Abstract
Purpose:
To promote understanding of cognitive impairment in multiple sclerosis (MS), recommend optimal screening, monitoring, and treatment strategies, and address barriers to optimal management.
Methods:
The National MS Society (“Society”) convened experts in cognitive dysfunction (clinicians, researchers, and lay people with MS) to review the published literature, reach consensus on optimal strategies for screening, monitoring, and treating cognitive changes, and propose strategies to address barriers to optimal care.
Recommendations:
Based on current evidence, the Society makes the following recommendations, endorsed by the Consortium of Multiple Sclerosis Centers and the International Multiple Sclerosis Cognition Society:
Increased professional and patient awareness/education about the prevalence, impact, and appropriate management of cognitive symptoms.
- For adults and children (8+ years of age) with clinical or magnetic resonance imaging (MRI) evidence of neurologic damage consistent with MS:
- As a minimum, early baseline screening with the Symbol Digit Modalities Test (SDMT) or similarly validated test, when the patient is clinically stable;
- Annual re-assessment with the same instrument, or more often as needed to (1) detect acute disease activity; (2) assess for treatment effects (e.g. starting/changing a disease-modifying therapy) or for relapse recovery; (3) evaluate progression of cognitive impairment; and/or (4) screen for new-onset cognitive problems.
For adults (18+ years): more comprehensive assessment for anyone who tests positive on initial cognitive screening or demonstrates significant cognitive decline, especially if there are concerns about comorbidities or the individual is applying for disability due to cognitive impairment.
For children (<18 years): neuropsychological evaluation for any unexplained change in school functioning (academic or behavioral).
Remedial interventions/accommodations for adults and children to improve functioning at home, work, or school.
Keywords: Multiple sclerosis, cognition, screening, treatment, rehabilitation, remediation, cognitive dysfunction
Introduction
Despite all that is known about cognitive impairment in multiple sclerosis (MS) and its impact on individuals with MS and their families, cognitive function is still not openly discussed, routinely assessed, or optimally treated.1 Ample evidence supports early and ongoing cognitive assessment and personalized treatment. However, significant barriers stand in the way of individuals with MS and their family members being able to access the care they need in this clinical domain.
The aims of this paper—which was developed by a multidisciplinary group of clinicians, researchers and people with MS chosen by the National Medical Advisory Committee of the National Multiple Sclerosis Society—are to:
Promote awareness of, and attention to, cognitive impairment—a common and highly disabling symptom of the disease;
Describe optimal screening, evaluation, and management of cognitive impairment as supported by the published literature;
Identify and address barriers that prevent people from getting the cognitive care they need;
Support the inclusion of cognition as a key component of comprehensive MS care and of lay and professional educational materials.
Recommendations to address the problem
Only by establishing high standards for the assessment and treatment of cognitive dysfunction is it possible to bring treatment of cognitive dysfunction up to the standards set in other areas of MS care and ensure that people with MS and their families receive adequate care in this critical domain. With this goal in mind, the National Multiple Sclerosis Society recommends the following (See Table 1).
Table 1.
Recommendations for education, assessment, treatment, and access.
| Education and awareness |
|---|
| • Individuals diagnosed with MS and their family members need information about common cognitive changes and their impact on activities, participation, and relationships. • Clinicians who treat people with MS need information about common cognitive changes and their impact on daily activities, medical decision-making, and adherence. • Clinicians need information about referral resources in the community for assessment and treatment. • Patients and their providers need to be aware of the high prevalence of cognitive symptoms, the importance of discussing cognition on a routine basis, and the need for early and ongoing assessment to identify and address problems. |
| Assessment and management |
| • Baseline cognitive screening with the Symbol Digit Modalities Test (SDMT)2 or other validated screening tool (Table 3), as a minimum, is recommended as an integral component of disease monitoring: ○ For all adults and children 8 years or older diagnosed with MS; ○ For those adults who have experienced a first clinical event or have evidence on magnetic resonance imaging (MRI) of asymptomatic white matter lesions that are consistent with MS (radiologically isolated syndrome), or evidence of early gray matter damage; ○ For any patient who reports changes in cognitive functioning at home or work, poor performance reviews, or whose family members or care providers express concern, whether or not the individual has screened positive on the SDMT or other validated measure. • Annual re-assessment with the same instrument, or more often as needed, is recommended for all adults and children 8 years or older with MS. • Depression screening at least yearly with the Beck Depression Inventory—Fast Screen3 or the Hospital Anxiety and Depression Scale4 for adults, or an age-appropriate screening tool for children, is recommended to identify mood changes that may be impacting cognition. • Routine monitoring is recommended for academic and behavioral changes for all children. • A more comprehensive neuropsychological assessment (including assessment of mood) is recommended: ○ For any adult who initially screens positive for cognitive deficits or whose yearly screening demonstrates a clinically significant drop in functioning from a previous assessment. Clinical significance can be assessed in a variety of ways, for example, a 4-point change or reduction of 10% on SDMT, or change in 0.5 standard deviations, or using Reliable Change Indices.2 ○ For any adult, with or without a positive screen, who reports problems at work or poor performance reviews; ○ For any child under age 18 years whose academic or behavioral functioning declines significantly for unexplained reasons, in collaboration with the school; ○ For any individual who is applying for private disability, Social Security Disability Insurance (SSDI), or Supplemental Security Income (SSI) because of cognitive problems, whether or not she or he has screened positive on the SDMT or other validated measure; ○ For any individual who wants or needs cognitive remediation, including compensatory tools and strategies to help manage existing deficits. • Remedial interventions by appropriately trained professionals are recommended to address objectively-measured deficits in attention, processing speed, memory and learning, and performance of everyday functional tasks. |
| Access |
| • Access to adequate screening, assessment, and remediation is essential due to the prevalence of cognitive deficits in the MS population—even in the earliest stages of the disease—and their impact on employment, activities of daily living, relationships, and communication. • Steps are required to obviate barriers to adequate diagnosis and management of cognitive deficits, including: ○ Insufficient knowledge about MS-related cognitive dysfunction on the part of people with MS, family members, healthcare providers or school personnel; ○ Stigma associated with cognitive changes; ○ Insufficient numbers of adequately trained clinicians to offer screening, assessment or remediation; ○ Insufficient financial resources. |
MS: multiple sclerosis.
Background
Etiology and prevalence of cognitive dysfunction
MS is characterized by inflammatory demyelination and neurodegeneration resulting in damage to both white and gray matter in the central nervous system (CNS). This CNS damage leads to a wide range of symptoms, including changes in cognitive functioning.5–7
Cognitive change is common in adults and children with MS. Depending on the sample studied (community vs clinic) and the criteria applied, the prevalence in adults ranges from 34% to 65%8–10 and is approximately 33% in patients under 18 years of age.11,12
Cognitive impairment occurs in all MS phenotypes,13–15 including clinically isolated syndrome (CIS),16,17 and has also been demonstrated in radiologically isolated syndrome (RIS).18 In fact, cognitive impairment appears to predate the appearance of structural abnormalities on magnetic resonance imaging (MRI) and may serve as an early marker of disease activity.16,19 In a prospective study of cognitive performance prior to the first clinical symptoms of MS, Cortese et al.20 found that men in the Norwegian Conscript Service database who later developed MS demonstrated significantly lower intelligent quotient scores than male controls, and those who developed primary progressive MS (PPMS) scored significantly lower than controls up to 20 years prior to their first progressive MS symptoms.
Progressive decline in cognitive functioning has been documented in some, but not all, longitudinal studies over short durations (1–3 years),21 and while controlled studies are lacking, there is strong consensus that cognition declines in patients over longer (10–20 years) periods of time.22,23 Overall, the prevalence and severity of cognitive impairment appears greatest in secondary progressive MS (SPMS) and PPMS patients.13,24 In a 10-year follow-up of cognitive functioning in patients with MS, degree of physical disability, progressive disease course, and increasing age predicted the extent of cognitive decline, and limitations in a person’s work and social activities were correlated with degree of cognitive decline independent of the person’s level of physical disability.22 However, not all individuals with MS experience cognitive impairment and not all of those with impairment progress significantly. Adults with early cognitive impairment tend to show greater decline.22,25,26 MRI predictors of cognitive outcomes over 7 years included diffuse brain damage and progressive central brain atrophy during the first 2 years after diagnosis.27
Some, but not all, longitudinal studies of cognition in pediatric MS demonstrate worsening over time.11 Younger age at onset may be a risk factor for pediatric MS-associated cognitive problems.
