Contemporary Research Into Neurological Disorders (VCE SSCE Psychology): Revision Notes

Contemporary Research Into Neurological Disorders

Introduction to neurological disorders

Neurological disorders encompass any condition affecting the nervous system, including the brain, spinal cord or peripheral nerves. With over 600 different types identified, these conditions represent a major health challenge globally.

These disorders can develop through various pathways. Some result from acquired brain injury (ABI), while others are congenital conditions that develop during foetal development. Throughout life, the nervous system remains vulnerable to damage from trauma, nutritional deficiencies, substance use, infections, and various diseases.

As populations grow and age globally, neurological disorders are becoming an increasingly prominent cause of death and disability. This trend underscores the importance of ongoing research to develop better understanding, treatments and potential cures for these conditions.

Epilepsy

Understanding epilepsy

Epilepsy is a neurological disorder characterized by sudden, intense bursts of abnormal brain activity that result in seizures. These are recurrent and unprovoked episodes, distinct from seizures caused by temporary conditions such as high fever, blood sugar fluctuations, substance withdrawal or concussion.

During normal brain function, neurons fire in an orderly sequence as messages pass through the brain. In epilepsy, this pattern is disrupted. Seizures occur when excessive numbers of neurons fire synchronously, creating abnormal electrical activity throughout affected brain regions.

Causes of epilepsy

Epilepsy affects approximately 1% of the Australian population and is most common in young children and older adults. In many cases, the cause remains unknown. However, identified causes include:

• Brain tumours
• Improperly formed blood vessels
• Serious head injuries
• Stroke
• Brain infections
• Alzheimer's disease
• Loss of oxygen at birth
• Hardening of the arteries
• Genetic factors

Some mild forms appearing in childhood may resolve before adulthood without treatment.

Types and symptoms of seizures

Various epilepsy syndromes exist, including Rett syndrome, Rasmussen's syndrome and juvenile absence epilepsy. Seizures fall into three main categories based on how much of the brain is affected:

Generalised onset seizures

These affect both brain hemispheres simultaneously. Symptoms include:

• Sustained rhythmic jerking movements
• Muscles becoming weak, limp, tense or rigid
• Repeated body flexing and extending
• Staring and making noises
• Falling down
• Loss of consciousness
• Confusion and tiredness upon regaining consciousness
• Breathing cessation
• Loss of bladder control
• Tongue biting

Focal onset seizures

These begin in one specific brain area on one side and affect particular body parts depending on seizure location. Symptoms include:

• Jerky or rhythmic movements
• Tense or rigid muscles
• Brief muscle twitching
• Lack of movement
• Repeated automatic movements (clapping, running, chewing)
• Tingling and dizziness
• Staring and confusion
• Changes in emotions
• Altered sensations

Unknown onset seizures

These occur when the beginning is not observed and may later be reclassified as generalised or focal.

Risks associated with epilepsy

Whilst seizures themselves rarely cause death directly, they present several serious risks.

From a psychosocial perspective, epilepsy can strain relationships and limit work and recreational activities. The stigma and discrimination surrounding epilepsy often concern individuals more than the seizures themselves.

Diagnosis

Epilepsy diagnosis involves several approaches:

Electroencephalograph (EEG)

An EEG detects, amplifies and records the brain's electrical activity. Electrodes placed on the scalp can identify unusual spikes or waves in brain activity patterns, aiding diagnosis based on epilepsy type.

Brain imaging

MRI (magnetic resonance imaging) and CT (computerised tomography) scans can identify affected brain locations and detect scar tissue, tumours or other structural abnormalities causing seizures.

Treatment options

Treatment is tailored to the type, frequency and severity of seizures, along with the individual's age, health and medical history.

Medication

For most people with epilepsy, anti-seizure medication can reduce seizure frequency or prevent them entirely. Some individuals may never experience another seizure. Finding the most effective medication may require trialling different options. People can also learn to identify and avoid personal seizure triggers.

Surgical interventions

When medication proves ineffective, several surgical options exist:

Vagus nerve stimulation

This involves implanting a device under the chest skin that sends regular, mild electrical impulses to the brain via the vagus nerve in the neck. A pulse generator connects to the vagus nerve through thin wires. The device automatically delivers programmed stimulation at specific intervals (e.g., 30 seconds on, 3 minutes off).

Other surgical implants

Deep brain stimulation and responsive neurostimulation work similarly, detecting seizure activity and delivering electrical stimulation to prevent or stop it.

Tissue removal

For severe cases where seizures consistently originate in one brain area, that specific region may be surgically removed to prevent the spread of abnormal electrical activity. This approach is only viable when the affected area is not involved in critical functions like speech, movement, memory or vision. Structural abnormalities such as tumours or abnormal blood vessel clusters can also be removed surgically.

Advanced techniques include MRI-guided laser ablation or radiation, which can remove tissue (such as scar tissue) without opening the skull. In extreme cases, the corpus callosum connecting the brain's hemispheres, or even an entire hemisphere, may be removed.

