Simply monitoring brain function

Van Schependom J, D’hooghe MB, Cleynhens K, D’hooge M, Haelewyck MC, De Keyser J, Nagels G. The Symbol Digit Modalities Test as sentinel test for cognitive impairment in multiple sclerosis.Eur J Neurol. 2014 May. doi: 10.1111/ene.12463. [Epub ahead of print]

BACKGROUND AND PURPOSE:Cognitive impairment (CI) is found in about half of the multiple sclerosis (MS) population and is an important contributor to employment status and social functioning. CI is encountered in all disease stages and correlates only moderately with disease duration or Expanded Disability Status Scale scores. Most present neuropsychological test batteries are time-demanding and expensive. The Symbol Digit Modalities Test (SDMT) has been suggested as a screening tool for CI in MS. In this paper, we aim to assess the performance of the SDMT in predicting the outcome of an extensive battery.
METHODS: Neuropsychological test results from 359 patients were assessed in a multidisciplinary MS center (National MS Center Melsbroek, Belgium). Using receiver operating characteristic curves, the performance of the SDMT in predicting the general cognitive outcome of the extensive Neuropsychological Screening Battery for MS (NSBMS) could be assessed. The performance of the SDMT was assessed for different levels of CI and compared with other cognitive tests. Finally, useful covariates were included in a logistic regression model.
RESULTS: At a specificity of 0.60 a high sensitivity (0.91) was obtained indicating the potential of the SDMT as a sentinel test for CI in MS. The SDMT outperformed the individual tests included in the NSBMS, used as benchmark. As the logistic regression model did not result in a relevant improvement, it is concluded that most clinical variables influence both the SDMT and the NSBMS in a similar way. Excluding patients with possible practice effects, an optimal cutoff of 40 was found for the SDMT.
CONCLUSION: As the SDMT is an easy, low-cost and fast test, this result may help to detect CI in everyday clinical practice.

The Symbol Digit Modalities Test (SDMT) detects cognitive impairment in less than five minutes. This  can detect changes in cognitive functioning over time and in response to treatment. It is an economical way to screen apparently normal children and adults (ages 8-78 years) for possible motor, visual, learning, or other cerebral dysfunction.

The SDMT involves a simple substitution task. Using a reference key (See above), the examinee has 90 seconds to pair specific numbers with given geometric figures. Because examinees can give either written or spoken responses, the test is well suited for use with individuals who have motor disabilities or speech disorders. Because it involves only geometric figures and numbers, the SDMT is relatively culture free as well and can be administered to individuals who do not speak English. 

About the author



By MouseDoctor



Recent Posts

Recent Comments