Posts Tagged stroke recovery

[Abstract + References] Vibrotactile cueing using wearable computers for overcoming learned non-use in chronic stroke

ABSTRACT

Outpatient stroke rehabilitation is often lengthy and expensive due to patients’ lack of functional use of the impaired arm outside of the clinic caused by “learned non-use.” Learned non-use is detrimental to stroke recovery, often resulting in chronic disability. To overcome learned non-use, a wearable “personal assistant” solution is proposed that employs ubiquitous cueing to stimulate patient use of the paretic arm while outside of therapy sessions. A pilot user study is presented that evaluated stroke survivors’ tolerance and acceptance of cueing, and the usability of the proposed implementation.

References

  1. V. L. Roger et al., “Heart disease and stroke statistics—2012 update: A report from the American Heart Association,” Circulation, vol. 125, no. 1, pp. e2–e220, Jan. 2012.Google Scholar
  2. E. Taub, J. E. Crago, L. D. Burgio, T. E. Groomes, E. W. Cook, S. C. DeLuca, and N. E. Miller, “An operant approach to rehabilitation medicine: Overcoming learned nonuse by shaping,” J Exp Anal Behav, vol. 61, no. 2, pp. 281–293, Mar. 1994.Google ScholarCross Ref
  3. C. E. Lang et al., “Upper extremity use in people with hemiparesis in the first few weeks after stroke,” Journal of Neurologic Physical Therapy, vol. 31, no. 2, pp. 55–63, Jun. 2007.Google ScholarCross Ref
  4. W. S. Verplanck, “The operant conditioning of human motor behavior,” Psychological Bulletin, vol. 53, no. 1, pp. 70–83, 1956.Google ScholarCross Ref
  5. M. S. Cameirão, S. B. i Badia, E. Duarte, A. Frisoli, and P. F. M. J. Verschure, “The combined impact of virtual reality neurorehabilitation and its interfaces on upper extremity functional recovery in patients with chronic stroke,” Stroke, vol. 43, no. 10, pp. 2720–2728, Oct. 2012.Google ScholarCross Ref
  6. J. Lieberman and C. Breazeal, “TIKL: Development of a wearable vibrotactile feedback suit for improved human motor learning,” IEEE Transactions on Robotics, vol. 23, no. 5, pp. 919–926, Oct. 2007. Google ScholarDigital Library
  7. P. Kapur, M. Jensen, L. J. Buxbaum, S. A. Jax, and K. J. Kuchenbecker, “Spatially distributed tactile feedback for kinesthetic motion guidance,” in IEEE Haptics Symposium, pp. 519–526, 2010. Google ScholarDigital Library
  8. T. Markow et al., “Mobile Music Touch: Vibration stimulus in hand rehabilitation,” in International Conference on Pervasive Computing Technologies for Healthcare (PervasiveHealth), pp. 1–8, 2010.Google Scholar
  9. P. Markopoulos, A. A. A. Timmermans, L. Beursgens, R. van Donselaar, and H. A. M. Seelen, “Us’em: The user-centered design of a device for motivating stroke patients to use their impaired arm-hand in daily life activities,” in Annual Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), pp. 5182–5187, 2011.Google Scholar
  10. G. Uswatte, C. Giuliani, C. Winstein, A. Zeringue, L. Hobbs, and S. L. Wolf, “Validity of accelerometry for monitoring real-world arm activity in patients with subacute stroke: Evidence from the extremity constraint-induced therapy evaluation trial,” Archives of Physical Medicine and Rehabilitation, vol. 87, no. 10, pp. 1340–1345, Oct. 2006.Google ScholarCross Ref

via Vibrotactile cueing using wearable computers for overcoming learned non-use in chronic stroke | Proceedings of the 7th International Conference on Pervasive Computing Technologies for Healthcare

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[Submissions from Readers] Stroke Recovery

How to improve stroke

by Sultan
(UK)

Question: How do you improve patient’s hand, fingers, and leg movement? Please tell me some exercises for my mother. Thanks.


Answer: If your mother already has some movement in her hand and fingers then I would recommend some of the exercises from this website’s hand exercises page at www.stroke-rehab.com/hand-exercises.html.

If she does not have any movement or only little movement in her hand, then I recommend trying to put weight through the arm to facilitate sensory input. This can be done by placing the hand on a firm surface and helping to support her elbow while she leans into the hand. When there is little movement in the upper extremity, it’s best to eliminate gravity as much as possible and provide assist as needed. I often place the hand on a ball and see if the patient can elicit movement. If approved by her MD, you could talk to a therapist about using electrical stimulation to facilitate movement.

