What is a Transient Ischemic Attack?

Jul 27

A stroke occurs when a blood vessel in the brain is either blocked (ischemic stroke) or ruptured (hemorrhagic stroke). Both of these will cause the parts of the brain that rely on blood from that vessel to become damaged or die. Strokes can be disabling, and lead to considerable neurological dysfunction.

A Transient Ischemic Attack, or TIA, is the third type of stroke, often considered a “mini-stroke.” TIAs are often the result of blood clots, however blood flow is only disrupted for a short period, usually 5 minutes or less. TIA symptoms look just like strokes, and need to be treated similarly as medical emergencies. They are known to be warning signs of future strokes, and up to 15% of people have a major stroke within 3 months of a TIA (3).

How Common Are Transient Ischemic Attacks?

Roughly 800,000 people suffer from strokes every year in the United States. About 1 in 3 people who suffer TIAs will eventually have a stroke (2).

What are the Symptoms of a Transient Ischemic Attack?

According to the American Stroke Association, when any of the symptoms in the mnemonic FAST become suddenly present, a stroke needs to be suspected and treated as a medical emergency.

FAST stands for:

Face Drooping: this can become obvious when a person is asked to smile
Arm Weakness: ask the person to raise both arms, see if one drifts downward
Speech: does speech become slurred, are they hard to understand, or unable to speak?
Time to call 911: If any of these symptoms present, even if they go away, call 911 and get them to the hospital immediately.

Some additional symptoms of stroke:

Sudden numbness: sudden numbness or weakness of the face, arm, or leg, especially on one side of the body
Sudden confusion: sudden confusion, trouble speaking, or trouble understanding speech
Sudden trouble seeing: sudden difficulty seeing with one or both eyes, or in one field of vision
Sudden trouble walking: sudden difficulty with balance, gait, dizziness, or coordination
Sudden severe headache: Sudden onset severe head pain with no evident cause

Any of these symptoms should also be considered a medical emergency, and 911 should be called (1).

What are the Risk Factors for Transient Ischemic Attack?

Strokes and TIAs share the same risk factors. High blood pressure is a major risk factor for TIA and stroke. Hypertension increases the likelihood that a clot or plaque fragment will become dislodged from a blood vessel wall and be shot up into the brain. Anything that increases blood pressure increases the risk for TIA and stroke. Factors such as obesity, lack of exercise, poor diet, smoking, and excessive alcohol intake can all increase the risk of TIA and stroke. Strokes are more common in men, and African American and Hispanic men have specifically elevated levels of TIA and stroke risk (19).

What Happens in the Brain During a Transient Ischemic Attack?

The brain is composed of many cell types. The ones we usually think of as brain cells are called neurons, which are the primary functional units of the brain. In order to survive, all neurons need a constant supply of blood to provide oxygen and glucose.

This blood supply is disrupted during a TIA, although symptoms usually last less than 1 hour but cause a brief episode of neurological dysfunction (4). This can nevertheless lead to an ischemic cascade, where energy production within neurons that depends on the availability of oxygen starts to fail. This leads to a sudden release of glutamate, a neurotransmitter chemical that causes neurons to fire faster than their metabolic machinery can sustain. The result of this process is the production of many damaging free radicals, calcium rushing in and triggering the breakdown of proteins in the neuron, and ultimately death of the neuron (20).

Blood vessel walls can also break down from the release of cellular enzymes that destroy connective tissue. This can lead to breakdown of the blood-brain barrier and cerebral swelling, which can create secondary brain injuries (4).

How are Transient Ischemic Attacks Usually Diagnosed?

A physical examination can reveal signs associated with a TIA, such as disturbances in gait, problems with speech, and so on. Advanced imaging techniques such as MRI and CT are useful to identify the region of damage and blood vessel involved. MRI is more useful for TIA because it can identify new and old TIAs (4). Laboratory tests to evaluate for vascular inflammation and levels of cholesterol are commonly employed as well.

How are Transient Ischemic Attacks Usually Treated?

In an acute stroke, various neurosurgical interventions may be necessary to break down the clot, stabilize the blood vessel, and remove pressure on the surrounding brain tissue. Usually by the time a TIA is diagnosed, this clot is no longer present. Treatment goals shift towards reducing the risk that another TIA can occur. Medications to lower clotting risk, decrease blood pressure, and prevent cholesterol plaquing are commonly used to prevent future strokes (21).

