Multiple sclerosis (MS) is a lifelong neurological disease that develops when a person’s immune system attacks the protective covering (myelin sheath) of nerve fibers in their brain and spinal cord. MS-related disability occurs as a result of relapses, the natural progression of the disease, or a combination of both.
The Multiple Sclerosis Functional Composite (MSFC) is a standardized three-part tool used to assess the degree of disability in patients with MS. The MSFC was created for use in clinical studies and measures three key areas of MS-related disability: leg/walking function, arm and hand function, and cognitive function.
This article will review these three components and explain how the MSFC is administered and scored.
Developed by the National MS Society (NMSS) Clinical Outcome Assessment Task Force in 1994, the MSFC reflects the progression of neurological disability through the following three distinct tests.
25 foot timed walk (T25W)
The T25W measures leg function and gait.
During T25W, the patient is asked to walk 25 feet as fast as possible (called Trial 1). The patient is then immediately asked to walk to the starting point (called Trial 2). A five-minute rest period after Trial 1 is allowed and a walking aid, such as a cane or walker, may be used during the trial.
The test is aborted if the patient cannot complete Trial 1 or Trial 2 within 180 seconds.
9-hole peg test (9HPT)
9HPT measures arm and hand function.
During 9HPT, in a seated position, the patient is asked to place pegs one by one into nine separate holes arranged in a board placed on a table. Then the patient is asked to remove the ankles. Each hand is tested twice.
The time required for the patient to place and remove all nine pegs is recorded for each trial. The test is aborted if the patient cannot complete the test within five minutes.
Paced Auditory Serial Addition Test (PASAT-3)
The PASAT-3 measures cognitive function, specifically information processing and speed, working memory, and attention.
During PASAT-3, a series of numbers is presented by an audio cassette or compact disc (CD) player every three seconds. The patient is asked to add the digits and the number of correct answers is recorded.
Up to three practice trials with a set of 10 numbers are allowed before the actual test. The test is interrupted if the patient does not obtain at least two correct answers (consecutive or not) on one of the three practical tests.
The MSFC is administered by a trained examiner, usually a neurologist (doctor who specializes in conditions of the brain and nervous system), nurse, physician assistant, or health technician. The administration time for the three measures is approximately 20 to 30 minutes.
At the start of MSFC, the examiner spells out the instructions exactly as they appear in the MSFC manual. Translations of the instructions are available in several languages, including French, German, Dutch, Greek and Hebrew.
The MSFC examiner is trained to be friendly and approachable, but also professional and objective. This means that they cannot share comments or information about the patient’s performance during the tests.
Since the whole process can be a bit difficult and extremely nerve-wracking, the examiner is trained to help the patient maintain physical and emotional comfort during all three tests.
The testing space for the MSFC is usually a separate, designated room; however, the 25-foot timed walk test can be performed in a public hallway.
To minimize distractions, only the patient and examiner are present in the testing area. Cell phones, pagers, and watches are turned off and the room is clear of any obstructions or unnecessary materials. A “Do Not Disturb” sign is usually placed on the door when testing is in progress.
How an MSFC score is calculated
The MSFC score is obtained by converting the scores of each component/test into a Z-score. If the tests cannot be completed due to disability or fatigue, a certain score (not necessarily zero) is assigned on the based on MSFC instructions.
Z-scores, which are calculated from standardized formulas, are then averaged to create an overall composite score.
Z-scores compare a patient’s individual results to the average found in a reference population.
Composite scores can be compared between treatment and control groups in MS clinical trials to assess the benefit of certain clinical interventions, such as taking disease-modifying antirheumatic drugs (DMARDs). They can also be analyzed over time to assess improvement or worsening of individual disability.
Besides the composite score, the three individual scores are also usually examined. This is because a patient may experience a worsening of their disability in one area such as walking over time, but an improvement in another area such as cognition (mental processes by which knowledge and understanding are enhanced).
As such, a patient’s overall MSFC score could remain stable since their scores in all three domains are average, even if their functioning in one domain deteriorates.
As with any clinical assessment tool or instrument, MSFC scores should be interpreted correctly and thoughtfully.
The MSFC is a three-part tool used in clinical studies to measure disability progression in patients with MS. It includes assessment of leg function, arm and hand function, and cognitive function. Scores for each of the three components are converted to Z-scores and averaged to create an overall composite score.
A word from Verywell
Scientific evidence consistently suggests that the MSFC is an appropriate and valid tool to assess the degree of impairment in patients with MS. Of course, like any research tool, the MSFC has some drawbacks, for example, it does not address issues associated with vision, sensory function, bladder, bowels, or sexual function.
Either way, getting some basic knowledge about the MSFC is a sensible and challenging strategy. Your neurologist can discuss this during an appointment, or you can meet with them one day if you or a loved one decides to participate in an MS clinical trial.