Neuropsychological assessment in myasthenia gravis

Neurometabolic and Brain Functional Alterations Associated with Cognitive Impairment in Patients with Myasthenia Gravis: A Combined 1H-MRS and fMRI Study

Whether patients with myasthenia gravis (MG) exhibit cognitive impairment is controversial. Also the underlying mechanisms are unknown. We aimed to investigate alterations in cognitive function, neurometabolite levels, and brain function in patients with MG and to explore the associations between abnormal regional brain functional activity, neurometabolite concentrations in the MPFC and left thalamus, and cognitive activity in patients with MG. Neuropsychological tests, proton magnetic resonance spectroscopy, and resting-state functional magnetic resonance imaging were performed on 41 patients with MG and 45 race-, sex-, age-, and education-matched healthy controls (HCs). The results suggest that MG is accompanied by cognitive decline, as indicated by global cognitive function, visual-spatial function, language, memory, abnormalities in regional brain functional activity, and neurometabolite alterations (including GABA, NAA, and Cho) in the medial prefrontal cortex (MPFC) and left thalamus. Cognitive impairment in patients with MG may be related to abnormal regional brain functional activity and changes in neurometabolites, and regional brain functional activity may be modulated by specific neurometabolites.

Systematic review of the patient burden of generalised myasthenia gravis in Europe, the Middle East, and Africa

BACKGROUND

Myasthenia gravis (MG) is a rare autoimmune disease characterised by muscle weakness, and progression from ocular (oMG) to generalised (gMG) symptoms results in a substantial negative impact on quality of life (QoL). This systematic review aimed to provide an overview of the patient burden experienced by people living with gMG.

METHODS

Electronic database searches (conducted March 2022), supplemented by interrogation of grey literature, were conducted to identify studies reporting patient burden outcomes in patients with gMG in Europe, the Middle East and Africa. Results were synthesised narratively due to the heterogeneity across trials.

RESULTS

In total, 39 patient burden publications (representing 38 unique studies) were identified as relevant for inclusion in the systematic review, consisting of 37 publications reporting formal patient-reported outcome measures (PROMs), and two publications describing alternative qualitative assessments of patient experience. The studies included a variety of measures including generic and disease-specific PROMs, as well as symptom-specific PROMs focusing on key comorbidities including depression, anxiety, fatigue and sleep disturbance. The findings showed some variation across studies and PROMs; however, in general there was evidence for worse QoL in patients with gMG than in healthy controls or in patients with oMG, and a trend for worsening QoL with increasing MG severity.

CONCLUSIONS

This review highlights the importance of considering patient QoL when developing and assessing treatment and management plans for patients with gMG. However, the heterogeneity identified across studies illustrates the need for further representative and well-powered studies in large cohorts administering consistent, validated questionnaires.

TRIAL REGISTRATION

The protocol for this systematic review was registered in PROSPERO: CRD42022328444.

Association between myasthenia gravis and cognitive disorders: a PRISMA-compliant meta-analysis

OBJECTIVE

This meta-analysis assessed the association between myasthenia gravis (MG) and cognitive disorders.

METHODS

The PubMed, Web of Science, OVID, EMBASE, CNKI and Wanfang electronic databases were comprehensively searched from inception to October 2020 for relevant studies. The primary outcomes were scores of the cognitive function battery. A random effects model was used to evaluate the cognitive function of patients with MG.

RESULTS

Eight cross-sectional studies containing 381 patients and 220 healthy controls were included in this meta-analysis. In relation to global cognitive function, patients with MG performed significantly worse than healthy individuals (SMD = -0.4, 95% CI = -0.63 to -0.16, p < 0.001, I2 = 10%). Specifically, the impaired cognitive domains included language, visuospatial function, information processing, verbal immediate and delayed recall memory, visual immediate recall memory, and response fluency, while attention, executive function, and visual delayed recall memory were unimpaired. The patients with early-onset (SMD= -0.527, 95% CI = -0.855 to -0.199, p = 0.002) and generalized MG (SMD= -0.577, 95% CI = -1.047 to -0.107, p = 0.016) had poorer global cognitive performance than the healthy population.

CONCLUSIONS

Patients with MG may have cognitive disorders, including those associated with the domains of language, visuospatial function, information processing, verbal immediate and delayed recall memory, visual immediate recall memory and response fluency. Furthermore, the age of onset and disease severity may be associated with cognitive disorders in patients with MG.