The residual motor, cognitive, and neurologic problems from stroke are usually addressed by physical, occupational, and speech therapy. While these are undoubtedly helpful, as recovery slows most therapy programs shift focus toward teaching the individual to compensate for their impaired function, rather than attempting to restore the functions and capacities that have been lost.

How is the NeuroRescue Program Different?

One of the fundamental problems seen in both TIA with residual neurological dysfunction and stroke is what is called a diaschisis. Neurons need 3 main things to survive: glucose, oxygen, and activation. Neurons need to be continuously stimulated in order for them to continue replicating all of the protein and cellular components they need to survive and keep firing efficiently. When someone suffers a stroke, neurons that are supplied by the involved blood vessel are deprived of glucose and oxygen. Unfortunately, most of these will die off unless blood flow is rapidly restored.

There is nothing that we or anyone else can do to bring back the neurons that have been lost. However, the dead neurons are usually not entirely responsible for the symptoms seen after a TIA or stroke.

This is because of the diaschisis phenomenon. Each neuron receives activation signals from an average of 10,000 other neurons. This input will either excite or inhibit the neuron, but either way, the presence of this activation causes it to keep replicating protein and stay healthy. If the neuron is outside of the vascular distribution of a TIA or stroke, it may still be affected if enough of the neurons that activate it are lost. When neurons die in a vascular event of any kind, the neurons that they stimulate, even though they have a different blood supply and are not directly affected by the disrupted blood flow, will undergo diaschisis and start to break down. They will lose endurance, will not be able to sustain high rates of firing, and will tend to fatigue and fail. This will be the case even though they still have a normal supply of glucose and oxygen.

If these remaining fragile neurons affected by diaschisis are not properly activated, they will ultimately die off. If they are overstimulated and caused to fire at a rate that they cannot withstand, they will also be lost (22).

However, if another neuron or pathway that supplies input to the fragile cells can be found, and these can be stimulated to activate the damaged neurons at a rate that they can withstand, they can be used to rebuild the function in the injured cells.

This is exactly the basis of all of our NeuroRescue stroke rehabilitation therapies. We use cutting edge neurodiagnostic technologies and examination procedures to not only identify what areas of your system are damaged, but also what systems are still present but impacted by diaschisis. We identify pathways that we can harness to rebuild the function of the fragile systems. We determine the exact frequency and intensity of stimulation of these pathways that leads to positive plastic changes without overstimulation. We then employ several of a vast array of therapies, chosen specifically for the unique needs of your system, to maximize your functional recovery.

Our therapies are constantly evolving, and are on the cutting edge of neurorehabilitation. Everything we do for rehabilitation is supported by the latest neuroscience research.

We use a wide array of neurostimulation strategies in restoring function after a TIA or stroke. Electrical therapies can be harnessed to stimulate neurons in the brain through the peripheral nervous system. There are many different kinds of currents and applications that we employ, but these are collectively known as repetitive peripheral sensory stimulation. RPSS has been demonstrated to be effective in restoring function in patients suffering from vascular injuries (5).

Photobiomodulation is another form of neurostimulation, using low level laser and LED light frequencies to help rebuild endurance and metabolic function in neurons after vascular injuries. We use several different types of laser and LED systems for TIA and stroke rehabilitation. Research shows that these can be very helpful to improve function in vascular injuries (6,7).

Hyperbaric oxygen therapy can prove useful in cases of TIA and stroke. Cells that have been deprived of oxygen for a time but not lost have been shown to improve in function when patients receive hyperbaric (above normal atmospheric pressure) oxygen treatment. Hyperbaric therapy can be an important adjunct to our therapies, and allows us to rehabilitate patients faster and more effectively without fatigue (8).

We regularly use transcranial magnetic stimulation (or TMS), which is an extremely effective form of neurostimulation in the treatment of TIAs and vascular injuries. TMS uses an MRI-strength magnet to apply a focused beam of electromagnetic energy through the skull and directly to the injured areas of the brain. This treatment is safe, comfortable, with minimal rare side effects. More importantly, it is extremely effective for helping people manage chronic pain and restore motor function after vascular injuries (9,10). We have such great success with our TMS treatment that we installed our second TMS unit this year.

