eLetters

647 e-Letters

  • Insights into Phenotypic and Genotypic Variability in MYH7-Related Myopathies

    Dear Editor,
    I am writing to commend the authors of the article, MYH7-related myopathies: clinical, myopathological and genotypic spectrum in a multicentre French cohort [1], for their meticulous analysis of MYH7-related myopathies (MYH7-RMs). Their study significantly enhances our understanding of the diverse clinical, genetic, and myopathological manifestations associated with pathogenic variants in MYH7, which encodes the slow/beta-cardiac myosin heavy chain. By examining a multicenter cohort of 57 individuals, this study offers critical insights into phenotype variability, imaging features, and mutation-specific implications, contributing to more precise diagnostic and management strategies for this heterogeneous group of myopathies.
    The study’s focus on muscle MRI findings, particularly the early and severe involvement of tibialis anterior and the concentric fibro-fatty replacement pattern, is of significant diagnostic value. The consistent and symmetrical fibro-fatty degeneration of distal muscles, coupled with the sparing of rectus femoris and adductor longus muscles in thigh regions, offers clinicians important imaging markers that can help differentiate MYH7-RMs from other myopathies, especially distal hereditary motor neuropathy (dHMN) and Pompe disease. This emphasis on early imaging features complements clinical assessments and may aid in reducing diagnostic delays, particularly in cases where high-amplitude MUPs and reduced interference patterns co...

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  • Caution required in interpretation of findings: Defining and conceptualising ‘sport’ matters

    Lennon and colleagues report on the associations between sport-related concussion (SRC), non-sports-related concussion (nSRC) and long-term cognitive and behavioural outcomes in a longitudinal cohort of community-dwelling adults. Findings suggest that those with SRC showed no long-term cognitive or behavioural deficits compared with those with no concussions. Moreover, it is suggested those with SRC showed better performance in working memory and verbal reasoning at the study baseline which is hypothesized to be due to the ‘benefits of sport’ in the form of physical, social and economic benefits. The authors suggest these findings will help inform physicians and public health authorities when communicating the risks and benefits of community sports to patients and the public.

    As the authors note, their findings are “at odds with much of the SRC literature”. This is likely a contributing factor to the media coverage of this research. At the time of writing, The Times, The Telegraph and the Guardian have all reported on the studies finding with variations on the benefits of ‘amateur sport’ outweighing the risk of concussion. The NIHR Applied Health Research and Care South West Peninsula, that supported the research, has also hosted a press release titled ‘Sports concussions in non-athletes not linked to long-term brain problems’. There is a common feature to all the press coverage so far: all have used images of adults or children playing what appears to be contact ru...

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  • Evaluating Cognitive Impairments in MOGAD: A Critical Review of the CogniMOG-Study’s Findings

    To the Editor,
    I am writing to commend and engage with the recently published study, "Cognition in patients with myelin oligodendrocyte glycoprotein antibody-associated disease: a prospective, longitudinal, multicentre study of 113 patients (CogniMOG-Study)." (1). This pioneering work addresses a crucial yet underexplored aspect of MOGAD, namely its impact on cognitive function. The study represents a significant advancement in understanding cognitive impairments associated with this rare but impactful condition.
    Significance of Findings: The CogniMOG-Study provides a comprehensive assessment of cognitive function in MOGAD patients, revealing that while cognitive deficits are present, they are relatively limited compared to other neuroinflammatory conditions. The observed impairments in semantic fluency and processing speed are particularly noteworthy. These findings suggest that cognitive deficits in MOGAD primarily affect verbal and information processing domains, which are critical for daily functioning and quality of life.
    The study’s longitudinal design is a particular strength, allowing for the observation of cognitive changes over time. The absence of significant cognitive decline over the follow-up periods is an encouraging finding, suggesting stability in cognitive function among MOGAD patients. However, it also raises questions about the factors contributing to cognitive stability and the potential for practice effects, which merit fur...

