Understanding The Sensory Impact Of Strokes

A stroke can cause a variety of physical effects, including weakness, numbness, and pain in the arm and shoulder. Arm weakness is a common symptom, with one arm feeling weak or numb, or drifting downward when trying to raise it. This occurs because a stroke can stop blood flow to different parts of the brain, which affects the ability to lift or control the arm on the opposite side of the body. The effects of a stroke can also lead to arm muscle weakness, tightness, or a lack of feeling in the arm. In addition, a stroke can cause partial shoulder dislocation, a frozen shoulder, and spasticity, which is increased muscle stiffness in the arm.

Weakness and numbness in the arm

A stroke can cause weakness and numbness in the arm. This is because a stroke occurs when there is a blockage or bleed in the brain, which causes brain cells to die due to a lack of oxygen-rich blood. This can result in tissue damage and a loss of important functions in the affected areas of the brain.

If the area of the brain that helps regulate sensation is affected, this may result in numbness or other sensory impairments. The thalamus, parietal lobe, and occipital lobe are key areas of the brain involved in sensory function. The thalamus relays the majority of sensory input in the brain, while the parietal lobe houses the somatosensory cortex and processes sensory information from the nerves. The occipital lobe differentiates input from the five senses, including touch. Therefore, numbness is commonly seen after a stroke in these areas of the brain.

However, a stroke can cause numbness even if it does not impact these specific areas. Additionally, the brain may misinterpret sensory signals after a stroke, leading to hypersensitivity and other abnormal sensory responses.

The effects of a stroke on the arms can include paralysis, weakness, or tightness in the muscles. You may also experience numbness or limited feeling in your arm. The shoulder joint is particularly vulnerable to problems after a stroke, as the weight of the arm can cause a partial dislocation, leading to pain and reduced range of motion.

If you are experiencing weakness and numbness in your arm, it is important to seek medical attention, as these could be signs of a stroke or other serious medical conditions.

Shoulder pain

A stroke can cause shoulder pain, which is the most common source of pain for stroke survivors, with up to 84% of survivors developing shoulder pain. Shoulder pain can be caused by a partial dislocation of the shoulder joint, known as shoulder subluxation, which is caused by weak rotator cuff muscles. This can lead to the arm being pulled down and away from the shoulder blade due to gravity. Slumped posture caused by weak back muscles can also contribute to shoulder subluxation.

• Physical therapy: Constraint-induced movement therapy, mental practice with motor imagery, and task-specific training can help improve arm function and strength, reducing the risk of shoulder subluxation.
• Slings and other support devices: Shoulder slings can reduce subluxation and promote the use of the arm during recovery. It is important to work with a physical therapist to choose the appropriate sling and learn how to wear it correctly.
• Electrical stimulation: Transcutaneous electrical nerve stimulation or functional electrical stimulation can be used to treat shoulder pain.
• Steroid injections: Intra-articular steroid injections may be used in resistant cases.
• Analgesics: Treatment for shoulder pain should initially include simple analgesics.
• Botulinum toxin injections: These injections can help relax the muscles and prevent injury.

It is important to work with a healthcare team, including a physiotherapist and occupational therapist, to develop a treatment plan that addresses shoulder pain and promotes recovery.

Muscle weakness and fatigue

Muscle weakness is often experienced on one side of the body, affecting the arms, legs, hands, and feet. The specific muscles affected depend on which part of the brain is impacted by the stroke. For example, if the blood flow to the left side of the brain is interrupted, the person may have difficulty lifting or controlling their right arm. This is because the left side of the brain controls movement on the right side of the body, and vice versa.

The severity of muscle weakness can vary, with some people experiencing partial paralysis or numbness in the affected limbs. In some cases, the muscles may feel tight and spastic, while in others, the muscles may become limp and heavy. Over time, the muscles may shorten and become very tight, making movement more difficult. This is known as spasticity and can lead to further complications such as joint instability and reduced range of motion.