Some simple hand and arm exercises I use after a stroke are as follows (stretch the hand prior to exercises):

1) Place patient’s open hand on ball and have them work on just keeping the hand on the ball without assistance

2) Once they can keep the hand on the ball, try rolling the ball gently side to side and forward and back

3) Once they can roll the ball, place both hands on the sides of the ball (soccer ball works well) and try to lift the ball off their lap using both hands and 

without the weak hand falling off

4) As they are able to lift the ball, work on lifting the ball higher or moving it side to side

5) Work on taking weak hand off the ball slowly and with controlled movement

6) Once they can move hand off/on ball with some control, work on placing hand on smaller objects such as a plastic cup and letting go. Progress to trying to lift the cup.

Some other options to help facilitate return of the hemiplegic arm include using e-stim with a therapist or tapping the muscles you are trying to stimulate. If trying to close the hand, turn the palm up and tap the forearm muscles. If trying to open the hand, turn the palm down and tap the back of the forearm.

Weight bearing is also good for the leg. If your mother is able to stand, have a therapist show her how to shift weight onto the weak leg and work on weight bearing on the affected side. A physical therapist can also show you tapping techniques to help facilitate movement. For example, to elicit straightening the knee, you would tap the top of the thigh.

If you are looking for therapy ideas, I suggest looking on You Tube for stroke rehab exercises. Many therapists and patients have recorded their therapy sessions which might give you ideas on what would work for your mother. You should always consult a therapist or physician that has worked with your mom to make sure any exercises would be appropriate for her.

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Gaining Strength After Stroke

by Jayesh Mehta
(Wellingborough in UK)

Question: I suffered a hemorrhagic stroke in April 2009 and subsequently got senses back in all of my body. As an effect of the stroke, my left side, even though movement feels OK, is a bit weak due to prolong time in bed (8 months in hospital+rehab). My body has lost its strength and hence I can’t get up from a sitting position. I have joined a gym to gain strength and am a full time worker post stroke. The reason for this note is to see what you can suggest to get some strength back – to be able to get up by myself and take a few steps, etc. (not looking for running down the street). Please share anything that you think might help.

Thanks
Jayesh

Answer: I like to use hi-lo mats to help patients improve their ability to stand from a sitting position. A hi-lo mat can be adjusted to a low or high position. I will have my patients sit on the mat and then raise the height. We will practice weight bearing through the legs with the mat elevated (with the buttocks still on the mat) and then will practice sit to stand from this position. I will block the knee on their weak side if necessary to prevent the leg from buckling. An air splint can also be used to help keep the leg from collapsing. Once a patient has gained confidence in standing then I work on the patient shifting weight side to side and learning to take more weight through the weak leg. I also vary the height of the hi-lo mat to work on sit to stand from different heights. As the legs and core get stronger, one will be able to get up from a lower height.

A physical therapist should be able to help you with the techniques described above. I don’t know about equipment in the UK but hi-lo mats are standard equipment in a US therapy clinic.

One might could use a hospital bed or lift chair to achieve the same effect as a hi-lo mat, however, I haven’t tried this out. You should always check with your medical provider before attempting any exercises and also have a therapist or trained caregiver with you when attempting such exercises as described above.

Below is an examples of a hi-lo mat. One can purchase these mats, however, they are expensive.

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[Abstract] Ergometer training in stroke rehabilitation: systematic review and meta-analysis

Abstract

Objective

Ergometer training is routinely used in stroke rehabilitation. How robust is the evidence of its effects?

Data source

The PubMed database and PEDro database were reviewed prior to 22/01/2019.

Study selection

Randomized controlled trials investigating the effects of ergometer training on stroke recovery were selected.

Data extraction

Two reviewers independently selected the studies, performed independent data extraction, and assessed the risk of bias.

Data synthesis

A total of 28 studies (including 1115 stroke subjects) were included. The data indicates that

(1) ergometer training leads to a significant improvement of walking ability, cardiorespiratory fitness, motor function and muscular force of lower limbs, balance and postural control, spasticity, cognitive abilities, as well as the brain’s resistance to damage and degeneration,

(2) neuromuscular functional electrical stimulation assisted ergometer training is more efficient than ergometer training alone,

(3) high-intensity ergometer training is more efficient that low-intensity ergometer training, and

(4) ergometer training is more efficient than other therapies in supporting cardiorespiratory fitness, independence in activities of daily living, and balance and postural control, but less efficient in improving walking ability.

Conclusion

Ergometer training can support motor recovery after stroke. However, current data is insufficient for evidence-based rehabilitation. More data is required about the effects of ergometer training on cognitive abilities, emotional status, and quality of life in stroke subjects.

via Ergometer training in stroke rehabilitation: systematic review and meta-analysis – Archives of Physical Medicine and Rehabilitation

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[ARTICLE] Recovery of upper limb function is greatest early after stroke but does continue to improve during the chronic phase: a two-year, observational study – Full Text

Abstract

Objectives

Investigate upper limb (UL) capacity and performance from <14-days to 24-months post-stroke.

Design

Longitudinal study of participants with acute stroke, assessed ≤14-days, 6-weeks, 3-, 6-, 12-, 18-, and 24-months post-stroke.

Setting

Two acute stroke units.

