NMES and Post Stroke Recovery

We were not planning on blogging today but would love for you all to see this particular movie. After having read so much literature in regards to NMES and the positive outcomes it can achieve in patients post stroke, we found it so refreshing to be able to finally visibly observe the life changing effect NMES has had on this particular stroke patient. Although this movie is not specific to upper limb recovery as it demonstrates restoring dorsiflexion of the foot, we could not help but share this exciting find! The movie is in Spanish, however, we feel visually it effectively portrays NMES improving function of the foot by electrically evoking muscle contractions, thus increasing muscular strength of the hemiparetic limb. ENJOY!

http://espanol.video.yahoo.com/watch/7497559/19860432 

Next blog will be reviewing the literature which demonstrates supportive evidence towards the NMES treatment of the upper limb recovery post stroke.

Meg and Hayley.

NMES Parameters

After another productive afternoon of reviewing the literature, we now feel we have successfully wrapped our heads around the appropriate NMES parameters for treatment in regards to rehabilitation of the upper limb post stroke. We found these parameters to be remarkably similar to those regarding the other limbs of the body post stroke, thus coming to the conclusion that NMES parameters do not change a great deal from limb to limb. Infact, the following parameters are enough to suffice the recovery of many different body segments post stroke. All the reviewed literature had varying stimulation parameters, thus leaving us to believe NMES stimulation parameters are not specifically crucial in determining the motor outcomes, as all of the studies we read through resulted in some degree of positive outcomes.

Table 3.1: An Example of Parameter Guidelines for NMES Upper Limb Function Post Stroke; (NMES Guidelines for Treatment, 2010)

Electrode Placement	Important to confine the electrode placement to the treatment area thus minimising the overflow to other muscles. Therefore selection of the largest possible electrode within these guidelines is optimal. Negative electrode placed over posterior deltoid. Positive electrode placed above spine of the scapula, over supraspinatus muscle (avoiding placement over the upper trapezius muscle)
Pulse Frequency	25-50Hz
Pulse Duration	200-300 microseconds
Ramp	Optimally 1-3 seconds (however use patient comfort as the guide)
On:Off Cycle	Initially 1:3 ratio implemented. Important muscular fatigue is avoided. Fatigue can be measured by palpating the amount of sublaxation evident at the end of the session of each treatment. GOAL; increase ‘on’ time by 2 seconds daily or every treatment session until achievement of 24-30 seconds. Once this ‘on’ time benchmark is achieved, aim is to decrease ‘off’ time in 2 second intervals. Optimal goal is to achieve a 12:1/ 15:1 ratio.
Waveform	Asmmetrical Biphasic. A symmetrical biphasic waveform has been shown  to reduce the amount of amplitude needed to achieve a stimulated muscle contraction. This reduced current intensity decreases the amount of superficial sensory activation, often making the patient more comfortable and, thus, more willing to comply with the treatment program.
Intensity	A tetanised-muscle contraction- 12.5Hz. Fatigue should be monitored during treatment sessions to ensure reduction is maintained.
Treatment Duration	NMES application in clinical setting à progressing to a home program as quickly as possible. Initially 3x 30 minute daily sessions. The program ideally continues until the individual regains independant functional control of the upper limb musculature.

After looking at the parameters for NMES responsible for optimal functional recovery, we began to wonder how they differ from other electrotherapy modalities. Balanger (2010) explains the varying optimal frequencies are the most significant difference between NMES and other electrical stimulation modalities. TENS for example, uses frequencies between 1-200Hz in comparison to the pulse frequency of 50Hz employed most commonly by NMES. The pulse frequency of 50Hz utilized by NMES is ideal for muscle strengthening due to the resulting fused titanic contraction within the muscle fibres, which in turn increases fibre strength (Balanger, 2010).


According to Chae, et al (2008) NMES is the electrical stimulation device of choice in relation to upper limb stroke as NMES provides therapeutic and functional benefits that lead to enhanced functions, however it doesn’t directly provide function. Chae, et al (2008) explains the importance of the prerequisites the patient must possess in order to achieve the most effective results. These include; mediated motor learning, concurrent volitional effort and high functional content. 

Figure 3.1; NMES stimulation of the wrist used for optimal functional recovery of the wrist

Excited by another discovery, we have included additional NMES Guidelines which include NMES parameters associated with finger flexion, extension, thumb opposition and grip re-education of the lumbrical muscles.

NMES Hand Rehabilitation Guidelines;

http://www.empi.com/uploadedFiles/Empi_Products/Pain_Management_-_TENS/hand.pdf

Figure 3.2; NMES has a significant impact on restoring optimal functional ability of a stroke patients hand

  Figure 3.3; An example of the use of NMES optimally mimicking functional tasks, for example the grasping action in a CVA patient

The next time we cross paths will be looking further into the research and studies which demonstrate supportive evidence towards the NMES treatment of the upper limb recovery post stroke - another area which promises exciting findings!

