Abstract
Background
The present review aimed to identify published studies that reported the validation of the Brief Cognitive Assessment for Multiple Sclerosis (BICAMS) in Latin America (LATAM).
Methods
To compile a comprehensive list of available validation studies, we performed a systematic review of the literature via an electronic search of PubMed and Web of Science via the keywords “Validation,” “Brief Cognitive Assessment for Multiple Sclerosis,” “BICAMS,” and “Latin America.”
Results
Twenty-seven sources of validation studies for the BICAMS were identified. Of the 27 citations identified, only four provide validation of the BICAMS in LATAM. These studies include a comparison of cognitive performance between multiple sclerosis (MS) patients and healthy controls (HCs) across all three BICAMS tests. Overall, the studies included a greater proportion of patients with RRMS and middle-aged adults and included participants with wide ranges of education levels.
Conclusion
We provide a detailed description of the BICAMS validation currently available for people living in LATAM. Although the validation of tests in diverse populations has gained interest in the field, there is still a need for more studies among people from LATAM countries.
Introduction
Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system (CNS) that primarily affects young adults (mean onset, 20–40 years).1,2 It is more common in women than in men. 3 According to a 2020 study conducted by Walton et al., an estimated 2.8 million people worldwide are living with MS. 4 Several studies have examined the prevalence of MS in Latin America (LATAM). In Argentina, the estimated prevalence ranges from 14 to 19.8 cases per 100,000 inhabitants. 5 Another study in the same country reported that the crude prevalence rate of MS in Rosario was 48.3/100,000 inhabitants (95% confidence interval [CI]: 48.28–48.35), 63.7/100,000 for females and 28.3/100,000 for males. 6 A study conducted in Brazil reported a prevalence of 15.54/100,000 inhabitants. 7 In 2021, another study in Brazil reported that the point-prevalence rate for MS was 26.4/100,000 people (95% CI, 19.7 to 34.6/100,000). 8 In Colombia, the prevalence rate was 4.41/100,000 inhabitants. 9 Studies conducted in Mexico reported that MS affects between 11% and 20% of the Mexican population.10,11
The clinical symptoms and signs of MS include sensory, motor, fatigue, depression, anxiety, pain and visual problems. 12 In addition to their physical symptoms, MS patients present with cognitive impairment (CI). 13 Several studies have reported that approximately 50%–70% of MS patients have CI.14–18 CI occurs independently of the course and stage of the disease.19,20 It interferes with the performance of activities of daily living (work, school, social functioning and quality of life).21–26 CI is characterized by alterations in information processing, memory, attention, verbal fluency, visuospatial perception and executive functioning.27–30
The cognitive assessment in MS patients provides information regarding baseline conditions and cognitive changes and allows for the planning of early cognitive interventions.15,31 Some studies have demonstrated that identifying cognitive dysfunction provides greater benefits to the quality of life of MS patients.32,33 The diagnosis of cognitive impairment in MS patients requires neuropsychological batteries. Several cognitive tools have been proposed for identifying cognitive deficits in patients with MS. The Rao Brief Repeatable Battery of Neuropsychological Tests (BRB-N), 34 the Minimal Assessment of Cognitive Function in MS (MACFIMS), 27 and the Brief International Cognitive Assessment for MS (BICAMS) are neuropsychological tools commonly and widely used to measure CI in MS patients. 35 The BICAMS has been validated in several countries. 36 It is a tool for monitoring cognitive function and should be incorporated into clinical practice as a cognitive battery for assessing cognitive function. 37
A number of studies highlight how appropriate norms improve the sensitivity and specificity of neuropsychological tests.38–40 Normative data can control for the influence of demographic variables that have been shown to affect cognitive performance on neuropsychological tests.41–43 Despite the recognition that cognitive tools are needed for cognitive assessment, there is a lack of available neuropsychological test normative data for Spanish-speaking patients with MS. In 2020, a study conducted by Matias-Guiu et al. validated the Neuronorma battery for neuropsychology assessment in MS, which included 280 MS patients and 280 HCs. Their findings indicated that most tests showed medium or large effect sizes, which suggests adequate criterion validity. 44 In 2022, Rivera et al. validated the Norma Latina neuropsychological assessment battery in patients with MS in Mexico. The sample included 100 MS patients and 100 HCs. The participants were subjected to a cognitive assessment with a neuropsychological battery, and their findings indicated that the neuropsychological battery is sensitive for discriminating cognitive deficits in MS patients. 45 However, there is a paucity of available normative neuropsychological test data for MS patients in LATAM.