Main outcome measures: Examination of UL capacity using Chedoke McMaster Stroke Assessment (combined arm and hand scores, 0 to 14), performance using Motor Activity Log (amount of movement and quality of movement, scored 0 to 5), and grip strength (kg) using Jamar dynamometer. Random effects regression models were performed to explore the change in outcomes at each time point. Routine clinical imaging was used to describe stroke location as cortical, subcortical or mixed.

Results

Thirty-four participants were enrolled: median age 67.7 years (IQR 60.7 to 76.2), NIHSS 11.5 (IQR 8.5 to 16), female n = 10 (36%). The monthly rate of change for all measures was consistently greatest in the 6-weeks post-baseline. On average, significant improvements were observed to 12- months in amount of use (median improvement 1.81, 95% CI 1.35 to 2.27) and strength (median improvement 8.29, 95% CI 5.90 to 10.67); while motor capacity (median improvement 4.70, 95% CI 3.8 to 5.6) and quality of movement (median improvement 1.83, 95% CI 1.37 to 2.3) improved to 18-months post-stroke. Some individuals were still demonstrating gains at 24-months post-stroke within each stroke location group.

Conclusion

This study highlights that the greatest rate of improvement of UL capacity and performance occurs early post-stroke. At the group level, improvements were evident at 12- to 18-months post-stroke, but at the individual level improvements were observed at 24-months.

Introduction

Up to 70% of individuals experience difficulties using their upper limb (UL, arm and hand) to perform meaningful activities after stroke [1]. There is an assumption that when a stroke survivor demonstrates a change in activity, it is underpinned by an improvement in their capacity (i.e., what a person can do in the clinical environment) and performance (i.e., does a person actually use their UL in real world environments outside of the clinic) [2]. However, UL recovery post-stroke is unlikely to be this simplistic [3]. Understanding how capacity and performance change over years post-stroke might help to identify which patients to target and when during their recovery.

Previous research has noted distinct recovery profiles during inpatient [4][5] and outpatient [6] rehabilitation. Firstly, survivors may demonstrate improvements in both capacity and performance after stroke. Secondly, survivors may demonstrate an improvement in capacity but not performance. Lastly, survivors may demonstrate little or no change in both capacity and performance. An improvement in performance but not capacity has not been documented in the literature. Combined, these profiles support our rationale that UL capacity and performance are interrelated, yet are different constructs that must be measured separately.

Stroke recovery is a long-term goal. It is important to complete observational studies that track recovery to establish whether there is a discrepancy between capacity and performance in the long-term. To date, longitudinal tracking of recovery has largely lacked investigation of natural recovery from an acute time point post-stroke (first 7- to 14-days), long-term follow up of patients beyond 3- to 6-months post-stroke, and characterisation of stroke variables such as lesion type and location that may modify or interact with observed recovery profiles [7].

In this exploratory study our objectives were to determine 1) whether UL capacity and performance improve over the first 24-months after stroke; and 2) if there is a window of greatest improvement in UL capacity and performance. This information is important to develop an understanding of the longterm timecourse of recovery after stroke to support evidence-based clinical practice guidelines to inform upper limb rehabilitation services.

[…]

Continue —-> Recovery of upper limb function is greatest early after stroke but does continue to improve during the chronic phase: a two-year, observational study – ScienceDirect

Fig. 2

Fig. 2. Upper limb motor capacity (Chedoke), performance (quality of movement & amount of use), and grip strength over 24-months post-stroke (n = 28)

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[WEB PAGE] 10 of the best apps for stroke recovery in 2018

Following a stroke, the body needs time to heal, and recovery time depends on the symptoms and severity of the stroke. We have identified the best apps to help stroke survivors with their recovery and rehabilitation.
older man looking at phone

Smartphone apps can assist with stroke recovery and rehabilitation.

More than 795,000 individuals in the United States have a stroke each year, and around 140,000 of these people die from stroke.

Ischemic strokes — wherein “blood flow to the brain is blocked” — account for roughly 87 percent of all strokes.

Stroke can cause significant injury to the brain that may result in many long-term problems.

For example, communication, concentration, memory, and executive function, as well as spatial awareness, are all cognitive functions that may be impacted by stroke.

Stroke can also trigger mental health issues such as anxiety and depression, as well as movement and coordination problems, paralysis, difficulties swallowing, visual impairment, and urinary incontinence and loss of bowel control.

The faster a person is treated after stroke, the more likely they are to recover from it. Surveys have shown that people who “arrived at the emergency room within 3 hours” of their first symptoms of stroke had “less disability” 3 months later than those who were treated later.

While some people recover quickly from stroke, others may need long-term support. Apps are available to help aid the stroke recovery process. They can help you or your loved one to track appointments and medications, provide language therapy, train the brain, and even lower some risk factors for future strokes.

Medical News Today have selected the top 10 apps to assist with stroke recovery.