Cognitive symptoms and their impact on functioning and quality of life
Information processing and memory are the most commonly affected cognitive domains in MS.2,5 Other cognitive symptoms include deficits in complex attention, executive functioning, verbal fluency, visuospatial perception5,10,28 and social cognition.29,30
Slowed information processing speed is the hallmark cognitive deficit in MS,2,5,24,31,32 with processing deficits found in newly diagnosed relapsing-remitting (RRMS) patients,32 as well as CIS16,18 and RIS.18 Processing speed is a foundation for higher-level cognitive processes—which means that slowed processing impacts downstream domains.31 For example, significant variance in new learning can be attributed to processing speed.33 Similarly, in one study, after controlling for processing speed, there are no differences between healthy controls and people with MS in executive functioning.34 And, cognitive speed is the primary factor impacting daily activities and participation in everyday life.35
However, like all symptoms of MS, cognitive impairment is highly variable in severity and progression. Some patients may not decline or decline slowly, while others may experience significant decline. Some changes may be relatively mild and easily compensated for, while others may impact functioning in key areas of daily life, including work, driving, or management of business affairs. Table 2 highlights the potential impact of cognitive deficits on daily functioning and quality of life—demonstrating the need to screen for deficits, assess their severity, and remediate cognitive challenges that impair functioning.
Table 2.
Impact of cognitive deficits on daily functioning and quality of life.
| Work, school, activity participation, coping, and quality of life |
|---|
| • Cognitive impairment predicts limitations in the workplace and in social settings independent of level of physical disability.36–39
○ Cognitive impairment at diagnosis predicts a change in vocational status seven years later.40 ○ In patients with SPMS, corpus callosum atrophy (correlated with cognitive flexibility, processing speed, reaction time and verbal fluency) predicts clinically meaningful cognitive decline and change in vocational status.41 • People who are cognitively impaired are more likely to be unemployed and to score lower on measures of quality of life.39,42 • Cognitive impairment is related to work problems such as verbal reprimands and the need for extra training in employed MS patients, representing an at-risk condition prior to job loss.43,44 • Slowed information processing is associated with lower income, independent of physical dysfunction.37 • Compared to healthy controls, people with MS perform more poorly on everyday life tasks (e.g. Internet use), as predicted by their performance on cognitive screening tasks.45 • Cognitive impairment in children and teens is associated with lack of age-appropriate cognitive development46 and academic difficulties, including grade retention, social challenges, depression, and behavior problems.26,47,48 |
| Driving |
| • Thalamic brain atrophy predicts number of motor vehicle violations among people with MS compared to healthy controls.49
• Slowed processing speed and impaired visual–spatial memory impair driving ability and safety.38 • Compared with unimpaired MS patients and healthy controls, cognitively impaired MS patients with mild physical disability perform less well on some tests of driving functions50 and are at higher risk of an accident.51 |
| Medical decision-making and adherence |
| • Progressive MS patients with deficits in verbal learning, memory, and verbal fluency perform less well on appreciation, reasoning, and understanding consent standards, suggesting that these individuals are less able to make informed decisions about their treatment.52
• Cognitive deficits are associated with poor adherence to treatments.53 |
| Money management |
| • Compared with healthy controls and cognitively intact MS patients, cognitively impaired people with MS have significantly reduced money management skills.54,55 |
| Impact on caregivers |
| • Caregivers of people with MS experience high levels of distress and a reduced quality of life related to their partners’ cognitive impairment and psychiatric symptoms, beyond that related to their physical symptoms.56
• Slowed information processing speed in individuals with MS is independently associated with more severe depressive symptoms and reduced quality of life in their family caregivers.57 • Caregiver challenges associated with cognitive dysfunction, bowel and bladder dysfunction, and impaired mobility may predict nursing home placement for people with MS.58 |
SPMS: secondary progressive MS; MS: multiple sclerosis.
Establishing a standard of care for cognitive dysfunction in MS
Appropriate management of cognitive dysfunction in MS includes education for people with MS and their family members, early screening and ongoing monitoring throughout the disease course, and interventions to remediate dysfunction and provide compensatory strategies to optimize function and participation.
Early screening followed by ongoing monitoring
The standard components of the neurologic exam, including the Mini-Mental State Exam or asking patients to remember three words or objects are not sufficient to detect cognitive impairment in MS.1,59–61 Several valid and reliable brief screening and evaluation tools have been used in MS (See Table 3).
Table 3.
Validated screening and evaluation tools used in MS.
| Screening and monitoring |
|---|
| Screening tools validated in MS populations |
|
The Symbol Digit Modalities Test (SDMT; 5 minutes)2 (proprietary with associated fees) is included in the Brief Repeatable Neuropsychological Battery (BRNB)10 and Minimal Assessment of Cognitive Function in MS (MACFIMS)62 to assess cognitive processing speed. • Recommended as the best rapid assessment tool in clinical practice with adults2,63–71 • Validated in children 8+ years;72,73 • Identified as a robust neuropsychological predictor of employment;74,75 • Sensitive to changes in mental status during clinical relapses involving evidence of cognitive change, and during isolated cognitive relapses without changes on EDSS;2,76,77 • Recommended by the Multiple Sclerosis Outcome Assessments Consortium as a cognitive outcome measure in clinical trials.2 |
|
Processing Speed Test (PST; 5 minutes)78(software available at no charge) • Self-administered iPad®-based tool, completed on a touch screen by the patient; similar to the SDMT but not identical (the key is randomly generated with each administration) • In one single-center study, correlated highly with the SDMT, was slightly more sensitive than the SDMT in discriminating MS patients from healthy controls, and correlated more highly with cerebral T2 lesion load. |
|
Computerized Speed Cognitive Test (CSCT; 5 minutes)79 (software available at no charge) • Performed orally; • Demonstrated reliability in people with MS and healthy controls; • Similar to the SDMT but not identical (the key is randomly generated with each administration); • Correlates highly with the SDMT and has high sensitivity for predicting processing speed impairment. |
|
Multiple Sclerosis Neuropsychological Screening Questionnaire (MSNQ; 5 minutes)80 (proprietary with associated fees) • Includes a self-report component that correlates more highly with anxiety and depression than cognitive performance and an informant component that correlates more highly with cognitive performance.81,82 |
| Brief Assessment Batteries |
|
Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS; 15 minutes) for use in adults63,67 and children83 (proprietary with associated fees) • Includes the Symbol Digit Modalities Test, California Verbal Learning Test–2nd ed., and Brief Visuospatial Memory Test–Revised. |
|
Brief Repeatable Neuropsychological Battery (BRNB; 45 minutes)10 (no longer available) • Includes the Paced Auditory Serial Addition Test, Single Digit Modalities Test, Selective Reminding Test, 10/36 Spatial Recall Test, and Controlled Oral Work Association Test. |
|
Minimal Assessment of Cognitive Function in MS (MACFIMS; 90 minutes)62 (proprietary with associated fees) • Includes the Paced Auditory Serial Addition Test, Single Digit Modalities Test, California Verbal Learning Test–2nd ed., Brief Visuospatial Memory Test–Revised, Controlled Oral Word Association Test, Judgment of Line Orientation Test, and Delis–Kaplan Executive Function System Sorting Test. |
MS: multiple sclerosis; EDSS: Expanded Disability Status Scale.
Assessment of cognitive function early in the disease course has been shown not only to identify individuals with cognitive impairment but also to predict future impairments, limitations, and MS disease progression. Therefore, early detection of cognitive change may lead to earlier, more targeted treatment interventions:
Given that significant cognitive impairment has been found in individuals with CIS and RIS,16,18 and that cognitive relapses can occur independent of sensorimotor changes or subjective cognitive deficits,76,84 early, regular cognitive assessments can help clinicians recognize MS disease activity and tailor treatment recommendations.
