Autobiographical memory in multiple sclerosis patients: assessment and cognitive facilitation

Episodic Past, Future, and counterfactual thinking in Relapsing-Remitting Multiple sclerosis

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Performance in episodic past, future or counterfactual thinking in relapsing-remitting MS and controls was explored.

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Behavioral and diffusion weighted imaging were used to evaluate associations between white matter integrity and group differences in performance.

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Relative to controls, MS patients showed reductions in episodic details across all three simulations.

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Reduced white matter integrity in three association tracts predicted this reduction in episodic details during counterfactual simulations.

Multiple sclerosis (MS) is a progressive disease characterized by widespread white matter lesions in the brain and spinal cord. In addition to well-characterized motor deficits, MS results in cognitive impairments in several domains, notably in episodic autobiographical memory. Recent studies have also revealed that patients with MS exhibit deficits in episodic future thinking, i.e., our capacity to imagine possible events that may occur in our personal future. Both episodic memory and episodic future thinking have been shown to share cognitive and neural mechanisms with a related kind of hypothetical simulation known as episodic counterfactual thinking: our capacity to imagine alternative ways in which past personal events could have occurred but did not. However, the extent to which episodic counterfactual thinking is affected in MS is still unknown. The current study sought to explore this issue by comparing performance in mental simulation tasks involving either past, future or counterfactual thoughts in relapsing-remitting MS. Diffusion weighted imaging (DWI) measures were also extracted to determine whether changes in structural pathways connecting the brain’s default mode network (DMN) would be associated with group differences in task performance. Relative to controls, patients showed marked reductions in the number of internal details across all mental simulations, but no differences in the number of external and semantic-based details. It was also found that, relative to controls, patients with relapsing-remitting MS reported reduced composition ratings for episodic simulations depicting counterfactual events, but not so for actual past or possible future episodes. Additionally, three DWI measures of white matter integrity—fractional anisotropy, radial diffusivity and streamline counts—showed reliable differences between patients with relapsing-remitting MS and matched healthy controls. Importantly, DWI measures associated with reduced white matter integrity in three association tracts on the DMN—the right superior longitudinal fasciculus, the left hippocampal portion of the cingulum and the left inferior longitudinal fasciculus—predicted reductions in the number of internal details during episodic counterfactual simulations. Taken together, these results help to illuminate impairments in episodic simulation in relapsing-remitting MS and show, for the first time, a differential association between white matter integrity and deficits in episodic counterfactual thinking in individuals with relapsing-remitting MS.

Memory deficits in aphantasics are not restricted to autobiographical memory - Perspectives from the Dual Coding Approach

Scene Construction Theory suggests similar neural mechanisms for visual imagery and autobiographical memory, supporting the seeming scientific consensus that a loss of visual imagery affects autobiographical memory. Based on the Dual Coding Theory and the Reverse Hierarchy Model, we also assumed influences of visual imagery on recent visual memory and even verbal memory, although little evidence has been provided so far. Thus, in a sample of 67 congenital aphantasics (= persons without mental imagery) and 32 demographically matched controls, it was investigated whether deficits in visual imagery are associated with deficits in visual as well as verbal short-term and long-term memory. The memory tasks were theoretically selected based on task difficulty, retrieval condition, and subcategories of stimuli, as previous null findings were attributed to insensitive tasks that were solvable by aphantasics by means of non-visual alternative strategies. Significant group differences were found in all memory components, with aphantasics performing worse than non-aphantasics. Therefore, evidence was obtained for the influence of visual imagery on all memory components beyond autobiographical memory.

Memory rehabilitation for people with multiple sclerosis

BACKGROUND

Problems with cognition, particularly memory, are common in people with multiple sclerosis (MS) and can affect their ability to complete daily activities and can negatively affect quality of life. Over the last few years, there has been considerable growth in the number of randomised controlled trials (RCTs) of memory rehabilitation in MS. To guide clinicians and researchers, this review provides an overview of the effectiveness of memory rehabilitation for people with MS.