Cozi

Android: Free

iPhone: Free

Cozi logo

Keep track of schedules with a shared color-coded calendar and set reminders for yourself or other family members so that medical appointments and medications are not missed.

Shopping and to-do lists can also be shared with everyone in the family to ensure that you have everything you need from the grocery store. All items added to lists are viewable instantly in real-time.

Medisafe

Android: Free

iPhone: Free

Medisafe logo

According to the app, mistakes with medicine use and dosage tracking result in 50 percent of individuals not taking medication as prescribed, 700,000 hospital visits, 125,000 deaths each year, and 44 in every 100 prescriptions not being collected from the pharmacy.

Whether you are taking one drug dose or multiple doses each day, it can be challenging to remember to take the right pill at the right time. Medisafe takes the stress out of having to remember if you or your loved one took their medications correctly.

Stop, Breathe & Think

Android: Free

iPhone: Free

Stop, Breathe & Think logo

Stop, Breathe & Think is a meditation and mindfulness app that helps to decrease stress and anxiety. The app provides guided meditations, breathing exercises, and yoga and acupressure videos to help you check in with your emotions.

Stop, Breathe & Think says that taking a few minutes every day to feel calm is just as important as getting frequent exercise and will reduce stress and promote peace of mind.

7 Minute Workout Challenge

Android: $2.99

iPhone: $2.99

7 Minute Workout Challenge logo

If you are unsure of how to start an exercise routine after stroke, the 7 Minute Workout Challenge app could be the perfect app for you. The 7-minute workout is a research-backed exercise program that has become a hit internationally.

Scientists have put together 12 exercises to perform for 30 seconds each with a rest period of 10 seconds in-between. The exercise sequences are easy to do, require no equipment, and can be done anywhere.

Language Therapy 4-in-1

Android: $59.99

iPhone: $59.99

Language Therapy logo

Language Therapy 4-in-1 is a scientifically proven speech therapy app that aims to improve speaking, listening, reading, and writing in those with aphasia. Get started by giving their free version, Language Therapy Lite, a try today.

Research led by the University of Cambridge in the United Kingdom found that using the app for 20 minutes each day for 4 weeks showed improvements in all study participants with chronic aphasia.

Constant Therapy

Android: Free trial

iPhone: Free trial

Constant Therapy logo

With more than 65 task categories, 100,000 exercises, and 10 levels of difficulty, Constant Therapy can help to improve cognition, memory, speech, language, reading, and comprehension skills.

Constant Therapy was developed by scientists at Boston University in Massachusetts and is recommended by neurologists, speech language pathologists, and occupational therapists. Research published in the journal Frontiers in Human Neuroscience showed a significant improvement in standardized tests for stroke survivors after using Constant Therapy.

VocalEyes AI

iPhone: Free

VocalEyes logo

VocalEyes is computer vision for the visually impaired. The app uses machine learning to help people with vision problems identify objects in their everyday lives. Take a photo, and the app will tell you what the camera sees.

VocalEyes’s audio response describes scenes and environments, identifies objects, label logos, and brands, reads text, detects faces, classifies emotions, recognizes ages, and distinguishes currency denominations.

Glasses

iPhone: Free

Glasses logo

If your vision is impaired after stroke or you have simply forgotten your glasses, the app can zoom in on labels and nutritional information in a grocery store and menus in dark restaurants as well as help you see how much to pay on the bill after eating out.

Glasses is simple to use. Double tapping quickly zooms in or out by 6x, while swiping uses a slow and continuous zoom method. If you have shaky hands, you can tap and hold to freeze the image on screen.

Elevate

Android: Free

iPhone: Free

Elevate logo

Elevate is a brain-training app that is designed to enhance speaking abilities, processing speed, focus, and memory. Elevate provides a personalized training program that adapts in difficulty over time to ensure you are always challenged.

Elevate features more than 40 games aimed at improving your skills, plus a workout calendar that tracks your streaks to keep you motivated. Users who train with Elevate at least three times each week have reported considerable gains in abilities and increased confidence.

Peak

Android: Free

iPhone: Free

Peak logo

Peak features a personal brain trainer, known as Coach, who selects the perfect workouts for you at the correct time. Choose your training exercises from Coach’s recommendations to challenge yourself and stay motivated by tracking your progress with in-depth insights.

Free games challenge your attention, memory, problem-solving skills, mental agility, coordination, emotional control, language, and creativity. Upgrade to Pro for additional features.

 

via 10 of the best apps for stroke recovery in 2018

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[WEB SITE] Glowing brain cells illuminate stroke recovery research

CAPTION
Gaussia luciferase (Gluc) is fused to the ChR protein. ChR can be activated by blue light or by light emitted by Gluc when binding to its substrate coelenterazine (CTZ). YFP = yellow fluorescent protein.
CREDIT
Shan Ping Yu

A promising strategy for helping stroke patients recover, transplanting neural progenitor cells to restore lost functions, asks a lot of those cells. They’re supposed to know how to integrate into a mature (but damaged) brain. The cells need help.

