What is spasticity? Challenges and Treatments

Author:
Paula Sánchez-Vegazo Silvosa (Clinical Specialist)

Spasticity is a complex neurological condition characterized by an abnormal increase in muscle tone, which significantly impacts the mobility and quality of life of those who suffer from it. Its management must be individualized, so there are pharmacological and physiotherapeutic treatments and, in recent years, robotic technology, such as exoskeletons, which have proven to be effective in reducing spasticity and optimizing rehabilitation.

For a quick vision of what you’ll find in this article, check out our spasticity infography at the end of the article.

What is spasticity?

It is commonly defined as a velocity-dependent increase in muscle tone due to exaggerated stretch reflexes^1,2,3,4,5. This is accompanied by hyperreflexia, i.e. increased reflexes, and is one of the signs of upper motor neuron syndrome⁴. This syndrome occurs when there is a lesion in the upper levels of the central nervous system⁶.

Many have objected to limitations to this definition. It has therefore evolved over the years^1,4. Thus, some aspects of the functional impact that this symptom has on the daily life of those who suffer from it have been introduced, which can lead to a limitation in their bodily functions, their activities and their participation, as it can lead to a significant economic cost for the person who pays for the rehabilitation and pharmacological treatment^4,7.

Spasticity can be caused by different pathophysiological mechanisms depending on the origin of the lesion, all of which have in common a loss of inhibitory signals (either due to a loss of cerebral or spinal origin). In the end, there is an increase in muscle tone due to hyperexcitable tonic elastic reflexes, i.e. the muscles remain contracted due to increased excitability in the neurons⁴. This clinical sign is often confused with the terms: contracture and rigidity, which are not dependent on the speed of movement, offering constant resistance throughout the range of motion³.

The different classifications that can be made of spasticity are given by clinical differences, aetiology, location (hemispasticity, paraspasticity and tetra-spasticity) and severity³.

Epidemiology

Spasticity is an often underdiagnosed clinical sign¹ that can occur in numerous pathologies such as multiple sclerosis, stroke, hypoxic brain damage, traumatic brain injury, spinal cord injury, tumours and degenerative diseases^3,4. A study carried out in 2020, reports the following epidemiological data:

• It is estimated that around 38-40% of patients who have suffered a stroke will have some degree of spasticity and that 16% of these will need treatment.
• In spinal cord injury, it is estimated that 40% of patients will have it.
• Meanwhile, the highest values will appear in multiple sclerosis, where more than 80% will have this sign at some point in their illness,
• in cerebral palsy, between 72-91% of subjects will show spasticity
• and in moderate-severe cranioencephalic trauma in more than 63.4%^4,6. 

Spasticity should be treated considering how it interferes with the patient’s daily life activities given that the manifestation of this symptom is variable³. In spinal cord injury, spasticity was found to be more problematic in patients with cervical lesion levels and incomplete ASIA (B-D)¹. While in multiple sclerosis it can become a symptom that correlates directly with disease progression.⁷ In these cases where spasticity is severe, this symptom is often accompanied by pain and can reduce the quality of life, making it difficult to perform basic activities of daily living (difficulty caring for skin integrity, ensuring hygiene and even going to the toilet) as well as participation in their environment, which it affects mainly the person taking care of the patient^1,7,8.  Furthermore, in some cases, it can immobilise the joint between the affected muscles due to this speed-dependent increase in tone. This increases the risk of subluxation and/or dislocation as well as heterotrophic ossification³.

However, it has been shown that spasticity can be beneficial for some patients, allowing them to be more efficient in transfers, standing and ambulation, resulting in a decreased risk of osteoporosis, increased circulation and improved mood³, as well as contributing to decreased muscle atrophy and prevention of bone calcification⁴.

Spasticity diagnose

As spasticity is multifactorial, it is complicated to assess. In addition, multiple triggers of spasticity have been identified such as bladder, bowel, posture, cold, menstruation, fatigue, stress, skin conditions, orthoses or even tight clothing. All these interfere with the objective measurement of this clinical sign¹.

This is why quantitative or instrumental measures (neurophysiological or spinal reflex studies) are sought for their inherent objectivity and reliability. However, these may not be as practical. For this reason, clinical assessment methods are more commonly used⁸.

