Working memory training impacts neural activity during untrained cognitive tasks in people with multiple sclerosis

Early attentional processing and cortical remapping strategies of tactile stimuli in adults with an early and late-onset visual impairment: A cross-sectional study

Neuroplastic changes appear in people with visual impairment (VI) and they show greater tactile abilities. Improvements in performance could be associated with the development of enhanced early attentional processes based on neuroplasticity. Currently, the various early attentional and cortical remapping strategies that are utilized by people with early (EB) and late-onset blindness (LB) remain unclear. Thus, more research is required to develop effective rehabilitation programs and substitution devices. Our objective was to explore the differences in spatial tactile brain processing in adults with EB, LB and a sighted control group (CG). In this cross-sectional study 27 participants with VI were categorized into EB (n = 14) and LB (n = 13) groups. They were then compared with a CG (n = 15). A vibrotactile device and event-related potentials (ERPs) were utilized while participants performed a spatial tactile line recognition task. The P100 latency and cortical areas of maximal activity were analyzed during the task. The three groups had no statistical differences in P100 latency (p>0.05). All subjects showed significant activation in the right superior frontal areas. Only individuals with VI activated the left superior frontal regions. In EB subjects, a higher activation was found in the mid-frontal and occipital areas. A higher activation of the mid-frontal, anterior cingulate cortex and orbitofrontal zones was observed in LB participants. Compared to the CG, LB individuals showed greater activity in the left orbitofrontal zone, while EB exhibited greater activity in the right superior parietal cortex. The EB had greater activity in the left orbitofrontal region compared to the LB. People with VI may not have faster early attentional processing. EB subjects activate the occipital lobe and right superior parietal cortex during tactile stimulation because of an early lack of visual stimuli and a multimodal information processing. In individuals with LB and EB the orbitofrontal area is activated, suggesting greater emotional processing.

Rehabilitation of working memory after acquired brain injury and multiple sclerosis: A systematic review

The objective is to study the effectiveness of working memory (WM) rehabilitation after Acquired brain injury (ABI) and multiple sclerosis (MS). A systematic database search of published studies, following PRISMA recommendations, with assessment of methodological quality and risk of bias, was conducted. The results were analysed according to the rehabilitation method used. 31 studies (including 14 class I) were included, and 11 different training programs were identified. Despite great variability in training methodology and outcome measures, the results were positive overall. However, only three rehabilitation programs showed a transfer effect to WM (near) and daily life with long-term maintenance. The results were more variable for protocols limited to the use of computerized n-back training tasks. Overall, the current evidence supports multi-task WM training rather than single-task-limited program. It also supports early and long duration training, with some therapist support. However, it is not possible, to date, to make strong recommendations regarding the rehabilitation program to be used preferentially. Although results are encouraging, level of evidence remains modest, particularly regarding the maintenance of the therapeutic effect after the end of training, and the transfer to everyday life skills. The influence of rehabilitation parameters (training duration, therapist involvement … ) remains difficult to assess.

Acousto-optic stimuli to promote coherent 40-Hz frequency entrainment effect

BACKGROUND

 Research has shown that a fundamental frequency of 40 Hz in continuous neural oscillation is indicative of normal brain activity; in Alzheimer disease (AD) patients, these oscillations either disappear or are significantly interrupted. Research has also indicated that the degenerative impacts of AD in mice were mitigated by the synchronization of 40-Hz acousto-optic stimulation (AOS).

OBJECTIVE

 To examine the impact of employing a 40-Hz AOS intervention on the induction of a substantial 40-Hz frequency entrainment and improvement in working memory performance among a sample of young individuals in good health. We conduct an analysis of event-related potentials (ERPs) derived from electroencephalogram (EEG) data following the presentation of AOS.

METHODS

 We recruited 20 healthy volunteers (median age: 25 years; 8 female subjects). Following the administration of various stimuli, including no stimuli, 40-Hz AOS, pink noise, and 40Hz acoustic stimuli (AS), the participants were required to complete a working memory task. A total of 62 electrodes were used to record EEG data, which was subsequently analyzed to investigate the impact of AOS on the activity of working memory. We also aimed to determine if AOS lead to a more pronounced 40-Hz frequency entrainment.