Fatigue, or extreme tiredness, is also a common symptom following a stroke. It can be a result of the physical and mental exertion required to perform everyday tasks, as well as the energy needed for the brain to heal and recover. Additionally, the emotional and psychological impact of adjusting to life after a stroke can contribute to fatigue.

Rehabilitation and support are crucial for managing muscle weakness and fatigue after a stroke. Physical therapy, occupational therapy, and assistive devices can help improve muscle strength, endurance, and range of motion. It is important to work with a healthcare team to develop a treatment plan that addresses individual needs and goals. Recovery is typically fastest in the first few months after a stroke, but improvements can continue to be made for months or even years.

Paralysis

The effects of a stroke on the arm and shoulder are well-documented. Many people lose the use of their arm and hand, with muscle weakness, tightness, or a lack of feeling in the arm. The shoulder is a key problem area, as the weight of the arm can cause the shoulder joint to partially dislocate, leading to pain and reduced range of motion.

To prevent further damage and promote recovery, proper arm care is essential after a stroke. This includes positioning the arm correctly, using support devices like a sling or brace, and preventing further injury. Rehabilitation for the arm and shoulder should begin as soon as possible after a stroke, ideally within 24 to 48 hours, and should include stretching and strengthening exercises to improve range of motion and rebuild strength.

There are various rehabilitation methods to help regain arm movement after a stroke, including active and passive arm exercises, constraint-induced movement therapy, electrical stimulation, bilateral training, and weight-bearing exercises. These methods aim to stimulate the brain and encourage neuroplasticity, which is the brain's ability to rewire itself and learn new skills.

While some people regain full use of their arm within a few weeks, others experience chronic pain and weakness, requiring months of physical therapy and ongoing rehabilitation.

Problems with balance

Balance is a complex function that requires coordination between the legs, feet, core, and even the arms. A stroke can change the way the brain controls balance, and you may feel unsteady or uncoordinated. Balance problems can also be caused by other underlying conditions, and treating these conditions can help improve your balance.

Causes of balance problems

Many areas of the brain are involved in balance, and a stroke can damage these areas, resulting in impaired balance. The brain can be divided into left and right hemispheres, and strokes usually affect one hemisphere while leaving the other side undamaged. Damage to only one side of the brain results in motor difficulties on the opposite side of the body, such as paralysis or weakness. Since balance requires coordination from both sides of the body, survivors with these conditions often experience impaired balance.

In addition to motor functions, the sensory systems also play a vital role in maintaining balance. Changes in a person's vision, sensation, vestibular system (sense of head motion and spatial orientation), or proprioception (sense of where the body is positioned in space) after a stroke can all impact one's balance.

Rehabilitation for balance problems

Rehabilitation is vital to regaining balance after a stroke. The brain can be adaptively rewired through neuroplasticity, allowing healthy brain tissue to take over functions controlled by damaged areas. This process is activated through repetitive practice, strengthening the neural pathways in the brain and improving task performance.

There are several effective interventions to help survivors regain balance, including:

• Consistent rehabilitative exercise to improve strength and coordination in the legs and core muscles.
• Addressing foot drop, a common cause of balance challenges after a stroke, with a brace called an ankle-foot orthotic.
• Aquatic therapy, which involves practicing rehabilitative exercises in a warm pool, can reduce muscle pain and tension and improve strength.
• Virtual reality training programs can be motivating for survivors and provide detailed feedback on performance.
• Yoga can help with balance and also promote relaxation and mindfulness while reducing stress and anxiety.

Practical considerations

The first 3 to 6 months after a stroke are the most vital for recovery, as the brain enters a state of heightened plasticity, allowing adaptive changes to occur more easily. By 6 months post-stroke, between 65% and 85% of survivors regain the ability to walk independently, and most would have significantly improved their balance.

During recovery, many stroke survivors with impaired balance may need to use a cane or walker. While this may be frustrating, these tools can improve safety and independence. It is important to work closely with a rehabilitation team, which may include nurses, physical therapists, and occupational therapists, to develop a specific plan for recovery.

Frequently asked questions