 

To provide that help, researchers at Emory University School of Medicine have developed an “optochemogenetics” approach that modifies a widely used neuroscience tool. The stimulation that transplanted cells need to flourish comes from light, generated within the brain. In a mouse model of stroke, neural progenitor cells received light stimulation, which promoted functional recovery in the mice.

The results are scheduled for publication in Journal of Neuroscience.

Neuroscience aficionados may be familiar with optogenetics, which allows scientists to study the brain conveniently, activating or inhibiting groups of neurons at the flip of a switch. (Mice with fiber optic cables attached to their heads can be found in many labs.) Emory investigators led by Shan Ping Yu, MD, PhD and Ling Wei, MD wanted to remove the cable: that is, figure out how to selectively stimulate brain cells non-invasively.

They teamed up with Jack Tung, PhD, Ken Berglund, PhD and Robert Gross, MD, who had created “luminopsins”, engineered proteins that are both light-sensitive and generate their own light when provided with a chemical called CTZ (coelenterazine). The protein components come from Volvox algae and from Gaussia princeps, a fingernail-sized crustacean that lives in the deep ocean.

Yu and Wei were looking for ways to coax neural progenitor cells – capable of multiplying and differentiating into mature neurons – to survive in the brain after the destruction of a stroke. They were working with a mouse model, in which the sensory and motor regions on one side of the brain are damaged.

“It is not sufficient to put the cells into the damaged brain and then not take care of them.” Yu says. “If we expect progenitor cells to differentiate and become functional neurons, the cells have to receive stimulation that mimics the kind of activity they will see in the brain. They also need growth factors and a supportive environment.”

Yu and Wei are in Emory University School of Medicine’s Department of Anesthesiology, while Tung, Berglund and Gross are in the Department of Neurosurgery and the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory.

In experiments described in the current paper, scientists introduced genes encoding luminopsins into induced pluripotent stem cells, which were cultured to form neural progenitor cells. The neural progenitor cells were delivered into the brains of mice a week after stroke. CTZ, which emits light when acted upon by luminopsins, was then provided intranasally twice a day for two weeks. Intranasal delivery bypasses the blood-brain barrier and repeated administrations are clinically feasible, Yu points out. Bioluminescence could be detected in the cell graft area and was visible for around one hour after CTZ administration.

CTZ promoted an array of positive effects in the progenitor cells: more survival and intact axons, more connections within the brain and better responses to electrical stimulation. It also promoted recovery of function in the affected limb in the mice. The mice were tested in activities such as: reaching and grasping food pellets, or removing adhesive dots from their paws. In young mice, CTZ and progenitor cells together could restore use of the stroke-affected limb back to normal levels, and even in older mice, they produced partial recovery of function.

When Yu was asked about clinical prospects, he said that optochemogenetics represents a significant advance, compared with its constituent technologies.

“Optogenetics is a fantastic technical tool, but it presents some barriers to clinical implementation,” he says. “You have the invasive fiber optic light delivery, and the limited distance of light diffusion, especially on the larger scale of the human brain.”

Delivery of cells into the brain and making them glow are complex, but they offer scientists some flexibility when designing experiments: direct light application, which can be turned on and off quickly, or the steady support of CTZ stimulation. Luminopsins can provide “the capabilities for the cells to be activated either in a way mimicking neuronal activities of fast activation or manipulations of the channel/cell in clinical treatments,” the authors write.

Yu and his colleagues are also testing their approach for the delivery of neural progenitor cells in the context of traumatic brain injury.

via Glowing brain cells illuminate stroke recovery research | EurekAlert! Science News

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[ARTICLE] Sensory retraining of the leg after stroke: systematic review and meta-analysis – Full Text

This systematic review aimed to investigate the effects of interventions intended for retraining leg somatosensory function on somatosensory impairment, and secondary outcomes of balance and gait, after stroke.

Databases searched from inception to 16 January 2019 included Cochrane Library, PubMed, MEDLINE, CINAHL, EMBASE, PEDro, PsycINFO, and Scopus. Reference lists of relevant publications were also manually searched.

All types of quantitative studies incorporating interventions that intended to improve somatosensory function in the leg post stroke were retrieved. The Quality Assessment Tool for Quantitative Studies was used for quality appraisal. Standardised mean differences were calculated and meta-analyses were performed using preconstructed Microsoft Excel spreadsheets.

The search yielded 16 studies, comprising 430 participants, using a diverse range of interventions. In total, 10 of the included studies were rated weak in quality, 6 were rated moderate, and none was rated strong. Study quality was predominantly affected by high risk of selection bias, lack of blinding, and the use of somatosensory measures that have not been psychometrically evaluated. A significant heterogeneous positive summary effect size (SES) was found for somatosensory outcomes (SES: 0.52; 95% confidence interval (CI): 0.04 to 1.01; I2 = 74.48%), which included joint position sense, light touch, and two-point discrimination. There was also a significant heterogeneous positive SES for Berg Balance Scale scores (SES: 0.62; 95% CI: 0.10 to 1.14; I2 = 59.05%). Gait SES, mainly of gait velocity, was not significant.