Frequency and Correlates of Mild Cognitive Impairment in Myasthenia Gravis

BACKGROUND

Antibodies against acetylcholine receptors (AChRs) can also target nicotinic AChRs that are present throughout the central nervous system, thus leading to cognitive dysfunctions in patients with myasthenia gravis (MG). However, the presence of cognitive impairment in MG is controversial, and the factors that may influence this risk are almost completely unknown. In this study, the frequency of mild cognitive impairment (MCI) in MG, as well as the clinical, immunological, and behavioral correlates of MCI in MG were evaluated.

METHODS

A total of 52 patients with MG underwent a comprehensive assessment including motor and functional scales, serological testing, and neuropsychological and behavioral evaluation.

RESULTS

The frequency of MCI was 53.8%, and the most impaired cognitive domains were, in order, visuoconstructive/visuospatial skills, memory, and attention. After multivariate analysis, only pyridostigmine use was inversely associated with the presence of MCI, while a trend toward a positive association between MCI and disease severity and arms/legs hyposthenia was found. Correlation analyses showed that daily doses of prednisone and azathioprine significantly correlated with depressive symptomatology, while disease severity significantly correlated with depressive symptomatology and sleep disturbance.

CONCLUSIONS

The presence of MCI is rather frequent in MG and is characterized by multidomain amnestic impairment. Such preliminary data need further confirmation on larger case series.

Association Between Myasthenia Gravis and Memory: A Systematic Review and Meta-Analysis

Objective: The studies have produced contradictory results regarding the association between myasthenia gravis (MG) and cognitive function, especially for the cognitive domains of memory. This meta-analysis was dedicated to exploring the association between MG and memory, which was represented by the immediate recall and delayed recall.

Methods: Using the random effects models, this study analyzed memory in MG based on data from the studies retrieved from four electronic databases from inception to February 2021. Disease severity was graded according to the Myasthenia Gravis Foundation of America (MGFA) classification. We defined ocular myasthenia gravis (OMG) (MGFA Grade I) as Class I, mild, and moderate generalized myasthenia gravis (GMG) (MGFA Grade IIa, IIb, IIIa, and IIIb) as Class II.

Results: In total, eight studies of 274 patients and 211 healthy controls were included. The significant associations were found between MG and memory. Compared with the healthy control group, the patients with MG performed significantly worse in the terms of immediate recall [standardized mean difference (SMD) = −0.65, 95% CI = −0.97 to −0.33, P < 0.001, I² = 64.1%] and delayed recall (SMD = −0.49, 95% CI = −0.88 to −0.1, P < 0.05, I² = 76.3%). Compared with the patients with Class I MG, those with Class II MG did not have significantly different scores in immediate recall (SMD = −0.07, 95% CI = −0.35 to 0.21, P = 0.614, I² = 0%) and delayed recall (SMD = 0.63, 95% CI = −0.29 to 1.55, P = 0.178, I² = 87.9%).

Conclusion: The patients with MG showed lower memory performance, such as both immediate and delayed recall ability. There was no association between the severity of MG and memory. Future studies should address whether these associations are casual and modifiable.

Cognitive performance in patients with Myasthenia Gravis: an association with glucocorticosteroid use and depression

ABSTRACT. We investigated the cognitive performance of patients with Myasthenia Gravis (MG) through a cross-sectional study. A battery of cognitive assessments and self-report questionnaires regarding quality of life (QoL), sleep, and depression were applied. The sample consisted of 39 patients diagnosed with MG. The scores showed a predominance of cognitive impairment in the Montreal Cognitive Assessment screening test (MoCA) (66.7%) and in the immediate (59.0%) and recent memory (56.4%) tests. However, after the Poisson regression analysis with robust variance, it was found that patients diagnosed with depression had a prevalence ratio (PR) of 1,887 (CI 1,166‒3,054) for lower MoCA scores, PR=9,533 (CI 1,600‒56,788) for poorer phonemic verbal fluency scores, and PR=12,426 (CI 2,177‒70,931) for the Semantic Verbal Fluency test. Moreover, concerning a decline in short-term memory retention, patients using glucocorticosteroids (GC) and with Beck Depression Inventory scores indicating depression showed PR=11,227 (CI 1,736‒72,604) and PR=0.35 (CI 0.13‒0.904), respectively. No correlation was found between the QoL questionnaire and performance in cognitive tests. We found worse performance in tasks of memory and executive functions in MG patients. These are not associated with the length and severity of the disease. However, a significant prevalence ratio was found for poorer memory performance in patients diagnosed with depression and in those using GC.