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  • Addressing Long-Term Outcomes and Neurodegeneration Biomarkers After Military Traumatic Brain Injury

    Dear Editor,
    I am writing to express my thoughts on the thought-provoking article titled, "Poor long-term outcomes and abnormal neurodegeneration biomarkers after military traumatic brain injury: the ADVANCE study." This comprehensive study delves into the long-term impacts of traumatic brain injury (TBI) on UK military personnel, focusing on the prevalence, psychological consequences, functional impairments, and the role of fluid biomarkers in elucidating the ongoing neurodegenerative processes associated with these injuries.
    One of the critical aspects of this study is its detailed examination of plasma biomarkers, including neurofilament light (NfL) and glial fibrillar acidic protein (GFAP), which serve as indicators of axonal damage and astrocytic activation, respectively. The sustained elevation of GFAP levels, detected even 8 years post-injury, suggests a prolonged neuroinflammatory response and astrocytic reactivity that could contribute to chronic neurodegeneration. This aligns with existing literature on the role of GFAP in central nervous system injury, where it is often linked to the activation and proliferation of astrocytes as part of the neuroinflammatory response. The finding of a 47% higher concentration of GFAP in moderate-to-severe TBI cases compared to mild cases indicates a dose-response relationship that highlights the progressive nature of astroglial activation in severe injuries.
    It is particularly intriguing that while GF...

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  • Early apheresis and MOGAD attack outcomes: confounding by indication?

    I read with great interest the article by Schwake et al, in which the authors performed a retrospective observational study evaluating clinical outcomes in 117 myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) attacks treated with apheresis.[1]

    One of the main findings and conclusions of the paper was that “apheresis was revealed to be most effective if started within 2 days of attack onset, with complete remission rates dropping radically afterwards”. Critically however, this finding may largely be due to selection bias (i.e., confounding by indication) rather than a true causal effect of apheresis timing.[2] As this was a retrospective study, assignment to first-line, second-line or third-line apheresis treatment was not random. Escalation to use of apheresis in the second-line or third-line groups would reasonably be expected to have occurred mainly due to persistent or worsening clinical deficits following treatment with high-dose corticosteroids. Conversely, in the early/first-line apheresis treatment, since the apheresis treatment was initiated as a first-line treatment (presumably concurrently with high-dose corticosteroids, though this is not explicitly stated by the authors in the article), it is quite possible that these attacks would have achieved complete remission even without the use of apheresis, either due to the effects of concomitant high-dose corticosteroids or due to the natural history of such attacks. Notably, demyelinati...

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  • Response to “Incidence and determinants of seizures in multiple sclerosis: a meta-analysis of randomised clinical trials”

    I read the recent meta-analysis from Pozzilli et al in Journal of Neurology, Neurosurgery and Psychiatry on seizure risk in multiple sclerosis (MS), which found a higher risk of seizures in patients with MS compared with the general population and a 2.45-fold higher risk in patients treated with sphingosine 1-phosphate (S1P) receptor modulators.1 I would like to address this claim with regards to the selective S1P receptor modulator ozanimod.

    The methodology behind this meta-analysis captured reports of seizures reported as common adverse events (AEs), serious AEs, or AEs of interest, but did not capture reports of seizures failing to meet the criteria for serious AEs or those that were not reported based on a small number of patients, a limitation noted by the authors. Another noted limitation was AE coding in the different trials, as a standardized framework for AE reporting was not developed until 2010. Since S1P receptor modulators were not developed until after 2010, the comparison with earlier trials is inconclusive. Also, as none of the trials included were designed to explore seizure risk, and event rates were very low, the results of this meta-analysis are at most hypothesis-generating.

    The methodology led to the erroneous representation that seizures occurred more frequently with ozanimod than with the active comparator interferon β-1a (IFN) in the RADIANCE (NCT02047734) trial. In the key publication from RADIANCE, AEs were reported if they were se...

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  • The revised NICE ME/CFS guideline: neither "robust" nor "thorough”

    People with ME/CFS have a serious condition with high symptom burden and impaired function. They deserve guidelines that favour good care and effective treatment supported by the best research evidence of efficacy and safety. Unfortunately, that is not what 2021 NICE guidelines have achieved.

    The 2007 NICE guidance recommended cognitive behaviour therapy (CBT) and graded exercise therapy (GET) “…as these interventions show clearest evidence of benefit.”(1) In spite of the strengthening of the evidence supporting these two treatments, the new 2021 guidance restricted the use of CBT to helping patients cope with illness related distress, and recommended that GET should not be used at all.(2)
    In response, 51 international clinicians and academics joined together to offer an alternative perspective, being particularly critical of the methods used to produce the guideline. (3)

    In response NICE advisors and staff have rejected this argument and have referred to the process as “robust” and “thorough”. (4) We are not convinced. We do not have space here to address every error but simply outline some of the most major areas of disagreement.

