Overview

Neurodegenerative disease is an encompassing term for a range of diseases that affect the neurons in the human brain (examples: Binswanger Disease and Alzheimer’s disease). Some of these diseases have similar features and symptoms when diagnosed. Differential diagnosis is a process of identifying a specific clinical feature present in a condition to provide effective management and treatment.

In this article, we will discuss the pathophysiology, clinical features and diagnostic criteria for Binswanger and Alzheimer’s disease.

Binswanger disease 

The brain is made up of white and grey matter. The white matter contains a group of large nerve fibers which allow communication amongst the cells in the brain. These nerve fibers are covered with myelin, which is a protective substance that also provides the white color, hence the white matter.

Binswanger disease is a disease whereby a patient experiences memory loss and intellectual abilities(Dementia) due to decreased blood flow to the white matter.¹

Alzheimer’s disease

This disease usually occurs in mid to late adulthood. It was recognised as the most common cause of dementia in the 21st century. This disease occurs when the nerve fibres, cells and neural connections are destroyed in the grey matter of the brain (cerebral cortex).²  This disease progresses to three(3) stages, which are the early, mid and late stages, each having different signs and symptoms.

Pathophysiology binswanger disease and alzheimer’s disease

Pathophysiology shows the development, progression and manifestation of the signs and symptoms of the diseases.

Binswagner’s disease is associated with small vessel disease of the brain, leading to subcortical ischemia. These small vessels found in the brain are responsible for transporting glucose and oxygen to the brain to aid the normal functioning of the brain. Atherosclerosis is one of the causes of damaged blood vessels, leading to a poor supply of blood. Hypertension plays a vital role in Binswanger disease. It affects the cognitive function of the brain by depositing collagen and fibronectin on the walls of the vessel, causing stiffness in the cerebral arteries, while on the smaller vessels, it affects the Blood-brain barrier, initiating an inflammatory reaction which produces reactive oxygen species in the brain, and this could lead to lacunar stroke.⁹

In Alzheimer's disease(AD), Tau protein is one of those things with a big reputation and short name, it plays a vital role in the brain. Proteins are vulnerable to denaturation due to some factors; Tau protein is not excluded. Tau proteins are messengers in the brain. When there are some external or internal changes, hyperphosphorylation occurs, causing the accumulation of tau protein and forming neurofibrillary tangles, which will damage microtubules and disrupt the functions of Neurons in the brain.³

When Amyloid Precursor Protein(APP) is broken down, it gives rise to Beta- which are 38, 40 or 42. The beta-amyloid 42 is toxic, thereby causing Amyloid plaque, which is formed in the cerebral cortex and affects the neuronal functions of the brain. This accumulation of the Amyloid plaque will lead to Amyloidosis.⁴

Mutation in the APP gene can also lead to AD.⁵

Clinical features of binswagners disease and alzheimer’s disease

Binswagners disease

• Gait disturbance 
• Urinary incontinence
• Hypertension 
• Cognitive  impairment 
• Mild Parkinsonism⁶

Alzheimer’s disease

• Disorientation and problems with making decisions 
• Personality issues, e.g. aggressiveness, impatience, irritant, etc
• Language impairment and impaired repetition of words
• Visuospatial and environmental dysfunction⁷

Diagnostic approaches for binswanger disease and alzheimer’s disease

Binswanger disease

• Spectroscopy of the white matter to determine the level of N-acetylaspartate
• Cardiovascular test: e.g lipid profile, blood pressure, and echocardiography
• Magnetic resonance imaging (MRI): This is looking out for brain atrophy, lacunar infarcts, and white matter hyperintensities(WMH)

Alzheimer’s disease

• Neuropsychological and mental testing
• Laboratory testing, which includes a cerebrospinal fluid test
• Brain imaging test: This will help distinguish different brain diseases and establish a degree of damage. The imaging test related to Alzheimer’s disease is magnetic resonance imaging (MRI): it looks out for Hippocampal atrophy and cortical atrophy
• Positron emission tomography (PET), using a specific amyloid tracer to detect amyloid plaque and computerised tomography (CT)⁸

Differential diagnoses of this disease are quite challenging because of some of the similarities they have, such as;

• Behavioural symptoms 
• Cognitive symptoms 
• Overlapping of some imaging findings
• There could be co-morbidity and the same disease in an individual.

Summary

Binswagner disease and Alzheimer’s disease are both progressive neurodegenerative diseases. BD affects the white matter, and AD affects the grey matter of the brain, and different factors are seen when diagnosing each disease.

FAQ’s

What is the age of onset?

Binswagner disease (BD) can occur at the age of 45 years and above, while Alzheimer's disease can occur at 65 years and above.

What cognitive profile does it affect?

BD affects the executive function in the brain, while AD affects the memory part of the brain.

What part of the brain is affected?

BD affects the white matter of the brain, while AD affects the grey matter of the brain.

What are the risk factors?

BD risk factors are hypertension, diabetes, stroke, etc, while AD is linked to the formation of Amyloid plaque.