This review suggests that interventions used for retraining leg somatosensory impairment after stroke significantly improved somatosensory function and balance but not gait.

 

Somatosensory impairment is common after stroke, occurring in up to 89% of stroke survivors.1Proprioception and tactile somatosensation are more impaired in the leg than in the arm post stroke,2 with the frequency increasing with increasing level of weakness and stroke severity.2,3 Leg somatosensory impairment also has a significant impact on independence in daily activities3 and activity participation in stroke survivors,4 as well as predicts longer hospital stays and lower frequency of home discharges.5

Leg somatosensory impairment negatively influences balance and gait. Post-stroke plantar tactile deficits correlate with lower balance scores and greater postural sway in standing.6 Tactile and proprioceptive feedback provide critical information about weight borne through the limb.7 Accordingly, tactile and proprioceptive somatosensory deficits may hinder paretic limb load detection ability, potentially leading to reduced weight-bearing and contributing to balance impairment and falls post stroke.8 Indeed, stroke survivors with somatosensory impairment have a higher falls incidence compared to those without somatosensory impairment.3 In addition to reduced balance, impaired load detection may also contribute to gait asymmetry, particularly in the push-off phase.8 In addition, leg proprioception influences variance in stride length, gait velocity,9 and walking endurance in stroke survivors.10 In fact, leg somatosensory impairment has been shown to be the third most important independent factor for reduced gait velocity in stroke survivors.11

Two systematic reviews have previously investigated the effects of interventions for retraining somatosensory function after stroke.12,13 In the first review, published more than a decade ago, only four of the 14 included studies targeted the leg,12 while the second only included studies of the arm.13 Nevertheless, both reviews reported that there were insufficient data to determine the effectiveness of these interventions. A third systematic review evaluating the effectiveness of proprioceptive training14 only included 16 studies with stroke-specific populations, of which only two specifically addressed the leg. From these three reviews, the effects of interventions for post-stroke leg somatosensory impairment remain unclear. In addition, the first review12 was critiqued for including studies with participants without somatosensory impairment, and that did not report somatosensory outcomes.15 Therefore, a targeted systematic review, addressing the limitations of previous reviews, is required to elucidate the effects of interventions for post-stroke leg somatosensory impairment.

It is of interest to clinicians and researchers to evaluate the effects of leg somatosensory retraining on factors that may ultimately influence activity and participation, as this could change practice. Therefore, this systematic review aimed to examine the effects of post-stroke leg somatosensory retraining on somatosensory impairment, balance, gait, motor impairment, and leg function.[…]

 

Continue —> Sensory retraining of the leg after stroke: systematic review and meta-analysis – Fenny SF Chia, Suzanne Kuys, Nancy Low Choy, 2019

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[Abstract] Differential Poststroke Motor Recovery in an Arm Versus Hand Muscle in the Absence of Motor Evoked Potentials

Background. After stroke, recovery of movement in proximal and distal upper extremity (UE) muscles appears to follow different time courses, suggesting differences in their neural substrates.

Objective. We sought to determine if presence or absence of motor evoked potentials (MEPs) differentially influences recovery of volitional contraction and strength in an arm muscle versus an intrinsic hand muscle. We also related MEP status to recovery of proximal and distal interjoint coordination and movement fractionation, as measured by the Fugl-Meyer Assessment (FMA).

Methods. In 45 subjects in the year following ischemic stroke, we tracked the relationship between corticospinal tract (CST) integrity and behavioral recovery in the biceps (BIC) and first dorsal interosseous (FDI) muscle. We used transcranial magnetic stimulation to probe CST integrity, indicated by MEPs, in BIC and FDI. We used electromyography, dynamometry, and UE FMA subscores to assess muscle-specific contraction, strength, and inter-joint coordination, respectively.

Results. Presence of MEPs resulted in higher likelihood of muscle contraction, greater strength, and higher FMA scores. Without MEPs, BICs could more often volitionally contract, were less weak, and had steeper strength recovery curves than FDIs; in contrast, FMA recovery curves plateaued below normal levels for both the arm and hand.

Conclusions. There are shared and separate substrates for paretic UE recovery. CST integrity is necessary for interjoint coordination in both segments and for overall recovery. In its absence, alternative pathways may assist recovery of volitional contraction and strength, particularly in BIC. These findings suggest that more targeted approaches might be needed to optimize UE recovery.