The Ashworth Scale (MAS) is the most widely used because of its ease of application with no tools required. Other commonly used scales are the Modified Tardieu Scale (MTS), the Penn Spasm Frequency Scale (PSFS) or the Spinal Cord Assessment Tool for Spastic Reflexes (SCATS)^1,4.

Spasticity treatment

t is not always necessary to treat this symptom. This is why a good clinical history and evaluation must be carried out to design a treatment plan. It is important to address it in those cases in which it is related to pain, muscle contractures and functional limitations^1,8.

One of the treatments for spasticity is pharmacological options such as botulinum toxin, which is the chosen treatment for local spasticity. However, it is an expensive treatment and can cause adverse effects such as muscle weakness², besides other pharmacological options (baclofen, oral antispastic) there are surgical ones (tenotomies, rhizotomy)^1,6.

There are also physiotherapy options such as manual therapy, cryotherapy, thermotherapy, transcutaneous electrical neuromuscular stimulation, transcutaneous epidural spinal cord stimulation, functional electrical stimulation, invasive techniques (acupuncture, electroacupuncture, dry needling) and robotic therapy^1,6.

Spasticity challenges in gait rehabilitation

This syntomn is often a problem in neurorehabilitation because of its effect on the lower limb musculature (spastic rigid agonists and flaccid antagonists). This can lead to pathological gait patterns affecting both stance and swing phase balance due to the inverted foot^2,8.

It has been shown that repetitive movements and functional training can help reduce spasticity, however, these usually can’t be achieved with conventional therapy. For this reason, robotic rehabilitation has been increasingly implemented in recent years (including static exoskeletons, portable exoskeletons, and end-effector devices). This approach enables repetitive, rhythmic, and reproducible training, offering significant benefits such as a marked reduction in spasticity in these patients⁹. 

References:

1. Billington, Z. J., Henke, A. M., & Gater, D. R. (2022). Spasticity Management after Spinal Cord Injury: The Here and Now. Journal of Personalized Medicine, 12(5), 808. https://doi.org/10.3390/jpm12050808
2. Chen, Y., Jiang, L., Cheng, Y., Chen, C., Hu, J., Zhang, A., Hua, Y., & Bai, Y. (2023). Focal vibration of the plantarflexor and dorsiflexor muscles improves poststroke spasticity: A randomized single-blind controlled trial. Annals of Physical and Rehabilitation Medicine, 66(3), 101670. https://doi.org/10.1016/j.rehab.2022.101670
3. Rivelis, Y., Zafar, N., & Morice, K. (2024). Spasticity. En StatPearls. StatPearls Publishing. http://www.ncbi.nlm.nih.gov/books/NBK507869/
4. Sáinz Pelayo, M. P., Albu, S., Murillo, N., & Benito Penalva, J. (2020). Espasticidad en la patología neurológica. Actualización sobre mecanismos fisiopatológicos, avances en el diagnóstico y tratamiento. Revista de Neurología, 70(12), 453. https://doi.org/10.33588/rn.7012.2019474
5. Suputtitada, A. (2023). Emerging theory of sensitization in post-stroke muscle spasticity. Frontiers in Rehabilitation Sciences, 4, 1169087. https://doi.org/10.3389/fresc.2023.1169087
6. Javier-Ormazábal, A., González-Platas, M., González-Sierra, E., & González-Sierra, M. (2022). Invasive Physiotherapy as a Treatment of Spasticity: A Systematic Review. Degenerative Neurological and Neuromuscular Disease, Volume 12, 23-29. https://doi.org/10.2147/DNND.S350192ç
7. Su, D., Wang, A., Zhu, M., Yang, F., Li, W., Ma, B., Liu, M., Li, Z., Wang, B., Tu, H., & Ning, B. (2023). Repetitive transcranial magnetic stimulation for treatment of limb spasticity following multiple sclerosis: A systematic review and meta-analysis. Brazilian Journal of Medical and Biological Research, 56, e12708. https://doi.org/10.1590/1414-431x2023e12708
8. Francisco, G. E., Wissel, J., Platz, T., & Li, S. (2021). Post-Stroke Spasticity. En T. Platz (Ed.), Clinical Pathways in Stroke Rehabilitation (pp. 149-173). Springer International Publishing. https://doi.org/10.1007/978-3-030-58505-1_9
9. https://doi.org/10.3390/jcm12237230