What are the causes and symptoms of Upper Motor Neuron (UMN) disorders?

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Last updated: May 13, 2025View editorial policy

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From the Guidelines

Upper motor neuron disorders, such as poststroke spasticity, should be managed with a focus on reducing spasticity and improving quality of life, using treatments like botulinum toxin injections and physical therapy, as the cost of care is significantly higher when spasticity is present 1. The management of upper motor neuron disorders involves addressing the underlying cause when possible and alleviating symptoms, particularly spasticity, which is a component of the upper motor neuron syndrome.

  • Spasticity is correlated with activity limitations associated with hygiene, dressing, and pain, and increases caregiver burden and reduces quality of life as measured by the EuroQol-5 1.
  • The prevalence of poststroke spasticity in any limb is in the range of 25% to 43% over the first year after stroke, highlighting the need for early intervention 1. Some key considerations in managing upper motor neuron disorders include:
  • The use of botulinum toxin injections for upper limb spasticity combined with therapy, although not found to be cost-effective compared with therapy alone in one study, may still be beneficial in certain cases 1.
  • Physical therapy is essential to maintain range of motion and prevent contractures, and should be tailored to the individual's needs and abilities.
  • Medications such as baclofen, tizanidine, and dantrolene may be used to reduce muscle tone, although the specific treatment regimen will depend on the individual's condition and response to treatment. Overall, the goal of management should be to reduce spasticity, improve quality of life, and maintain functional independence, while also considering the potential impact on caregiver burden and overall cost of care 1.

From the Research

Upper Motor Neuron Disorders

  • Upper motor neuron disorders, such as amyotrophic lateral sclerosis (ALS), are characterized by the degeneration of upper motor neurons in the motor cortex and lower motor neurons in the brainstem and spinal cord 2.
  • This combined loss of function causes spastic paralysis, flaccid muscle weakness, wasting, and fasciculations, while sparing the sensory, autonomic, and oculomotor neurons 2.
  • ALS is the most common of the motor neuron disease (MND) syndromes in adults, accounting for 80%-90% of cases 3.

Symptoms and Diagnosis

  • Symptoms of upper motor neuron disorders include progressive weakness and wasting of voluntary muscles, with an average life expectancy of 3-5 years for ALS patients 4.
  • Electrodiagnostic examination, specifically electromyography (EMG) and nerve conduction studies (NCS), is one of the key diagnostics of ALS 4.
  • Differentiation between primary lateral sclerosis (PLS) and ALS can be made based on symptoms and signs at disease onset and during follow-up, with stiffness being a significant symptom at presentation in PLS patients 5.

Treatment and Management

  • Riluzole is a benzothiazole derivative that blocks glutamatergic neurotransmission in the CNS, exerting neuroprotective effects, and is the only disease-specific treatment available for ALS 6.
  • Riluzole has been approved by the US FDA and has modest efficacy in ALS, prolonging tracheostomy-free survival by only 2-3 months 6.
  • Other treatments are aimed at managing the devastating symptoms of ALS, with a thorough understanding of the symptomatology, potential cause(s), progression, and treatment being essential to provide timely and high-quality patient care 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Amyotrophic lateral sclerosis: current understanding.

The Journal of neuroscience nursing : journal of the American Association of Neuroscience Nurses, 2001

Research

Riluzole for the treatment of amyotrophic lateral sclerosis.

Neurodegenerative disease management, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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