MMT Limitations and Considerations 2 — Questions and Answers
Question 1: Why is MMT considered less reliable when testing muscles in the antigravity position for patients with spasticity?
- Spasticity increases passive resistance, artificially inflating apparent muscle strength (Correct answer)
- Spasticity reduces pain sensitivity, making grading easier
- Spasticity causes atrophy that prevents full ROM
- Spasticity only affects Grade 1 and Grade 2 muscles
Correct answer: Spasticity increases passive resistance, artificially inflating apparent muscle strength
Spasticity adds passive resistance during movement, making a muscle appear stronger than it truly is on voluntary activation.
Question 2: Which of the following represents a PRIMARY psychometric limitation of the standard MMT ordinal scale?
- The intervals between grades are not mathematically equal (Correct answer)
- The scale cannot detect full paralysis
- The scale requires expensive dynamometry equipment
- The scale is only valid for lower extremity muscles
Correct answer: The intervals between grades are not mathematically equal
MMT uses an ordinal scale, meaning grade intervals (e.g., 3 to 4) do not represent equal increments of actual force.
Question 3: A patient has severe joint effusion in the knee. How does this most directly affect MMT validity for quadriceps testing?
- Arthrogenic inhibition reflexively reduces quadriceps activation, underestimating true strength (Correct answer)
- Effusion increases quadriceps recruitment, overestimating strength
- Effusion has no effect because MMT measures isometric force only
- Effusion prevents positioning but does not alter the grade
Correct answer: Arthrogenic inhibition reflexively reduces quadriceps activation, underestimating true strength
Joint effusion triggers arthrogenic muscle inhibition, which reflexively suppresses muscle activation and leads to underestimation of volitional strength.
Question 4: When testing a patient who is obese, the examiner's ability to palpate muscle contraction for Grade 1 detection is most likely to be:
- Reduced due to increased subcutaneous tissue obscuring contraction (Correct answer)
- Enhanced because adipose tissue transmits force more effectively
- Unaffected because Grade 1 relies on visual observation only
- Improved because body weight assists gravity-eliminated positioning
Correct answer: Reduced due to increased subcutaneous tissue obscuring contraction
Excess subcutaneous adipose tissue dampens palpatory feedback, making it harder to detect a trace Grade 1 contraction.
Question 5: Which statement best describes the limitation of MMT in detecting early strength deficits in high-level athletes?
- MMT ceiling effects prevent detection of deficits in muscles that are strong enough to resist manual force (Correct answer)
- MMT is too time-consuming for use in athletic populations
- Athletes always score Grade 5, making MMT inapplicable
- MMT overestimates deficits in athletes due to high pain tolerance
Correct answer: MMT ceiling effects prevent detection of deficits in muscles that are strong enough to resist manual force
A Grade 5 ceiling effect means manual resistance cannot distinguish a 10% strength deficit from normal in a well-trained athlete.
Question 6: How does examiner fatigue most commonly introduce error into a serial MMT assessment session?
- The examiner applies progressively less resistance over time, inflating grades in later tests (Correct answer)
- Fatigue causes the examiner to shorten stabilization, deflating grades
- Fatigue increases examiner sensitivity, making grades more accurate
- Examiner fatigue has no documented effect on MMT reliability
Correct answer: The examiner applies progressively less resistance over time, inflating grades in later tests
As the examiner tires, the magnitude of applied resistance decreases, leading to artificially higher grades for muscles tested later in the session.
Question 7: In a patient with upper motor neuron lesion, why is MMT grading of individual muscles particularly problematic?
- UMN lesions impair selective voluntary motor control, making isolated muscle testing nearly impossible (Correct answer)
- UMN lesions cause flaccid paralysis that eliminates all reflexes needed for testing
- UMN lesions restrict ROM to gravity-eliminated planes only
- UMN lesions only affect sensory grading, not motor output
Correct answer: UMN lesions impair selective voluntary motor control, making isolated muscle testing nearly impossible
UMN lesions disrupt the ability to selectively activate individual muscles, so movement patterns rather than isolated contractions are observed.
MMT Limitations and Considerations 2
Why is MMT considered less reliable when testing muscles in the antigravity position for patients with spasticity?