously, the periventricular and deep white matter may be affected; however, the juxtacortical white matter remains unaffected. MRI can encapsulate dynamic contrast enhancement MRI to show any disturbances of the blood-brain barrier and blood supply impacts, or MRI diffusion tensor imaging to evaluate white matter intensity.⁵

Differential diagnosis

There are several conditions falling under the category of dementia, which have similar clinical manifestations and symptoms. This is the reason for neurological imaging and why it plays a vital role during diagnosis. Images can show differences in areas of the brain affected and how it is affected. Early onset symptoms are also key indicators distinguishing between different types of dementia that should be utilised during diagnosis. Below shows the different diseases associated with dementia along with their first symptoms and how or where the brain is affected, respectively:⁶

Alzheimer's disease:

• first symptom - memory loss
• effect on the brain - entorhinal cortex and hippocampal atrophy

Creutzfeldt-Jakob disease:

• first symptoms - mood swings, dementia, movement disorders
• effect on the brain - cortical ribboning and basal ganglia or thalamic hyperintensity on diffusion/FLAIR MRI

Lewy Body dementia:

• first symptoms - hallucinations, sleep disorder, delirium
• effect on the brain - posterior parietal atrophy; hippocampi is larger than in Alzheimer’s

Frontotemporal degeneration:

• first symptoms - apathy, poor judgement, speech/language difficulties
• effect on the brain - frontal, insular, and/or temporal atrophy; spares posterior parietal lobe

Vascular disease:

• first symptoms - apathy, focal weakness
• effect on the brain - cortical or subcortical infarctions or confluent white matter disease⁶

Combining clinical and imaging data

As mentioned, only performing a clinical evaluation may result in a misdiagnosis, therefore a combination of clinical and imaging information can result in a more accurate diagnosis. This can then lead to a better management plan and a better understanding of the specific way Binswanger disease may affect someone.

FAQs

What are some risk factors of the disease?

The sex assigned at birth has no impact on the likelihood of developing the disease. Many individuals that develop Binswanger disease have previous episodes of strokes and transient ischemic attacks. Those that have diabetes or smoke have an increased risk of disease appearance.⁸

How is Binswanger disease treated?

Currently, there are no therapies that specifically target Binswanger disease. However, there are various treatments that aim to improve behaviour and prevent progression of the disease. Blood pressure reduction techniques can be used to reduce the incidence of strokes and the progression of cognitive deterioration that contribute to dementia. Antiplatelet therapy can be used when lacunar strokes occur to reduce their occurrence. There is a three times higher risk of stroke with white matter hyperintensities. The use of statins can also prevent secondary stroke prevention through their pleotropic properties, which include reducing atherosclerosis and inflammation. Lifestyle changes such as physical activity and diet changes can reduce or prevent cognitive impairment and strokes.¹

Summary

Binswanger disease is a neuropsychiatric, progressive disease caused by injury to small blood vessels within the brain. It is mainly characterised by motor, behavioural and cognitive impairments. Whilst there is no direct treatment or cure to the disease, lifestyle changes, blood pressure control and various other therapies can contribute to slow the progression of the disease. If you have any of the mentioned symptoms, you should consult a healthcare professional for neuroimaging diagnostic techniques.