Clinically silent T2 lesions in the frontal, parietal, and temporal lobes impact cognition, with deficits in cognitive processing speed, executive function, and memory occurring in the absence of Expanded Disability Status Scale (EDSS) progression.85
Cognitive impairment at the time of diagnosis, particularly processing speed and memory, predicts disability progression and conversion to SPMS.86–88 In a 10-year longitudinal study, patients with cognitive impairment at baseline had a three times greater rate of reaching an EDSS of 4.0 and two times greater rate of conversion to SPMS compared to patients without cognitive impairment.88
- Early and ongoing cognitive screening could identify: ○
- Patients at risk of income or job loss43,44,74 so that potential accommodations could be implemented in the workplace. In addition, successful applications for Social Security Disability Insurance (SSDI) and Supple-mental Security Income (SSI) require clear documentation in the medical record of symptom worsening over time;
- Deficits that interfere with driving and inform necessary accommodations to improve safety;
Since cognitive deficits in children can be present as early as the first relapse or diagnosis of CIS,12 early recognition and monitoring are essential for ensuring optimal academic, social, and emotional support and for minimizing future vocational problems.11,90 Such monitoring can also assist with planning as pediatric-onset MS patients may be at greater risk for physical and cognitive disability than adult-onset patients.91
- Current definitions of “benign MS” take physical disability into account but do not consider cognitive impairment:92,93
- In a study comparing non-benign and benign patients, Gajofatto and colleagues found that both groups were cognitively impaired at baseline. Although significantly more subjects in the non-benign group progressed on the Expanded Disability Status Scale (EDSS) after 5 years, the proportion of subjects with cognitive impairment increased by the same amount in both groups during the same time period.94
- No evidence of disease activity (NEDA) diminishes from 31% to 17% when cognitive function is accounted for in MS.95
- Cognitive assessment and MRI metrics in people with benign MS can predict short-term disease evolution to SPMS and EDSS ⩾ 4.96
- A longitudinal cohort study of benign MS patients led investigators to conclude that routine monitoring of non-motor symptoms (including cognitive dysfunction) and imaging studies can improve diagnostic accuracy and treatment recommendations.97
A positive cognitive screen at any point in time may indicate the need for a more comprehensive evaluation to assess a person’s cognitive and emotional status and suggest accommodations to enhance functioning at home and work.
Comprehensive evaluation as needed to identify areas of cognitive deficit and strength
Following a positive screen with the Symbol Digit Modalities Test (SDMT) or other validated measure, a more thorough assessment by a neuropsychologist or other trained specialist (psychologist, speech/language pathologist, or occupational therapist) is recommended to assess areas of cognitive deficit and strength, as well as to evaluate all factors that could be impacting cognitive functioning, such as cognitive reserve,98–101 depression and/or anxiety102–107 fatigue, co-morbid health conditions, and medications. Studies have demonstrated the importance of identifying a person’s areas of deficit in order to determine which remedial interventions are likely to be of greatest benefit and in which order they should be provided.102,103 For example, processing speed, which impacts a variety of cognitive functions,2,108 also impacts a person’s ability to benefit from memory retraining interventions. However, these assessments are long, expensive, not always covered by insurance, and may be unavailable in some areas of the country (see potential barriers below). Some speech/language pathologists and occupational therapists also provide evaluations, although their assessment tools may be less sensitive and comprehensive.
For a person who is planning to apply for private disability or SSDI/SSI with cognitive impairment as a reason for leaving the workforce, a thorough assessment is essential, even if the person must travel some distance for that evaluation.109
The Minimal Assessment of Cognitive Function in MS (MACFIMS) covers the essential components of a neuropsychological assessment to quantify MS-associated neurocognitive disorder.62 In the absence of a complete neuropsychological assessment, the Brief Repeatable Neuropsychological Battery (BRNB),10 and the shorter Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS)63 assess the cognitive functions that are most likely to be impaired in MS. The MACFIMS is unique in assessing executive function (Delis–Kaplan Executive Function Scale; D-KEFS). The BICAMS has been shown to predict actual performance of everyday tasks more accurately than self-report.45
Treatment to address functional deficits
Various treatment modalities have been studied to address cognitive dysfunction in MS, including cognitive remediation, exercise, and pharmacologic management. Although studies have been limited by symptom variation, as well as design issues, recent findings highlight the positive impact of cognitive remediation110 and suggest a potential benefit of some exercise strategies. The evidence for pharmacologic interventions remains very limited (See Table 4).
Table 4.
Treatment modalities for cognitive impairment in MS.
| Remediation |
|---|
| Contextualized treatment impacting everyday life activities |
| • Building on prior research demonstrating that items self-generated by an individual are remembered more accurately than items presented by someone else,111,112 a randomized controlled trial involving six training sessions provided Class I evidence that the self-generated intervention improves memory, some aspects of self-awareness related to the learning process, functional status, mood, and quality of life in people with MS. This technique is beneficial for remembering laboratory-based activities as well as for activities of daily living.110,113
• Combining self-generated learning with a spaced learning strategy, in which learning trials are spread out over time rather than massed, may provide added benefit.114 • Chiaravalloti et al.33 have provided Class I evidence that the modified Story Memory Technique (mSMT), in which patients are taught to use context and imagery to improve learning, improves immediate and longer-term objective and everyday memory. On fMRI, the mSMT is accompanied by increased activation in frontal and temporal regions.115 |
| Non-contextualized treatment |
| • Sumowski et al.116 demonstrated that memory retrieval practice through spaced testing (the testing effect) is more effective than restudy for improving memory in people with MS. • An 8-week computer-based, controlled cognitive rehabilitation trial demonstrated improved processing speed and visual and verbal sustained memory, as well as increased functional connectivity in areas of the default mode network in persons with MS.117 • In the largest randomized clinical trial (RCT) of cognitive rehabilitation to date, a home-based, remotely supervised and delivered, 60-hour (over 12 weeks) cognitive remediation program, compared to ordinary computer games, provided Class I evidence of high compliance as well as improved performance on cognitive measures and motor tasks.118 • In another RCT, individuals who underwent an intensive at-home, computer-based attention intervention accompanied by in-person psychological counseling, demonstrated significantly improved simple and divided attention as well as cued alertness.119 • Parisi et al.120 demonstrated that changes in brain resting state functional connectivity helped to explain the lasting effects of cognitive rehabilitation in patients with RRMS several months after the intervention, as well as improvements in depression and quality of life. • Remediation for pediatric patients has not been extensively studied; however, accommodations in the academic setting, careful attention to the mood and behavioral disorders that appear to accompany cognitive impairment, and education and support for the family are essential.11 |
| Exercise |
| • In an RCT of a multimodal exercise training program in persons with marked mobility impairment, Sandroff et al.121 demonstrated significant improvements in walking performance and cognitive processing speed, perhaps related to increased cardiorespiratory capacity. • Several small studies pointing to a relationship between cardiovascular fitness and different measures of brain volume and functional connectivity122–124 have stimulated significant interest in evaluating the impact of combining cognitive rehabilitation with exercise training to impact both cognitive functioning and walking ability in people with MS.125 |
| Pharmacologic management |
| • The variable rate at which cognitive changes progress in MS makes it difficult to study pharmacological interventions in controlled clinical trials. To date, clinical trials of symptomatic treatments for cognitive impairment in MS have produced mixed results, although some individuals appear to have derived limited benefit (amantadine,126 fampridine-SR,127
l-amphetamine,128,129 lisdexamfetamine dimesylate,130 memantine,131 rivastigmine,132,133 donepezil,134,135 and ginkgo biloba136). • Very few of the pivotal trials of the disease-modifying therapies have included cognitive outcome measures and those that have produced mixed results, most likely due to the short duration of the trials and/or methodological problems. The recommended inclusion of the SDMT as an outcome measure in future trials may shed additional light.2 |
MS: multiple sclerosis.
An updated review of the literature on cognitive rehabilitation for people with MS identifies specific tools that can be considered as practice standard for use by rehabilitation specialists.137 Patients who require rehabilitation to address cognitive changes impacting their functioning at home or at work should be referred to a specialist. The optimal referral is to a specialist in MS neuropsychological rehabilitation (neuropsychologist, speech/language pathologist or occupational therapist); the second option is referral to a neuropsychological rehabilitation specialist without MS-specific expertise; the third option is referral to a behavioral health specialist who is willing to learn about MS and cognition.
Managing other factors that impact cognition
The assessment and management of cognitive impairment must take into account a variety of factors that are known to impact cognition since adequate management of those factors may improve cognitive performance.
The interaction of mood, fatigue, sleep problems, and cognition.
The research in this area suggests a complex interrelationship between mood, fatigue, and sleep in people with MS, which in turn have a variable impact on both objective and self-reported cognitive functioning. Effective management of each of these factors is likely to improve the accuracy of both objective and subjective assessments of cognitive dysfunction:
Depression and anxiety appear to worsen memory, processing speed and executive functioning in people with MS.105–107,138,139
Self-reported sleep problems in MS patients with depression, fatigue, or pain, contribute to perceived cognitive problems above and beyond the impact of depressive symptoms.140
Sleep disturbance and obstructive sleep apnea are associated with decreased visual and verbal memory, executive function, attention, processing speed and working memory, such that optimal management of sleep problems may improve cognitive functioning in people with MS.141,142
Medications and Cannabis.
