Vascular dementia is a decrease in the blood flow through blood vessels in the brain, leading to cognitive decline. There are various subcategories of vascular dementia, one being Binswanger disease (BD) which specifically affects the white matter of the brain. Vascular dementia is the second most common dementia diagnosis, after Alzheimer’s disease, and is projected to increase, as the population grows older.¹ Therefore, it is important that future research is targeted towards improving treatment methods and discovering biomarkers to distinguish BD in order to aid in earlier diagnosis and improve patient outcomes.

What is vascular dementia?

Vascular dementia is caused by a decrease in the supply of blood to the brain, commonly due to various conditions and injuries affecting the brain's vascular system. As a consequence of decreased blood flow through the brain, cognitive decline ensues involving a loss of planning, judgement, memory and other cognitive processes (NIH). 

Risk factors

There is an increased risk of vascular dementia in patients with pre-existing conditions which affect the blood flow and oxygen supply to the brain (NIH). These conditions can include previous strokes, hypertension, diabetes and cardiovascular diseases.

A strong link has been made between these pre-existing vascular conditions and subsequent cognitive impairment and dementia (NIH). In fact, Vascular diseases have been shown to contribute to one-fourth to one-half of all of all dementia cases (NIH). 

What are the consequences of disrupted blood flow to the brain? 

Disrupted blood flow and oxygen supply to the brain can manifest in various clinical presentations, contributing to the development of vascular dementia. Cerebral hypoperfusion, infarcts in areas lacking blood supply, haemorrhages due to ruptured or damaged blood vessels, small vessel disease in the brain associated with white matter hyperintensities, and stroke. 

Symptoms of vascular dementia

The level of cognitive decline is significantly correlated to the size, location, and number of vascular changes in the brain (NIH). The symptoms of vascular dementia can be very similar to those typical of Alzheimer's disease. People with vascular dementia may experience:

• Difficulty with attention and decision-making
• Difficulty performing tasks that previously used to be easy
• Trouble following instructions or learning new information and routines
• Memory difficulties such as forgetting current or past events, Misplacing items, and problems with language
• Cognitive changes such as altered sleep patterns, loss of interest in things or people, changes in personality, experiencing hallucinations or delusions, and a loss of judgement

How does Binswanger disease differ from vascular dementia?

Binswanger disease is a form of vascular dementia, involving damage to the small blood vessels of the brain which is further characterised by white matter hyperintensities.² Both have similar vascular origins, however, Binswanger disease preferentially affects the white matter whereas vascular dementia encompasses all vascular diseases contributing to dementia. Both Binswanger disease and vascular dementia share similar risk factors however symptom progression can vary. 

What is ‘white matter’? 

White matter is the brain’s network of axons which lies beneath the grey matter, facilitating the relay of information between different regions.² 

Symptoms of Binswanger disease 

The risk factors for Binswanger’s disease are similar to those of vascular dementia. Furthermore, symptoms also often overlap due to shared vascular origins. However, symptom progression can vary. In Binswanger's disease symptoms are always steadily progressive, however, they can show a waning pattern and at times a stepped course.³

Diagnosis

BD can be diagnosed using clinical information and neuroimaging testing combined.

Clinical assessment 

Medical history

Often patients with BD have had previous episodes of ‘mini strokes’.³ A ‘mini-stroke’ is caused by a temporary disruption in the blood supply and thus oxygen supply to part of the brain. This can lead to common symptoms of a stroke, however, it does not last as long with symptoms fully residing before 24 hours (NHS). 

Physical examination 

Physical examination of BD patients often reveals upper motor symptoms as a key clinical feature. These include gait and balance disturbances.³ Asymmetric hyperreflexia is also a common symptom and involves hyperactive or repeating reflexes.^3,4 Hypertension is a defining factor in the diagnosis of BD as it is almost always present.³ Furthermore, its absence points to further questioning to reach a different diagnosis.

Neuropsychological testing

Executive function and processing speed are the most common cognitive functions affected in BD, with memory dysfunction being less common.⁵ These cognitive deficits can be examined using The mini-mental status examination (MMSE) and The Montreal Cognitive Assessment (MOCA).³ The mini-mental status examination (MMSE) is used for the diagnosis of memory impairment in AD, however, is often in the normal range in BD.³ Therefore, The Montreal Cognitive Assessment (MOCA) is often the preferred screening test for BD.³ MOCA involves testing for executive function and is often abnormal in BD patients.⁶ However, alone these tests are not reliable for the diagnosis of BD and require additional confirmation through imaging studies.³ 