OBJECTIVES

To determine whether people with MS who received memory rehabilitation compared to those who received no treatment, or an active control showed better immediate, intermediate, or longer-term outcomes in their: 1. memory functions, 2. other cognitive abilities, and 3. functional abilities, in terms of activities of daily living, mood, and quality of life.

SEARCH METHODS

We searched CENTRAL which includes Clinicaltrials.gov, World Health Organization (The Whoqol) International Clinical Trials Registry Portal, Embase and PubMed (MEDLINE), and the following electronic databases (6 September 2020): CINAHL, LILACS, the NIHR Clinical Research Network Portfolio database, The Allied and Complementary Medicine Database, PsycINFO, and CAB Abstracts.

SELECTION CRITERIA

We selected RCTs or quasi-RCTs of memory rehabilitation or cognitive rehabilitation for people with MS in which a memory rehabilitation treatment group was compared with a control group. Selection was conducted independently first and then confirmed through group discussion. We excluded studies that included participants whose memory deficits were the result of conditions other than MS, unless we could identify a subgroup of participants with MS with separate results.

DATA COLLECTION AND ANALYSIS

Eight review authors were involved in this update in terms of study selection, quality assessment, data extraction and manuscript review. We contacted investigators of primary studies for further information where required. We conducted data analysis and synthesis in accordance with Cochrane methods. We performed a 'best evidence' synthesis based on the methodological quality of the primary studies included. Outcomes were considered separately for 'immediate' (within the first month after completion of intervention), 'intermediate' (one to six months), and 'longer-term' (more than six months) time points.

MAIN RESULTS

We added 29 studies during this update, bringing the total to 44 studies, involving 2714 participants. The interventions involved various memory retraining techniques, such as computerised programmes and training on using internal and external memory aids. Control groups varied in format from assessment-only groups, discussion and games, non-specific cognitive retraining, and attention or visuospatial training. The risk of bias amongst the included studies was generally low, but we found eight studies to have high risk of bias related to certain aspects of their methodology. In this abstract, we are only reporting outcomes at the intermediate timepoint (i.e., between one and six months). We found a slight difference between groups for subjective memory (SMD 0.23, 95% CI 0.11 to 0.35; 11 studies; 1045 participants; high-quality evidence) and quality of life (SMD 0.30, 95% CI 0.02 to 0.58; 6 studies; 683 participants; high-quality evidence) favoring the memory rehabilitation group. There was a small difference between groups for verbal memory (SMD 0.25, 95% CI 0.11 to 0.40; 6 studies; 753 participants; low-quality evidence) and information processing (SMD 0.27, 95% CI 0.00 to 0.54; 8 studies; 933 participants; low-quality evidence), favoring the memory rehabilitation group.  We found little to no difference between groups for visual memory (SMD 0.20, 95% CI -0.11 to 0.50; 6 studies; 751 participants; moderate-quality evidence), working memory (SMD 0.16, 95% CI -0.09 to 0.40; 8 studies; 821 participants; moderate-quality evidence), or activities of daily living (SMD 0.06, 95% CI -0.36 to 0.24; 4 studies; 400 participants; high-quality evidence).  AUTHORS' CONCLUSIONS: There is evidence to support the effectiveness of memory rehabilitation on some outcomes assessed in this review at intermediate follow-up. The evidence suggests that memory rehabilitation results in between-group differences favoring the memory rehabilitation group at the intermediate time point for subjective memory, verbal memory, information processing, and quality of life outcomes, suggesting that memory rehabilitation is beneficial and meaningful to people with MS. There are differential effects of memory rehabilitation based on the quality of the trials, with studies of high risk of bias inflating (positive) outcomes. Further robust, large-scale, multi-centre RCTs, with better quality reporting, using ecologically valid outcome assessments (including health economic outcomes) assessed at longer-term time points are still needed to be certain about the effectiveness of memory rehabilitation in people with MS.