Validation studies conducted in countries other than the U.S. have been valuable resources for clinicians and researchers. However, to our knowledge, this is the first publication providing a review of available studies on the validation of BICAMS in LATAM. Our objective was to identify studies that have validated the BICAMS specifically in adults living in LATAM countries.
Methods
To compile a comprehensive list of available validation tests for the BICAMS, we used a systematic review of the literature to identify published validation studies for LATAM countries. We conducted a search on PubMed and Web of Science via the keywords “Validation,” “Brief Cognitive Assessment for Multiple Sclerosis,” “BICAMS,” and “Latin America.” This search yielded 27 citations from which relevant studies were selected. From that search, four citations contained validation of the BICAMS, specifically for adults in LATAM.
Cognitive instrument
The administration of the BICAMS can be completed in approximately 15 minutes and does not require any special equipment or specific assessor training. 27 This instrument mainly assesses processing speed (the Symbols-Digit Modalities Test-SDMT), learning and verbal memory (the California Verbal Learning Test-CVLT), and visuospatial memory (the Brief Visuospatial Memory Test-BVSMT-R). These subtests are reliable and sensitive for identifying cognitive impairment in MS patients. 36
This instrument consists of three different tests: (1) The SDMT has good psychometric properties (a sensitivity of 82% and a specificity of 60%).27,43 This instrument involves two key rows, where the upper row contains a series of nine abstract geometric symbols and the lower row contains corresponding numbers (1–9). The SDMT can be completed within 5 minutes and includes instructions, tests and responses. The participants are instructed to verbally associate each symbol with its corresponding number as quickly as possible within a 90-second time frame. The score for this test is determined by the number of correct substitutions completed within the given time limit, with a maximum score of 110.28,46,47 The CVLT-II has excellent sensitivity and good predictive validity.48,49 (2) The CVLT-II requires the examiner to read a list of 16 words in five trials. All trials, including instructions, tests and responses, can be completed in 5–10 minutes. The participants are then asked to recall as many words as they can remember (in any order) a list given by the psychometrist of the study. The score for this test is calculated on the basis of the total number of words correctly recalled across the five trials. 50 (3) The BVMT-R has good psychometric properties. 27 In the BVMT-R, participants are shown a sheet of paper containing six abstract geometric designs. There are three learning trials, each with a duration of 10 seconds. After the stimulus is removed, the participants are given paper and pencil to draw the geometric designs from memory. Scores are determined by summing the scores from three trials (each drawing received a score of 0–2 points). 51
Results
Table 1 includes a summary of all validation studies for the BICAMS (including studies from LATAM and other countries). These studies compared cognitive performance between MS patients and healthy controls (HCs) via all three BICAMS tests.52–78 Below is a description of each study (four in total) that provides validation of the BICAMS for adults living in LATAM. Information on the other countries (23 in total) is available in Table 1 but will not be further described.
Study design and participant demographics.
Note: PAML: Prueba de Aprendizaje y Memoria con Codificacion Libre; BVMT-R: Brief Memory Test Revised; SDMT: Symbols Digit Modalities Test; GVLT: Greek Verbal Learning Test; FVLT: French Verbal Learning Test; VMAT: Verbal Memory Test; TVLT: The Tunisian Verbal Learning Test.