Anticholinergic medications used on a chronic basis to treat overactive bladder significantly reduce information processing speed and some memory functions.143
Because polypharmacy may result in cognitive impairment and/or fatigue that can compound the cognitive issues, a thorough medication review is recommended.144
Smoked cannabis users are more cognitively impaired than non-users, particularly in information processing speed and memory,145–147 with more marked cognitive deficits associated with decreased gray and white matter volume.148 Male users are potentially more vulnerable to cognitive deficits.149
Acknowledging and addressing the barriers to optimal care
Information about the barriers to optimal care comes primarily from anecdotal reporting by people with MS and healthcare providers in various clinical settings. The authors of this paper represent the perspectives of patients and providers as well as the experiences in MS specialty centers, academic centers, and community settings. Based on these sources, the following barriers have been identified:
- Insufficient knowledge on the part of people with MS, family members, and healthcare professionals regarding:
- Prevalence, scope, and impact of cognitive dysfunction.
- Impact of mood changes, fatigue, sleep disruption, and medications on cognition.
- Availability of, or access to, validated screening and assessment tools and remediation strategies.
- Reluctance to discuss cognitive symptoms on the part of:
- Clinicians who feel they do not have referral options or the time or expertise to address assessment and treatment options.
- Patients who feel embarrassed or are afraid to report changes because it might threaten their employment, custody of children, license to drive, and/or independence.
- Reluctance to address cognitive symptoms due to:
- Number of disease- and symptom management issues needing attention during an office visit.
- Insufficient numbers of trained clinicians to do screening, testing, and remediation.
- Poor communication and coordination of care either within a single care team or from one provider to another.
- Cost of screening tools.
- Inadequate reimbursement for screening and treatment.
- Inadequate financial resources for MS treatment centers to hire the appropriate staff.
Although these barriers must be acknowledged and overcome, doing nothing in the meantime to address cognitive challenges among people living with MS is not acceptable. The critical steps going forward are to ensure that people with MS get the care they need while efforts are made to reduce the barriers. Strategies to address barriers to optimal care are listed in Table 5.
Table 5.
Strategies to address barriers to optimal care.
| Strategies to increase early screening and ongoing monitoring |
| • Enhancing education, via the development and dissemination of “toolkits” for everyone affected by MS (patients, family members, and healthcare providers) about the impact of MS on cognition and available screening and treatment options. • Utilizing social media to expand online conversations about cognition and empower people with MS to self-advocate for adequate screening. • Gaining acknowledgment by the neurologic community that assessment and management of cognitive function is as critical as the assessment and management of physical symptoms of MS. • Allotting time at every neurology visit for the SDMT or a self-administered, computerized version of the SDMT or other brief screening tool. • Including the SDMT or other cognitive outcome measure in every MS clinical trial. • Identifying existing or creating new screening tools that can be used remotely and evaluation and cost/benefit analysis of these strategies. • Advocating for adequate reimbursement for screening and monitoring during neurology visits. |
| Strategies to increase access to more complete cognitive evaluation |
| • Providing referral resources for patients and providers, including the National MS Society (800-344-4867); American Psychological Association (APA—www.apa.org/helpcenter/index.aspx); individual state Psychology, Speech/Hearing, and Occupational Therapy associations. • Increasing the number of clinicians who are trained to assess MS-related cognitive dysfunction via increased online training opportunities and collaboration with professional organizations and graduate programs. • Completing an environmental scan of reimbursement for cognitive care in MS and initiating advocacy activities to increase access to this care. |
| Strategies to enhance comprehensive management of cognitive dysfunction |
| • Increasing the number of clinicians who are trained to treat cognitive dysfunction by integrating educational content into existing training programs for psychologists, occupational therapists, speech/language pathologists, brain injury specialists, and others. • Promoting awareness of the ways in which mood, fatigue, sleep disturbances, and cognition interact with one another. • Supporting research to evaluate treatment options, including in-person and remote remedial strategies, pharmaceutical interventions, and exercise. • Encouraging more posters, presentations, workshops, seminars, webinars, and stories in traditional and online media to raise awareness of the impact of cognitive changes in MS and the strategies to manage them. • Encouraging governments, non-profit organizations, and industry to support research and training in MS cognition. |
MS: multiple sclerosis; SDMT: Symbol Digit Modalities Test.
Summary
Comprehensive MS care requires (1) improved education about cognition for healthcare providers and individuals and families affected by MS; (2) baseline screening, as a minimum, with the SDMT or other validated screening tool when the patient is stable; annual re-assessment with the same tool for all adults and children 8 years of age or older to (a) detect acute disease activity, (b) assess for treatment effects (e.g. starting or switching disease-modifying therapy) or recovery from relapses, (c) evaluate progression of cognitive impairment, and/or (d) screen for new-onset cognitive problems; (3) a more comprehensive cognitive assessment for any adult or child who tests positive on initial cognitive screening or demonstrates a significant cognitive decline, as well as any individual who is applying for private disability, SSDI/SSI due to cognitive impairment; and (4) remedial interventions to improve functioning at home, work, or school.
Together, the MS community—including people with MS, family members, healthcare providers, MS advocacy organization—can improve the quality of care and access to care for MS-related cognitive dysfunction.
Footnotes
Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article.
Contributor Information
Rosalind Kalb, National Multiple Sclerosis Society, New York, NY, USA.
Meghan Beier, Division of Rehabilitation Psychology and Neuropsychology, Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Ralph HB Benedict, Department of Neurology, University at Buffalo, Buffalo, NY, USA.
Leigh Charvet, Department of Neurology, Langone Medical Center, New York University, New York, NY, USA.
Kathleen Costello, National Multiple Sclerosis Society, New York, NY, USA.
Anthony Feinstein, Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
Jeffrey Gingold, National Multiple Sclerosis Society, New York, NY, USA.
Yael Goverover, New York University, New York, NY, USA.
June Halper, The Consortium of Multiple Sclerosis Centers and International Organization of Multiple Sclerosis Nurses, Multiple Sclerosis Nurses International Certification Board, Hackensack, NJ, USA.
Colleen Harris, Multiple Sclerosis Center, University of Calgary, Calgary, AB, Canada.
Lori Kostich, The Mandell Center for Multiple Sclerosis, Mount Sinai Rehabilitation Hospital, Hartford, CT, USA.
Lauren Krupp, Department of Neurology, NYU Langone Health, New York University, New York, NY, USA.
Ellen Lathi, The Elliot Lewis Center for Multiple Sclerosis Care, Wellesley, MA, USA.
Nicholas LaRocca, National Multiple Sclerosis Society, New York, NY, USA.
Ben Thrower, Emory University, Atlanta, GA, USA/Andrew C. Carlos Multiple Sclerosis Institute at Shepherd Center, Atlanta, GA, USA.
John DeLuca, Department of Physical Medicine and Rehabilitation and Department of Neurology, Rutgers New Jersey Medical School, Newark, NJ, USA.