Prospective study of stress, depression and personality in myasthenia gravis relapses

Background

Psychopathology and personality traits may influence the course of autoimmune disorders. With this prospective longitudinal cohort study, we aimed to assess personality, stress and depression in myasthenia patients who relapse and those who remain stable or improve (non-relapsers).

Method

We collected data from 155 consecutive adult patients with confirmed MG attending the Neuromuscular Clinic, Toronto General Hospital, between March 2017 and July 2018, for this study. Patients were assessed at baseline and 6 months, or at the time of MG relapse. At both visits, the patients were assessed clinically and were asked to complete self-administered questionnaires for disease severity, chronic stress and depression. Personality type was assessed at baseline only. Relapsing patients were defined as those patients with MGII score increasing by more than 5.5 points from visit 1 to visit 2.

Results

Relapsers had higher baseline scores for depression (p = 0.01) and the change in disease severity correlated with the change in depression score (r = 0.2534, p = 0.0015, 95% CI: 0.098 0.3961). Higher levels of stress at baseline and neuroticism predicted higher relapse rates (p = 0.01 and p < .0001, respectively). In the linear regression model, with change of the MGII score as the dependent variable, change in depression scores (p = 0.0004) and age (p = 0.03) predicted change in disease severity.

Conclusions

Since emotional factors and personality type may influence MG, attention to these factors might improve care in MG patients.

Prevalence and Associated Factors of Depressive Symptoms in Patients with Myasthenia Gravis: A Cross-Sectional Study of Two Tertiary Hospitals in Riyadh, Saudi Arabia

Objectives

This study is aimed at elucidating the prevalence of depression in patients with myasthenia gravis (MG) and examining the risk factors associated with depression.

Methods

We evaluated adult patients with MG who were recruited from two tertiary hospitals in the central region (Riyadh) of Saudi Arabia. Data were collected with a two-part standardized questionnaire: the first part included data on sociodemographic and clinical features of MG including disease type and duration, therapies, prednisolone dose, time of the last relapse, previous critical care unit admissions, MG status (controlled, partially controlled, or uncontrolled), and comorbid diseases; the second part included items from the previously validated Arabic version of the Patient Health Questionnaire-9 (PHQ-9).

Results

In total, 104/150 (69.3%) patients participated (72 females) with a mean age of 38.0 ± 16.0 years. The mean PHQ-9 score was 7.02 ± 6.1. Among all the participants, 27 (26.0%) patients had depression (PHQ-9 ≥ 10). Multiple logistic regression analysis revealed that uncontrolled MG status (OR = 12.31, 95%CI = 1.13-133.8, P = 0.04) was the only factor independently associated with depression. Collectively, the prevalence of depression among patients of the primary care clinics (PCC) as reported by 5 previous studies across multiple regions of the country was 15.8%. The odds of depression among MG patients were twofold higher than those among PCC patients (OR = 2.05, 95%CI = 1.30-3.22, P = 0.002).

Conclusions

Approximately a quarter of MG patients have depression. Achieving a minimal manifestation or better MG status may decrease the depression rate in these patients.

Chronic stress, depression and personality type in patients with myasthenia gravis

BACKGROUND AND PURPOSE

Stress is a known risk factor for the onset and modulation of disease activity in autoimmune disorders. The aim of this cross-sectional study was to determine any associations between myasthenia gravis (MG) severity and chronic stress, depression and personality type.

METHODS

In all, 179 consecutive adult patients with confirmed MG attending the Neuromuscular Clinic between March 2017 and December 2017 were included. At baseline, patients were assessed clinically and they completed self-administered scales for disease severity, perceived stress, depression and personality type.

RESULTS

Higher disease severity [Myasthenia Gravis Impairment Index (MGII)] showed a moderate correlation with depression score (Beck's Depression Inventory, Second Edition, r = 0.52, P < 0.001) and a lower correlation with chronic stress (Trier Inventory for Assessment of Chronic Stress, r = 0.28, P = 0.001). Chronic stress scores were different according to personality types (anova, P = 0.02). The linear regression model with MGII score as the dependent variable showed R² = 0.34, likelihood ratio chi-squared 74.55, with P < 0.0001. The only variables that predicted disease severity were depression scores (P < 0.0001) and female sex (P = 0.003).

CONCLUSIONS

A significant association of MG severity with depression and chronic stress was found, as well as with female gender. These findings should raise awareness that the long-term management of MG should address depression and potential stress and consider behavioural management to prevent stress-related immune imbalance.