 

via Differential Poststroke Motor Recovery in an Arm Versus Hand Muscle in the Absence of Motor Evoked Potentials – Heidi M. Schambra, Jing Xu, Meret Branscheidt, Martin Lindquist, Jasim Uddin, Levke Steiner, Benjamin Hertler, Nathan Kim, Jessica Berard, Michelle D. Harran, Juan C. Cortes, Tomoko Kitago, Andreas Luft, John W. Krakauer, Pablo A. Celnik, 2019

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[ARTICLE] Diffusion Tensor Imaging Biomarkers to Predict Motor Outcomes in Stroke: A Narrative Review – Full Text

Stroke is a leading cause of disability worldwide. Motor impairments occur in most of the patients with stroke in the acute phase and contribute substantially to disability. Diffusion tensor imaging (DTI) biomarkers such as fractional anisotropy (FA) measured at an early phase after stroke have emerged as potential predictors of motor recovery. In this narrative review, we: (1) review key concepts of diffusion MRI (dMRI); (2) present an overview of state-of-art methodological aspects of data collection, analysis and reporting; and (3) critically review challenges of DTI in stroke as well as results of studies that investigated the correlation between DTI metrics within the corticospinal tract and motor outcomes at different stages after stroke. We reviewed studies published between January, 2008 and December, 2018, that reported correlations between DTI metrics collected within the first 24 h (hyperacute), 2–7 days (acute), and >7–90 days (early subacute) after stroke. Nineteen studies were included. Our review shows that there is no consensus about gold standards for DTI data collection or processing. We found great methodological differences across studies that evaluated DTI metrics within the corticospinal tract. Despite heterogeneity in stroke lesions and analysis approaches, the majority of studies reported significant correlations between DTI biomarkers and motor impairments. It remains to be determined whether DTI results could enhance the predictive value of motor disability models based on clinical and neurophysiological variables.

Introduction

Stroke is the second cause of death and the third leading cause of loss of DALYs (Disability-Adjusted Life Years) worldwide. Despite substantial advances in prevention and treatment, the global burden of this condition remains massive (1). In ischemic stroke (IS; 80–85% of the cases), hypoperfusion leads to cell death and tissue loss while in hemorrhagic stroke (HS), primary injury derives from hematoma formation and secondary injury, from a cascade of events resulting in edema and cellular death (2). In IS, cytotoxic edema is a result of glucose and oxygen deprivation, leading to a failure of ion pumps in the cell membranes and consequently to collapse of osmotic regulation, when water shifts from the extracellular to the intracellular compartment (3). In HS, heme degradation products are the primary cytotoxic event and secondarily, an inflammatory process based on degradation of the hematoma takes place (4).

Diffusion MRI (dMRI) is a powerful diagnostic tool in acute IS (5) and is widely used in clinical practice (6). dMRI sequences are sensitive to water displacement. Acute infarcts appear hyperintense on diffusion-weighted imaging (DWI) reflecting the decrease in the apparent diffusion coefficient of water molecules. DWI can be acquired and interpreted over a few minutes. It provides key information for eligibility to reperfusion therapies from 6 to 24 h after onset of symptoms (DAWN study) (7) and in wake-up strokes (8). A search on MEDLINE using the terms “stroke” and “diffusion MRI” yielded 1 article in 1991 and 279, in 2018. Diffusion tensor imaging (DTI) involves more complex post-processing, mathematical modeling of the DW signal (9) and provides measures associated with white matter (WM) microstructural properties (10).

Stroke can directly injure WM tracts and also lead to Wallerian degeneration, the anterograde distal degeneration of injured axons accompanied by demyelination (11). DTI metrics have been studied as biomarkers of recovery or responsiveness to rehabilitation interventions (1214). The bulk of DTI studies addressed specifically the corticospinal tract (CST), crucial for motor performance or recovery (1215), and frequently affected by stroke lesions. Paresis occurs in the majority of the subjects in the acute phase and contributes substantially to disability (16). It is thus understandable that the CST is in the spotlight of research in the field.

Two meta-analyses included from six to eight studies and reported strong correlations between DTI metrics and upper-limb motor recovery in IS and HS (1718). In both meta-analyses, heterogeneity between the studies was moderate. In addition, the quality of the evidence of DTI as a predictor of motor recovery was considered only moderate by a systematic review of potential biomarkers (19). The main limitations of the reviewed studies were the lack of cross-validation and evaluation of minimal clinically important differences for motor outcomes as well as the small sample sizes. Heterogeneity in DTI data collection and analysis strategies may also contribute to inconsistencies and hinder comparisons between studies.

In this narrative review, first we review the key concepts of dMRI. Second, we present an overview of state-of-art methodological practices in DTI processing. Third, we critically review challenges of DTI in stroke and results of studies that investigated the correlation between DTI metrics in the CST and motor outcomes at different stages after stroke, according to recommendations of the Stroke Recovery and Rehabilitation Roundtable taskforce (20).

Concepts of Diffusion MRI

Different MRI paradigms address WM qualitatively and quantitatively (i.e., volume, contrast as signal hyperintensities), but only dMRI allows indirect inferences about WM microstructure by providing information about the underlying organization of the tissue. In regions of little restriction of water displacement (such as the ventricles), water molecules tend to move almost freely (randomly). On the other hand, within tracts, the environment tends to be organized within sets of axons aligned in parallel orientation. Water movement usually follows a specific orientation near axons compactly organized and constrained by the myelin packing (21).

