Posts Tagged cortical plasticity

[Abstract] Tele-Rehabilitation after Stroke: An Updated Systematic Review of the Literature

Abstract

BACKGROUND:

Tele-rehabilitation for stroke survivors has emerged as a promising intervention for remotely supervised administration of physical, occupational, speech, and other forms of therapies aimed at improving motor, cognitive, and neuropsychiatric deficits from stroke.

OBJECTIVE:

We aimed to provide an updated systematic review on the efficacy of tele-rehabilitation interventions for recovery from motor, higher cortical dysfunction, and poststroke depression among stroke survivors.

METHODS:

We searched PubMed and Cochrane library from January 1, 1980 to July 15, 2017 using the following keywords: “Telerehabilitation stroke,” “Mobile health rehabilitation,” “Telemedicine stroke rehabilitation,” and “Telerehabilitation.” Our inclusion criteria were randomized controlled trials, pilot trials, or feasibility trials that included an intervention group that received any tele-rehabilitation therapy for stroke survivors compared with a control group on usual or standard of care.

RESULTS:

This search yielded 49 abstracts. By consensus between 2 investigators, 22 publications met the criteria for inclusion and further review. Tele-rehabilitation interventions focused on motor recovery (n = 18), depression, or caregiver strain (n = 2) and higher cortical dysfunction (n = 2). Overall, tele-rehabilitation interventions were associated with significant improvements in recovery from motor deficits, higher cortical dysfunction, and depression in the intervention groups in all studies assessed, but significant differences between intervention versus control groups were reported in 8 of 22 studies in favor of tele-rehabilitation group while the remaining studies reported nonsignificant differences.

CONCLUSION:

This updated systematic review provides evidence to suggest that tele-rehabilitation interventions have either better or equal salutary effects on motor, higher cortical, and mood disorders compared with conventional face-to-face therapy.

 

via Tele-Rehabilitation after Stroke: An Updated Systematic Review of the Literature. – PubMed – NCBI

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[BLOG] The Importance of Cortical Plasticity in Stroke Rehabilitation – Saebo

the-importance-of-cortical-plasticity-in-stroke-rehabilitation-blog

Those who have survived a stroke may experience neurological damage that leads to deficiencies in their sensory and motor systems, such as limited use in their hands and/or arms. This damage also affects the sensory communication to the brain and impairs the ability to touch, feel, or be aware of joint movement. The combination of motor and sensory impairments significantly impacts stroke patients’ capacity to perform daily activities.

The Motor Cortex

Located in the frontal lobe of the brain is the area known as the motor cortex. There are three areas that comprise this important part of the cerebellum: the primary motor cortex, the premotor cortex, and the supplementary motor area. The motor cortex controls the higher levels of movement, such as voluntary action. When the neurons experience electrical stimulation in this part of the brain, associated body parts move. It is a complex process that involves making decisions and coordinating movements appropriately to perform an intended action.

How Strokes Affect the Motor Cortex

Human body with a head ache of the brain with a migrain and stroke accident caused by poor circulation representing neurology with heart blood health problems.

When the motor cortex becomes damaged from head injuries, including strokes or other accidents, it affects the ability of the brain to control the body’s movement.

The brain is divided into two halves, the right and the left hemispheres. Each hemisphere controls the voluntary movement of the half of the body opposite it, which is known as crossed control (e.g., the right half of the brain controls the left side of the body). Because of this, when one hemisphere of the brain experiences damage, the movement of the opposite side of the body is affected. When the damage is severe enough to completely destroy the system, paralysis occurs.

Any damage impacts a person’s ability to control movement. For example, when a patient whose motor cortex is injured from a stroke tries to hold an object, the communication between the brain and rest of the body is delayed. This might cause the patient to have unsteady hands, stop prior to the target, move past it, or simply move too late.

Physical Conditions Resulting From Stroke

Common physical conditions after a stroke include:

  • Weakness, paralysis, and problems with balance or coordination
  • Pain, numbness, or burning and tingling sensations
  • Fatigue
  • Inattention to one side of the body, also known as neglect. In extreme cases, the patient may not be aware of their arm or leg
  • Urinary or bowel incontinence
  • Speech problems or difficulty understanding speech, reading, or writing
  • Difficulty swallowing
  • Memory problems, poor attention span, or difficulty solving problems
  • Visual problems
  • Depression, anxiety, or mood swings with emotional outbursts
  • Difficulty recognizing limitations caused by the stroke

How the Motor Cortex is Repaired

How the motor cortex is repaired

Damage to the brain does not have to be permanent; the brain has the capability to repair itself thanks to cortical plasticity (neuroplasticity). Upon experiencing damage or injury, the brain builds new neural connections using cues from the environment and individual experiences.

