What is the Pyramidal Functional Score (FS) for a patient with a slight downward drift of the right leg in the pronator drift test, who is unaware of the deficit and has a normal walking range?

From the Guidelines

The Pyramidal FS score in this case would be 1, as indicated by the slight downward drift of the right leg during the position test, which corresponds to a score of 1 for Motor Leg in the National Institutes of Health Stroke Scale (NIHSS) 1. This score reflects a mild neurological deficit in the pyramidal system, characterized by the slight downward drift of the right leg during the position test, despite the patient being unaware of the deficit and maintaining normal walking range.

• The NIHSS is an 11-part scale that measures the neurologic examination in a codified manner, with the Motor Leg component assessing the ability to raise the leg to 30 degrees and hold for 5 seconds, testing both sides 1.
• A score of 1 for Motor Leg indicates drift but does not hit the bed, which matches the clinical finding of a slight downward drift of the right leg in this case.
• The Pyramidal FS score is part of various neurological assessments, where 0 represents normal function and higher scores indicate increasing disability.
• A score of 1 indicates abnormal signs without disability, which matches this clinical scenario perfectly, as the patient has a normal walking range and is not aware of the deficit.
• The downward drift suggests subtle weakness or impaired motor control in the right leg, likely due to a minor upper motor neuron lesion affecting the corticospinal tract, but not severe enough to impact functional mobility or cause noticeable symptoms for the patient 1.
• This subtle finding warrants documentation and follow-up to monitor for any progression of neurological deficits over time.

From the Research

Pyramidal FS Score

The Pyramidal Functional System (FS) score is used to assess the severity of pyramidal tract lesions in multiple sclerosis patients.

• A slight downward drift of the right leg in the position test indicates a mild pyramidal tract lesion.
• According to the studies, the Pyramidal FS score is typically graded on a scale from 0 to 6, with higher scores indicating more severe impairment 2, 3, 4.
• However, the exact score for a slight downward drift of the right leg is not explicitly stated in the provided studies.
• The studies suggest that the Pyramidal FS score is an important component of the Expanded Disability Status Scale (EDSS) and is used to assess disability progression in multiple sclerosis patients 2, 3, 4.
• The Pyramidal FS score is often affected in patients with multiple sclerosis, and changes in this score can contribute to changes in the overall EDSS score 3, 4.

Determining the Pyramidal FS Score

• The studies do not provide a clear definition of the Pyramidal FS score for a slight downward drift of the right leg.
• However, based on the information provided, it can be inferred that a slight downward drift of the right leg would likely correspond to a low Pyramidal FS score, possibly a 1 or 2, indicating mild impairment 2, 3, 4.
• Further evaluation by a physician or a detailed assessment of the patient's condition would be necessary to determine the exact Pyramidal FS score.

Relationship to Other Studies

• The concept of pyramidal weakness has been explored in other studies, which have investigated the pattern of weakness observed in central nervous system (CNS) lesions 5.
• These studies have found that the phrase "pyramidal weakness" has been used to describe a specific pattern of motor weakness involving upper limb extensors and lower limb flexors, although this pattern is not universally observed in CNS lesions 5.