    Defining ME/CFS
    ----------------------
    Barry and colleagues state they appraised criteria to diagnose ME/CFS with the AGREE II instrument. This is a misuse of AGREE II, which is a tool to assess the robustness of procedures for developing guidelines: this is not a tool that can be used to examine the criter...

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  • Optimizing Oral Corticosteroid Regimens for Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD) Onset

    Dear Editor,
    I am writing to offer a comprehensive analysis and reflection on the manuscript titled "Oral corticosteroid dosage and taper duration at onset in myelin oligodendrocyte glycoprotein antibody-associated disease influences time to first relapse" (1). This study, which delves into the intricate nuances of managing MOGAD, presents crucial findings that could significantly impact clinical practice and patient outcomes.
    The complexity of MOGAD lies not only in its diverse clinical presentations but also in its variable response to treatment modalities. As highlighted in the manuscript's introduction, MOGAD encompasses a spectrum of neurological manifestations, ranging from optic neuritis and transverse myelitis to acute disseminated encephalomyelitis. The recent establishment of consensus diagnostic criteria marks a pivotal advancement in early recognition and intervention, underscoring the urgency for evidence-based therapeutic strategies.
    One of the most compelling aspects of the study is its exploration of the optimal corticosteroid regimen at MOGAD onset, aiming to delay the time to first relapse (TTFR) while minimizing cumulative corticosteroid exposure. By retrospectively analyzing data from a multicenter cohort comprising 109 patients, the authors meticulously assessed the relationship between corticosteroid dosage and taper duration and the subsequent risk of relapse. The utilization of Cox proportional hazards models, along...

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  • Re: Predictors of persistent postural-perceptual dizziness (PPPD) and similar forms of chronic dizziness precipitated by peripheral vestibular disorders: a systematic review

    Dear Editor,
    I read with interest the recent systematic review by Trinidade et al. on predictors of persistent postural-perceptual dizziness (PPPD) following peripheral vestibular disorders (1). The authors provided a thoughtful synthesis of the literature and identified key psychological factors associated with PPPD development. However, I believe the review overlooked some relevant evidence regarding additional predictors and pathophysiological mechanisms of chronic dizziness.
    Specifically, the authors did not discuss the potential role of cervical spine dysfunction and somatosensory abnormalities as PPPD risk factors. Several studies have identified exaggerated cervical spine proprioceptive signals and impaired cervical graviceptive processing in patients with PPPD (2). Additionally, there is evidence that migraine and migraine-related vestibulopathy may predispose individuals to developing chronic subjective dizziness after acute peripheral vestibular events (3,4). Investigation of these factors may provide further insight into PPPD pathophysiology.
    Moreover, the authors focused their review on peripheral vestibular disorders as PPPD triggers. However, central vestibular disorders like vestibular migraine can also lead to PPPD, especially among those with pre-existing migraine. (5) A review incorporating evidence from central vestibular precipitants could offer a more comprehensive view of PPPD development.
    In summary, while Trinidade et al. pre...

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  • Cognitive function after first-ever ischaemic stroke

    Dear Editor,

    I am writing to provide a more in-depth discussion on the recently published article, "Cognitive trajectory in the first year after first-ever ischaemic stroke in young adults: the ODYSSEY study." [1]. This study offers valuable insights into the intricate dynamics of cognitive recovery following ischaemic strokes in young adults, shedding light on the challenges and potential predictors of cognitive outcomes.
    The central finding, highlighting the persistent prevalence of cognitive impairment in young stroke patients even one year post-event, underscores the gravity of the issue. The study's longitudinal design, incorporating cognitive assessments at distinct time points within the first year, provides a nuanced understanding of the trajectory of cognitive changes. Notably, the observation of specific improvements in processing speed, visuoconstruction, and executive functioning among initially cognitively impaired patients adds granularity to our comprehension of post-stroke recovery.
    The study's discussion on the complex factors influencing cognitive recovery, such as age and lesion volume, enriches the narrative. However, the candid acknowledgment of the challenges in predicting cognitive recovery at an individual level reflects the intricate nature of post-stroke outcomes. Exploring the potential role of post-stroke fatigue and the absence of uniform predictors for recovery contribute to the depth of the article. The...

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