References
- 1. Foley FW, Benedict RHB, Gromisch ES, et al. The Need for screening, assessment, and treatment for cognitive dysfunction in multiple sclerosis: Results of a multidisciplinary CMSC consensus conference, September 24, 2010. Int J MS Care 2012; 14: 58–64. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Benedict RH, DeLuca J, Phillips G, et al. Validity of the Symbol Digit Modalities Test as a cognition performance outcome measure for multiple sclerosis. Mult Scler 2017; 23: 721–733. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3. Benedict R, Fishman I, McClellan M, et al. Validity of the Beck Depression Inventory–Fast Screen in multiple sclerosis. Mult Scler 2003; 9: 393–396. [DOI] [PubMed] [Google Scholar]
- 4. Honarmand K, Feinstein A. Validation of the Hospital Anxiety and Depression Scale for use with multiple sclerosis patients. Mult Scler 2009; 15: 1518–1524. [DOI] [PubMed] [Google Scholar]
- 5. Chiaravalloti ND, DeLuca J. Cognitive impairment in multiple sclerosis. Lancet Neurol 2008; 7: 1139–1151. [DOI] [PubMed] [Google Scholar]
- 6. Zhang X, Zhang F, Huang D, et al. Contribution of gray and white matter abnormalities to cognitive impairment in multiple sclerosis. Int J Mol Sci 2017; 18: 46. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. Trapp BD, Ransohoff R, Rudick R. Axonal pathology in multiple sclerosis: Relationship to neurologic disability. Curr Opin Neurol 1999; 12: 295–302. [DOI] [PubMed] [Google Scholar]
- 8. Achiron A, Chapman J, Magalashvili D, et al. Modeling of cognitive impairment by disease duration in multiple sclerosis: A cross-sectional study. PLoS ONE 2013; 8: e71058. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Olazarán J, Cruz I, Benito-León J, et al. Cognitive dysfunction in multiple sclerosis: Methods and prevalence from the GEDMA study. Eur Neurol 2009; 61: 87–93. [DOI] [PubMed] [Google Scholar]
- 10. Rao SM, Leo GJ, Bernardin L, et al. Cognitive dysfunction in multiple sclerosis. I. Frequency, patterns, and prediction. Neurology 1991; 41: 685–691. [DOI] [PubMed] [Google Scholar]
- 11. Amato MP, Krupp LB, Charvet LE, et al. Pediatric multiple sclerosis: Cognition and mood. Neurology 2016; 87: S82–S87. [DOI] [PubMed] [Google Scholar]
- 12. Julian L, Serafin D, Charvet L, et al. Cognitive impairment occurs in children and adolescents with multiple sclerosis: Results from a United States network. J Child Neurol 2013; 28: 102–107. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Johnen A, Landmeyer NC, Bürkner P-C, et al. Distinct cognitive impairments in different disease courses of multiple sclerosis—A systematic review and meta-analysis. Neurosci Biobehav Rev 2017; 83: 568–578. [DOI] [PubMed] [Google Scholar]
- 14. Gouveia A, Dias SP, Santos T, et al. Cognitive impairment and magnetic resonance imaging correlates in primary progressive multiple sclerosis. Acta Neurol Scand 2017; 136: 109–115. [DOI] [PubMed] [Google Scholar]
- 15. Ruano L, Portaccio E, Goretti B, et al. Age and disability drive cognitive impairment in multiple sclerosis across disease subtypes. Mult Scler 2017; 23: 1258–1267. [DOI] [PubMed] [Google Scholar]
- 16. Hynčicová E, Vyhnálek M, Kalina A, et al. Cognitive impairment and structural brain changes in patients with clinically isolated syndrome at high risk for multiple sclerosis. J Neurol 2017; 264: 482–493. [DOI] [PubMed] [Google Scholar]
- 17. Diker S, Has AC, Kurne A, et al. The association of cognitive impairment with gray matter atrophy and cortical lesion load in clinically isolated syndrome. Mult Scler Relat Disord 2016; 10: 14–21. [DOI] [PubMed] [Google Scholar]
- 18. Labiano-Fontcuberta A, Martínez-Ginés ML, Aladro Y, et al. A comparison study of cognitive deficits in radiologically and clinically isolated syndromes. Mult Scler 2016; 22: 250–253. [DOI] [PubMed] [Google Scholar]
- 19. Glanz BI, Holland CM, Gauthier SA, et al. Cognitive dysfunction in patients with clinically isolated syndromes or newly diagnosed multiple sclerosis. Mult Scler 2007; 13: 1004–1010. [DOI] [PubMed] [Google Scholar]
- 20. Cortese M, Riise T, Bjørnevik K, et al. Preclinical disease activity in multiple sclerosis: A prospective study of cognitive performance prior to first symptom. Ann Neurol 2016; 80: 616–624. [DOI] [PubMed] [Google Scholar]
- 21. Amato MP, Razzolini L, Goretti B, et al. Cognitive reserve and cortical atrophy in multiple sclerosis: A longitudinal study. Neurology 2013; 80: 1728–1733. [DOI] [PubMed] [Google Scholar]
- 22. Amato MP, Ponziani G, Siracusa G, et al. Cognitive dysfunction in early-onset multiple sclerosis: A reappraisal after 10 years. Arch Neurol 2001; 58: 1602–1606. [DOI] [PubMed] [Google Scholar]
- 23. Lacy M, Hauser M, Pliskin N, et al. The effects of long-term interferon-beta-1b treatment on cognitive functioning in multiple sclerosis: A 16-year longitudinal study. Mult Scler 2013; 19: 1765–1772. [DOI] [PubMed] [Google Scholar]
- 24. Bergendal G, Fredrikson S, Almkvist O. Selective decline in information processing in subgroups of multiple sclerosis: An 8-year longitudinal study. Eur Neurol 2007; 57: 193–202. [DOI] [PubMed] [Google Scholar]
- 25. Amato MP, Portaccio E, Goretti B, et al. Relevance of cognitive deterioration in early relapsing-remitting MS: A 3-year follow-up study. Mult Scler 2010; 16: 1474–1482. [DOI] [PubMed] [Google Scholar]
- 26. Amato MP, Goretti B, Ghezzi A, et al. Neuropsychological features in childhood and juvenile multiple sclerosis: Five-year follow-up. Neurology 2014; 83: 1432–1438. [DOI] [PubMed] [Google Scholar]
- 27. Deloire MSA, Ruet A, Hamel D, et al. MRI predictors of cognitive outcome in early multiple sclerosis. Neurology 2011; 76: 1161–1167. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28. Benedict RHB, Fischer JS, Archibald CJ, et al. Minimal neuropsychological assessment of MS patients: A consensus approach. Clin Neuropsychol 2002; 16: 381–397. [DOI] [PubMed] [Google Scholar]
- 29. Carotenuto A. Look beyond the door, not through the keyhole: Evidence from a cognitive assessment including social cognition evaluation in multiple sclerosis. Eur J Neurol 2018; 25: 205–206. [DOI] [PubMed] [Google Scholar]
- 30. Cotter J, Firth J, Enzinger C, et al. Social cognition in multiple sclerosis: A systematic review and meta-analysis. Neurology 2016; 87: 1727–1736. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31. Denney DR, Lynch SG, Parmenter BA. A 3-year longitudinal study of cognitive impairment in patients with primary progressive multiple sclerosis: Speed matters. J Neurol Sci 2008; 267: 129–136. [DOI] [PubMed] [Google Scholar]
- 32. Van Schependom J, D’hooghe MB, Cleynhens K, et al. Reduced information processing speed as primum movens for cognitive decline in MS. Mult Scler 2015; 21: 83–91. [DOI] [PubMed] [Google Scholar]
- 33. Chiaravalloti ND, Moore NB, Nikelshpur OM, et al. An RCT to treat learning impairment in multiple sclerosis: The MEMREHAB trial. Neurology 2013; 81: 2066–2072. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34. Genova HM, DeLuca J, Chiaravalloti N, et al. The relationship between executive functioning, processing speed, and white matter integrity in multiple sclerosis. J Clin Exp Neuropsychol 2013; 35: 631–641. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35. Goverover Y, Strober L, Chiaravalloti N, et al. Factors that moderate activity limitation and participation restriction in people with multiple sclerosis. Am J Occup Ther 2015; 69: 6902260020. [DOI] [PubMed] [Google Scholar]
- 36. Cattaneo D, Lamers I, Bertoni R, et al. Participation restriction in people with multiple sclerosis: Prevalence and correlations with cognitive, walking, balance, and upper limb impairments. Arch Phys Med Rehabil 2017; 98: 1308–1315. [DOI] [PubMed] [Google Scholar]