Until then,

Hayley and Meg

REFERENCES;

Belanger, A.Y. (2010) Therapeutic Electrophysical Agents. Evidence Based Practice. 2^nd Edition. Philadelphia. Lippincott Williams & Wilkins.

Chae, J., Bethoux, F., Bohinc, T., Dobos, L., Davis, T. & Friedl, A. (1998) Neuromuscular Stimulation for Upper Extremity Motor and Functional Recovery in Acute Hemiplegia. Stroke. (29) 975-979.

NMES Guidelines for Treatment. (2010) Retrieved February 25, 2011.

http://www.empi.com/uploadedFiles/Empi_Products/Pain_Management_-_TENS/gait

IMAGES;

http://www.drakecenter.com/page/Neuromuscular-re-education-and-strengthening.aspx

http://www.couragecenter.org/ContentPages/stilwellmed4.aspx

http://www.electrostim.ro/index_e.php?p=MICROSTIM2v2_stimulator

http://www.sciencephoto.com/images/download_lo_res.html?id=777200448

http://www.flickr.com/photos/existentialexits/323164114/

An Exciting Find on NMES and Shoulder Sublaxation

Whilst sitting back on a Friday afternoon and reflecting upon our last blog post (now with a significantly greater understanding of hemiplegia and how it has the potential to affect a stroke victims everyday life so drastically), we began reviewing the literature surrounding NMES parameters and clinical studies. Chae et al (1998), explains that the nerve fibre recruitment properties elicited by normal physiological mechanisms and NMES have contrasting preferences. Normal physiological mechanisms initially recruit the neurons with the smallest diameter prior to the recruitment of larger diameter fibres. This differs from Neuromuscular Electrical Stimulation (NMES) which mediates a nerve recruitment pattern following the principle of ‘reverse recruitment order’, thus preferentially recruiting the large-diameter nerve fibres which are responsible for innervating the larger motor units (Sheffler et al, 2007).

As we continued to read articles in relation to NMES and upper limb recovery post stroke, we came across an interesting article and substantial supportive evidence in regards to NMES and its ability to reduce sublaxation of the shoulder joint. This is achieved through NMES inducing contractions of the shoulder muscles, thus pulling the head of the humerus into the glenoid fossa (Chae et al, 1998). Re-education of the glenohumeral joint is an essential requirement of a post stroke rehabilitation program as it ensures the anatomically correct positioning of the humeral head in the glenoid fossa. As a result of NMES ensuring this correct joint alignment, a stable base is maintained for optimal functional use of the upper extremity (NMES Guidelines for Treatment, 2010). Whilst reflecting upon this article we began to appreciate NMES’ ability to ensure that the correct alignment of the shoulder joint is achieved post stroke.

Figure 2.1. Shoulder subluxation and the use of electrical stimulation. The top image displays chronic shoulder sublaxation. The bottom image shows the alignment of the shoulder during application of electrical stimulation.

Excited by our new found understanding of the role NMES plays in post stroke recovery of the upper limb, we continued to review the literature. Baker & Parker (1986) ensured our knowledge of the topic continued to develop. They stated that the primary advantage of NMES is its ability to maintain joint integrity throughout the flaccid period of post stroke recovery, thus preventing the early implementation of stretching the shoulder capsule (Baker et al, 1986). Due to the complexities of this multi-articular joint, NMES is most useful in the initial phase of ROM. As we continued to reflect upon what we were reading, our understanding grew. We were now fully aware that because of the multi-articular nature of the shoulder joint, NMES provides the initial foundation and enhances the development of muscle strength and function of the upper limb post stroke. AMAZING!

       

Figure 2.2. Comparison of a stable shoulder capsule and a shoulder capsule post sublaxation

According to Chae et al (1998), early protection of the shoulder capsule has the capability to result in a faster recovery of the upper extremity function post stroke. Just as we began to think nothing could hamper the positive outcomes of NMES and its' ability to facilitate recovery post stroke, Sheffler et al (2007) proved us wrong. Sheffler et al (2007) explains that the clinical application of NMES is currently limited to neurological injuries involving the Upper Motor Neuron (UMN), including conditions such as spinal cord injury, stroke and cerebral palsy, being dependant on intact alpha Lower Motor Neurons (LMN). We can therefore conclude that NMES treatment and UMN conditions are inextricably linked.

Figure 2.3. NMES and its limitation to neurological injuries involving the Upper Motor Neuron

With our understanding of NMES and the positive impact it has on reducing sublaxation of the shoulder capsule post stroke now completely fuelled, we look forward to going into greater detail of the NMES parameters specific to post stroke upper limb recovery next time!

Until then,
Meg and Hayley.

REFERENCES

Baker. L.L. & Parker. K. (1986) Neuromuscular Electrical Stimulation of the Muscles Surrounding the Shoulder. Annual Biomedical Eng 66 (12).

