Cognitive Deficit Screening in MS

A short screening tool is a valid instrument as a time- and cost-efficient first assessment of cognitive deficits in multiple sclerosis (MS) patients, according to a new study.

Up to two-thirds of MS patients have neuropsychological deficits that impact their quality of life, most commonly deficits in attention and information-processing speed as well as long-term and working memory. Yet the deficits frequently remain undiscovered during routine clinical examinations due to time constraints. 

To tackle this problem, clinicians can use short test batteries with the explicit purpose of diagnosing cognitive deficits in MS. The Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) and the Brief Repeatable Battery of Neuropsychological Tests (BRB) are widely accepted as valid screening tools for testing MS patients, noted the authors, led by Sacha Hansen of the Department of Neurology, Klinikum Bayreuth, Bayreuth, Germany.

The BICAMS takes only approximately 15 minutes of testing time, while the BRB entails a relatively lengthy testing procedure that takes approximately 90 minutes. The BICAMS focuses on processing speed as well as verbal and nonverbal memory, but lacks assessment of executive functions, they noted.

A pioneering shortened version of the BRB, designed to be a quick and economic screening tool, showed high sensitivity and specificity.

The German researchers examined the sensitivity and specificity of the short version of the BRB with regards to the presence or absence of cognitive deficits as determined by an extensive neuropsychological diagnostic procedure not including three BRB subtests in question. This two-hour procedure thoroughly examined all cognitive domains that may be deficient in MS patients.

The short version of the BRB was matched against the gold standard of an extensive test battery comprehensively assessing neuropsychological functions.

“The proportion of patients who were identified as displaying cognitive deficits was relatively similar between the screening (59.5%) and the extensive procedure (57.1%). As such, it resembles common estimates, according to which neuropsychological deficits occur in about 40-65% of MS patients,” the researchers stated.

The original pioneering study reported specificity estimates of 84% and sensitivity estimates of 94% for the short version of the BRB, but the new study estimated specificity at 64.8% and sensitivity at 77.8%.

Even so, “estimates were still reasonable, when the screening was considered as a global predictor,” they stated, in particular with regards to sensitivity, representing the proportion of patients adequately identified as cognitively impaired by the screening.

They believe that the findings complement previous suggestions and provide further support for the utility of the short version of the BRB as a valid screening tool, particularly when screening is regarded as a global indicator.

The researchers conclude that “the short BRB is reasonably sensitive and specific in detecting cognitive deficits. However, these qualities only emerge, if the short BRB is administered as a whole, whereas sensitivity is considerably lower than suggested by previous work, when relying on subtests separately. While the short BRB may not be regarded as conclusive as an extensive test battery, it represents a valid and economic screening instrument.”

Reference: Hansen S, et al. Cognitive screening tools in multiple sclerosis revisited: sensitivity and specificity of a short version of Rao's Brief Repeatable Battery. BMC Neurol. 2015 Nov 26;15:246.