eLetters

55 e-Letters

published between 2019 and 2022

  • An overestimation of diagnosing functional foreign accent syndrome?

    Elucidating the nature of the foreign accent syndrome (FAS) can contribute to improve its diagnosis and treatment approaches. To understand this apparently rare syndrome, McWhirter et al. 1 studied a large case series of 49 subjects self-reporting having FAS. The participants were recruited via unmoderated online FAS support groups and surveys shared with neurologists and speech-language therapists from several countries. Participants completed an online protocol including validated scales tapping somatic symptoms, anxiety and depression, social-occupational function, and illness perception. They were also requested to provide speech samples recorded via computers or smartphones during oral reading and picture description. The overall clinical presentation of FAS in each participant was classified by consensus reached by three authors (2 neuropsychiatrists and 1 neurologist) in (1) “probably functional”, (2) “possibly structural” or (3) “probably structural”, wherein (1) meant no evidence of a neurological event or injury suggestive of a functional disorder but with no spontaneous remission; (2) alluded to the presence of some features suggestive of a functional disorder but with some uncertainty about a possible structural basis; and (3) denoted the evidence of a neurological event or injury coincident with the onset of FAS. The recorded speech samples were examined by experts to diagnose FAS and their frequent associated speech-language deficits (apraxia of speech, dysar...

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  • Response to: Comparison of fingolimod, dimethyl fumarate and teriflunomide for multiple sclerosis: when methodology does not hold the promise

    We thank Dr Platt and colleagues for their critical review of our work, especially of the methodology that we have used in this study. It is understandable that comparative studies of treatment effectiveness trigger constructive discussions among industry and academics. We also vehemently agree that rigorous methodology and cautious interpretation of results is mandatory, especially for analyses of observational data.1 2 Therefore, in this letter, we will provide additional clarifications in response to the concerns raised.

    We appreciate that the categories that are underrepresented in multivariable logistic regression models may lead to inflation of estimates of the corresponding coefficients and their variance. Such inflation would, however, result in an overly conservative matching rather than the opposite. Due to the use of a caliper, patients with an extreme propensity score can not be matched to patients within the bulk of the distribution of the propensity scores. Such patients were excluded from the matched cohorts.

    The issue of residual imbalance is important in any non-randomised comparative study. We acknowledge that the standardised mean difference in annualised relapse rates (ARR) between teriflunomide and fingolimod exceeded the nominal threshold of 20%. It is therefore reassuring that the sensitivity analyses, in which the residual imbalance fell below the accepted threshold of 20% (patients with prior on-treatment relapses, Cohen’s d 14%, and...

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  • Comparison of fingolimod, dimethyl fumarate and teriflunomide for multiple sclerosis: when methodology does not hold the promise

    Dear Editor,

    We read with interest the article by Kalincik et al. [1] comparing fingolimod, dimethyl fumarate and teriflunomide in a cohort of relapsing-remitting multiple sclerosis (MS) patients. The authors investigated several endpoints and performed various sensitivity analyses, and we commend them for reporting technical details in the online supplementary material. We, however, have some concerns about the design, analysis and reporting of the study.

    1. In the primary analyses, three separate propensity score models were developed to construct a matched cohort for each of the three pairwise comparisons. Supplementary Table 6 clearly indicates the existence of zero or low frequencies in some variables (e.g., most active previous therapy and magnetic resonance imaging [MRI] T2 lesions). Yet, those variables were used as covariates in the propensity score models, unsurprisingly resulting in extremely high point estimates and standard errors (SE; as reported in Supplementary Table 7). For example, teriflunomide was not the most active therapy for any patient in the dimethyl fumarate cohort (n=0 from Supplementary Table 6), but that category was nevertheless included in the propensity score model, leading to an unrealistic point estimate of 18.65 with SE of 434.5 (Supplementary Table 7). Even higher SEs (greater than 1000) are observed in the other propensity score models. Propensity scores estimated from these poorly constructed models were then used to cr...

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  • Seizures and movement disorders : cortico-subcortical networks

    Seizures and movement disorders : cortico-subcortical networks

    Dr Aileen McGonigal

    Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
    APHM, Timone Hospital, Clinical Neurophysiology, Marseille, France

    Corresponding author: Dr Aileen McGonigal, Service de Neurophysiologie Clinique, CHU Timone, AP-HM, Marseille, France
    Email : aileen.mcgonigal@univ-amu.fr
    Tel: 00 33 491384995
    Fax:00 33 491385826

    To the Editors

    I was interested to read the recent review by Dr Freitas and colleagues1. This interesting article highlights diagnostic challenges, clinical overlap and possible shared pathophysiological processes in epileptic seizures and movement disorders. I would like to add a couple of points that seem important to acknowledge.
    Firstly, in terms of clinical expression, the authors rightly mention that automatic movements occurring during focal epileptic seizures can sometimes resemble those seen in certain movement disorders, and they give the examples of orofacial automatisms (most often seen in temporal lobe seizures), as well as hyperkinetic behaviors. While the authors highlight sleep-related epilepsy as the main cause of hyperkinetic behavior, in fact hyperkinetic behavior may be seen in seizures from various cortical origins both in wakefulness and in sleep. It should be recognized that especially (though not exclusivel...

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  • Refining diagnosis of early POEMS syndrome

    We applaud Suichi et al.[1] for proposing new diagnostic criteria for POEMS syndrome. There is clearly a need for simplified validated criteria that permit early diagnosis of this rare, elusive and devastating paraneoplastic disorder, especially because early local or systemic treatment of the underlying plasma cell malignancy can dramatically improve prognosis.[2] Our recent clinical experience[3] is in full agreement with the three proposed cardinal features of POEMS syndrome, namely polyneuropathy, vascular endothelial growth factor (VEGF) level elevation, and the presence of monoclonal protein. The authors argue that the triad alone may be insufficiently specific; therefore they propose the additional requirement of two of four secondary features, namely extravascular fluid accumulation, skin changes, organomegaly, and sclerotic bone lesion.

    We would like to draw attention to clinical and methodological aspects that could further enhance or refine the diagnosis of POEMS syndrome. First, the process of diagnosis starts with clinical suspicion. Polyneuropathy is usually the earliest symptom of POEMS syndrome. POEMS syndrome should be considered in any patient with a severely progressive polyneuropathy of acute to subacute onset that is not otherwise explained, and VEGF level measurement should be offered. Routine screening for monoclonal protein (with immunofixation) and skeletal survey may be negative initially, and could remain negative for a long duration into...

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