Chae, J., Bethoux, F., Bohinc, T., Dobos, L., Davis, T. & Friedl, A. (1998) Neuromuscular Stimulation for Upper Extremity Motor and Functional Recovery in Acute Hemiplegia. Stroke. (29) 975-979.

Sheffer, L.,R. & Chae, J. (2007) Neuromuscular electrical stimulation in neurorehabilitation 35(5); 562- 590.

NMES Guidelines for Treatment. (2010) Retrieved February 25, 2011.
http://www.empi.com/uploadedFiles/Empi_Products/Pain_Management_-_TENS/gait

Images;
http://stroke.ahajournals.org/cgi/content/full/30/5/963/F1
http://www.ottobock.com/cps/rde/xchg/ob_us_en/hs.xsl/15708.html
http://mywellcare.ca/physiotherapy/tens_units
http://injuryexplained.com/frozenshoulder.html
http://www.inmotionjax.com/exercise/Instability.html

Introducing Stroke and NMES

The purpose of this blog is to provide our class mates with an in-depth guide to the use of Neuromuscular Electrical Stimulation (NMES) in the rehabilitation of the upper limb post stroke.  As physiotherapy students, we were already aware that stroke can commonly result in hemiplegia (Umphred, 2007). However, we were surprised to discover that a flaccid upper extremity is, in fact, evident in up to 90% of patients following the occurrence of a stroke (NMES Guidelines for Treatment, 2010). This results in a decreased ability to perform functional movements, with some of even the most basic activities of daily living becoming somewhat impossible (Porth & Matfin, 2009). 

Hemiplegia following stroke can affect an individuals ability to perform even the most basic ADL's, such as brushing the teeth.

Feeling somewhat upset by such a realization, we endeavored to find out more about hemiplegia, how it affects stroke victims lives and, most importantly, the methods by which it can be improved. We discovered that, according to Sheffer & Chae (2007), it is important to avoid stretching of the shoulder capsule during early rehabilitation of the upper limb post stroke in order to prevent further functional complications of this area, such as:

-          Difficulty with functional use of the upper extremity

-          Autonomic dysfunction of the upper limb

-          Shoulder pain

-          Potential damage to the brachial plexus as a result of prolonged separation of the joint.

An illustration of hemiplaegia that can occur post stroke.

Now we were confused. Hmmm, we wondered. If stretching and exercise cannot be utilized, what can be done for such individuals?

Our queries led us to discover that, increasingly, the role of NMES in the recovery of upper limb function following stroke is being recognized (Robertson, Ward, Low & Reed, 2006). According to Chae, Bethoux, Bohinc, Dobos, Davis & Freidl (1998), this electrotherapeutic device has the ability to reduce sublaxation of the shoulder joint (a common complication of stroke) by pulling the head of the humerus into the glenoid fossa. This means that is has the potential to prevent disuse atrophy, assist in muscle re-education of the upper limb (NMES Guidelines for Treatment, 2010) and ultimately lead to a faster recovery time post-stroke (Chae et al, 1998). Additionally, Robertson et al (1996) states that NMES may also be beneficial in improving the function of the wrist, hand and fingers following stroke.

WOW, we thought. Could this be true? Could a tiny machine really be capable of returning function to hemiplaegic individuals? We intend to further investigate the answer to this question throughout the duration of our blog posts, so stay tuned for further information. For additional understanding concerning stroke itself, please refer to the following website
http://www.strokefoundation.com.au/ or take the time to view the following short film. 

References

Chae, J., Bethoux, F., Bohinc, T., Dobos, L., Davis, T. & Friedl, A. (1998) Neuromuscular Stimulation for Upper Extremity Motor and Functional Recovery in Acute Hemiplegia. Stroke. (29) 975-979.

Porth, C.M. & Matfin, G. (2009). Pathophysiology: Concepts of Altered Health States (8^th Ed.). Lippincott Williams & Wilkins: Philadelphia, PA.

Robertson, V., Ward, A., Low, J. & Reed, A. (2006). Electrotherapy Explained: Principles & Practices (4^th Ed.). Elsevier: Philadelphia, PA.
Sheffer, L.,R. & Chae, J. (2007) Neuromuscular electrical stimulation in neurorehabilitation 35(5); 562- 590.
Umphred, D.A. (2007). Neurological  Rehabiliation (5^th Ed.). Mosby Elsevier: St. Louis, Missouri.
NMES Guidelines for Treatment. (2010) Retrieved February 25, 2011. http://www.empi.com/uploadedFiles/Empi_Products/Pain_Management_-_TENS/gait

Images
http://som.flinders.edu.au/FUSAWikis/dsrswiki01/doku.php?id=cerebral_palsy_-_athetoid09

http://www.thewellingtonrehabunit.com/images/occupational.jpg