Spedo et al. validated the BICAMS for adults living in Brazil. The sample consisted of 58 MS patients and 58 HCs. The HCs were selected from community sources affiliated with the MS center in Brazil. The groups did not differ in terms of age (MS patients = 41.2 ± 12.2 years; HCs group = 40.3 ± 11.9; P = .689) or education level (MS patients = 12.7 ± 5.2 years; HCs group = 12.5 ± 3.6, P = .803). Student's t test revealed statistically significant differences in cognitive performance between MS patients and HCs across all three neuropsychological test scores. These significant differences were observed on the Symbol Digit Modalities Test (SDMT; t = 4.28; P < .001), the California Verbal Learning Test (CVLT-II; t = 5.21; P < .001), and the Brief Visuospatial Memory Test (BVMT-R; t = 2.52; P = .013). A sample of MS participants (n = 49) underwent follow-up assessments (within a two-week interval) of the BICAMS, using the same test forms as previously taken to enable test‒retest reliability analysis. The test-retest reliability for each test was high (SDMT [r = .86; P < .001], CVLT-II [r = .84; P < .001], and BVMT-R [r = .77; P < .001]). Additionally, the diagnostic validity of the BICAMS revealed that age was negatively correlated with all BICAMS tests for MS patients in the SDMT (r = −.30; P < .05), CVLT-II (r = −.30; P < .05), and BVMT-R (r = −.29; P < .05). Furthermore, education was positively correlated with all BICAMS tests for MS patients (CVLT-II, r = .18, P < .05; BVMT-R, r = .27, P < .05; and SDMT, r = .29, P < .05). Moreover, the study controlled for the main effects of age, education, Hospital Anxiety and Depression Scale-Depression (HADS-D), and Hospital Anxiety and Depression Scale-Anxiety (HADS-A) scores in an ANCOVA test but did not eliminate the significance of the group effect on any of the BICAMS tests: CVLT-II (F1,110 = 28.99; P < .001), BVMT-R (F1,110 = 7.77; P < .01), and SDMT (F1,110 = 21.09; P < .001). This study utilized mixed-factor ANCOVAs to model the learning curves of MS samples and HCs on the CVLT-II and BVMT-R. First, on the CVLT-II, HCs performed significantly better than did MS samples in all trials (F1,110 = 29.03; P < .001) and presented a significantly steeper learning curve (F1,111 = 10.82; P < .01). Second, for the BVMT-R, HCs performed significantly better than did the MS sample in all trials (F1,110 = 7.816; P < .01), with the interaction effect of time and learning curve demonstrating significance (F1,111 = 7.747; P < .01). 75
Vanotti et al. validated the BICAMS for adults living in Argentina. The sample consisted of 50 MS patients and 100 HCs. Participants were recruited from the general population of Buenos Aires City, Argentina. The groups did not differ significantly with respect to age (MS patients = 43.42 ± 10.17 years; HCs=42.37 ± 10.07 years; P = .55), education level (MS patients = 14.86 ± 2.78 years; HCs=14.94 ± 2.49 years; P = .86) or sex. A greater proportion of patients had relapsing-remitting MS (RRMS = 78%), followed by secondary progressive MS (SPMS=18%) and primary progressive MS (PPMS=4%). The mean Expanded Disability Status Scale (EDSS) score was 3.29 ± 2.55. Student's t test revealed statistically significant differences in cognitive performance between MS patients and HCs across all three BICAMS test scores. These significant differences were observed in the SDMT (P < .001), CVLT-II (P < .001), and BVMT-R (P = .017). The SDMT and CVLT-II tests (Cohen's d = 0.85) had large size effects (Cohen's d = 0.87), whereas the BVMT-R was small (Cohen's d = 0.40). A sample of MS patients (n = 25) underwent follow-up assessments (within a two-week interval) of the BICAMS, using alternate forms to mitigate practice effects (SDMT; CVLT-I = form 4 was used, and BVMT-R = form 4 was used to enable test‒retest reliability analysis). The test-retest reliability for each test was high (SDMT [r = .95], CVLT-I [r = .87] and BVMT-R [r = .82]).
