Accounting for Practice Effects on the MS Performance Test
Stephen Rao, PhD, ABPP-Cn, the Ralph and Luci Schey Chair and Director of the Schey Center for Cognitive Neuroimaging at Cleveland Clinic, discussed the development of the MSPT.
Stephen Rao, PhD, ABPP-Cn
A recent study presented at the 2021 American Academy of Neurology (AAN) Annual Meeting, April 17-22, by Shirley Liao, PhD, MS, biostatistician, Biogen, revealed that several facets of the Multiple Sclerosis Performance Test (MSPT) battery are susceptible to significant practice effects (PE).
Liao and colleagues found that the Processing Speed Test (average increase, 3 points; P <.001) and Manual Dexterity Test (average decrease, 1 second; P = .005) showed significant PE. Walking speed test scores did not show significant PE (P = .07). Larger PE was seen with younger patients (P <.001), patients with fewer self-reported depression symptoms (P <.001), and patients with lower baseline Patient Determined Disease Steps (P <.001) after Bonferroni correction.
NeurologyLive spoke with senior author Stephen Rao, PhD, ABPP-Cn, the Ralph and Luci Schey Chair and director, Schey Center for Cognitive Neuroimaging, Cleveland Clinic, about the development of the MSPT. He detailed why PE pose an issue in interpreting performance.
NeurologyLive: Can you provide some background on the MSPT?
Stephen Rao, PhD, ABPP-Cn: So, probably about 6, 7 years ago, we developed a battery of tests called the MSPT. This is a completely automated system delivered to patients on an iPad. When a patient with MS comes into see their doctor, they're led into a room with several cubicles. In those cubicles is an iPad and some other equipment. It's completely self-administered. So, they take 1 test, a measure of cognition, which we call the processing speed test. Another 1 looks at manual upper extremity manual dexterity and the patient has to move a peg over the top of the iPad, and it automatically records the speed at which they're able to move the peg from one location to the other. Then we do a walking speed test they time on their own in which they have to walk 25 feet, we have a special room for that.
The processing speed test measures what we call sustained attention. The person is given a key at the top with 9 different symbols and below are the numbers 1 through 9. The middle row has just the symbols but no numbers underneath it. The patient has to put the correct number under the symbol for 2 minutes. It turns out that particular test, which is based on a clinical measure, is very sensitive to the cognitive problems that people with MS have.
All that makes up the MSPT. It started off in the Cleveland Clinic and has now been administered in around 50 medical centers now. We've developed a database of patients' performance, which is called the MS PATHS.
How do PE present an issue?
The problem is that people learn how to take a test, and that’s called PE. If you take the test several times, your performance will get slightly better every time because you are becoming more familiar with how the test operates and you get slightly better. So that's a problem when it comes to interpretation of whether the person has gotten worse, because technically, they could have gotten worse, but their performance looks like it's flat, because PE have negated the deterioration in performance. We give this test on average about every 6 months because we want to know if the patient has worsened, and PE gets in the way of that.
If a person has experienced a significant deterioration in their cognitive function, they may need to be referred to a more comprehensive neuropsychological battery and use that to help guide them in terms of providing more accurate information to family members to the patient, and maybe put them in a cognitive rehabilitation program. So that's why we want to correct for those longitudinal effects, so that we can understand and gain a better understanding of true deterioration effects, minus the PE that are more of an artifact of testing.
Transcript edited for clarity. For more coverage of AAN 2021, click here.