Imaging studies 

Advanced imaging with brain MRI is required for the diagnosis of BD. White matter lesions are visualised as hyperintensities on magnetic resonance imaging (MRI) scans and serve as markers for small vessel disease.²

As with clinical examination, although imaging features are suggestive of the disease, a diagnosis cannot be made based only on imaging. The clinical features are crucial for the diagnosis of the disease and further additional studies are sometimes required.³

The link between Binswanger's disease and Alzheimer’s disease

Comorbidity of Binswanger’s and Alzheimer's disease is common.³ This occurs due to the increasing prevalence of both diseases in older patients.³ Binswanger’s disease enhances the negative effects of Alzheimer’s disease. Decreased cerebral vascularisation as seen in Binswanger's disease accelerates the accumulation and decreases the clearance of Aβ42 and other metabolic waste products in the brain contributing to the onset and progression of Alzheimer’s disease.³ 

Comorbidity can make diagnosis in patients older than 70 increasingly difficult.³ Therefore, diagnosis in older patients should be considered carefully alongside alternate diagnoses such as Alzheimer’s disease, mixed disease or “normal ageing”.³ Improvement in diagnosis is on the horizon with the discovery of additional biomarkers to better distinguish Binswanger’s disease.³ 

Treatment and management of Binswanger’s disease 

The treatment effect of specific therapies for Binswanger’s disease is still unknown due to no specific clinical studies targeting therapies for BD.³ Therefore, this is a critical area of research which could greatly improve patient outcomes. Despite the lack of studies, treatments can still be generalised from multiple studies surrounding vascular dementia.³ 

Effective management of Binswanger's disease involves a combination of medical treatment, lifestyle changes, cognitive and behavioural therapies, and supportive care. Early diagnosis and tailored interventions are crucial for improving patients' quality of life.

Blood pressure control 

Hypertension plays a central role in BD pathogenesis, being consistently associated with a higher incidence of strokes and white matter lesions. Antihypertensive treatment including ACE inhibitors and calcium channel blockers reduces blood pressure and has been shown to reduce the growth of WMH, which is a major pathology of BD.³ Furthermore, blood pressure control has also proved to reduce the progression of cognitive impairment and the onset of dementia.³ 

Reducing vascular risk factors

Prescribing antiplatelet agents such as aspirin in addition to statins helps to manage diabetes effectively, which reduces the risk factors for BD. Targeting risk factors can improve overall patient outcomes. 

Managing cognitive symptoms 

Cognitive symptoms of BD can be improved by a combination of behavioural therapies and pharmacological intervention. Pharmacological treatments include cholinesterase inhibitors such as donepezil and NMDA receptor antagonists such as memantine which help to manage the declining cognitive aspect of BD. Furthermore, antidepressants and antipsychotics can also be used to manage depression and psychosis which can accompany BD. 

Lifestyle modifications

The benefits of exercise and physical activity for stroke prevention and hypertension treatment are also well-stated. In addition, smoking cessation has been positively correlated with decreased risk of stroke and vascular disease, which reduces the progression of BD. 

Future directions

There is much research potential to determine whether the methods used to treat cerebrovascular disease and heart disease could also be used as a treatment for vascular dementia. Ongoing research may lead to new treatments and advanced therapeutic techniques.

Summary 

Vascular dementia, the second most common dementia after Alzheimer's, results from decreased blood flow to the brain, leading to cognitive decline. Binswanger's disease (BD) is a subcategory that affects the brain's white matter.

Risk Factors

• Vascular dementia is linked to conditions affecting brain blood flow, such as strokes, hypertension, diabetes, and cardiovascular diseases. These conditions contribute significantly to dementia cases

Symptoms

• Symptoms include difficulties with attention, decision-making, task performance, memory, and cognitive changes like altered sleep patterns and personality changes. Binswanger's Disease shows progressive symptoms often including gait and balance disturbances and hypertension

Diagnosis

• BD diagnosis involves medical history, physical exams, neuropsychological tests (e.g., MOCA), and brain MRI scans showing white matter lesions. Clinical features are crucial for diagnosis, often complicated by comorbidity with Alzheimer's

Treatment and Management

• Blood Pressure Control: Use of antihypertensives (ACE inhibitors, calcium channel blockers)
• Vascular Risk Reduction: Antiplatelet agents (aspirin), statins, and diabetes management
• Cognitive Management: Behavioural therapies, cholinesterase inhibitors (donepezil), NMDA receptor antagonists (memantine), antidepressants, and antipsychotics
• Lifestyle Changes: Regular exercise and smoking cessation

Future Directions

• Research is ongoing to improve treatment methods and discover biomarkers to distinguish BD from other dementias. Early diagnosis and tailored interventions are crucial for better patient outcomes