RESULTS

 Following the administration of AOS, a notable enhancement in the 40-Hz power of pertinent cerebral areas was observed, accompanied by a substantial improvement in the performance of the subjects on working memory tests subsequent to the stimulation.

CONCLUSION

 The findings unequivocally establish the efficacy of using AOS to enhance the 40-Hz power and working memory.

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

BACKGROUND

Cognitive deficits, especially in working memory (WM) and information processing (IP) efficiency, are common in people with multiple sclerosis (PwMS). Few studies have examined the efficacy of n-back training in improving these two cognitive functions in PwMS. In the present study, we examined the effects of an intensive n-back training program by measuring the gains on the trained task (2- and 3-back tasks), but we also studied possible near transfer effects to other tests that assess WM and IP, as well as far transfer effects or improvements in other cognitive functions.

METHODS

A sample consisting of 35 PwMS with different cognitive statuses. All the participants underwent an adaptive n-back training for 10 days (60 min/day), and they were neuropsychologically assessed at baseline (D1) and after training (D10). The effectiveness of the training was tested: (1) by using mean-based comparisons and Cohen's d values; (2) by estimating and comparing the quartile values of the D1 and D10 distributions. Two indexes of improvement in individual performance were calculated, the net score improvement index (NSI) and the percent of maximum possible individualized improvement (PMPI).

RESULTS

Repeat practice improves 2- and 3-back performance, showing more correct responses (CR) and lower reaction times (RT) on D10 compared to D1. These results were corroborated by the NSI and PMPI scores, but the gains after training were more statistically significant for the 3-back (observing higher CR and lower RT after training) than for the 2-back (observing gains in CR, but not in RT). We also observed a possible transference of this improvement on the n-back task to other WM/IPS tests. Specifically, statistically significant pre-post training differences were found in the values in three quartiles of the Paced Auditory Serial Addition Test (PASAT; q25, p < 0.03; q50, p < 0.001; q75, p < 0.002) and of the Symbol Digit Modalities Test (SDMT; q25, p < 0.03; q50, p < 0.001; q75, p < 0.001) as well as in two quartiles of the Letter-Number Sequencing Task (LNST; q50, p < 0.004; q75 p < 0.001), and in one quartile of the Digit Backwards Span Test (DSBT; q75, p < 0.001). Reliable change analyses confirmed these performance improvements on the PASAT, SDMT, and LNST.

CONCLUSIONS

This study confirmed that the intensive and adaptive n-back training produced improvements in the trained task in PwMS with different cognitive statuses. Furthermore, these gains were not only observed on the trained task, but they seemed to be also transferred to other tests that measured WM and IP functions.

Non-Pharmacological Treatments of Cognitive Impairment in Multiple Sclerosis: A Review

Cognitive impairment (CI) represents a common symptom in patients suffering from multiple sclerosis (MS), which can affect every stage of the disease course. Recent studies seem to support cognitive rehabilitation (CR) for minimizing the CI consequences. We reviewed the currently available evidence on the non-pharmacological approaches to CI, with the aim of giving an overview of the treatments used worldwide, from the traditional methods to the most recent techniques. A search of the literature was conducted on PubMed (articles in English performed in the last five years on humans). A total of 37 articles met our eligibility criteria after screening titles, abstracts and full-text and were divided into three main groups: in-presence interventions; studies performed via tele-rehabilitation and miscellaneous. Despite the great heterogeneity of the intervention and assessment methods, the evidence suggests that a non-pharmacological approach can improve MS-related CI. Cognitive rehabilitation seems effective and well established, as well as the use of computerized CR having the benefit of being even more appealing. Limited conclusions can be drawn on group CR due to the small number of studies focused on this kind of intervention. Some of the innovative approaches (virtual reality, EEG-based neurofeedback, brain stimulation, exercise, diet modification) may play a role in future studies and should be deeply explored.