A Multidimensional Assessment of Metacognition Across Domains in Multiple Sclerosis

OBJECTIVE

In neurological diseases, metacognitive judgements have been widely used in order to assess the degree of disease awareness. However, as yet little research of this type has focused on multiple sclerosis (MS).

METHOD

We here focused on an investigation of item-by-item metacognitive predictions (using feeling-of-knowing judgements) in episodic and semantic memory and global metacognitive predictions in standard neuropsychological tests pertinent to MS (processing speed and verbal fluency). Twenty-seven relapsing-remitting MS (RR-MS) patients and 27 comparison participants took part.

RESULTS

We found that RR-MS patients were as accurate as the group of comparison participants on our episodic and semantic item-by-item judgements. However, for the global predictions, we found that the MS group initially overestimated their performance (ds = .64), but only on a task on which performance was also impaired (ds = .89; processing speed). We suggest that MS patients, under certain conditions, show inaccurate metacognitive knowledge. However, postdictions and item-by-item predictions indicate that online metacognitive processes are no different from participants without MS.

CONCLUSION

We conclude that there is no monitoring deficit in RR-MS and as such these patients should benefit from adaptive strategies and symptom education.

Treatment and management of cognitive dysfunction in patients with multiple sclerosis

Cognitive impairment is a common and devastating manifestation of multiple sclerosis (MS). Although disease-modifying therapies have been efficacious for reducing relapse rates in MS, such treatments are ineffective for treating cognitive dysfunction. Alternative treatment approaches for mitigating cognitive problems are greatly needed in this population. To date, cognitive rehabilitation and exercise training have been identified as possible candidates for treating MS-related cognitive impairment; however, cognitive dysfunction is still often considered to be poorly managed in patients with MS. This Review provides a comprehensive overview of recent developments in the treatment and management of cognitive impairment in people with MS. We describe the theoretical rationales, current states of the science, field-wide challenges and recent advances in cognitive rehabilitation and exercise training for treating MS-related cognitive impairment. We also discuss future directions for research into the treatment of cognitive impairment in MS that should set the stage for the inclusion of cognitive rehabilitation and exercise training into clinical practice within the next decade.

Repeated Working Memory Training Improves Task Performance and Neural Efficiency in Multiple Sclerosis Patients and Healthy Controls

BACKGROUND/OBJECTIVE

To explore the effectiveness of a specific working memory (WM) training program in MS patients and healthy controls (HC).

METHOD

29 MS patients and 29 matched HC were enrolled in the study. MS and HC were randomly split into two groups: nontraining groups (15HC/14 MS) and training groups (14 HC/15 MS). Training groups underwent adaptive n-back training (60 min/day; 4 days). Functional magnetic resonance imaging (fMRI) was used to monitor brain activity during n-back performance (conditions: 0-back, 2-back, and 3-back) at 3 time points: (1) baseline, (2) post-training (+7days), and (3) follow-up (+35days).

RESULTS

In post-training and follow-up fMRI sessions, trained groups (HC and MS patients) exhibited significant reaction time (RT) reductions and increases in Correct Responses (CRs) during 2-back and 3-back performance. This improvement of task performance was accompanied by a decrease in brain activation in the WM frontoparietal network. The two effects were significantly correlated.

CONCLUSIONS

After WM training, both cognitively preserved MS patients and HC participants showed task performance improvement made possible by neuroplastic processes that enhanced neural efficiency.

Cognitive Deficits in Multiple Sclerosis: Recent Advances in Treatment and Neurorehabilitation

PURPOSE OF REVIEW

This article highlights recent progress in research on treatment and neurorehabilitation of cognitive impairment in multiple sclerosis (MS) including pharmacological interventions, physical exercise, and neuropsychological rehabilitation, both in conventional and technology-assisted settings.