- 37. Kavaliunas A, Danylaite Karrenbauer V, Gyllensten H, et al. Cognitive function is a major determinant of income among multiple sclerosis patients in Sweden acting independently from physical disability. Mult Scler. Epub ahead of print 1 November 2017. DOI: 10.1177/1352458517740212. [DOI] [PubMed] [Google Scholar]
- 38. Morrow SA, Classen S, Monahan M, et al. On-road assessment of fitness-to-drive in persons with MS with cognitive impairment: A prospective study. Mult Scler 2018; 24: 1499–1506. [DOI] [PubMed] [Google Scholar]
- 39. Rao SM, Leo GJ, Ellington L, et al. Cognitive dysfunction in multiple sclerosis. II. Impact on employment and social functioning. Neurology 1991; 41: 692–696. [DOI] [PubMed] [Google Scholar]
- 40. Ruet A, Deloire M, Hamel D, et al. Cognitive impairment, health-related quality of life and vocational status at early stages of multiple sclerosis: A 7-year longitudinal study. J Neurol 2013; 260: 776–784. [DOI] [PubMed] [Google Scholar]
- 41. Papathanasiou A, Messinis L, Zampakis P, et al. Corpus callosum atrophy as a marker of clinically meaningful cognitive decline in secondary progressive multiple sclerosis. Impact on employment status. J Clin Neurosci 2017; 43: 170–175. [DOI] [PubMed] [Google Scholar]
- 42. Campbell J, Rashid W, Cercignani M, et al. Cognitive impairment among patients with multiple sclerosis: Associations with employment and quality of life. Postgrad Med J 2017; 93: 143–147. [DOI] [PubMed] [Google Scholar]
- 43. Kordovski VM, Frndak SE, Fisher CS, et al. Identifying employed multiple sclerosis patients at-risk for job loss: When do negative work events pose a threat? Mult Scler Relat Disord 2015; 4: 409–413. [DOI] [PubMed] [Google Scholar]
- 44. Benedict RHB, Rodgers JD, Emmert N, et al. Negative work events and accommodations in employed multiple sclerosis patients. Mult Scler 2014; 20: 116–119. [DOI] [PubMed] [Google Scholar]
- 45. Goverover Y, Chiaravalloti N, DeLuca J. Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) and performance of everyday life tasks: Actual reality. Mult Scler 2016; 22: 544–550. [DOI] [PubMed] [Google Scholar]
- 46. Till C, Racine N, Araujo D, et al. Changes in cognitive performance over a 1-year period in children and adolescents with multiple sclerosis. Neuropsychology 2013; 27: 210–219. [DOI] [PubMed] [Google Scholar]
- 47. Charvet LE, O’Donnell EH, Belman AL, et al. Longitudinal evaluation of cognitive functioning in pediatric multiple sclerosis: Report from the US pediatric multiple sclerosis network. Mult Scler 2014; 20: 1502–1510. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 48. Mikaeloff Y, Caridade G, Billard C, et al. School performance in a cohort of children with CNS inflammatory demyelination. Eur J Paediatr Neurol 2010; 14: 418–424. [DOI] [PubMed] [Google Scholar]
- 49. Dehning M, Kim J, Nguyen CM, et al. Neuropsychological performance, brain imaging, and driving violations in multiple sclerosis. Arch Phys Med Rehabil 2014; 95: 1818–1823. [DOI] [PubMed] [Google Scholar]
- 50. Lamargue-Hamel D, Deloire M, Saubusse A, et al. Cognitive evaluation by tasks in a virtual reality environment in multiple sclerosis. J Neurol Sci 2015; 359: 94–99. [DOI] [PubMed] [Google Scholar]
- 51. Schultheis MT, Garay E, Millis SR, et al. Motor vehicle crashes and violations among drivers with multiple sclerosis. Arch Phys Med Rehabil 2002; 83: 1175–1178. [DOI] [PubMed] [Google Scholar]
- 52. Gerstenecker A, Lowry K, Myers T, et al. Medical decision-making capacity and its cognitive predictors in progressive MS: Preliminary evidence. J Neurol Sci 2017; 380: 38–43. [DOI] [PubMed] [Google Scholar]
- 53. Bruce JM, Hancock LM, Arnett P, et al. Treatment adherence in multiple sclerosis: Association with emotional status, personality, and cognition. J Behav Med 2010; 33: 219–227. [DOI] [PubMed] [Google Scholar]
- 54. Goverover Y, Haas S, DeLuca J. Money management activities in persons with multiple sclerosis. Arch Phys Med Rehabil 2016; 97: 1901–1907. [DOI] [PubMed] [Google Scholar]
- 55. Tracy VL, Basso MR, Marson DC, et al. Capacity for financial decision making in multiple sclerosis. J Clin Exp Neuropsychol 2017; 39: 46–57. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 56. Figved N, Myhr K-M, Larsen J-P, et al. Caregiver burden in multiple sclerosis: The impact of neuropsychiatric symptoms. J Neurol Neurosurg Psychiatry 2007; 78: 1097–1102. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 57. Labiano-Fontcuberta A, Mitchell AJ, Moreno-García S, et al. Anxiety and depressive symptoms in caregivers of multiple sclerosis patients: The role of information processing speed impairment. J Neurol Sci 2015; 349: 220–225. [DOI] [PubMed] [Google Scholar]
- 58. Thorpe LU, Knox K, Jalbert R, et al. Predictors of institutionalization for people with multiple sclerosis. Disabil Health J 2015; 8: 271–277. [DOI] [PubMed] [Google Scholar]
- 59. Romero K, Shammi P, Feinstein A. Neurologists’ accuracy in predicting cognitive impairment in multiple sclerosis. Mult Scler Relat Disord 2015; 4: 291–295. [DOI] [PubMed] [Google Scholar]
- 60. Beatty WW, Goodkin DE. Screening for cognitive impairment in multiple sclerosis. An evaluation of the Mini-Mental State Examination. Arch Neurol 1990; 47: 297–301. [DOI] [PubMed] [Google Scholar]
- 61. Peyser JM, Edwards KR, Poser CM, et al. Cognitive function in patients with multiple sclerosis. Arch Neurol 1980; 37: 577–579. [DOI] [PubMed] [Google Scholar]
- 62. Benedict RHB, Cookfair D, Gavett R, et al. Validity of the minimal assessment of cognitive function in multiple sclerosis (MACFIMS). J Int Neuropsychol Soc 2006; 12: 549–558. [DOI] [PubMed] [Google Scholar]
- 63. Langdon DW, Amato MP, Boringa J, et al. Recommendations for a Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS). Mult Scler 2012; 18: 891–898. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 64. Roy S, Rodgers J, Drake AS, et al. Stable neuropsychiatric status in multiple sclerosis: A 3-year study. Mult Scler 2016; 22: 569–574. [DOI] [PubMed] [Google Scholar]
- 65. Conradsson D, Ytterberg C, von Koch L, et al. Changes in disability in people with multiple sclerosis: A 10-year prospective study. J Neurol 2018; 265: 119–126. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 66. López-Góngora M, Querol L, Escartín A. A one-year follow-up study of the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test (PASAT) in relapsing-remitting multiple sclerosis: An appraisal of comparative longitudinal sensitivity. BMC Neurol 2015; 15: 40. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 67. Niccolai C, Portaccio E, Goretti B, et al. A comparison of the brief international cognitive assessment for multiple sclerosis and the brief repeatable battery in multiple sclerosis patients. BMC Neurol 2015; 15: 204. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 68. Van Schependom J, D’hooghe MB, Cleynhens K, et al. The Symbol Digit Modalities Test as sentinel test for cognitive impairment in multiple sclerosis. Eur J Neurol 2014; 21: 1219–1225; e71–e72. [DOI] [PubMed] [Google Scholar]
- 69. Sonder JM, Burggraaff J, Knol DL, et al. Comparing long-term results of PASAT and SDMT scores in relation to neuropsychological testing in multiple sclerosis. Mult Scler 2014; 20: 481–488. [DOI] [PubMed] [Google Scholar]
- 70. Morrow SA, O’Connor PW, Polman CH, et al. Evaluation of the Symbol Digit Modalities Test (SDMT) and MS Neuropsychological Screening Questionnaire (MSNQ) in natalizumab-treated MS patients over 48 weeks. Mult Scler 2010; 16: 1385–1392. [DOI] [PubMed] [Google Scholar]
- 71. Parmenter BA, Weinstock-Guttman B, Garg N, et al. Screening for cognitive impairment in multiple sclerosis using the Symbol Digit Modalities Test. Mult Scler 2007; 13: 52–57. [DOI] [PubMed] [Google Scholar]
- 72. Bigi S, Marrie RA, Till C, et al. The computer-based Symbol Digit Modalities Test: Establishing age-expected performance in healthy controls and evaluation of pediatric MS patients. Neurol Sci 2017; 38: 635–642. [DOI] [PubMed] [Google Scholar]