Muscle strength and psychiatric symptoms influence health-related quality of life in patients with myasthenia gravis

Myasthenia gravis (MG) is a neuromuscular autoimmune disease characterized by skeletal muscle weakness which can impact motor function and, furthermore, produce negative impact on the health-related quality of life (HRQOL).

OBJECTIVE

To evaluate the predictors for HRQOL in patients with MG.

METHODS

Eighty patients were evaluated with the MG Foundation of America classification and the MG Composite scale. HRQOL was estimated by the MGQOL15, while anxious and depressive symptoms were evaluated with the Hospital Anxiety and Depression Scale (HAD).

RESULTS

The mean age of patients was 41.9 years with mean illness duration of 13.5 years. Almost half of the patients (43.75%) had significant anxiety and more than a quarter (27.50%) had depressive symptoms. Factors that influenced the HRQOL in MG were skeletal muscle weakness and anxiety and depressive symptoms (p < .001 in logistic regression model).

CONCLUSION

Anxiety and depressive symptoms, besides motor symptoms, influence HRQOL in MG. Mental health must be a clinical focus in addition to the treatment of somatic symptoms during the course of MG.

Association between myasthenia gravis and cognitive function: A systematic review and meta-analysis

The course of myasthenia gravis (MG) is complicated by increased reports of cognitive defects in both human and animal models, which suggests potential central nervous system (CNS) damage. We conducted a systematic review of the relationships between MG and cognitive function. This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Major databases were searched to examine the neuropsychological studies of adults with MG. Weighted effect sizes were pooled by cognitive domain. Eight studies representing 300 subjects were included. Eight cognitive domain categories were identified: (i) Mini-Mental State Examination (MMSE), (ii) language, (iii) processing speed, (iv) verbal learning and memory, (v) visual learning and memory, (vi) attention span, (vii) response fluency, and (viii) motor performance. Nine (cognitive domain categories, MMSE, language, processing speed, verbal learning and memory (except for delayed recall memory), and motor performance) of 16 cognitive tasks revealed significant moderate effect sizes. Verbal logical-delayed memory, finger tapping with the preferred hand, and the Symbol Digit Modalities Test showed a greater magnitude relationship to cognitive function than did other specific cognitive domains. Verbal learning and memory seems to be the most significant affected according to cognitive domain categories. For MG, the ability of attention, response fluency, visual learning, and memory seems to be reserved. The MG patients seem to perform significantly worse than the non-MG controls in a range of cognitive domains. Our findings should be interpreted with caution because of the clinical and methodological heterogeneity of included studies.

Cognitive impairment as a central cholinergic deficit in patients with Myasthenia Gravis

Background

The purpose of this study was to investigate with neurophysiological and neuropsychological methods such as pupillometry, cognitive test and Hamilton Depression Rating Scale (HAM-D) the hypothesis of Central Nervous System (CNS) cholinergic involvement in patients with Myasthenia Gravis (MG).

Methods

Thirty-two patients (32) with MG and a mean age of 51.1 ± 17.2 volunteered to participate in this investigation, while thirty-three (33) healthy subjects with a mean age of 50.2 ± 14.8 served as controls. All subjects underwent pupillometric measurements and performed the Wechsler Memory Scale (WMS) and HAM-D. The pupillometric indices studied were: 1) latency for the onset of constriction (T1), 2) maximum constriction velocity (VCmax) and 3) maximum constriction acceleration (ACmax).

Results

T1 was found significantly increased by 21.7% (p < 0.05) in MG patients as compared to healthy subjects. Conversely, VCmax and ACmax were significantly decreased in MG patients by 33.3% (p < 0.05) and 43.5% (p < 0.05) respectively, as opposed to healthy subjects. Additionally, MG patients showed significantly decreased score in WMS by 41.6% (p < 0.05) as compared to healthy controls. No significant difference was found for HAM-D between the two groups.

Conclusions

VCmax and ACmax are governed mainly by the action of the Parasympathetic Nervous System, through acetylcholine. The results of this study demonstrate that the CNS may be affected in MG and support the hypothesis that MG has central cholinergic effects manifested by cognitive dysfunction.

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Myasthenia Gravis has central cholinergic deficits manifested by cognitive dysfunction.

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The hypothesis of Central Nervous System cholinergic involvement was examined with pupillometry and cognitive tests.

