Learning impairments in multiple sclerosis (MS) are detected differently by the two most commonly used neuropsychological tests, a new study by the Kessler Foundation shows.
The research, titled “Comparing the Open Trial – Selective Reminding Test results with the California Learning Verbal Test II in multiple sclerosis,” was published in the journal Applied Neuropsychology: Adult.
Cognitive impairments in MS patients may include deficits in learning and memory, attention, concentration and information-processing speed, and other processes.
In the OT-SRT, a person is asked to learn a list of 10 words until they achieve complete recall on two consecutive trials. Research showed that patients with MS required more trials to reach this goal than healthy controls.
CVLT-II was originally proposed as the standard test to assess verbal memory in MS. Diverse studies have reported that a significant proportion of MS patients perform poorly on this test.
Although prior studies showed that both tests had similar sensitivity in detecting differences between MS patients and controls, they did not compare how the same individuals perform on the two tests.
Research in traumatic brain injury and stroke showed that CVLT-II and SRT may lead to different results for learning impairments, which underscores that the two tests should not be used interchangeably, the authors noted.
The research team then compared the OT-SRT and CVLT-II as tests of learning impairment in MS. A total of 112 participants (79 women) completed both tests in two days. They also completed tests assessing working memory, information-processing speed, and executive function, which comprises the control of goal-directed action and adaptive responses.
Results revealed that while all individuals were classified as impaired with OT-SRT, only 34 percent had a similar identification with CVLT-II. This difference may be explained by the extent to which the tests rely on cognitive skills other than learning and memory, the authors stated.
Detailed analysis showed that patients who failed both tests performed more poorly in tests of working memory, executive function, and information-processing speed than those who failed only the OT-SRT.
The data also showed that executive function correlates with learning on the CVLT-II, but not the OT-SRT.
“The CVLT II and the OT-SRT are not equivalent tests: while the CVLT II appears to be sensitive to overall cognitive dysfunction, the OT-SRT is more sensitive to focal learning and memory impairments,” the researchers wrote.
“It is essential that the neuropsychological assessment accurately pinpoint the deficits in MS,” Silvana L. Costa, PhD, the study’s lead author and a research scientist at Kessler, said in a press release. “This is fundamental to developing interventions to address these deficits, and tailoring cognitive rehabilitation programs for maximal outcomes in this population.”