Background: Recent research has convincingly shown that the ability to work mainly depends on the cognitive status in multiple sclerosis (MS). An international committee of experts recommended a brief neuropsychological battery to evaluate cognitive performance in MS. BICAMS comprises three tests, the Symbol Digit Modalities Test (SDMT), the learning trials of the California Verbal Learning Test II (CVLT-II), and the Brief Visuospatial Memory Test-Revised (BVMT-R).
Objective: To validate BICAMS on a sample of German MS patients and healthy controls (HCs).
Methods: According to the international guidelines for validation, examiner's instructions were standardized and translated into German. Due to the availability of better normative data for future applications in routine clinical care and classification of individual performance degree, the Rey Auditory Verbal Learning Test (RAVLT) (German version: Verbaler Lern- und Merkfähigkeits-Test, VLMT) was chosen instead of CVLT-II. 172 MS patients and 100 HCs entered the study. BICAMS was administered at baseline and retest (after 3-4 weeks).
Results: The groups did not differ in age, gender or education. Mean age of MS patients was 43.33 years (SD 11.64); 68% were female and 86.9% had relapsing-remitting MS. Patients performed significantly worse than HCs on the SDMT (p < 0.01) and on BVMT-R (p < 0.05) but not on VLMT. In addition, BICAMS was shown to be reliable over time: r = 0.71 for BVMT-R, r = 0.72 for VLMT and r = 0.85 for SDMT. SDMT z-score proved to be a good predictor for the ability to work in a full-time (p < 0.001) as well as in a part-time job (p < 0.001). VLMT z-score turned out to be a significant predictor only for the ability to work in a part-time job, while BVMT-R z-score showed no significant predictive value.
Conclusion: In this German validation study with the VLMT, the modified BICAMS (BICAMS-M) turned out to reliably detect cognitive problems in MS patients and to monitor cognitive performance over time. SDMT revealed the best predictive value for working ability. Moreover, only the SDMT was able to predict the ability to work in a part-time or full-time job. Following these results, application of the SDMT is recommended for medical statements on working ability of MS patients.
Keywords: BICAMS; Cognition; Multiple sclerosis; Validation; Working ability.