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Central Cholinergic System and/or the iris sphincter smooth muscle might be affected in Myasthenia Gravis.

Experiences of living with myasthenia gravis: a qualitative study with Taiwanese people

Myasthenia gravis (MG) is an auto-immune, neuromuscular disorder, which presents with symptoms of fluctuating muscle fatigue because of a dysfunction of the neuromuscular junction. This study explores the illness experience of patients with MG, their experiences of illness, its challenges, and their coping and support strategies. In-depth interviews were undertaken with nine participants with MG (six for a generalized type of MG, three for ocular type). Data were subjected to inductive content and thematic analysis. Four themes emerged from MG patients with associated subthemes. They were "perceptions of MG," "challenges of MG, "social support," and "adapting and adjusting to MG." The study reveals the way in which individuals respond to and cope with their diagnosis. The importance of social and peer support is a key factor as well as the development of psychological strategies to live with MG. The recognition that there was a need to recognize the role of Western medicine in controlling their disease was also an important finding.

Facial Affect Recognition in Myasthenia Gravis

The assessment of facial expression is an important aspect of a clinical neurological examination, both as an indicator of a mood disorder and as a sign of neurological damage. To date, although studies have been conducted on certain psychosocial aspects of myasthenia, such as quality of life and anxiety, and on neuropsychological aspects such as memory, no studies have directly assessed facial emotion recognition accuracy. The aim of this study was to assess the facial emotion recognition accuracy (fear, surprise, sadness, happiness, anger, and disgust), empathy, and reaction time of patients with myasthenia. Thirty-five patients with myasthenia and 36 healthy controls were tested for their ability to differentiate emotional facial expressions. Participants were matched with respect to age, gender, and education level. Their ability to differentiate emotional facial expressions was evaluated using the computer-based program Feel Test. The data showed that myasthenic patients scored significantly lower (p < 0.05) than healthy controls in the total Feel score, fear, surprise, and higher reaction time. The findings suggest that the ability to recognize facial affect may be reduced in individuals with myasthenia.

Risk factors for selective cognitive decline in dialyzed patients with end-stage renal disease: evidence from verbal fluency analysis

Although dialyzed patients often have cognitive problems, little is known about the nature of these deficits. We hypothesized that, in contrast to semantic fluency relying mainly on temporal lobes, phonemic fluency, preferentially depending on functions of frontal-subcortical systems, would be particularly sensitive to the constellation of physiological pathological processes associated with end-stage renal disease and dialysis. Therefore, we longitudinally compared phonemic and semantic fluency performance between 49 dialyzed patients and 30 controls. Overall, patients performed below controls only on the phonemic fluency task. Furthermore, their performance on this task declined over time, whereas there was no change in semantic fluency. Moreover, this decline was related to the presence of hypertension and higher blood urea nitrogen. We suggest that these findings may be due to a combination of vascular and topic effects that impact more on fronto-subcortical than temporal lobe networks, but this speculation requires direct confirmation.

Psychiatric disorders in myasthenia gravis

OBJECTIVE: To investigate the prevalence of psychiatric disorders in patients with myasthenia gravis (MG). METHOD: Forty-one patients with MG answered to a structured psychiatric interview (MINI-Plus). RESULTS: Eleven (26.1%) patients were diagnosed with a depressive disorder and 19 (46.3%) were diagnosed with an anxiety disorder. Patients with dysthymia were older (p=0.029) and had longer disease duration (p=0.006). Patients with social phobia also had longer disease duration (p=0.039). CONCLUSION: Psychiatric disorders in MG are common, especially depressive and anxiety disorders.

Long-acting anticholinesterases for myasthenia gravis: synthesis and activities of quaternary phenylcarbamates of neostigmine, pyridostigmine and physostigmine

The N-monophenylcarbamate analogues of neostigmine methyl sulfate (6) and pyridostigmine bromide (8) together with their precursors (5), (7), and the N(1)-methylammonium analogues of (-)-phenserine (12), (-)-tolserine (14), (-)-cymserine (16) and (-)-phenethylcymserine (18) were synthesized to produce long-acting peripheral inhibitors of acetylcholinesterase or butyrylcholinesterase. Evaluation of their cholinesterase inhibition against human enzyme ex vivo demonstrated that, whereas compounds 5-8 possessed only marginal activity, 12, 14, 16 and 18 proved to be potent anticholinesterases. An extended duration of cholinesterase inhibition was determined in rodent, making them of potential interest as long-acting agents for myasthenia gravis.