Neuroplasticity and Neurorehabilitation

A certain amount of neuroplasticity occurs throughout a person’s life, as it is part of learning to respond to a particular activity or behavior. This can be seen in brain scans  when a person learns a new motor skill and corresponding regions in larger cortical territories light up.

Neurorehabilitation has been shown to support the brain’s efforts to rebuild and reprogram itself. It requires task-orientated arm training and extensive practice to re-teach the brain. The surrounding tissue that remains healthy takes over some of the work of the damaged tissue. By conducting task training, this healthy tissue is stimulated, which facilitates the building of new connections between the healthy, intact neurons.

For these changes to occur in the motor cortex, it is important to conduct skill-dependent activities rather than use-dependent. For an activity to be considered skill-dependent, it requires a challenge rather than simple repetition. Training using tasks that require problem solving, or some other meaningful challenge, has greater success. Neural remodeling might occur anytime during the weeks to months after an injury, based on the experiences of an individual.

How Quickly Do Changes in the Motor Cortex Begin?

The old saying, “if you don’t use it, you lose it,” is very apt for the motor cortex. Upon immobilization of a limb, there is a window of just nine days before the potential for recovery decreases. After not using the affected limb, the tissue around the cortical lesion or other damage in the brain starts to experience problems, which leads to further loss of function.

Thus, the sooner a patient begins therapy, the better. Starting a program with occupational therapists that stimulates and retrains the limb as soon as five days after the injury has the potential to minimize cortical loss and enhance the brain’s reorganizing capabilities. The brain constantly conducts neuroplastic changes through a variety of mechanisms, such as motor learning and peripheral deafferentation. Most likely, this plasticity leads to spontaneous recovery. However, it is best to stimulate reorganization in the damaged hemisphere to increase chances of recovery.

Effective Ways to Retrain Limb Use

Effective Ways to Retrain Limb Use

There are several factors that affect stroke recovery: the amount of brain damage, the location of the damage, and the presence of healthy areas of the brain. Less damage tends to correspond with less disability, which translates to the greatest chance for recovery. And rehabilitation plays an important role in healing.

You will typically be in stage 1 or 2 of stroke recovery right after a stroke.

Treatments for Stage 1 of Stroke Recovery

For stage 1, follow the exercises and treatments laid out here. Treatments include:

  • supporting affected limbs
  • passive range of motion
  • muscle facilitation
  • movement exercises
  • mirror-box therapy
  • mental visualization

Treatments for Stage 2 of Stroke Recovery

For stage 2, follow exercises and treatments laid out here. Treatments include:

Exercises Based on Stroke Severity

It is important to remember that motor cortex deficits will differ depending on how severe the stroke is. For the patient with severe motor, sensory, and functional deficits, ensure that the arm and hand are in the proper position, mobile, and comfortable with no pain. There should be support during rest, and the upper limb should be handled carefully during the activities. Then, practice self range-of-motion exercises. You can use some of the same means of external support for the upper limb from stages 1 or 2.

For patients with moderate impairments who demonstrate high motivation and potential for functional motor gains, it is important to use repetitive, novel tasks that truly challenge the person. This helps to build the necessary neural networks to increase functional ability. Motor-learning training using imagery is very beneficial as well.

Rehabilitation is Key to Recovery

Stroke recovery is possible for many occupational therapists’ patients. Although it ultimately depends on the severity of the brain injury and the area affected, rehabilitation plays a key role in chances of success. Starting as soon as possible is key, since after nine days any repair becomes increasingly difficult. During rehab, a therapist may recommend products such as the SaeboGlove and other items that are made to improve motor functions.


All content provided on this blog is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. If you think you may have a medical emergency, call your doctor or 911 immediately. Reliance on any information provided by the Saebo website is solely at your own risk.

via The Importance of Cortical Plasticity in Stroke Rehabilitation

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[Abstract] The interaction of pulse width and current intensity on the extent of cortical plasticity evoked by vagus nerve stimulation.

