Wondering what to expect after an internal capsule stroke?
An internal capsule stroke affects the tiny blood vessels deep within the brain.
Many motor, sensory, and cognitive fibers run through the internal capsule as they travel between the cerebral cortex (the outer layer of the brain) and the brainstem (the lower area of the brain that connects to the spinal cord).
Because so many important fibers pass through the internal capsule, even a small stroke in this area can result in a significant loss of motor control or sensation.
To help you better understand the effects of an internal capsule stroke, this article will explain which functions are affected in various regions of the internal capsule.
Anatomy of the Internal Capsule
Each side of your brain has an internal capsule. Damage to the left internal capsule will affect movement and sensation on the right side of your body, and damage to the right internal capsule will affect the left side of your body.
The internal capsule is a V-shaped structure that consists of 5 regions:
- Anterior Limb (the upper portion)
- Genu (the center portion where there’s a bend)
- Posterior Limb (the bottom portion)
- Retrolentiform segment (area behind part of the basal ganglia)
- Sublentiform segment (area below part of the basal ganglia)
Different fibers run through each region of the internal capsule. Depending on the location of your internal capsule stroke, you can expect different outcomes.
Secondary Effects of Internal Capsule Stroke
A stroke occurs when a blood vessel in the brain gets blocked (ischemic stroke) or bursts (hemorrhagic stroke).
The blood vessels in the internal capsule are very small, which increases the likelihood of a blood clot getting stuck, causing a stroke.
Blood is rich in oxygen and other essential nutrients that fuel brain activity. When blood supply is cut off, brain cells start to die, which can cause sensory, motor, and cognitive problems.
Secondary effects you may experience after an internal capsule stroke include:
1. Pure Motor Stroke
The fibers that pass through the posterior limb affect movement and coordination.
Because these fibers are grouped so closely together, internal capsule stroke survivors often experience pure motor stroke.
Pure motor stroke is when the effects of the stroke are strictly related to movement. In other words, there is weakness or paralysis in the face, upper and/or lower limb, but no other symptoms are present such as cognitive, language, or sensory deficits.
This is the most common secondary effect of internal capsule strokes.
2. Facial Weakness
The muscles of the face and neck are innervated by the corticobulbar tract fibers of the genu.
Damage to this area of the internal capsule can make it difficult to communicate and eat because it affects functions like speaking, chewing, and swallowing.
3. Cognitive Impairments
The fibers that run through the anterior limb of the internal capsule affect cognitive functions such as:
- the processing of emotions
- decision making
Internal capsule stroke survivors with anterior limb damage will likely experience cognitive fatigue (mental exhaustion) because the brain has to work harder to concentrate.
This can result in behavioral changes like increased agitation and confusion.
4. Sensory Loss
Somatosensory fibers run through both the genu and posterior limb.
Therefore, damage to either one of these areas of the internal capsule can result in loss of sensation on the opposite side of the body.
Generally, loss of sensation occurs in the face, arm, and leg equally because the fibers for these areas of the body are arranged closely together.
Sensory impairments are often reported in the form of heaviness, numbness, or loss of feeling.
5. Hearing Impairments
Auditory fibers run through the sublenticular segment of the internal capsule.
These auditory fibers are called auditory radiations, and they connect auditory signals from the thalamus to the auditory cortex.
A stroke in this area of the internal capsule can result in hearing deficits.
6. Visual Impairments
Damage to the retrolenticular segment of the internal capsule affects the optic radiation fibers.
Individuals often experience visual impairments like hemianopia (losing half your visual field) and quadrantanopia (losing a quarter of your visual field).
Rehabilitation After Internal Capsule Stroke
Rehabilitation after internal capsule stroke requires an individualized approach and will depend on what kind of secondary effects you experience.
Although every stroke is unique, recovery from any type of stroke ultimately relies on neuroplasticity.
Neuroplasticity is the brain’s ability to rewire itself so that functions affected by stroke can be recovered through massed practice.
The more you stimulate the brain, the more rewiring occurs, and the more efficient functions become.
Common rehabilitation therapies for internal capsule stroke include:
- Physical Therapy. Physical therapy will help individuals recover motor functions through exercise. Frequent and repetitive muscle activation is necessary to stimulate connections between the brain and muscles.
- Speech Therapy. If internal capsule stroke has left you with facial weakness, speech therapy can help. A speech-language pathologist will help guide you through exercises specifically designed to strengthen the muscles around the mouth so that you can chew, swallow, and speak more effectively.
- Occupational Therapy. Some of the effects of an internal capsule stroke could make it difficult to engage in your typical daily tasks, such as dressing, bathing, and toileting. If this is the case, occupational therapy can help you to regain some of your independence, and can also focus on strengthening your upper extremity and improving coordination skills.
- Sensory Reeducation. To restore sensation, stroke survivors should work on sensory reeducation exercises. They help stimulate the brain to promote the rewiring of sensory processing for properties like texture and temperature. This may be part of your occupational therapy treatment as well, if necessary.
- Visual Restoration Therapy. If you’re experiencing visual field cuts after internal capsule stroke, consider visual restoration therapy. It involves using light to stimulate the boundary between visible and blind spots in your vision.
Whether you’re trying to relearn how to control your movements or recover sensation, it’s all about stimulating the brain through repetitions.
Understanding Internal Capsule Stroke
Because the blood vessels in the internal capsule are so small, they are susceptible to getting blocked, which can cause a stroke.
Depending on the location of the damage, an internal capsule stroke can affect various motor, sensory, and cognitive functions.
Thanks to neuroplasticity, any function affected by internal capsule stroke can potentially be recovered through massed practice.
The brain is always adapting based on your actions, so trust in the process and keep practicing. Good luck!