RECENT FINDINGS

The most consistent evidence in terms of improvement or preservation of circumscribed cognitive scores in MS patients comes from moderately sampled randomized clinical trials on multimodal approaches that combine conventional or computerized neuropsychological training with psychoeducation or cognitive behavioral therapy. Disease-modifying treatments also appear to have beneficial effects in preventing or attenuating cognitive decline, whereas there is little evidence for agents such as donepezil or stimulants. Finally, physical exercise may yield some cognitive improvement in MS patients. Despite substantial and often promising research efforts, there is a lack of validated and widely accepted clinical procedures for cognitive neurorehabilitation in MS. Development of such approaches will require collaborative efforts towards the design of interventions that are fundamentally inspired by cognitive neuroscience, potentially guided by neuroimaging, and composed of conventional neuropsychological training and cognitive behavioral therapy as well as physical exercise and therapeutic video games. Subsequently, large-scale validation will be needed with meaningful outcome measures reflecting transfer to everyday cognitive function and maintenance of training effects.

Neuropsychological Assessment in Multiple Sclerosis

Abstract. Neuropsychological deficits in multiple sclerosis (MS) are common. Over the past decades, many different procedures have been employed in diagnosing these deficits. Even though certain aspects of cognitive performance such as information processing speed and working memory may be affected more frequently than other cognitive functions, no specific deficit profile has been established in MS. This article provides an overview of the neuropsychological diagnostic procedures in MS and allows the reader to reach an informed decision on the applicability of specific procedures and the availability of study data in the context of MS. Additionally, it makes recommendations on the compilation of both screening procedures and extensive test batteries.

Reporting interventions in trials evaluating cognitive rehabilitation in people with multiple sclerosis: a systematic review

OBJECTIVE

To determine the quantity and quality of description of cognitive rehabilitation for cognitive deficits in people with multiple sclerosis, using a variety of published checklists, and suggest ways of improving the reporting of these interventions.

DATA SOURCES

A total of 10 electronic databases were searched, including MEDLINE, EMBASE, CINAHL and PsycINFO, from inception to May 2017. Grey literature databases, trial registers, reference lists and author citations were also searched.

REVIEW METHODS

Papers were included if participants were people with multiple sclerosis aged 18 years and over and if the effectiveness of cognitive rehabilitation in improving functional ability for memory, attention or executive dysfunction, with or without a control group, was being evaluated.

RESULTS

A total of 54 studies were included in this review. The reporting of a number of key aspects of cognitive rehabilitation was poor. This was particularly in relation to content of interventions (reported completely in 26 of the 54 studies), intervention procedures (reported completely in 16 of the 54 studies), delivery mode (reported completely in 24 of the 54 studies) and intervention mechanism of action (reported completely in 21 of the 54 studies).

CONCLUSION

The quality of reporting of cognitive rehabilitation for memory, attention and executive function for multiple sclerosis, across a range of study designs, is poor. Existing reporting checklists do not adequately cover aspects relevant to cognitive rehabilitation, such as the approaches used to address cognitive deficits. Future checklists could consider these aspects we have identified in this review.

Benefits from an autobiographical memory facilitation programme in relapsing-remitting multiple sclerosis patients: a clinical and neuroimaging study

While the efficacy of mental visual imagery (MVI) to alleviate autobiographical memory (AM) impairment in multiple sclerosis (MS) patients has been documented, nothing is known about the brain changes sustaining that improvement. To explore this issue, 20 relapsing-remitting MS patients showing AM impairment were randomly assigned to two groups, experimental (n = 10), who underwent the MVI programme, and control (n = 10), who followed a sham verbal programme. Besides the stringent AM assessment, the patients underwent structural and functional MRI sessions, consisting in retrieving personal memories, within a pre-/post-facilitation study design. Only the experimental group showed a significant AM improvement in post-facilitation, accompanied by changes in brain activation (medial and lateral frontal regions), functional connectivity (posterior brain regions), and grey matter volume (parahippocampal gyrus). Minor activations and functional connectivity changes were observed in the control group. The MVI programme improved AM in MS patients leading to functional and structural changes reflecting (1) an increase reliance on brain regions sustaining a self-referential process; (2) a decrease of those reflecting an effortful research process; and (3) better use of neural resources in brain regions sustaining MVI. Functional changes reported in the control group likely reflected ineffective attempts to use the sham strategy in AM.