The diffusion tensor is the most commonly used mathematical modeling of the diffusion signal and can be decomposed into its eigenvalues (λ) and eigenvectors (ε), required to characterize the signal of water displacement within a voxel. Each eigenvector represents an axis of dominant diffusion with the magnitude of diffusion determined by the corresponding eigenvalues. If the diffusion is isotropic (the same along each orientation), then the eigenvalues have approximately the same magnitude (λ1 ≈ λ2 ≈ λ3), which can be depicted by a sphere. By contrast, if there is a preferential orientation of the diffusion, then the first eigenvalue is bigger than the other two, which can be visualized typically by an ellipsoid (λ1 >> λ2, λ3) (Figure 1).

FIGURE 1

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Figure 1. Model of the tensor showing the eingenvalues. Diffusivities are depicted in FA representation (λll—parallel or axial diffusivity—AD, λperpendicular or radial diffusivity—RD).

Hence, the tensor calculation is typically based on a 3 × 3 symmetric matrix, in which the eigenvalues derived from each combination of directions provide different metrics. At least one b0 (non-diffusion-weighted) and 6 non-collinear directions of diffusion-weighted acquisitions are required to minimally describe water displacement with DTI (10). Generally, the more directions, the better.

The most widely used DTI metrics are: fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). FA describes the degree of anisotropy (represented as an ellipsoid), a value between 0 (isotropic) and 1 (the most anisotropic). Anisotropy tends to increase in the presence of highly oriented fibers (Figure 1). The biggest value is supposed to be found in the center of the tracts. In particular, for CST analysis in stroke or other focal brain lesions, FA results can be reported as ratios between FA extracted from the ipsilesional and the contralesional hemispheres (rFA = FA ipsilesional/FA contralesional). Alternatively, asymmetry in FA can be described (aFA = (FA ipsilesional – FA contralesional)/(FA ipsilesional + FA contralesional).

MD describes the magnitude of diffusion and the biggest value is supposed to be found in the ventricles. RD represents the average diffusivity perpendicular to the first eigenvector and AD is the first eigenvalue (λ1) representing the diffusivity along the dominant diffusion direction.

Many studies have focused exclusively on FA. The proper interpretation of FA often demands knowledge about results of the other three DTI metrics (22). Changes in anisotropy may reflect several biological underpinnings, such as axonal packing density, axonal diameter, myelinization, neurite density, and orientation distribution (2123). FA can be decreased in conditions that injure the WM but also when multiple crossing fibers are present in the voxel. In case of partial volume effects, both FA and MD may be altered (2425).[…]

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https://www.frontiersin.org/articles/10.3389/fneur.2019.00445/full

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[Abstract] High-Intensity Interval Training After Stroke: An Opportunity to Promote Functional Recovery, Cardiovascular Health, and Neuroplasticity.

Abstract

INTRODUCTION:

Stroke is the leading cause of adult disability. Individuals poststroke possess less than half of the cardiorespiratory fitness (CRF) as their nonstroke counterparts, leading to inactivity, deconditioning, and an increased risk of cardiovascular events. Preserving cardiovascular health is critical to lower stroke risk; however, stroke rehabilitation typically provides limited opportunity for cardiovascular exercise. Optimal cardiovascular training parameters to maximize recovery in stroke survivors also remains unknown. While stroke rehabilitation recommendations suggest the use of moderate-intensity continuous exercise (MICE) to improve CRF, neither is it routinely implemented in clinical practice, nor is the intensity always sufficient to elicit a training effect. High-intensity interval training (HIIT) has emerged as a potentially effective alternative that encompasses brief high-intensity bursts of exercise interspersed with bouts of recovery, aiming to maximize cardiovascular exercise intensity in a time-efficient manner. HIIT may provide an alternative exercise intervention and invoke more pronounced benefits poststroke.

OBJECTIVES:

To provide an updated review of HIIT poststroke through ( a) synthesizing current evidence; ( b) proposing preliminary considerations of HIIT parameters to optimize benefit; ( c) discussing potential mechanisms underlying changes in function, cardiovascular health, and neuroplasticity following HIIT; and ( d) discussing clinical implications and directions for future research.

RESULTS:

Preliminary evidence from 10 studies report HIIT-associated improvements in functional, cardiovascular, and neuroplastic outcomes poststroke; however, optimal HIIT parameters remain unknown.

CONCLUSION:

Larger randomized controlled trials are necessary to establish ( a) effectiveness, safety, and optimal training parameters within more heterogeneous poststroke populations; (b) potential mechanisms of HIIT-associated improvements; and ( c) adherence and psychosocial outcomes.

 

via High-Intensity Interval Training After Stroke: An Opportunity to Promote Functional Recovery, Cardiovascular Health, and Neuroplasticity. – PubMed – NCBI

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