Abstract

Background

Repeatedly pairing a tone with a brief burst of vagus nerve stimulation (VNS) results in a reorganization of primary auditory cortex (A1). The plasticity-enhancing and memory-enhancing effects of VNS follow an inverted-U response to stimulation intensity, in which moderate intensity currents yield greater effects than low or high intensity currents. It is not known how other stimulation parameters effect the plasticity-enhancing effects of VNS.

Objective

We sought to investigate the effect of pulse-width and intensity on VNS efficacy. Here, we used the extent of plasticity induced by VNS-tone pairing to assess VNS efficacy.

Methods

Rats were exposed to a 9 kHz tone paired to VNS with varying current intensities and pulse widths. Cortical plasticity was measured as changes in the percent of area of primary auditory cortex responding to a range of sounds in VNS-treated rats relative to naïve rats.

Results

We find that a combination of low current intensity (200 μA) and short pulse duration (100 μs) is insufficient to drive cortical plasticity. Increasing the pulse duration to 500 μs results in a reorganization of receptive fields in A1 auditory cortex. The extent of plasticity engaged under these conditions is less than that driven by conditions previously reported to drive robust plasticity (800 μA with 100 μs wide pulses).

Conclusion

These results suggest that the plasticity-enhancing and memory-enhancing effects of VNS follow an inverted-U response of stimulation current that is influenced by pulse width. Furthermore, shorter pulse widths may offer a clinical advantage when determining optimal stimulation current. These findings may facilitate determination of optimal VNS parameters for clinical application.

via The interaction of pulse width and current intensity on the extent of cortical plasticity evoked by vagus nerve stimulation – Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation

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[WEB SITE] What is Cortical Priming?

The brain consists of two hemispheres each responsible for controlling the opposite side of the body. Normally, each hemisphere inhibits the opposite side to avoid mirror movements (both sides performing same movement simultaneously).

After a stroke, the two hemispheres experience an unbalancing of both sides with the unaffected hemisphere receiving more signals than the affected hemisphere. This imbalance leads to increased excitability and decreased inhibition to the healthy side. 

Priming is a technique used to enhance the brain’s ability to re-balance the two hemispheres following a stroke. Priming interventions include invasive and non-invasive techniques and can be administered prior to or during recovery. 

Stimulate Recovery. 

Sensory electrical stimulation using the SaeboStim Micro is an example of a safe, non-invasive technique used to improve cortical excitability of the affected side of the brain. By priming the brain with the SaeboStim Micro, prior to or during functional training, cortical plasticity and rebalancing of the hemispheres may lead to better functional outcomes.

Source: What is Cortical Priming?

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[Abstract] Plasticity and Reorganization in the Rehabilitation of Stroke. The Constraint-Induced Movement Therapy (CIMT) Example

Source: Plasticity and Reorganization in the Rehabilitation of Stroke: Plasticity and Reorganization in the Rehabilitation of Stroke: Zeitschrift für Psychologie: Vol 224, No 2

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[REVIEW] The impact of electrical stimulation techniques on behavior – Full Text HTML

Abstract

Low-intensity transcranial electrical stimulation (tES) methods are a group of noninvasive brain stimulation techniques, whereby currents are applied with intensities typically ranging between 1 and 2 mA, through the human scalp. These techniques have been shown to induce changes in cortical excitability and activity during and after the stimulation in a reversible manner. They include transcranial direct current simulation (tDCS), transcranial alternating current simulation (tACS), and transcranial random noise stimulation (tRNS).

Currently, an increasing number of studies have been published regarding the effects of tES on cognitive performance and behavior. Processes of learning and increases in cognitive performance are accompanied by changes in cortical plasticity. tES can impact upon these processes and is able to affect task execution. Many studies have been based on the accepted idea that by increasing cortical excitability (e.g., by applying anodal tDCS) or coherence of oscillatory activity (e.g., by applying tACS) an increase in performance should be detected; however, a number of studies now suggest that the basic knowledge of the mechanisms of action is insufficient to predict the outcome of applied stimulation on the execution of a cognitive or behavioral task, and so far no standard paradigms for increasing cortical plasticity changes during learning or cognitive tasks have been established.

The aim of this review is to summarize recent findings with regard to the effects of tES on behavior concentrating on the motor and visual areas…

more –> The impact of electrical stimulation techniques on behavior – Antal – 2014 – Wiley Interdisciplinary Reviews: Cognitive Science – Wiley Online Library.

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