It is extremely common that people can develop balance difficulties after suffering a vascular injury. This greatly increases the risk of injury from falls, including further traumatic brain injuries. We go to great lengths to ensure that all of our patients have their fall risk reduced through precise vestibular therapy, which is part of every NeuroRescue program. Vestibular therapy has been shown to be very effective to improve balance after a vascular injury (11).

Vision can often become impaired after suffering a TIA or stroke. It is common for people to develop difficulty visually mapping their world, holding their eyes still on targets, following moving objects, and processing complicated visual environments. In many cases, an entire visual field can be lost through damage to visual pathways. We use several types of visual exercises and rehabilitation to help resolve these difficulties, tailored to the unique needs of the patient. The effectiveness of visual therapies has solid support in neuroscience literature (12).

Specific types of eye movement exercises have been shown to be helpful in not only restoring visual function, but also in restoration of cognitive and executive function. Specific eye movement therapies have been shown help with cognitive retraining (13), and have demonstrated significant improvement in brainwaves and reduction in symptom scales after vascular injuries (14).

We also use a number of unique therapies to help your brain remap your body and restore movement patterns after strokes. Sometimes the best way to restore movement in a paretic limb after a stroke is to constrain the movement of the opposite limb while engaging in high intensity motor retraining exercises. Movement constraint therapy can be very helpful to restore motor function over time (15). Using different visual representations of the impaired limb by mirroring the good limb while engaging in movement exercises can be very helpful as well (16). Mirror therapy is particularly helpful when employed in a virtual reality environment (17), and we regularly see rapid changes in motor function when using our Virtualis VR system. And physical exercises and soft tissue rehabilitation techniques can be helpful once central neurological function has been addressed. In particular, joint manipulation can often lead to significant improvement in motor function after stroke (18). We find these same therapies to be effective in resolving any residual neurological dysfunction that may be present following a TIA.

How Does the NeuroRescue Program Work?

We design your unique NeuroRescue Program to be among the most comprehensive diagnostic and therapeutic protocols available today. We create individual NeuroRescue Programs based on a comprehensive analysis of every relevant neurological system and pathway, using gold-standard, cutting edge neurodiagnostic technologies and examination procedures and state-of-the-art therapies.

We begin with your Discovery Day, wherein we perform a comprehensive history of not only your condition, but also of your life on a timeline. This allows us to dive deeply into your case and see all of the factors that led to where you are now. It helps us uncover hidden problems and associated conditions that may be making it difficult for you to move your recovery forward.

Our examination allows us to identify the areas and pathways of your brain that have been directly and indirectly affected by your TIA. We do this by precisely quantifying the function of your visual, vestibular, and proprioceptive systems through computerized analysis of your eye movements, your inner ear reflexes, and your balance in a host of different sensory conditions. We also assess risk factors for future events.

We employ technologies including Videooculography and Saccadometry to measure several classes of eye movements. We use Video Head Impulse Testing to measure the function of your inner ear, and Computerized Dynamic Posturography to assess your balance in different sensory conditions.

We use NeuroSensoryMotor Integration testing to evaluate hand-eye coordination and cognition, and Virtualis testing to assess dynamic eye tracking and perception of vertical in a virtual reality environment.

We combine all of this with a comprehensive physical and neurological examination of your sensory, motor, autonomic, and cognitive systems. We review any relevant laboratory testing, radiological imaging, and prior neurodiagnostic testing, and integrate that information with our findings.

We use this information to identify which parts of your nervous system are working properly, which systems are struggling, and the precise point at which your systems fatigue.

We can then design a NeuroRescue Program that is unique and specific to your brain, and yours alone. Your NeuroRescue Program works to rejuvenate and reintegrate the damaged neurons and pathways in your central nervous system. It works to improve energy, endurance, and functional capacity within your involved fragile systems.

We use our technologies and procedures to not only see what we need to address, but also when it is time to stop and let you rest. We address your impaired neurological function from multiple angles of therapy, and provide metabolic support to improve neurological recovery.

While we cannot bring back neurons that have been lost, your NeuroRescue Program allows us to take the pathways that remain and maximize their efficiency and endurance. And by focusing on the integration of systems, we can do more than just get pathways working better, we can get them working together again. This gives us our best opportunity to return you to living a healthy, vibrant, and fulfilling life.

Your Next Best Step:

Living with transient ischemic attacks can be challenging, but there is hope for recovery and remission. To see if the NeuroRescue Program is right for you, contact one of our patient care coordinators to schedule your Discovery Day.

And remember, it’s never too late to start getting better.