Additionally, this study presented regression-based normative models for the BICAMS, controlling for demographic variables (Age, Age2, Sex, and Education). For the SDMT (Constant=10.9231; Age=−0.2218; Age2 = 0.0013; Sex=0.2850; Education=0.3714; and SD of residuals=2.5842); CVLT-II (Constant=4.8721; Age=−0.0603; Age2 = 0.001; Sex=1.079; Education=0.3819; and SD of residuals=2.7956); and BVMT-R (Constant=6.5162; Age=0.1438; Age2=−0.0029; Sex=−0.1892; Education=0.2111; and SD of residuals=2.8341). 76
Alarcón et al. validated the BICAMS for adults living in Colombia. The sample consisted of 50 MS patients and 100 HCs. HCs were recruited from the general population in Bogotá, Colombia. The groups did not differ significantly with respect to age (MS patients = 41.44 ± 10.99 years; HCs=37.75 ± 12.63 years; P = .089), education level (MS patients = 14.76 ± 2.61 years; HCs=14.73 ± 3.57 years; P = .57) or sex. All patients had RRMS, and the EDSS score was 1.33 ± 1.54. Student´s test revealed statistically significant differences in cognitive performance between MS patients and HCs across all three BICAMS test scores (SDMT, PAMCL = Prueba de Aprendizaje y Memoria con Codificación Libre, and BVMT). These significant differences were observed in the SDMT (P < .001), PAMCL (P = .04), and BVMT-R (P < .001). The effect sizes for the SDMT (Cohen's d = 0.59) and the BVMT-R were medium (Cohen's d = 0.58) and small for the PAMCL (Cohen's d = 0.38). A subsample of MS patients (n = 16) underwent follow-up assessments within a two-week interval using the same test forms (SDMT; PAMCL; and BVMT-R) used in session one, enabling test‒retest reliability analysis. The test‒retest reliability for each test was high (SDMT [r = .88], PAMCL [r = .86], and BVMT-R [r = .93]). Additionally, this study presented regression-based normative models for the BICAMS, controlling for demographic variables (Age, Education, and Sex) as follows: SDMT (Constant=7.901; Age=−0.107; Education=0.315; Sex=1.114; and SD of residuals=2.13463); PAMCL (Constant=8.05; Age=−0.055; Education=0.205; Sex=−; and SD of residuals=2.62747); and BVMT-R (Constant=8.367; Age=−0.116; Education=0.397; Sex=−; and SD of residuals=2.66933). 52
Valdivia-Tangarife et al. validated the BICAMS for adults living in Mexico. The sample consisted of 100 MS patients and 100 HCs. HCs were recruited from the general population in Guadalajara, Mexico. The groups did not differ significantly in terms of age (MS patients = 43.48 ± 5.96 years; HCs=43.39 ± 6.03 years; P = .916), education level (MS patients = 12.71 ± 2.29 years; HCs=12.55 ± 2.52 years; P = .640) or sex. A greater proportion of patients had RRMS (94%), followed by SPMS (4.0%) and PPMS (2.0%). The mean EDSS score was 3.75 ± 1.92. Student's t test revealed statistically significant differences in cognitive performance between MS patients and HCs across all three BICAMS test scores. These significant differences were observed in the SDMT (P < .001), CVLT-II (P = .002), and BVMT-R (P = .009). The SDMT (Cohen’s d = 0.58) and CVLT-II (Cohen’s d = 0.61) had medium-sized effects, whereas the BVMT-R had a small-sized effect (Cohen’s d = 0.18). A subsample of MS patients (n = 30) underwent follow-up assessments (within a two-week interval) of the BICAMS, using alternate forms to mitigate practice effects (SDMT; CVLT-II = form 4, and BVMT-R = form 4 enabling test‒retest reliability analysis). The test–retest reliability for each test was considered high (SDMT r = .95, CVLT-I r = .84, and BVMT-R r = .81). Additionally, this study presented regression-based normative models for the BICAMS, controlling for demographic variables (Age, Age2, Sex, and Education) as follows: SDMT (Constant=7.621; Age=0.242; Age2=−0.003; Sex=−0.837; Education=−0.118; and SD of residuals=2.95957); CVLT-II (Constant=14.083; Age=−0.590; Age2 = 0.006; Sex=−0.493; Education=−0.086; and SD of residuals=2.95203); and BVMT-R (Constant=7.758; Age=−0.681; Age2 = 0.008; Sex=0.274; Education=0.124; and SD of residuals=2.95367). 77
Additional details about the aforementioned four validation studies in LATAM can be found in Table 1, including information on the validation of BICAMS in other countries.