- 73. Charvet LE, Beekman R, Amadiume N, et al. The Symbol Digit Modalities Test is an effective cognitive screen in pediatric onset multiple sclerosis (MS). J Neurol Sci 2014; 341: 79–84. [DOI] [PubMed] [Google Scholar]
- 74. Strober LB, Rao SM, Lee J-C, et al. Cognitive impairment in multiple sclerosis: An 18 year follow-up study. Mult Scler Relat Disord 2014; 3: 473–481. [DOI] [PubMed] [Google Scholar]
- 75. Morrow SA, Drake A, Zivadinov R, et al. Predicting loss of employment over three years in multiple sclerosis: Clinically meaningful cognitive decline. Clin Neuropsychol 2010; 24: 1131–1145. [DOI] [PubMed] [Google Scholar]
- 76. Pardini M, Uccelli A, Grafman J, et al. Isolated cognitive relapses in multiple sclerosis. J Neurol Neurosurg Psychiatry 2014; 85: 1035–1037. [DOI] [PubMed] [Google Scholar]
- 77. Morrow SA, Jurgensen S, Forrestal F, et al. Effects of acute relapses on neuropsychological status in multiple sclerosis patients. J Neurol 2011; 258: 1603–1608. [DOI] [PubMed] [Google Scholar]
- 78. Rao SM, Losinski G, Mourany L, et al. Processing speed test: Validation of a self-administered, iPad®-based tool for screening cognitive dysfunction in a clinic setting. Mult Scler 2017; 23: 1929–1937. [DOI] [PubMed] [Google Scholar]
- 79. Ruet A, Deloire MSA, Charré-Morin J, et al. A new computerised cognitive test for the detection of information processing speed impairment in multiple sclerosis. Mult Scler 2013; 19: 1665–1672. [DOI] [PubMed] [Google Scholar]
- 80. Benedict RHB, Cox D, Thompson LL, et al. Reliable screening for neuropsychological impairment in multiple sclerosis. Mult Scler 2004; 10: 675–678. [DOI] [PubMed] [Google Scholar]
- 81. Akbar N, Honarmand K, Feinstein A. Self-assessment of cognition in multiple sclerosis: The role of personality and anxiety. Cogn Behav Neurol 2011; 24: 115–121. [DOI] [PubMed] [Google Scholar]
- 82. O’Brien A, Gaudino-Goering E, Shawaryn M, et al. Relationship of the Multiple Sclerosis Neuropsychological Questionnaire (MSNQ) to functional, emotional, and neuropsychological outcomes. Arch Clin Neuropsychol 2007; 22: 933–948. [DOI] [PubMed] [Google Scholar]
- 83. Charvet LE, Shaw M, Frontario A, et al. Cognitive impairment in pediatric-onset multiple sclerosis is detected by the Brief International Cognitive Assessment for Multiple Sclerosis and computerized cognitive testing. Mult Scler 2017; 24: 512–519. [DOI] [PubMed] [Google Scholar]
- 84. Benedict RH, Morrow S, Rodgers J, et al. Characterizing cognitive function during relapse in multiple sclerosis. Mult Scler 2014; 20: 1745–1752. [DOI] [PubMed] [Google Scholar]
- 85. Wybrecht D, Reuter F, Pariollaud F, et al. New brain lesions with no impact on physical disability can impact cognition in early multiple sclerosis: A ten-year longitudinal study. PLoS ONE 2017; 12: e0184650. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 86. Deloire M, Ruet A, Hamel D, et al. Early cognitive impairment in multiple sclerosis predicts disability outcome several years later. Mult Scler 2010; 16: 581–587. [DOI] [PubMed] [Google Scholar]
- 87. Pitteri M, Romualdi C, Magliozzi R, et al. Cognitive impairment predicts disability progression and cortical thinning in MS: An 8-year study. Mult Scler 2017; 23: 848–854. [DOI] [PubMed] [Google Scholar]
- 88. Moccia M, Lanzillo R, Palladino R, et al. Cognitive impairment at diagnosis predicts 10-year multiple sclerosis progression. Mult Scler 2016; 22: 659–667. [DOI] [PubMed] [Google Scholar]
- 89. Patti F. Optimizing the benefit of multiple sclerosis therapy: The importance of treatment adherence. Patient Prefer Adherence 2010; 4: 1–9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 90. Marin SE, Banwell BB, Till C. Cognitive trajectories in 4 patients with pediatric-onset multiple sclerosis: Serial evaluation over a decade. J Child Neurol 2013; 28: 1577–1586. [DOI] [PubMed] [Google Scholar]
- 91. Ruano L, Branco M, Portaccio E, et al. Patients with paediatric-onset multiple sclerosis are at higher risk of cognitive impairment in adulthood: An Italian collaborative study. Mult Scler 2018; 24: 1234–1242. [DOI] [PubMed] [Google Scholar]
- 92. Amato MP, Portaccio E, Stromillo ML, et al. Cognitive assessment and quantitative magnetic resonance metrics can help to identify benign multiple sclerosis. Neurology 2008; 71: 632–638. [DOI] [PubMed] [Google Scholar]
- 93. Amato MP, Zipoli V, Goretti B, et al. Benign multiple sclerosis: Cognitive, psychological and social aspects in a clinical cohort. J Neurol 2006; 253: 1054–1059. [DOI] [PubMed] [Google Scholar]
- 94. Gajofatto A, Turatti M, Bianchi MR, et al. Benign multiple sclerosis: Physical and cognitive impairment follow distinct evolutions. Acta Neurol Scand 2016; 133: 183–191. [DOI] [PubMed] [Google Scholar]
- 95. Damasceno A, Damasceno BP, Cendes F. No evidence of disease activity in multiple sclerosis: Implications on cognition and brain atrophy. Mult Scler 2016; 22: 64–72. [DOI] [PubMed] [Google Scholar]
- 96. Portaccio E, Stromillo ML, Goretti B, et al. Neuropsychological and MRI measures predict short-term evolution in benign multiple sclerosis. Neurology 2009; 73: 498–503. [DOI] [PubMed] [Google Scholar]
- 97. Correale J, Peirano I, Romano L. Benign multiple sclerosis: A new definition of this entity is needed. Mult Scler 2012; 18: 210–218. [DOI] [PubMed] [Google Scholar]
- 98. Modica CM, Bergsland N, Dwyer MG, et al. Cognitive reserve moderates the impact of subcortical gray matter atrophy on neuropsychological status in multiple sclerosis. Mult Scler 2016; 22: 36–42. [DOI] [PubMed] [Google Scholar]
- 99. Sandroff BM, Schwartz CE, DeLuca J. Measurement and maintenance of reserve in multiple sclerosis. J Neurol 2016; 263: 2158–2169. [DOI] [PubMed] [Google Scholar]
- 100. Feinstein A, Lapshin H, O’Connor P, et al. Sub-threshold cognitive impairment in multiple sclerosis: The association with cognitive reserve. J Neurol 2013; 260: 2256–2261. [DOI] [PubMed] [Google Scholar]
- 101. Benedict RHB, Morrow SA, Weinstock Guttman B, et al. Cognitive reserve moderates decline in information processing speed in multiple sclerosis patients. J Int Neuropsychol Soc 2010; 16: 829–835. [DOI] [PubMed] [Google Scholar]
- 102. Chiaravalloti ND, DeLuca J. The influence of cognitive dysfunction on benefit from learning and memory rehabilitation in MS: A sub-analysis of the MEMREHAB trial. Mult Scler 2015; 21: 1575–1582. [DOI] [PubMed] [Google Scholar]
- 103. Goverover Y, Chiaravalloti N, DeLuca J. The influence of executive functions and memory on self-generation benefit in persons with multiple sclerosis. J Clin Exp Neuropsychol 2013; 35: 775–783. [DOI] [PubMed] [Google Scholar]
- 104. Mohr DC, Hart SL, Julian L, et al. Screening for depression among patients with multiple sclerosis: Two questions may be enough. Mult Scler 2007; 13: 215–219. [DOI] [PubMed] [Google Scholar]
- 105. Arnett PA, Higginson CI, Randolph JJ. Depression in multiple sclerosis: Relationship to planning ability. J Int Neuropsychol Soc 2001; 7: 665–674. [DOI] [PubMed] [Google Scholar]
- 106. Arnett PA, Higginson CI, Voss WD, et al. Depression in multiple sclerosis: Relationship to working memory capacity. Neuropsychology 1999; 13: 546–556. [DOI] [PubMed] [Google Scholar]
- 107. Arnett PA, Higginson CI, Voss WD, et al. Depressed mood in multiple sclerosis: Relationship to capacity-demanding memory and attentional functioning. Neuropsychology 1999; 13: 434–446. [DOI] [PubMed] [Google Scholar]
- 108. Leavitt VM, Wylie G, Krch D, et al. Does slowed processing speed account for executive deficits in multiple sclerosis? Evidence from neuropsychological performance and structural neuroimaging. Rehabil Psychol 2014; 59: 422–428. [DOI] [PubMed] [Google Scholar]
- 109. National Multiple Sclerosis Society. Applying for social security disability benefits: A guidebook for people with MS and their healthcare providers, www.nationalmssociety.org/SSDGuide (2017, accessed 10 April 2018).