Neural correlates of episodic future thinking impairment in multiple sclerosis patients

BACKGROUND

Recent clinical investigations showed impaired episodic future thinking (EFT) abilities in multiple sclerosis (MS) patients. On these bases, the aim of the current study was to explore the structural and functional correlates of EFT impairment in nondepressed MS patients.

METHOD

Twenty-one nondepressed MS patients and 20 matched healthy controls were assessed with the adapted Autobiographical Interview (AI), and patients were selected on the bases of an EFT impaired score criterion. The 41 participants underwent a functional magnetic resonance imaging (fMRI) session, distinguishing the construction and elaboration phases of the experimental EFT, and the categorical control tests. Structural images were also acquired.

RESULTS

During the EFT fMRI task, increased cerebral activations were observed in patients (relative to healthy controls) within the EFT core network. These neural changes were particularly important during the construction phase of future events and involved mostly the prefrontal region. This was accompanied by an increased neural response mostly in anterior, and also posterior, cerebral regions, in association with the amount of detail produced by patients. In parallel, structural measures corroborated a main positive association between the prefrontal regions' volume and EFT performance. However, no association between the hippocampus and EFT performance was observed in patients, at both structural and functional levels.

CONCLUSION

We have documented significant overlaps between the structural and functional underpinnings of EFT impairment, with a main role of the prefrontal region in its clinical expression in MS patients.

Memory rehabilitation for people with multiple sclerosis

BACKGROUND

This is an update of the Cochrane review 'Memory rehabilitation for people with multiple sclerosis' (first published in the Cochrane Library 14 March 2012, Issue 3). Impairments in cognitive function, particularly memory, are common in people with multiple sclerosis (MS) and can potentially affect their ability to complete functional activities. There is evidence from single-case or small group studies that memory rehabilitation can be beneficial for people with MS, but findings from randomised controlled trials (RCTs) and systematic reviews have been inconclusive.

OBJECTIVES

To determine whether people with MS who received memory rehabilitation showed: 1. better outcomes in their memory functions compared to those given no treatment or receiving a placebo control; and 2. better functional abilities, in terms of activities of daily living, mood, and quality of life, than those who received no treatment or a placebo.

SEARCH METHODS

We searched the Trials Specialised Register of the Cochrane Multiple Sclerosis and Rare Diseases of the CNS Group (2 June 2015) and the following electronic databases: The NIHR Clinical Research Network Portfolio database (NIHR CRN) (from 2010 to June 2015), The Allied and Complementary Medicine Database (AMED) (2010 to June 2015), British Nursing Index (BNI) (2010 to June 2015), PsycINFO (2011 to June 2015), and CAB Abstracts (2010 to June 2015). Start dates for the electronic databases coincided with the last search for the previous review. We handsearched relevant journals and reference lists.

SELECTION CRITERIA

We selected RCTs or quasi-randomised trials of memory rehabilitation or cognitive rehabilitation for people with MS in which a memory rehabilitation treatment group was compared to a control group. Selection was conducted independently first and then confirmed through group discussion. We excluded studies that included participants whose memory deficits were the result of conditions other than MS unless we could identify a subgroup of participants with MS with separate results.

DATA COLLECTION AND ANALYSIS

Three review authors were involved in this update in terms of study selection, quality assessment, and data extraction. We contacted investigators of primary studies for further information where required. We conducted data analysis and synthesis in accordance with the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We performed a 'best evidence' synthesis based on the methodological quality of the primary studies included.