Discussion
While considerable efforts have been undertaken over the last few years to validate neuropsychological tests for assessing cognitive function in MS patients living in LATAM, these data are limited, particularly compared with the available data in the U.S. and Europe, especially for the BICAMS.
BICAMS has been validated in different countries (the Czech Republic, Hungary, Ireland, Brazil, Lithuania, Canada, Argentina, Greece, Japan, Turkey, Belgium, Portugal, Germany, Norway, Indonesia, Denmark, France, Colombia, Finland, Egypt, Georgia, Poland, Tunisia, Russia, Serbia, Lebanon, and Mexico) (Table 1). Among the 27 sources of validation identified by the BICAMS, only four provide validation data for adults living in LATAM. Regression-based norms have been recommended for BICAMS validation.27,79 However, the findings from the present literature review indicate a relative paucity of validated neuropsychological tests for detecting cognitive impairment in MS patients in LATAM.
Considering the studies of BICAMS validation conducted in LATAM. Highlights, the study was conducted in Brazil. Their objective was to investigate the reliability and validity of a Brazilian-Portuguese adaptation of the BICMAS. In this study, the translation of the SDMT, CVLT-II, and BVMT-R was necessary. They followed the published consensus opinion guidelines for a new language validation of BICAMS. 27 Conversely, the studies conducted in Argentina, Colombia, and Mexico used a Spanish adaptation of the BICAMS battery. 27 On the other hand, these studies included 100 HCs to develop normative data.52,76,77 In contrast, the study conducted in Brazil included 57 HCs. 75 According to the international standard for validating BICAMS, a sample size of at least 65 healthy volunteers is recommended for the development of normative data. This minimum sample size should provide enough power to detect a medium effect size in a two-group comparison.
In the test-retest reliability analysis, we identified several methodological characteristics. For example, (1) the BICAMS forms used for cognitive assessment at Time 1 and Time 2 (Time 1; Test, and Time 2; retest) in the studies conducted in LATAM. The study conducted in Argentina used an alternate form of the BICAMS in Time 1 (SDMT, CVLT-I, and BVMT-R) and Time 2 (SDMT, form 4 was used; CVLT-I, list B was used; and for BVMT-R, form 4 was used). The study conducted in Brazil used the same form of the BICAMS (CVLT-II, BVMT-R, and SDMT) at both Time 1 and Time 2. In Colombia, the same form of the BICAMS (SDMT, PAMCL, BVMT-R) was used at both Time 1 and Time 2. In Mexico, an alternate form of the BICMAS was used at Time 1 (SDMT, CVLT-II, and BVMT-R) and Time 2 (SDMT, form 4 was used; CVLT-I, list B was used; and for BVMT-R, form 4 was used).