- 110. Goverover Y, Chiaravalloti N, Genova H, et al. A randomized controlled trial to treat impaired learning and memory in multiple sclerosis: The self-GEN trial. Mult Scler 2018; 24: 1096–1104. [DOI] [PubMed] [Google Scholar]
- 111. Goverover Y, Chiaravalloti N, DeLuca J. Self-generation to improve learning and memory of functional activities in persons with multiple sclerosis: Meal preparation and managing finances. Arch Phys Med Rehabil 2008; 89: 1514–1521. [DOI] [PubMed] [Google Scholar]
- 112. Chiaravalloti ND, Deluca J. Self-generation as a means of maximizing learning in multiple sclerosis: An application of the generation effect. Arch Phys Med Rehabil 2002; 83: 1070–1079. [DOI] [PubMed] [Google Scholar]
- 113. Goverover Y, Chiaravalloti ND, Deluca J. Task meaningfulness and degree of cognitive impairment: Do they affect self-generated learning in persons with multiple sclerosis? Neuropsychol Rehabil 2014; 24: 155–171. [DOI] [PubMed] [Google Scholar]
- 114. Goverover Y, Basso M, Wood H, et al. Examining the benefits of combining two learning strategies on recall of functional information in persons with multiple sclerosis. Mult Scler 2011; 17: 1488–1497. [DOI] [PubMed] [Google Scholar]
- 115. Chiaravalloti ND, Wylie G, Leavitt V, et al. Increased cerebral activation after behavioral treatment for memory deficits in MS. J Neurol 2012; 259: 1337–1346. [DOI] [PubMed] [Google Scholar]
- 116. Sumowski JF, Chiaravalloti N, Deluca J. Retrieval practice improves memory in multiple sclerosis: Clinical application of the testing effect. Neuropsychology 2010; 24: 267–272. [DOI] [PubMed] [Google Scholar]
- 117. Bonavita S, Sacco R, Della Corte M, et al. Computer-aided cognitive rehabilitation improves cognitive performances and induces brain functional connectivity changes in relapsing remitting multiple sclerosis patients: An exploratory study. J Neurol 2015; 262: 91–100. [DOI] [PubMed] [Google Scholar]
- 118. Charvet LE, Yang J, Shaw MT, et al. Cognitive function in multiple sclerosis improves with telerehabilitation: Results from a randomized controlled trial. PLoS ONE 2017; 12: e0177177. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 119. Pusswald G, Mildner C, Zebenholzer K, et al. A neuropsychological rehabilitation program for patients with multiple sclerosis based on the model of the ICF. NeuroRehabilitation 2014; 35: 519–527. [DOI] [PubMed] [Google Scholar]
- 120. Parisi L, Rocca MA, Mattioli F, et al. Changes of brain resting state functional connectivity predict the persistence of cognitive rehabilitation effects in patients with multiple sclerosis. Mult Scler 2014; 20: 686–694. [DOI] [PubMed] [Google Scholar]
- 121. Sandroff BM, Motl RW, Deluca J. The influence of cognitive impairment on the fitness-cognition relationship in multiple sclerosis. Med Sci Sports Exerc 2017; 49: 1184–1189. [DOI] [PubMed] [Google Scholar]
- 122. Motl RW, Hubbard EA, Sreekumar N, et al. Pallidal and caudate volumes correlate with walking function in multiple sclerosis. J Neurol Sci 2015; 354: 33–36. [DOI] [PubMed] [Google Scholar]
- 123. Klaren RE, Hubbard EA, Motl RW, et al. Objectively measured physical activity is associated with brain volumetric measurements in multiple sclerosis. Behav Neurol 2015; 2015: 482536. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 124. Leavitt VM, Cirnigliaro C, Cohen A, et al. Aerobic exercise increases hippocampal volume and improves memory in multiple sclerosis: Preliminary findings. Neurocase 2014; 20: 695–697. [DOI] [PubMed] [Google Scholar]
- 125. Motl RW, Sandroff BM, DeLuca J. Exercise training and cognitive rehabilitation: A symbiotic approach for rehabilitating walking and cognitive functions in multiple sclerosis? Neurorehabil Neural Repair 2016; 30: 499–511. [DOI] [PubMed] [Google Scholar]
- 126. Geisler MW, Sliwinski M, Coyle PK, et al. The effects of amantadine and pemoline on cognitive functioning in multiple sclerosis. Arch Neurol 1996; 53: 185–188. [DOI] [PubMed] [Google Scholar]
- 127. Morrow SA, Rosehart H, Johnson AM. The effect of Fampridine-SR on cognitive fatigue in a randomized double-blind crossover trial in patients with MS. Mult Scler Relat Disord 2017; 11: 4–9. [DOI] [PubMed] [Google Scholar]
- 128. Sumowski JF, Chiaravalloti N, Erlanger D, et al. L-amphetamine improves memory in MS patients with objective memory impairment. Mult Scler 2011; 17: 1141–1145. [DOI] [PubMed] [Google Scholar]
- 129. Morrow SA, Kaushik T, Zarevics P, et al. The effects of L-amphetamine sulfate on cognition in MS patients: Results of a randomized controlled trial. J Neurol 2009; 256: 1095–1102. [DOI] [PubMed] [Google Scholar]
- 130. Morrow SA, Smerbeck A, Patrick K, et al. Lisdexamfetamine dimesylate improves processing speed and memory in cognitively impaired MS patients: A phase II study. J Neurol 2013; 260: 489–497. [DOI] [PubMed] [Google Scholar]
- 131. Peyro SaintPaul L, Creveuil C, Heinzlef O, et al. Efficacy and safety profile of memantine in patients with cognitive impairment in multiple sclerosis: A randomized, placebo-controlled study. J Neurol Sci 2016; 363: 69–76. [DOI] [PubMed] [Google Scholar]
- 132. Huolman S, Hämäläinen P, Vorobyev V, et al. The effects of rivastigmine on processing speed and brain activation in patients with multiple sclerosis and subjective cognitive fatigue. Mult Scler 2011; 17: 1351–1361. [DOI] [PubMed] [Google Scholar]
- 133. Shaygannejad V, Janghorbani M, Ashtari F, et al. Effects of rivastigmine on memory and cognition in multiple sclerosis. Can J Neurol Sci 2008; 35: 476–481. [DOI] [PubMed] [Google Scholar]
- 134. Krupp LB, Christodoulou C, Melville P, et al. Donepezil improved memory in multiple sclerosis in a randomized clinical trial. Neurology 2004; 63: 1579–1585. [DOI] [PubMed] [Google Scholar]
- 135. Krupp LB, Christodoulou C, Melville P, et al. Multicenter randomized clinical trial of donepezil for memory impairment in multiple sclerosis. Neurology 2011; 76: 1500–1507. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 136. Lovera JF, Kim E, Heriza E, et al. Ginkgo biloba does not improve cognitive function in MS: A randomized placebo-controlled trial. Neurology 2012; 79: 1278–1284. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 137. Goverover Y, Chiaravalloti ND, O’Brien AR, et al. Evidenced-based cognitive rehabilitation for persons with multiple sclerosis: An updated review of the literature from 2007 to 2016. Arch Phys Med Rehabil 2018; 99: 390–407. [DOI] [PubMed] [Google Scholar]
- 138. Morrow SA, Rosehart H, Pantazopoulos K. Anxiety and depressive symptoms are associated with worse performance on objective cognitive tests in MS. J Neuropsychiatry Clin Neurosci 2016; 28: 118–123. [DOI] [PubMed] [Google Scholar]
- 139. Portaccio E. Differential diagnosis, discerning depression from cognition. Acta Neurol Scand 2016; 134(Suppl. 200): 14–18. [DOI] [PubMed] [Google Scholar]
- 140. Hughes AJ, Parmenter BA, Haselkorn JK, et al. Sleep and its associations with perceived and objective cognitive impairment in individuals with multiple sclerosis. J Sleep Res 2017; 26: 428–435. [DOI] [PubMed] [Google Scholar]
- 141. Patel VP, Walker LAS, Feinstein A. Processing speed and distractibility in multiple sclerosis: The role of sleep. Mult Scler Relat Disord 2017; 11: 40–42. [DOI] [PubMed] [Google Scholar]
- 142. Braley TJ, Kratz AL, Kaplish N, et al. Sleep and cognitive function in multiple sclerosis. Sleep 2016; 39: 1525–1533. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 143. Cruce R, Vosoughi R, Freedman MS. Cognitive impact of anticholinergic medication in MS: Adding insult to injury? Mult Scler Relat Disord 2012; 1: 156–161. [DOI] [PubMed] [Google Scholar]
- 144. Thelen JM, Lynch SG, Bruce AS, et al. Polypharmacy in multiple sclerosis: Relationship with fatigue, perceived cognition, and objective cognitive performance. J Psychosom Res 2014; 76: 400–404. [DOI] [PubMed] [Google Scholar]
- 145. Feinstein A, Banwell E, Pavisian B. What to make of cannabis and cognition in MS: In search of clarity amidst the haze. Mult Scler 2015; 21: 1755–1760. [DOI] [PubMed] [Google Scholar]
- 146. Pavisian B, Staines WR, Feinstein A. Cannabis-induced alterations in brain activation during a test of information processing speed in patients with MS. Mult Scler J Exp Transl Clin 2015; 1: 2055217315588223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 147. Pavisian B, MacIntosh BJ, Szilagyi G, et al. Effects of cannabis on cognition in patients with MS: A psychometric and MRI study. Neurology 2014; 82: 1879–1887. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 148. Romero K, Pavisian B, Staines WR, et al. Multiple sclerosis, cannabis, and cognition: A structural MRI study. Neuroimage Clin 2015; 8: 140–147. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 149. Patel VP, Feinstein A. Cannabis and cognitive functioning in multiple sclerosis: The role of gender. Mult Scler J Exp Transl Clin 2017; 3: 205521731771302. [DOI] [PMC free article] [PubMed] [Google Scholar]