MAIN RESULTS

We added seven studies during this update, bringing the total to 15 studies, involving 989 participants. The interventions involved various memory retraining techniques, such as computerised programmes and training on internal and external memory aids. Control groups varied in format from assessment-only groups, discussion and games, non-specific cognitive retraining, and attention or visuospatial training. The risk of bias of the included studies was generally low, but we found eight studies to have high risk of bias related to certain aspects of their methodology.We found significant effect of intervention on objective assessments of memory in both the immediate and long-term follow-ups: standardised mean difference (SMD) 0.23 (95% confidence interval (CI) 0.05 to 0.41) and SMD 0.26 (95% CI 0.03 to 0.49), respectively. We also found significant effect of intervention for quality of life in the immediate follow-up (SMD 0.23 (95% CI 0.05 to 0.41)). These findings showed that the intervention group performed significantly better than the control group. We also found a significant difference for activities of daily living (ADL) in the long-term follow-up (SMD -0.33 (95% CI -0.63 to -0.03)), showing that the control groups had significantly less difficulty completing ADLs than the intervention groups. We found no significant effects, either immediate or long-term, on subjective reports of memory problems (SMD 0.04 (95% CI -0.19 to 0.27) and SMD 0.04 (95% CI -0.19 to 0.27)); on mood (SMD 0.02 (95% CI -0.16 to 0.20) and SMD -0.01 (95% CI -0.21 to 0.20)); and on immediate follow-up for ADL (SMD -0.13 (95% CI -0.60 to 0.33)) and in the long term for quality of life (SMD 0.16 (95% CI -0.03 to 0.36)). We could not complete a sensitivity analysis of intention-to-treat in comparison with per-protocol analysis, due to insufficient information from the included papers. However, a sensitivity analysis of high- versus low-risk studies suggested that while quality of the trials did not affect most outcomes, differences were seen in the objective memory outcomes (both at immediate and long term) and quality of life (immediate) outcome, with studies with higher risk of bias inflating the overall effect size estimates for these outcomes, and the test of overall effect changing from being statistically significant to not significant when studies at high risk of bias were excluded. This suggests that lower-quality studies may have positively influenced the outcomes.

AUTHORS' CONCLUSIONS

There is some evidence to support the effectiveness of memory rehabilitation on memory function, as well as on quality of life. However, the evidence is limited and does not extend to subjective reports of memory functioning or mood. Furthermore, the objective measures used are not ecologically valid measures, and thus potentially limit generalisability of these findings into daily life. Further robust RCTs of high methodological quality and better quality of reporting, using ecologically valid outcome assessments, are still needed.

Induced brain plasticity after a facilitation programme for autobiographical memory in multiple sclerosis: a preliminary study

This preliminary study tackles the assessment and treatment of autobiographical memory (AbM) in relapsing-remitting multiple sclerosis (RR-MS) patients. Our aim was to investigate cerebral activation changes, following clinical improvement of AbM due to a cognitive training based on mental visual imagery (MVI). We assessed AbM using the Autobiographical Interview (AI) in eight patients and 15 controls. The latter subjects established normative data. The eight patients showed selective defective performance on the AI. Four patients were trained cognitively and underwent pre- and post-AI and fMRI. The remaining four patients took a second AI, at the same interval, but with no intervention in between. Results showed a significant improvement of AbM performance after the facilitation programme that could not be explained by learning effects since the AI scores remained stable between the two assessments in the second group of patients. As expected, AbM improvement was accompanied by an increased cerebral activity in posterior cerebral regions in post-facilitation fMRI examination. We interpret this activation changes in terms of reflecting the emphasis made on the role of MVI in memory retrieval through the facilitation programme. These preliminary significant clinical and neuroimaging changes suggest the beneficial effects of this technique to alleviate AbM retrieval deficit in MS patients.