Several studies have recommended alternate methods to mitigate practice effects. In a study conducted by Benedict and Zgaljardic, 80 30 healthy participants were included and divided into two groups: the alternative form (AF) group with 15 participants and the same form (SF) group with 15 participants. These groups were matched for age, education, and baseline memory test performance. The study investigated practice effects during repeated administrations of verbal and nonverbal memory tests.
They employed the Hopkins Verbal Learning Test-Revised and the BVMT-R.51,81 The results showed that participants in the SF group, who were tested with the same form every two weeks, improved significantly over four sessions. Participants in the AF group, who completed alternate forms of the nonverbal memory test, produced a small practice effect. This study revealed that verbal memory was resistant to practice effects when alternate forms were employed. Additionally, a study conducted by Benedict82,83 examined test‒retest effects in MS patients randomly assigned to the alternative form (AF) group (17 MS patients) or the same form (SF) group (17 MS patients). They employed the Minimal Assessment of Cognitive Function in MS, which includes the following tests with alternate forms: the CVLT-II, the BVMT-R, the Paced Auditory Serial Addition Test (PASAT), 84 the Controlled Oral Word Association Test (COWAT), 85 and the Sorting Test from the Delis-Kaplan Executive Functions System. 86 The author concluded that the use of alternative forms of the CVLT-II and BVMT-R helps preserve test validity without compromising test‒retest reliability.
(2) In the BICAMS validation studies conducted in LATAM, a subsample of MS patients (Argentina, n = 25; Brazil, n = 49; Colombia, n = 16; and Mexico, n = 30) underwent cognitive assessments at two different times: Time 1 (test) and Time 2 (retest), separated by 2 weeks. Benedict et al. recommended a test‒retest interval ranging from 1 to 3 weeks. 27 Charter mentioned that test–test reliability can vary depending on the sample assessment and amount of time between test and retest. 87
(3) When the reliability values were evaluated, the studies in which the BICAMS was validated in LATAM reported a Pearson correlation coefficient >.70 for all three neuropsychological tests. Some authors have reported r values for test‒retest correlation of .70‒.79 as “adequate” and .80‒.89 as “high.”27,88–90 Additionally, several studies mentioned that test‒retest reliability is one psychometric property that neuropsychologists can use when selecting a test battery and evaluating test scores.91,92
The majority of studies on BICAMS available specifically for LATAM are based on adult MS patients living in Argentina, Brazil, Colombia, and Mexico.52,75–77 Only three studies included norms based on a multiple regression model that allows for obtaining an individuaĺs predicted score while controlling for the influence of demographic variables (age, sex, and education).52,76,77 The norms based on multiple regression equations are important, as they increase the clinical utility of results and their applicability.93–96 Regression equations permit the prediction of an individuaĺs level of performance on a cognitive instrument at retest from their score at initial testing. 97
The validation of BICAMS is necessary in other LATAM countries. Several studies indicate that cultural differences and variations in educational systems can influence cognitive performance.98,99 Although normative data for the BICAMS have been developed for Argentina, Brazil, Colombia and Mexico, these normative data are not necessarily interchangeable due to cultural differences between these countries. In summary, we argue that local norms are essential for accurately identifying the presence or absence of cognitive impairment.
Conclusion
The present review provides a list of twenty-seven published studies on BICAMS validation worldwide. Of the 27 citations identified, only four validate BICAMS in LATAM. The BICAMS battery is a reliable tool for assessing cognitive function in MS patients and can be used in clinical practice. The BICAMS consists of three different tests: the SDMT, CVLT-II, and BVMT-R. These instruments have strong psychometric properties. This review aims to advance the field of neuropsychological assessment in MS patients in LATAM and promote the clinical application of BICAMS validation in Argentina, Brazil, Colombia, and Mexico.
Footnotes
Acknowledgments
This study was conducted by members of the Research Group for the Development and Validation of Cognitive Instruments, led by Teresita J. Villaseñor-Cabrera. The group comprised a multidisciplinary team of researchers dedicated to advancing the field of cognitive assessment.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
