Postural instability and lower extremity dysfunction in upper motor neuron-dominant amyotrophic lateral sclerosis

Area of Science:

• Neurology
• Neurodegenerative Diseases
• Motor Neuron Diseases

Background:

• Upper motor neuron-dominant ALS (UMND ALS) is characterized by early onset and a generally good prognosis.
• However, UMND ALS can present with gait instability and rapid motor function decline early in the disease.
• This study focuses on lower extremity function in UMND ALS, especially in patients with postural instability or falls (UMND ALS plus).

Purpose of the Study:

• To investigate changes in lower extremity function in UMND ALS patients.
• To compare UMND ALS and UMND ALS plus patients with classic ALS regarding motor function and prognosis.
• To determine if UMND ALS represents a distinct subgroup of ALS.

Main Methods:

• Retrospective review of 2,353 ALS patients.
• Identification of 211 patients (9.0%) with UMND ALS.
• Comparison of lower extremity function, strength, time to assistance, and ambulation loss between UMND ALS, UMND ALS plus, and classic ALS groups.

Main Results:

• UMND ALS patients had a longer diagnosis delay and restricted symptoms.
• While initially showing better lower extremity function than classic ALS, UMND ALS patients did not differ in time to needing assistance or losing ambulation.
• UMND ALS plus patients exhibited severe upper motor neuron symptoms and a rapid motor function decline comparable to classic ALS, with no better lower extremity function.
• Both UMND ALS and UMND ALS plus demonstrated significantly better prognoses than overall ALS.

Conclusions:

• UMND ALS, despite restricted symptoms, shows a rapid early decline in lower extremity function.
• The motor function decline in UMND ALS plus mirrors that of classic ALS.
• Further research is needed to ascertain if these patient groups constitute distinct ALS subgroups.