Emerging epilepsy research

Current and emerging research aims to improve outcomes for people with epilepsy. Exciting developments include:

• New drug formulations
• Wearable or implantable technology to detect seizures or falls
• Advances in vagus nerve stimulation, laser ablation, EEG, MRI and ultrasound
• Implantable cooling devices
• Better understanding of ketogenic diets, gene therapy and cannabinoids
• Improved diagnostic tests, fall safety equipment and seizure prediction algorithms

Chronic traumatic encephalopathy (CTE)

History and definition

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease linked to repeated head impacts. It was first identified in 1928 by Dr Harrison Martland as "punch drunk syndrome" through a small case study of boxers. These athletes experienced various cognitive impairments and developed a severe, progressive syndrome including Parkinson's disease and dementia.

As more cases emerged, the condition acquired various names, including "traumatic progressive encephalopathy" and "dementia pugilistica". From the 1940s onwards, "chronic traumatic encephalopathy" became the accepted term, acknowledging that the condition arises not only from boxing but from various sources involving brain trauma.

Physiological basis of CTE

As a neurodegenerative disease, CTE causes gradual, progressive and widespread brain damage. The key pathological feature involves the accumulation of tau protein within neurons and other brain cells.

The accumulated tau disrupts important cellular processes that keep cells alive and healthy, and interferes with communication between adjacent neurons. This compromises brain tissue integrity and begins killing neurons and other cells, resulting in widespread atrophy of many brain regions and reduced brain volume.

CTE is often mistaken for Alzheimer's disease because both conditions involve tau protein accumulation. The brain changes in CTE and Alzheimer's disease are physically similar, as shown in the comparison of brain tissue cross-sections above.

Causes and risk factors

Whilst not every concussion or traumatic brain injury leads to CTE, such head injuries appear necessary to trigger the disease. The precise amount of trauma required remains unknown, but those experiencing increased head impacts face greatest risk. All blows to the head, whether causing concussion or not, likely contribute to disease development.

Symptoms and stages

CTE worsens progressively over many years. Research has identified four main stages, demonstrating declining function as the disease progresses. Early symptoms become more severe over time, and new symptoms emerge. These stages correlate with increasing tau protein pathology and subsequent brain tissue degeneration.

Diagnosis challenges

Currently, no conclusive tests can diagnose CTE in living patients due to a lack of distinct biomarkers or measurable indicators. Clear diagnosis is only possible post-mortem during autopsy.

The repetitive trauma or tau accumulation in CTE may provoke further abnormal protein development, potentially triggering other neurodegenerative diseases.

Treatment and prevention

Treatment limitations

CTE is currently incurable and irreversible. Similar to other neurodegenerative diseases, treatment focuses on managing symptoms with medications and therapies aimed at improving impaired behavioural and cognitive functioning, such as memory, mood and alertness. Lifestyle habits promoting health and wellbeing are encouraged, including good nutrition, physical activity, and mental and social engagement. Like time-sensitive stroke treatment, timely traumatic brain injury treatment could reduce CTE development risk.

Prevention strategies

Prevention remains the most effective approach to combating CTE. Several strategies have been implemented:

Sports rule changes

Modifications to how contact sports are played, including rules for safe tackles and penalties for reckless play, have helped prevent head injuries. Clear processes are needed to track injuries and symptoms over time.

Protective gear considerations

American football helmets protect against skull fractures but may not prevent concussions and CTE. Traumatic brain injury can result from violent brain acceleration and deceleration inside the skull, against which helmets offer no protection.

Emerging CTE research

Given the importance of physical exercise and popularity of contact sports, ongoing CTE research is vital. Much remains to be learned about the disease.

Drug development

Researchers are experimenting with drugs to stop dementia development from repeated head injuries. New drugs may block certain neurotransmitters that cause abnormal tau protein accumulation following head injury. Success in animal models has led to plans for human clinical trials.

Early detection methods

Studies have investigated early detection and quantification of CTE in living patients using neuroimaging techniques. MRI technology advances enable brain volume measurement and white matter abnormality detection associated with CTE. PET (positron emission tomography) neuroimaging may use tracers to bind to and track tau protein. These techniques, alongside genetic testing, may enable early CTE detection.

Diagnostic criteria development

Research aims to develop agreed-upon criteria for diagnosing CTE during life. Consensus is needed regarding necessary features for CTE diagnosis. Proposed criteria require both substantial exposure to repeated head impacts and core clinical features not fully explained by other conditions. Reaching consensus in diagnostic features will help advance research with greater confidence in finding validity and reliability.

Additional research areas

The 2020 case of 29-year-old AFLW player Jacinta Barclay highlighted these needs. Post-mortem analysis revealed cerebral white matter degradation unusual for someone so young and physically healthy, emphasizing the importance of research into younger athletes and gender equity in concussion studies. It also shed light on CTE's detrimental effects on mental wellbeing.

Key science skills: presenting data in tables, charts and graphs

When presenting research data, choosing an appropriate format is essential for others to understand findings. The presentation format depends on the data type, as what works for one type may not suit another. In VCE Psychology, you need to use tables, bar charts and line graphs.

Tables

Use when:

• Data cannot be presented in one to two sentences
• Highlighting important data for quick reference
• Showing precise values is more important than showing trends

Bar charts

Use when:

• Showing trends, patterns and relationships is more important than exact values
• Data has discrete (separate) categories
• Visually comparing several categories quickly
• Data has large differences between categories
• May include grouped or stacked data for subsections

Line graphs

Use when:

• Showing trends, patterns and relationships is more important than exact values
• Data is numerical and continuous
• Tracking small changes over time
• The straight line shows how one data point continues to the next
• Can estimate values between points
• Comparing multiple data sets using multiple lines