Possible evidence of near transfer effects after adaptive working memory training in persons with multiple sclerosis

Pre-training working memory/information processing capabilities and brain atrophy limit the improving effects of cognitive training

“…In this regard, different studies using computerized n-back training have reported enhancements in the trained task, 2 , 3 with some studies even further describing positive near transfer effects to another test that assesses WM/IP. 4 – 7 In a previous study conducted in our laboratory, 8 we observed a general improvement in the execution of the 2- and 3-back tasks in a sample of PwMS with different cognitive statuses after undergoing an n-back training. 8 Some of the participants (but not all), were able to transfer this optimization to other tests that measure WM/IP such as the Paced Auditory Serial Addition Test (PASAT), the Symbol Digit Modalities Test (SDMT), and the Letters and Numbers Sequencing Test (LNST).…”

“…The sample was composed of a group of 35 PwMS diagnosed according to the revised McDonald criteria, 13 without any depression- or anxiety-related diagnosis, and free of exacerbation or steroid treatment in the 3 months prior to enrollment of the study (for a more detailed description of the inclusion and exclusion criteria see Esbrí et al 8 ). Of this sample, 25 patients were classified as relapsing-remitting, 5 as having a secondary progressive form, and 5 as primary progressive.…”

“…As described in Esbrí et al, 8 PwMS were neuropsychologically assessed before (D1) and after the n-back training (D10) using the Spanish version of the Brief Repeatable Battery of Neuropsychological Tests (BRB-N). 14 To explore possible effects of baseline cognitive performance on the effectiveness of training, normative data were used to transform individuals’ pre-training scores in the BRB-N tests into their Z scores for verbal memory (Z V ), visual memory (Zv I ), WM/IP (Z WM/IP ), and fluency (Z F ) as described in Sepulcre et al 14 Because our training program and main hypotheses focused on WM/IP capabilities, the Z WM/IP scores were employed to split the original sample into the two groups of main interest for the present study: “WM/IP-impaired” (those individuals exhibiting Z WM/IP scores equal to or smaller than −1.5) and “WM/IP-preserved” (individuals exhibiting Z WM/IP scores higher than −1.5).…”

“…The adaptive and intensive n-back training protocol (described in the Supplementary Material and study by Esbrí et al 8 ) consisted of 10 sessions, with a total duration of 60 min/per session. Within each session, participants first completed three practice runs, each composed of eight blocks that varied the WM load (1-back, 2-back, and 3-back) according to the participant's performance.…”

“…One of the main goals of making further progress in the field of cognitive rehabilitation in PwMS is not only to detect the most appropriate cognitive treatments, but also to identify the clinical conditions associated with the disease which are capable of predicting the effectiveness of such treatments. Considering the results previously observed in our laboratory, 8 the main aim of this study was to explore the influence of clinical and radiological variables on predicting the positive effects of WM/IP training in a sample of PwMS with different cognitive statuses. Based on the results of previous studies, [9][10][11][12] we specifically hypothesized that PwMS with preserved WM/IP abilities and/ or less gray matter atrophy in brain areas sustaining WM would benefit more from this training program.…”